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OBJECTIVE : In a cardiothoracic and vascular intensive care unit , to compare nasal high-flow ( NHF ) oxygen therapy and st and ard high-flow face mask ( HFFM ) oxygen therapy in patients with mild to moderate hypoxemic respiratory failure . METHODS : In a prospect i ve r and omized comparative study , 60 patients with mild to moderate hypoxemic respiratory failure were r and omized to receive NHF or HFFM . We analyzed the success of allocated therapy , noninvasive ventilation rate , and oxygenation . RESULTS : Significantly more NHF patients succeeded with their allocated therapy ( P = .006 ) . The rate of noninvasive ventilation in the NHF group was 3/29 ( 10 % ) , compared with 8/27 ( 30 % ) in the HFFM group ( P = .10 ) . The NHF patients also had significantly fewer desaturations ( P = .009 ) . CONCLUSIONS : NHF oxygen therapy may be more effective than HFFM in treating mild to moderate hypoxemic respiratory failure Introduction Noninvasive ventilation ( NIV ) , as a weaning-facilitating strategy in predominantly chronic obstructive pulmonary disease ( COPD ) mechanically ventilated patients , is associated with reduced ventilator-associated pneumonia , total duration of mechanical ventilation , length of intensive care unit ( ICU ) and hospital stay , and mortality . However , this benefit after planned extubation in patients with acute respiratory failure of various etiologies remains to be eluci date d. The aim of this study was to determine the efficacy of NIV applied immediately after planned extubation in contrast to oxygen mask ( OM ) in patients with acute respiratory failure ( ARF ) . Methods A r and omized , prospect i ve , controlled , unblinded clinical study in a single center of a 24-bed adult general ICU in a university hospital was carried out in a 12-month period . Included patients met extubation criteria with at least 72 hours of mechanical ventilation due to acute respiratory failure , after following the ICU weaning protocol . Patients were r and omized immediately before elective extubation , being r and omly allocated to one of the study groups : NIV or OM . We compared both groups regarding gas exchange 15 minutes , 2 hours , and 24 hours after extubation , reintubation rate after 48 hours , duration of mechanical ventilation , ICU length of stay , and hospital mortality . Results Forty patients were r and omized to receive NIV ( 20 patients ) or OM ( 20 patients ) after the following extubation criteria were met : pressure support ( PSV ) of 7 cm H2O , positive end-expiratory pressure ( PEEP ) of 5 cm H2O , oxygen inspiratory fraction ( FiO2 ) ≤ 40 % , arterial oxygen saturation ( SaO2 ) ≥ 90 % , and ratio of respiratory rate and tidal volume in liters ( f/TV ) < 105 . Comparing the 20 patients ( NIV ) with the 18 patients ( OM ) that finished the study 48 hours after extubation , the rate of reintubation  in NIV group was 5 % and 39 % in OM group ( P = 0.016 ) . Relative risk for reintubation was 0.13 ( CI = 0.017 to 0.946 ) . Absolute risk reduction for reintubation showed a decrease of 33.9 % , and analysis of the number needed to treat was three . No difference was found in the length of ICU stay ( P = 0.681 ) . Hospital mortality was zero in NIV group and 22.2 % in OM group ( P = 0.041 ) . Conclusions In this study population , NIV prevented 48 hours reintubation if applied immediately after elective extubation in patients with more than 3 days of ARF when compared with the OM group . Trial Registration numberIS RCT N : 41524441 PURPOSE High flow nasal cannula ( HFNC ) may decrease preload being associated with beneficial hemodynamic and respiratory effects in adults with heart failure . METHODS This is a sequential intervention prospect i ve study including 10 adults with New York Heart Association ( NYHA ) class III and left ventricle ejection fraction 45 % or less .  High flow gas was administered ( fraction of inspired oxygen , 0.21 ) through nasal cannula ( Optiflow(TM ) ; Fisher & Paykel , Auckl and , New Zeal and ) . Sequential echocardiographies were performed at baseline , using HFNC with 20 lpm and 40 lpm and post-HFNC . A reduction greater than 20 % in the estimated inspiratory collapse of the inferior vena cava ( IVC ) from baseline was considered clinical ly significant . RESULTS Ten patients were included , with median age of 57 ( 44 - 65 ) years ; 6 ( 60 % ) were female , and 8 ( 80 % ) had dilated cardiomyopathy .  Median IVC inspiratory significantly ( P<.05 ) decreased from baseline ( 37 % ) to HFNC with 20 lpm ( 28 % ) and HFNC with 40 lpm ( 21 % ) , representing mean attributable reductions of 20 % ( 95 % confidence interval , 6 - 55 ) and 53 % ( 95 % confidence interval , 36 - 67 ) from baseline . Changes in the IVC inspiratory collapse were reversible after HFNC withdrawal . Respiratory rate was significantly reduced from 23 breaths per minute at baseline to 17 breaths per minute at HFNC with 20 lpm and 13 breaths per minute at HFNC with 40 lpm . In contrast , no significant changes in other echocardiographic or clinical variables were documented . CONCLUSION These findings suggest that patients with NYHA class III heart failure may benefit with HFNC supportive therapy CONTEXT Continuous positive airway pressure ( CPAP ) is widely used in the belief that it may reduce the need for intubation and mechanical ventilation in patients with acute hypoxemic respiratory insufficiency . OBJECTIVE To compare the physiologic effects and the clinical efficacy of CPAP vs st and ard oxygen therapy in patients with acute hypoxemic , nonhypercapnic respiratory insufficiency . DESIGN , SETTING , AND PATIENTS R and omized , concealed , and unblinded trial of 123 consecutive adult patients who were admitted to 6 intensive care units between September 1997 and January 1999 with a PaO(2)/FIO(2 ) ratio of 300 mm Hg or less due to bilateral pulmonary edema ( n = 102 with acute lung injury and n = 21 with cardiac disease ) . INTERVENTIONS Patients were r and omly assigned to receive oxygen therapy alone ( n = 61 ) or oxygen therapy plus CPAP ( n = 62 ) . MAIN OUTCOME MEASURES Improvement in PaO(2)/FIO(2 ) ratio , rate of endotracheal intubation at any time during the study , adverse events , length of hospital stay , mortality , and duration of ventilatory assistance , compared between the CPAP and st and ard treatment groups . RESULTS Among the CPAP vs st and ard therapy groups , respectively , causes of respiratory failure ( pneumonia , 54 % and 55 % ) , presence of cardiac disease ( 33 % and 35 % ) , severity at admission , and hypoxemia ( median [ 5th-95th percentile ] PaO(2)/FIO(2 ) ratio , 140 [ 59 - 288 ] mm Hg vs 148 [ 62 - 283 ] mm Hg ; P = .43 ) were similarly distributed . After 1 hour of treatment , subjective responses to treatment ( P<.001 ) and median ( 5th-95th percentile ) PaO(2)/FIO(2 ) ratios were greater with CPAP ( 203 [ 45 - 431 ] mm Hg vs 151 [ 73 - 482 ] mm Hg ; P = .02 ) . No further difference in respiratory indices was observed between the groups . Treatment with CPAP failed to reduce the endotracheal intubation rate ( 21 [ 34 % ] vs 24 [ 39 % ] in the st and ard therapy group ; P = .53 ) , hospital mortality ( 19 [ 31 % ] vs 18 [ 30 % ] ; P = .89 ) , or median ( 5th-95th percentile ) intensive care unit length of stay ( 6.5 [ 1 - 57 ] days vs 6.0 [ 1 - 36 ] days ; P = .43 ) . A higher number of adverse events occurred with CPAP treatment ( 18 vs 6 ; P = .01 ) . CONCLUSION In this study , despite early physiologic improvement , CPAP neither reduced the need for intubation nor improved outcomes in patients with acute hypoxemic , nonhypercapnic respiratory insufficiency primarily due to acute lung injury . JAMA . 2000;284:2352 - 2360 Importance High-flow conditioned oxygen therapy delivered through nasal cannulae and noninvasive mechanical ventilation ( NIV ) may reduce the need for reintubation . Among the advantages of high-flow oxygen therapy are comfort , availability , lower costs , and additional physiopathological mechanisms . Objective To test if high-flow conditioned oxygen therapy is noninferior to NIV for preventing postextubation respiratory failure and reintubation in patients at high risk of reintubation . Design , Setting , and Participants Multicenter r and omized clinical trial in 3 intensive care units in Spain ( September 2012-October 2014 ) including critically ill patients ready for planned extubation with at least 1 of the following high-risk factors for reintubation : older than 65 years ; Acute Physiology and Chronic Health Evaluation II score higher than 12 points on extubation day ; body mass index higher than 30 ; inadequate secretions management ; difficult or prolonged weaning ; more than 1 comorbidity ; heart failure as primary indication for mechanical ventilation ; moderate to severe chronic obstructive pulmonary disease ; airway patency problems ; or prolonged mechanical ventilation . Interventions Patients were r and omized to undergo either high-flow conditioned oxygen therapy or NIV for 24 hours after extubation . Main Outcomes and Measures Primary outcomes were reintubation and postextubation respiratory failure within 72 hours . Noninferiority margin was 10 percentage points . Secondary outcomes included respiratory infection , sepsis , and multiple organ failure , length of stay and mortality ; adverse events ; and time to reintubation . Results Of 604 patients ( mean age , 65 [ SD , 16 ] years ; 388 [ 64 % ] men ) , 314 received NIV and 290 high-flow oxygen . Sixty-six patients ( 22.8 % ) in the high-flow group vs 60 ( 19.1 % ) in the NIV group were reintubation ( absolute difference , -3.7 % ; 95 % CI , -9.1 % to ∞ ) ; 78 patients ( 26.9 % ) in the high-flow group vs 125 ( 39.8 % ) in the NIV group experienced postextubation respiratory failure ( risk difference , 12.9 % ; 95 % CI , 6.6 % to ∞ ) [ corrected ] . Median time to reintubation did not significantly differ : 26.5 hours ( IQR , 14 - 39 hours ) in the high-flow group vs 21.5 hours ( IQR , 10 - 47 hours ) in the NIV group ( absolute difference , -5 hours ; 95 % CI , -34 to 24 hours ) . Median postr and omization ICU length of stay was lower in the high-flow group , 3 days ( IQR , 2 - 7 ) vs 4 days ( IQR , 2 - 9 ; P=.048 ) . Other secondary outcomes were similar in the 2 groups . Adverse effects requiring withdrawal of the therapy were observed in none of patients in the high-flow group vs 42.9 % patients in the NIV group ( P < .001 ) . Conclusions and Relevance Among high-risk adults who have undergone extubation , high-flow conditioned oxygen therapy was not inferior to NIV for preventing reintubation and postextubation respiratory failure . High-flow conditioned oxygen therapy may offer advantages for these patients . Trial Registration clinical trials.gov Identifier : NCT01191489 PURPOSE The purpose of this study was to determine the impact of high-flow nasal cannula oxygen ( HFNC ) on patients with acute respiratory failure ( ARF ) in comparison with conventional oxygen therapy . MATERIAL S AND METHODS This was a prospect i ve observational study . Patients with persistent ARF despite oxygen with conventional facemask without indication for immediate intubation were treated with HFNC oxygen .  Clinical respiratory parameters and arterial blood gases were compared under conventional and HFNC oxygen therapy . RESULTS Twenty patients , aged 59 years ( 38 - 75 years ) and SAPS2 ( simplified acute physiology score ) 33 ( 26.5 - 38 ) , were included in the study . Etiology of ARF was mainly pneumonia ( n = 11 ) , sepsis ( n = 3 ) , and miscellaneous ( n = 6 ) . Use of HFNC enabled a significant reduction of respiratory rate , 28 ( 26 - 33 ) vs 24.5 ( 23 - 28.5 ) breath per minute ( P = .006 ) , and a significant increase in oxygen saturation , oxygen saturation as measured by pulse oximetry 93.5 % ( 90 - 98.5 ) vs 98.5 % ( 95.5 - 100 ) ( P = .0003 ) . Use of HFNC significantly increased Pao(2 ) from 8.73 ( 7.13 - 11.13 ) to 15.27 ( 9.66 - 25.6 ) kPa ( P = .001 ) and moderately increased Paco(2 ) , 5.26 ( 4.33 - 5.66 ) to 5.73 ( 4.8 - 6.2 ) kPa ( P = .005 ) without affecting pH. Median duration of HFNC  was 26.5 ( 17 - 121 ) hours . Six patients were secondarily intubated , and 3 died in the intensive care unit . CONCLUSION Use of HFNC in patients with persistent ARF was associated with significant and sustained improvement of both clinical and biologic parameters Background The aim of this prospect i ve study was to determine whether a level of positive airway pressure was generated in participants receiving nasal high flow ( NHF ) delivered by the Optiflow ™ system ( Fisher and Paykel Healthcare Ltd , Auckl and , New Zeal and ) in a cardiothoracic and vascular intensive care unit ( ICU ) . Methods Nasopharyngeal airway pressure was measured in 15 postoperative cardiac surgery adult patients who received both NHF and st and ard facemask therapy  at a flow rate of 35 litre min−1 . Measurements were repeated in the open mouth and closed mouth positions . Mean airway pressure was determined by averaging the pressures at the peak of inspiration of each breath within a 1 min period , allowing the entire pressure profile of each breath to be included within the calculation . Results Low level positive pressure was demonstrated with NHF at 35 litre min−1 with mouth closed when compared with a facemask . NHF generated a mean nasopharyngeal airway pressure of mean ( sd ) 2.7 ( 1.04 ) cm H2O with the mouth closed . Airway pressure was significantly higher when breathing with mouth closed compared with mouth open ( P≤0.0001 ) . Conclusions This study demonstrated that a low level of positive pressure was generated with NHF at 35 litre min−1 of gas flow . This is consistent with results obtained in healthy volunteers . Australian Clinical Trials Registry www.actr.org.au ACTRN012606000139572 Background Although noninvasive positive pressure ventilation ( NPPV ) has been successfully used for various kinds of acute respiratory failure , the data are limited regarding its application in postoperative respiratory failure after cardiac surgery . Therefore , we conducted a prospect i ve r and omized control study in a university surgical intensive care unit to evaluate the efficacy and safety of NPPV in the treatment of acute respiratory failure after cardiac surgery , and explore the predicting factors of NPPV failure . Methods From September 2011 to November 2012 patients with acute respiratory failure after cardiac surgery who had indication for the use of NPPV  were r and omly divided into a NPPV treatment group ( NPPV group ) and the conventional treatment group ( control group ) . The between‐group differences in the patients ’ baseline characteristics , re‐intubation rate , tracheotomy rate , ventilator associated pneumonia ( VAP ) incidence , in‐hospital mortality , mechanical ventilation time after enrollment ( MV time ) , intensive care unit ( ICU ) and postoperative hospital stays were compared . The factors that predict NPPV failure were analyzed . Results During the study period , a total of 139 patients who had acute respiratory failure after cardiac surgery were recorded , and 95 of them met the inclusion criteria , which included 59 males and 36 females with a mean age of ( 61.5±11.2 ) years . Forty‐three patients underwent coronary artery bypass grafting ( CABG ) , 23 underwent valve surgery , 13 underwent CABG+valve surgery , 13 underwent major vascular surgery , and three underwent other surgeries . The NPPV group had 48 patients and the control group had 47 patients . In the NPPV group , the re‐intubation rate was 18.8 % , tracheotomy rate was 12.5 % , VAP incidence was 0 , and the in‐hospital mortality was 18.8 % , significantly lower than in the control group 80.9 % , 29.8 % , 17.0 % and 38.3 % respectively , P < 0.05 or P < 0.01 . The MV time and ICU stay ( expressed as the median ( P25 , P75 ) ) were 18.0 ( 9.2 , 35.0 ) hours and 4.0 ( 2.0 , 5.0 ) days , which were significantly shorter than in the control group , 96.0 ( 26.0 , 240.0 ) hours and 6.0 ( 4.0 , 9.0 ) days respectively , P < 0.05 or P < 0.01 . The postoperative hospital stays of the two groups were similar . The univariate analysis showed that the NPPV success subgroup had more patients with acute lung injury ( ALI ) ( 17 vs. 0 , P=0.038 ) , fewer patients with pneumonia ( 2 vs. 7 , P < 0.001 ) and lower acute physiology and chronic health evaluation II ( APACHE II ) scores ( 16.1±2.8 vs. 21.8±3.2 , P < 0.001 ) . Multivariate analysis showed that pneumonia ( P=0.027 ) and a high APACHE II score > 20 ( P=0.002 ) were the independent risk factors of NPPV failure . Conclusions We conclude that NPPV can be applied in selected patients with acute respiratory failure after cardiac surgery to reduce the need of re‐intubation and improve clinical outcome as compared with conventional treatment . Pneumonia and a high APACHE II score > 20 might be the independent risk factors of NPPV failure in this group of patients RATIONALE Respiratory failure after extubation and reintubation is associated with increased morbidity and mortality . OBJECTIVES To assess the efficacy of noninvasive ventilation in averting respiratory failure after extubation in patients at increased risk . METHODS A prospect i ve r and omized controlled trial was conducted in 162 mechanically ventilated patients who tolerated a spontaneous breathing trial after recovery from the acute episode but had increased risk for respiratory failure after extubation . Patients were r and omly allocated after extubation to receive noninvasive ventilation for 24 h ( n = 79 ) , or conventional management with oxygen therapy ( control group , n = 83 ) . MEASUREMENTS AND MAIN RESULTS The primary end-point variable was the decrease in respiratory failure after extubation . In the noninvasive ventilation group , respiratory failure after extubation was less frequent ( 13 , 16 vs. 27 , 33 % ; p = 0.029 ) and the intensive care unit mortality was lower ( 2 , 3 versus 12 , 14 % ; p = 0.015 ) . However , 90-d survival did not change significantly between groups . Separate analyses of patients without and with hypercapnia ( arterial CO(2 ) tension greater than 45 mm Hg ) during the spontaneous breathing trial showed that noninvasive ventilation improved intensive care unit mortality ( 0 vs. 4 , 18 % ; p = 0.035 ) and 90-d survival ( p = 0.006 ) in hypercapnic patients only ; of them , 98 % had chronic respiratory disorders . CONCLUSIONS The early use of noninvasive ventilation averted respiratory failure after extubation and decreased intensive care unit mortality among patients at increased risk . The beneficial effect of noninvasive ventilation in improving survival of hypercapnic patients with chronic respiratory disorders warrants a new prospect i ve clinical trial BACKGROUND : Electrical impedance tomography measures changes in lung impedance , which are mainly related to changes in lung volume . We used electrical impedance tomography to investigate the effects of high-flow nasal cannula ( HFNC ) and body position on global and regional end-expiratory lung impedance variation ( ΔEELI ) . METHODS : Prospect i ve study with 20 healthy adults . Two periods were defined : the first in supine position and the second in prone position . Each period was divided into 3 phases . In the first and the third phases the subjects were breathing ambient air , and in the second HFNC was implemented . Four regions of interest were defined : 2 ventral and 2 dorsal . For each respiratory cycle , global and regional ΔEELI were measured by electrical impedance tomography and were expressed as a function of the tidal variation of the first stable respiratory cycle ( units ) . RESULTS : HFNC  increased global EELI by 1.26 units ( 95 % CI 1.20–1.31 , P < .001 ) in supine position , and by 0.87 units ( 95 % CI 0.82–0.91 , P < .001 ) in prone position . The distribution of ΔEELI was homogeneous in prone position , with no difference between ventral and dorsal lung regions ( −0.01 units , 95 % CI −0.01 to 0 , P = .18 ) , while in supine position a significant difference was found ( 0.22 units , 95 % CI 0.21–0.23 , P < .001 ) with increased EELI in ventral areas . CONCLUSIONS : HFNC  increased global EELI in our population , regardless of body position , suggesting an increase in functional residual capacity . Prone positioning was related to a more homogeneous distribution of ΔEELI , while in supine position ΔEELI was higher in the ventral lung regions OBJECTIVE To compare the comfort of oxygen therapy via high-flow nasal cannula ( HFNC ) versus via conventional face mask in patients with acute respiratory failure . Acute respiratory failure was defined as blood oxygen saturation < 96 % while receiving a fraction of inspired oxygen > or = 0.50 via face mask . METHODS Oxygen was first humidified with a bubble humidifier and delivered via face mask for 30 min , and then via HFNC with heated humidifier for another 30 min . At the end of each 30-min period we asked the patient to evaluate dyspnea , mouth dryness , and overall comfort , on a visual analog scale of 0 ( lowest ) to 10 ( highest ) . The results are expressed as median and interquartile range values . RESULTS We included 20 patients , with a median age of 57 ( 40 - 70 ) years . The total gas flow administered was higher with the HFNC than with the face mask ( 30 [ 21.3 - 38.7 ] L/min vs 15 [ 12 - 20 ] L/min , P < .001 ) . The HFNC was associated with less dyspnea ( 3.8 [ 1.3 - 5.8 ] vs 6.8 [ 4.1 - 7.9 ] , P = .001 ) and mouth dryness ( 5 [ 2.3 - 7 ] vs 9.5 [ 8 - 10 ] , P < .001 ) , and was more comfortable ( 9 [ 8 - 10 ] ) versus 5 [ 2.3 - 6.8 ] , P < .001 ) . HFNC was associated with higher P(aO(2 ) ) ( 127 [ 83 - 191 ] mm Hg vs 77 [ 64 - 88 ] mm Hg , P = .002 ) and lower respiratory rate ( 21 [ 18 - 27 ] breaths/min vs 28 [ 25 - 32 ] breaths/min , P < .001 ) , but no difference in P(aCO(2 ) ) . CONCLUSIONS HFNC was better tolerated and more comfortable than face mask . HFNC was associated with better oxygenation and lower respiratory rate .  HFNC could have an important role in the treatment of patients with acute respiratory failure Purpose Intubation of hypoxemic patients is associated with life-threatening adverse events . High-flow therapy by nasal cannula ( HFNC ) for preoxygenation before intubation has never been assessed by r and omized study . Our objective was to evaluate the efficiency of HFNC for preoxygenation , compared to high fraction-inspired oxygen facial mask ( HFFM ) . Methods Multicenter , r and omized , open-labelled , controlled PREOXYFLOW trial ( NCT 01747109 ) in six French intensive care units . Acute hypoxemic adults requiring intubation were r and omly allocated to HFNC  or  HFFM . Patients were eligible if PaO2/FiO2 ratio was below 300 mmHg , respiratory rate at least 30/min and if they required FiO2 50 % or more to obtain at least 90 % oxygen saturation .  HFNC was maintained throughout the procedure , whereas HFFM was removed at the end of general anaesthesia induction . Primary outcome was the lowest saturation throughout intubation procedure . Secondary outcomes included adverse events related to intubation , duration of mechanical ventilation and death . Results A total of 124 patients were r and omized . In the intent-to-treat analysis , including 119 patients ( HFNC n = 62 ; HFFM n = 57 ) , the median ( interquartile range ) lowest saturation was 91.5 % ( 80–96 ) for HFNC and 89.5 % ( 81–95 ) for the HFFM group ( p = 0.44 ) . There was no difference for difficult intubation ( p = 0.18 ) , intubation difficulty scale , ventilation-free days ( p = 0.09 ) , intubation-related adverse events including desaturation < 80 % or mortality ( p = 0.46 ) . Conclusions Compared to HFFM , HFNC as a preoxygenation device did not reduce the lowest level of desaturation BACKGROUND : Beneficial effects of high-flow nasal cannula ( HFNC ) oxygen on oxygenation and respiratory parameters have been reported in a small number of subjects with acute respiratory failure ( ARF ) . We aim ed to evaluate its effect in subjects with ARDS . METHODS : This was an observational single-center study . Prospect ively obtained data were retrospectively analyzed . All patients admitted over 1 y to a university hospital medicosurgical ICU were included . Classification was according to the highest ventilatory support required . HFNC indications were review ed , and demographics , clinical characteristics , and course of subjects with ARDS according to intubation need were compared . RESULTS : Of 607 subjects admitted , 560 required  ventilatory or oxygen support  , among whom 180 received noninvasive ventilatory support . HFNC was used in 87 subjects and as first-line treatment in 51 subjects ( 29 % of first-line noninvasively treated subjects ) , 45 of which had ARDS ( PaO2/FIO2 of 137 mm Hg ; 22 men , 57.9 y of age ) .  Pneumonia accounted for 82 % of ARDS causes . The intubation rate in these subjects was 40 % . Higher Simplified Acute Physiology Score II ( SAPS II ; 46 vs 29 , P = .001 ) , occurrence of additional organ failure ( 76 % vs 26 % , P = .002 ) , mainly hemodynamic ( 50 % vs 7 % , P = .001 ) or neurological ( 22 % vs 0 , P = .01 ) , and trends toward lower PaO2/FIO2 and higher breathing frequency after HFNC initiation were evidence d in subjects who failed HFNC . Higher SAPS II scores were associated with HFNC failure in multivariate analysis . CONCLUSIONS : In daily care , over one fourth of subjects requiring noninvasive ventilatory support were treated via HFNC , with a high success rate in subjects with severe ARDS . We conclude that HFNC may be considered as first-line therapy in ARF , including patients with ARDS BACKGROUND Whether noninvasive ventilation should be administered in patients with acute hypoxemic respiratory failure is debated . Therapy with high-flow oxygen through a nasal cannula may offer an alternative in patients with hypoxemia . METHODS We performed a multicenter , open-label trial in which we r and omly assigned patients without hypercapnia who had acute hypoxemic respiratory failure and a ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen of 300 mm Hg or less to high-flow oxygen therapy , st and ard oxygen therapy delivered through a face mask , or noninvasive positive-pressure ventilation . The primary outcome was the proportion of patients intubated at day 28 ; secondary outcomes included all-cause mortality in the intensive care unit and at 90 days and the number of ventilator-free days at day 28 . RESULTS A total of 310 patients were included in the analyses .  The intubation rate ( primary outcome ) was 38 % ( 40 of 106 patients ) in the high-flow-oxygen group , 47 % ( 44 of 94 ) in the st and ard group , and 50 % ( 55 of 110 ) in the noninvasive-ventilation group ( P=0.18 for all comparisons ) . The number of ventilator-free days at day 28 was significantly higher in the high-flow-oxygen group ( 24±8 days , vs. 22±10 in the st and ard-oxygen group and 19±12 in the noninvasive-ventilation group ; P=0.02 for all comparisons ) . The hazard ratio for death at 90 days was 2.01 ( 95 % confidence interval [ CI ] , 1.01 to 3.99 ) with st and ard oxygen versus high-flow oxygen ( P=0.046 ) and 2.50 ( 95 % CI , 1.31 to 4.78 ) with noninvasive ventilation versus high-flow oxygen ( P=0.006 ) . CONCLUSIONS In patients with nonhypercapnic acute hypoxemic respiratory failure , treatment with high-flow oxygen , st and ard oxygen , or noninvasive ventilation did not result in significantly different intubation rates . There was a significant difference in favor of high-flow oxygen in 90-day mortality . ( Funded by the Programme Hospitalier de Recherche Clinique Interrégional 2010 of the French Ministry of Health ; FLORALI Clinical Trials.gov number , NCT01320384 . ) Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more Background : Current knowledge of the risk for  postoperative pulmonary complications ( PPCs  ) rests on studies that narrowly selected patients and procedures . Hypothesizing that PPC occurrence could be predicted from a reduced set of perioperative variables , we aim ed to develop a predictive index for a broad surgical population . Methods : Patients undergoing surgical procedures given general , neuraxial , or regional anesthesia in 59 hospitals were r and omly selected for this prospect i ve , multicenter study . The main outcome was the development of at least one of the following : respiratory infection , respiratory failure , bronchospasm , atelectasis , pleural effusion , pneumothorax , or aspiration pneumonitis . The cohort was r and omly divided into a development sub sample to construct a logistic regression model and a validation sub sample . A PPC predictive index was constructed . Results : Of 2,464 patients studied , 252 events were observed in 123 ( 5 % ) . Thirty-day mortality was higher in patients with a PPC ( 19.5 % ; 95 % [ CI ] , 12.5–26.5 % ) than in those without a PPC ( 0.5 % ; 95 % CI , 0.2–0.8 % ) . Regression modeling identified seven independent risk factors : low preoperative arterial oxygen saturation , acute respiratory infection during the previous month , age , preoperative anemia , upper abdominal or intrathoracic surgery , surgical duration of at least 2 h , and emergency surgery . The area under the receiver operating characteristic curve was 90 % ( 95 % CI , 85–94 % ) for the development sub sample and 88 % ( 95 % CI , 84–93 % ) for the validation sub sample . Conclusion : The risk index based on seven objective , easily assessed factors has excellent discriminative ability . The index can be used to assess individual risk of PPC and focus further research on measures to improve patient care OBJECTIVE : Heated and humidified high flow nasal cannula oxygen therapy ( HFNC ) represents a new alternative to conventional oxygen therapy that has not been evaluated in the emergency department ( ED ) . We aim ed to study its feasibility and efficacy in patients exhibiting acute respiratory failure presenting to the ED . METHODS : Prospect i ve , observational study in a university hospital 's ED . Patients with acute respiratory failure requiring > 9 L/min oxygen or with ongoing clinical signs of respiratory distress despite oxygen therapy were included . The device of oxygen administration was then switched from non-rebreathing mask to HFNC .  Dyspnea , rated by the Borg scale and a visual analog scale , respiratory rate , and SpO2 were collected before and 15 , 30 , and 60 min after beginning HFNC . Feasibility was assessed through caregivers ' acceptance of the device in terms of practicality and perceived effect on the subjects , evaluated by question naire . RESULTS : Seventeen subjects , median age 64 y ( 46–84.7 y ) , were studied .  Pneumonia was the most common reason for oxygen therapy ( n = 9 ) . HFNC was associated with a significant decrease in both dyspnea scores : Borg scale from 6 ( 5–7 ) to 3 ( 2–4 ) ( P < .001 ) , and visual analog scale from 7 ( 5–8 ) to 3 ( 1–5 ) ( P < .01 ) . Respiratory rate decreased from 28 breaths/min ( 25–32 breaths/min ) to 25 breaths/min ( 21–28 breaths/min ) ( P < .001 ) , and SpO2 increased from 90 % ( 88.5–94 % ) to 97 % ( 92.5–100 % ) ( P < .001 ) . Fewer subjects exhibited clinical signs of respiratory distress ( 10/17 vs 3/17 , P = .03 ) . HFNC was well tolerated and no adverse event was noted . Altogether , 76 % of healthcare givers declared preferring HFNC , as compared to conventional oxygen therapy . CONCLUSIONS : HFNC is possible in the ED , and it alleviated dyspnea and improved respiratory parameters in subjects with acute hypoxemic respiratory failure PURPOSE Oxygen delivery after extubation is critical to maintain adequate oxygenation and to avoid reintubation . The delivery of oxygen in such situations is usually by high-flow face mask ( HFFM ) . Yet , this may be uncomfortable for some patients . A recent advance in oxygen delivery technology is high-flow nasal prongs ( HFNP ) . There are no r and omized trials comparing these 2 modes . METHODS Patients were r and omized to either protocol A ( n = 25 ; HFFM followed by HFNP ) or protocol B ( n = 25 ; HFNP followed by HFFM ) after a stabilization period of 30 minutes after extubation . The primary objective was to compare the efficacy of HFNP to HFFM in maintaining gas exchange as measured by arterial blood gas . Secondary objective was to compare the relative effects on heart rate , blood pressure , respiratory rate , comfort , and tolerance . RESULTS Patients in both protocol s were comparable in terms of age , demographic , and physiologic variables including arterial blood gas , blood pressure , heart rate , respiratory rate , Glasgow Coma Score , sedation , and Acute Physiology and Chronic Health Evaluation ( APACHE ) III scores . There was no significant difference in gas exchange , respiratory rate , or hemodynamics . There was a significant difference ( P = .01 ) in tolerance , with nasal prongs being well tolerated . There was a trend ( P = .09 ) toward better patient comfort with HFNP . CONCLUSIONS High-flow nasal prongs are as effective as HFFM in delivering oxygen to extubated patients who require high-flow oxygen . The tolerance of HFNP was significantly better than in HFFM Introduction Critically ill patients with respiratory failure undergoing bronchoscopy have an increased risk of hypoxaemia-related complications . Previous studies have shown that in awake , hypoxaemic patients non-invasive ventilation ( NIV ) is helpful in preventing gas exchange deterioration during bronchoscopy . An alternative and increasingly used means of oxygen delivery is its application via high-flow nasal cannula ( HFNC ) . This study was conducted to compare HFNC with NIV in patients with acute hypoxaemic respiratory failure undergoing flexible bronchoscopy . Methods Prospect i ve r and omised trial r and omising 40 critically ill patients with hypoxaemic respiratory failure to receive either NIV or HFNC during bronchoscopy in the intensive care unit . Results After the initiation of NIV and HFNC , oxygen levels were significantly higher in the NIV group compared to the HFNC group . Two patients were unable to proceed to bronchoscopy after the institution of HFNC due to progressive hypoxaemia . During bronchoscopy , one patient on HFNC deteriorated due to intravenous sedation requiring non-invasive ventilatory support . Bronchoscopy was well tolerated in all other patients . There were no significant differences between the two groups regarding heart rate , mean arterial pressure and respiratory rate . Three patients in the NIV group and one patient in the HFNC group were intubated within 24 hours after the end of bronchoscopy ( P = 0.29 ) . Conclusions The application of NIV was superior to HFNC with regard to oxygenation before , during and after bronchoscopy in patients with moderate to severe hypoxaemia . In patients with stable oxygenation under HFNC , subsequent bronchoscopy was well tolerated . Trial registration Clinical Trials.gov NCT01870765 . Registered 30 May 2013 BACKGROUND The need for reintubation after extubation and discontinuation of mechanical ventilation is not uncommon and is associated with increased mortality . Noninvasive positive-pressure ventilation has been suggested as a promising therapy for patients with respiratory failure after extubation , but a single-center , r and omized trial recently found no benefit . We conducted a multicenter , r and omized trial to evaluate the effect of noninvasive positive-pressure ventilation on mortality in this clinical setting . METHODS Patients in 37 centers in eight countries who were electively extubated after at least 48 hours of mechanical ventilation and who had respiratory failure within the subsequent 48 hours were r and omly assigned to either noninvasive positive-pressure ventilation by face mask or st and ard medical therapy . RESULTS A total of 221 patients with similar baseline characteristics had been r and omly assigned to either noninvasive ventilation ( 114 patients ) or st and ard medical therapy ( 107 patients ) when the trial was stopped early , after an interim analysis . There was no difference between the noninvasive-ventilation group and the st and ard-therapy group in the need for reintubation ( rate of reintubation , 48 percent in both groups ; relative risk in the noninvasive-ventilation group , 0.99 ; 95 percent confidence interval , 0.76 to 1.30 ) . The rate of death in the intensive care unit was higher in the noninvasive-ventilation group than in the st and ard-therapy group ( 25 percent vs. 14 percent ; relative risk , 1.78 ; 95 percent confidence interval , 1.03 to 3.20 ; P=0.048 ) , and the median time from respiratory failure to reintubation was longer in the noninvasive-ventilation group ( 12 hours vs. 2 hours 30 minutes , P=0.02 ) . CONCLUSIONS Noninvasive positive-pressure ventilation does not prevent the need for reintubation or reduce mortality in unselected patients who have respiratory failure after extubation Purpose High-flow nasal cannula ( HFNC ) oxygen therapy is attracting increasing interest in acute medicine as an alternative to st and ard oxygen therapy ; however , its use to prevent hypoxaemia after major abdominal surgery has not been evaluated . Our trial was design ed to close this evidence gap . Methods A multicentre r and omised controlled trial was carried out at three university hospitals in France . Adult patients at moderate to high risk of postoperative pulmonary complications who had undergone major abdominal surgery using lung-protective ventilation were r and omly assigned using a computer-generated sequence to receive either HFNC oxygen therapy or st and ard oxygen therapy ( low-flow oxygen delivered via nasal prongs or facemask ) directly after extubation . The primary endpoint was absolute risk reduction ( ARR ) for hypoxaemia at 1 h after extubation and after treatment discontinuation . Secondary outcomes included occurrence of postoperative pulmonary complications within 7 days after surgery , the duration of hospital stay , and in-hospital mortality . The analysis was performed on data from the modified intention-to-treat population . This trial was registered with Clinical Trials.gov ( NCT01887015 ) . Results Between 6 November 2013 and 1 March 2015 , 220 patients were r and omly assigned to receive either HFNC ( n = 108 ) or st and ard oxygen therapy ( n = 112 ) ; all of these patients completed follow-up . The median duration of the allocated treatment was 16 h ( interquartile range 14–18 h ) with st and ard oxygen therapy and 15 h ( interquartile range 12–18 ) with HFNC therapy . Twenty-three ( 21 % ) of the 108 patients treated with HFNC 1 h after extubation and 29 ( 27 % ) of the 108 patients after treatment discontinuation had postextubation hypoxaemia , compared with 27 ( 24 % ) and 34 ( 30 % ) of the 112 patients treated with st and ard oxygen ( ARR 4 , 95 % CI –8 to 15 % ; p = 0.57 ; adjusted relative risk [ RR ] 0.87 , 95 % CI 0.53–1.43 ; p = 0.58 ) . Over the 7-day postoperative follow-up period , there was no statistically significant difference between the groups in the proportion of patients who remained free of any pulmonary complication ( ARR 7 , 95 % CI –6 to 20 % ; p = 0.40 ) . Other secondary outcomes also did not differ significantly between the two groups . Conclusions Among patients undergoing major abdominal surgery , early preventive application of high-flow nasal cannula oxygen therapy after extubation did not result in improved pulmonary outcomes compared with st and ard oxygen therapy BACKGROUND Non-invasive ventilation can prevent respiratory failure after extubation in individuals at increased risk of this complication , and enhanced survival in patients with hypercapnia has been recorded . We aim ed to assess prospect ively the effectiveness of non-invasive ventilation after extubation in patients with hypercapnia and as rescue therapy when respiratory failure develops . METHODS We undertook a r and omised controlled trial in three intensive-care units in Spain . We enrolled 106 mechanically ventilated patients with chronic respiratory disorders and hypercapnia after a successful spontaneous breathing trial . We r and omly allocated participants by computer to receive after extubation either non-invasive ventilation for 24 h ( n=54 ) or conventional oxygen treatment ( n=52 ) . The primary endpoint was avoidance of respiratory failure within 72 h after extubation . Analysis was by intention to treat . This trial is registered with clinical trials.gov , identifier NCT00539708 . FINDINGS Respiratory failure after extubation was less frequent in patients assigned non-invasive ventilation than in those allocated conventional oxygen therapy ( 8 [ 15 % ] vs 25 [ 48 % ] ; odds ratio 5.32 [ 95 % CI 2.11 - 13.46 ] ; p<0.0001 ) . In patients with respiratory failure , non-invasive ventilation as rescue therapy avoided reintubation in 17 of 27 patients . Non-invasive ventilation was independently associated with a lower risk of respiratory failure after extubation ( adjusted odds ratio 0.17 [ 95 % CI 0.06 - 0.44 ] ; p<0.0001 ) . 90-day mortality was lower in patients assigned non-invasive ventilation than in those allocated conventional oxygen ( p=0.0146 ) . INTERPRETATION Early non-invasive ventilation after extubation diminished risk of respiratory failure and lowered 90-day mortality in patients with hypercapnia during a spontaneous breathing trial . Routine implementation of this strategy for management of mechanically ventilated patients with chronic respiratory disorders is advisable . FUNDING IDIBAPS , CibeRes , Fondo de Investigaciones Sanitarias , European Respiratory Society Objective : Compared with st and ard medical therapy ( SMT ) , noninvasive ventilation ( NIV ) does not reduce the need for reintubation in unselected patients who develop respiratory failure after extubation . The goal of this study was to assess whether early application of NIV , immediately after extubation , is effective in preventing postextubation respiratory failure in an at-risk population . Design : Multiple-center , r and omized controlled study . Setting : Multiple hospitals . Patients : Ninety-seven consecutive patients with similar baseline characteristics , requiring > 48 hrs of mechanical ventilation and considered at risk of developing postextubation respiratory failure ( i.e. , patients who had hypercapnia , congestive heart failure , ineffective cough and excessive tracheobronchial secretions , more than one failure of a weaning trial , more than one comorbid condition , and upper airway obstruction ) . Interventions : After a successful weaning trial , the patients were r and omized to receive NIV for ≥8 hrs a day in the first 48 hrs or SMT . Primary outcome was the need for reintubation according to st and ardized criteria . Secondary outcomes were intensive care unit and hospital mortality , as well as time spent in the intensive care unit and in hospital . Measurements and Main Results : Compared with the SMT group , the NIV group had a lower rate of reintubation ( four of 48 vs. 12 of 49 ; p = .027 ) . The need for reintubation was associated with a higher risk of mortality ( p < .01 ) . The use of NIV result ed in a reduction of risk of intensive care unit mortality ( −10 % , p < .01 ) , mediated by the reduction for the need of reintubation . Conclusions : NIV was more effective than SMT in preventing postextubation respiratory failure in a population considered at risk of developing this complication IMPORTANCE Noninvasive ventilation delivered as bilevel positive airway pressure ( BiPAP ) is often used to avoid reintubation and improve outcomes of patients with hypoxemia after cardiothoracic surgery .  High-flow nasal oxygen therapy is increasingly used to improve oxygenation because of its ease of implementation , tolerance , and clinical effectiveness . OBJECTIVE To determine whether high-flow nasal oxygen therapy was not inferior to BiPAP for preventing or resolving acute respiratory failure after cardiothoracic surgery . DESIGN AND SETTING Multicenter , r and omized , noninferiority trial ( BiPOP Study ) conducted between June 15 , 2011 , and January 15 , 2014 , at 6 French intensive care units . PARTICIPANTS A total of 830 patients who had undergone cardiothoracic surgery , of which coronary artery bypass , valvular repair , and pulmonary thromboendarterectomy were the most common , were included when they developed acute respiratory failure ( failure of a spontaneous breathing trial or successful breathing trial but failed extubation ) or were deemed at risk for respiratory failure after extubation due to preexisting risk factors . INTERVENTIONS Patients were r and omly assigned to receive high-flow nasal oxygen therapy delivered continuously through a nasal cannula ( flow , 50 L/min ; fraction of inspired oxygen [ FiO2 ] , 50 % ) ( n = 414 ) or BiPAP delivered with a full-face mask for at least 4 hours per day ( pressure support level , 8 cm H2O ; positive end-expiratory pressure , 4 cm H2O ; FiO2 , 50 % ) ( n = 416 ) . MAIN OUTCOMES AND MEASURES The primary outcome was treatment failure , defined as reintubation , switch to the other study treatment , or premature treatment discontinuation ( patient request or adverse effects , including gastric distention ) . Noninferiority of high-flow nasal oxygen therapy would be demonstrated if the lower boundary of the 95 % CI were less than 9 % . Secondary outcomes included mortality during intensive care unit stay , changes in respiratory variables , and respiratory complications . RESULTS High-flow nasal oxygen therapy was not inferior to BiPAP : the treatment failed in 87 of 414 patients with high-flow nasal oxygen therapy ( 21.0 % ) and 91 of 416 patients with BiPAP ( 21.9 % ) ( absolute difference , 0.9 % ; 95 % CI , -4.9 % to 6.6 % ; P = .003 ) . No significant differences were found for intensive care unit mortality ( 23 patients with BiPAP [ 5.5 % ] and 28 with high-flow nasal oxygen therapy [ 6.8 % ] ; P = .66 ) ( absolute difference , 1.2 % [ 95 % CI , -2.3 % to 4.8 % ] . Skin breakdown was significantly more common with BiPAP after 24 hours ( 10 % vs 3 % ; 95 % CI , 7.3%-13.4 % vs 1.8%-5.6 % ; P < .001 ) . CONCLUSIONS AND RELEVANCE Among cardiothoracic surgery patients with or at risk for respiratory failure , the use of high-flow nasal oxygen therapy compared with intermittent BiPAP did not result in a worse rate of treatment failure . The findings support the use of high-flow nasal oxygen therapy in similar patients . TRIAL REGISTRATION clinical trials.gov Identifier : NCT01458444 During bronchoscopy hypoxemia is commonly found and oxygen supply can be delivered by interfaces fed with high gas flows . Recently , the high-flow nasal cannula ( HFNC ) has been introduced for oxygen therapy in adults , but they have not been used so far during bronchoscopy in adults . Forty-five patients were r and omly assigned to 3 groups receiving oxygen : 40 L/min through a Venturi mask ( V40 , N = 15 ) , nasal cannula ( N40 , N = 15 ) , and 60 L/min through a nasal cannula ( N60 , N = 15 ) during bronchoscopy .  Gas exchange and circulatory variables were sample d before ( FiO2 = 0.21 ) , at the end of bronchoscopy ( FiO2 = 0.5 ) , and thereafter ( V40 , FiO2 = 0.35 ) . In 8 healthy volunteers  oxygen was r and omly delivered according to V40 , N40 , and N60 setting s , and airway pressure was measured . At the end of bronchoscopy , N60 presented higher PaO2 , PaO2/FiO2 , and SpO2 than V40 and N40 that did not differ between them . In the volunteers ( N60 ) median airway pressure amounted to 3.6 cmH2O . Under a flow rate of 40 L/min both the Venturi mask and HFNC behaved similarly , but nasal cannula associated with a 60 L/min flow produced the better results , thus indicating its use in mild respiratory dysfunctions Background Aim of the study was to compare the short-term effects of oxygen therapy via a high-flow nasal cannula ( HFNC ) on functional and subjective respiratory parameters in patients with acute hypoxic respiratory failure in comparison to non-invasive ventilation ( NIV ) and st and ard treatment via a Venturi mask . Methods Fourteen patients with acute hypoxic respiratory failure were treated with HFNC ( FiO2 0.6 , gas flow 55 l/min ) , NIV ( FiO2 0.6 , PEEP 5 cm H2O Hg , tidal volume 6–8 ml/kg ideal body weight , ) and Venturi mask ( FiO2 0.6 , oxygen flow 15 l/min , ) in a r and omized order for 30 min each . Data collection included objective respiratory and circulatory parameters as well as a subjective rating of dyspnea and discomfort by the patients on a 10-point scale . In a final interview , all three methods were comparatively evaluated by each patient using a scale from 1 ( = very good ) to 6 ( = failed ) and the patients were asked to choose one method for further treatment . Results PaO2 was highest under NIV ( 129 ± 38 mmHg ) compared to HFNC ( 101 ± 34 mmHg , p < 0.01 vs. NIV ) and VM ( 85 ± 21 mmHg , p < 0.001 vs. NIV , p < 0.01 vs. HFNC , ANOVA ) . All other functional parameters showed no relevant differences . In contrast , dyspnea was significantly better using a HFNC ( 2.9 ± 2.1 , 10-point Borg scale ) compared to NIV ( 5.0 ± 3.3 , p < 0.05 ) , whereas dyspnea rating under HFNC and VM ( 3.3 ± 2.3 ) was not significantly different . A similar pattern was found when patients rated their overall discomfort on the 10 point scale : HFNC 2.7 ± 1.8 , VM 3.1 ± 2.8 ( ns vs. HFNC ) , NIV 5.4 ± 3.1 ( p < 0.05 vs. HFNC ) . In the final evaluation patients gave the best ratings to HFNC 2.3 ± 1.4 , followed by VM 3.2 ± 1.7 ( ns vs. HFNC ) and NIV 4.5 ± 1.7 ( p < 0.01 vs. HFNC and p < 0.05 vs. VM ) . For further treatment 10 patients chose HFNC , three VM and one NIV . Conclusions In hypoxic respiratory failure HFNC offers a good balance between oxygenation and comfort compared to NIV and Venturi mask and seems to be well tolerated by patients .Trial registration German clinical trials register : DRKS00005132 Introduction In immunocompromised patients , acute respiratory failure ( ARF ) is associated with high mortality , particularly when invasive mechanical ventilation ( IMV ) is required . In patients with severe hypoxemia , high-flow nasal oxygen ( HFNO ) therapy has been used as an alternative to delivery of oxygen via a Venturi mask . Our objective in the present study was to compare HFNO and Venturi mask oxygen in immunocompromised patients with ARF . Methods We conducted a multicenter , parallel-group r and omized controlled trial in four intensive care units . Inclusion criteria were hypoxemic ARF and immunosuppression , defined as at least one of the following : solid or hematological malignancy , steroid or other immunosuppressant drug therapy , and HIV infection . Exclusion criteria were hypercapnia , previous IMV , and immediate need for IMV or noninvasive ventilation ( NIV ) . Patients were r and omized to 2 h of HFNO or Venturi mask oxygen . Results The primary endpoint was a need for IMV or NIV during the 2-h oxygen therapy period . Secondary endpoints were comfort , dyspnea , and thirst , as assessed hourly using a 0–10 visual analogue scale . We r and omized 100 consecutive patients , including 84 with malignancies , to HFNO ( n = 52 ) or Venturi mask oxygen ( n = 48 ) . During the 2-h study treatment period , 12 patients required IMV or NIV , and we found no significant difference between the two groups ( 15 % with HFNO and 8 % with the Venturi mask , P = 0.36 ) . None of the secondary endpoints differed significantly between the two groups . Conclusions In immunocompromised patients with hypoxemic ARF , a 2-h trial with HFNO improved neither mechanical ventilatory assistance nor patient comfort compared with oxygen delivered via a Venturi mask . However , the study was underpowered because of the low event rate and the one-sided hypothesis . Trial registration Clinical Trials.gov identifier : NCT02424773 . Registered 20 April 2015 BACKGROUND Respiratory complications after cardiac surgery increase morbidity , mortality , and length of stay . Studies suggest that routine delivery of positive airway pressure after extubation may be beneficial . We sought to determine whether the routine administration of nasal high-flow oxygen therapy ( NHF ) improves pulmonary function after cardiac surgery . METHODS A pragmatic r and omized controlled trial ; participants received either NHF ( 45 litre min(-1 ) ) or usual care from extubation to Day 2 after surgery . The primary outcome was number of patients with / ratio ≥445 on Day 3 after surgery . The secondary outcomes included atelectasis score on chest X-ray ; spirometry ; intensive care and hospital length of stay ; mortality on Day 28 ; oxygenation indices ; escalation of respiratory support ; and patient comfort . RESULTS We r and omized 340 patients over 14 months .  The number of patients with a / ratio of ≥445 on Day 3 was 78 ( 46.4 % ) in the NHF group vs 72 ( 42.4 % ) st and ard care [ odds ratio ( OR ) 1.18 , 95 % confidence interval ( CI ) 0.77 - 1.81 , P=0.45 ] . was reduced at both 4 h post-extubation and at 9 a.m. on Day 1 in the NHF group ( 5.3 vs 5.4 kPa , P=0.03 and 5.1 vs 5.3 kPa , P=0.03 , respectively ) . Escalation in respiratory support at any time in the study occurred in 47 patients ( 27.8 % ) allocated to NHF compared with 77 ( 45 % ) st and ard care ( OR 0.47 , 95 % CI 0.29 - 0.7 , P=0.001 ) . CONCLUSIONS Routine use of NHF did not increase / ratio on Day 3 but did reduce the requirement for escalation of respiratory support . TRIAL REGISTRATION Australia New Zeal and Clinical Trials Registry www.anzctr.org.au ( ACTRN12610000973011 ) BACKGROUND : Effective O2 delivery and accurate end-tidal CO2 ( ETCO2 ) sampling are essential features of nasal cannulae ( NCs ) in patients with compromised respiratory status . We studied 4 NC design s : bifurcated nasal prongs ( NPs ) with O2 delivery and CO2 sensing in both NPs ( Hudson ) , separate O2/CO2 NPs ( Salter ) , and CO2 sensing in NPs with cloud O2 delivery outside the NPs via multi vents ( Oridion ) and dual vents ( Medline ) . We hypothesized that design differences between NCs would influence O2 delivery and ETCO2 detection . METHODS : Forty-five healthy volunteers , 18 to 35 years , participated in an unrestricted , r and omized block design , each subject serving as their own control in a 4-period crossover study design of 4 NCs during one session . Monitoring included  electrocardiogram , posterior pharynx O2 sampling  from a Hauge Airway ( Sharn Anesthesia Products , Tampa , FL ) , and NC ETCO2 .  In 11 volunteers , radial artery blood was sample d from a catheter for partial pressures of O2 and carbon dioxide ( PaO2 and PaCO2 ) determination . Per r and omization , each NC was positioned , and data were collected over 2 minutes ( ETCO2 , pharyngeal O2 , PaO2 , and PaCO2 ) during room air and during O2 fresh gas flows ( FGFs ) of 2 , 4 , and 6 Lpm . Statistical analyses were performed with SAS Analytics Pro , Version 9.3 , and JMP Statistical Software , Version 11 ( SAS Institute Inc. , Cary , NC ) , significance at P < 0.05 . RESULTS : Blood gas analyses indicated PaCO2 during steady state at each experimental time period remained unchanged from physiologic baseline . PaO2 did not differ between NC devices at baseline or 2 Lpm O2 . The PaO2 at 4 Lpm from the separate NPs and bifurcated NCs was significantly higher than the multi-vented NC . Pharyngeal O2 with the NC with separate NPs was significantly higher than multivented and dual-vented cloud delivery NCs at 2 , 4 , and 6 Lpm FGF . Pharyngeal O2 with the NC with bifurcated NPs was significantly higher than the multi-vented NC at 2 Lpm , and higher than cloud delivery NCs at 4 and 6 Lpm FGF . ETCO2 was significantly lower with the NC with bifurcated NPs compared to the other 3 NCs , consistent with errant CO2 tracings at higher FGF . CONCLUSIONS : NCs provide supplemental inspired O2 concentrations for patients with impaired pulmonary function . Accurate measures of ETCO2 are helpful in assessing respiratory rate and determining whether CO2 retention is occurring from hypoventilation . These findings suggest the NC with separate NPs was the most effective in delivering O2 and the most consistent at providing reliable CO2 waveforms at higher FGFs BACKGROUND : Humidified high-flow nasal cannula ( HFNC ) is a novel method of oxygen delivery with increasing use in emergency departments and intensive care setting s despite little evidence showing benefit over st and ard oxygen delivery methods ( st and ard O2 ) . The aim of this study was to determine whether HFNC compared with st and ard O2 given to subjects in acute respiratory distress would reduce the need for noninvasive ventilation or invasive ventilation . METHODS : This was a pragmatic open r and omized controlled trial in adult subjects with hypoxia and tachypnea presenting to a tertiary academic hospital emergency department . The primary outcome was the need for mechanical ventilation in the emergency department . RESULTS : We screened 1,287 patients , 322 met entry criteria and 19 were excluded from analysis . Of these , 165 r and omized to HFNC  and 138 to st and ard O2 were analyzed . Baseline characteristics were similar . In the HFNC group , 3.6 % ( 95 % CI 1.5–7.9 % ) versus 7.2 % ( 95 % CI 3.8–13 % ) in the st and ard O2 group required mechanical ventilation in the emergency department ( P = .16 ) , and 5.5 % ( 95 % CI 2.8–10.2 % ) in HFNC versus 11.6 % ( 95 % CI 7.2–18.1 % ) in the st and ard O2 group required mechanical ventilation within 24 h of admission ( P = .053 ) . There was no difference in mortality or stay . Adverse effects were infrequent ; however , fewer subjects in the HFNC group had a fall in Glasgow coma score due to CO2 retention , 0 % ( 95 % CI 0–3 % ) versus 2.2 % ( 95 % CI 0.4–6 % ) . One in 12 subjects did not tolerate  HFNC . CONCLUSIONS : HFNC was not shown to reduce the need for mechanical ventilation in the emergency department for subjects with acute respiratory distress compared with st and ard O2 , although it was safe and may reduce the need for escalation of oxygen therapy within the first 24 h of admission Purpose Intubation in patients with respiratory failure can be avoided by high-flow nasal cannula ( HFNC ) use . However , it is unclear whether waiting until HFNC fails , which would delay intubation , has adverse effects . The present retrospective observational study assessed overall ICU mortality and other hospital outcomes of patients who received HFNC therapy that failed . Methods All consecutive patients in one tertiary hospital who received HFNC therapy that failed and who then required intubation between January 2013 and March 2014 were enrolled and classified according to whether intubation started early ( within 48 h ) or late ( at least 48 h ) after commencing HFNC . Results Of the 175 enrolled patients , 130 ( 74.3 % ) and 45 ( 25.7 % ) were intubated before and after 48 h of HFNC , respectively . The groups were similar in terms of most baseline characteristics . The early intubated patients had better overall ICU mortality ( 39.2 vs. 66.7 % ; P = 0.001 ) than late intubated patients . A similar pattern was seen with extubation success ( 37.7 vs. 15.6 % ; P = 0.006 ) , ventilator weaning ( 55.4 vs. 28.9 % ; P = 0.002 ) , and ventilator-free days ( 8.6 ± 10.1 vs. 3.6 ± 7.5 ; P = 0.011 ) . In propensity-adjusted and -matched analysis , early intubation was also associated with better overall ICU mortality [ adjusted odds ratio ( OR ) = 0.317 , P = 0.005 ; matched OR = 0.369 , P = 0.046 ] . Conclusions Failure of HFNC might cause delayed intubation and worse clinical outcomes in patients with respiratory failure . Large prospect i ve and r and omized controlled studies on HFNC failure are needed to draw a definitive conclusion CONTEXT Dyspnea is one of the most distressing symptoms for cancer patients . The role of high-flow oxygen ( HFO ) and bilevel positive airway pressure ( BiPAP ) in the palliation of dyspnea has not been well characterized . OBJECTIVES To determine the feasibility of conducting a r and omized trial of HFO and BiPAP in cancer patients and examine the changes in dyspnea , physiologic parameters , and adverse effects with these modalities . METHODS In this r and omized study ( Clinical Trials.gov Identifier : NCT01518140 ) , we assigned hospitalized patients with advanced cancer and persistent dyspnea to either HFO or BiPAP for two hours . We assessed dyspnea with a numeric rating scale ( NRS ) and  modified Borg scale ( MBS ) before and after the intervention . We also documented vital signs , transcutaneous carbon dioxide , and adverse effects . RESULTS Thirty patients were enrolled ( 1:1 ratio ) and 23 ( 77 % ) completed the assigned intervention . HFO was associated with improvements in both NRS ( mean 1.9 ; 95 % CI 0.4 - 3.4 ; P = 0.02 ) and MBS ( mean 2.1 ; 95 % CI 0.6 - 3.5 ; P = 0.007 ) . BiPAP also was associated with improvements in NRS ( mean 3.2 ; 95 % CI 1.3 - 5.1 ; P = 0.004 ) and MBS ( mean 1.5 ; 95 % CI -0.3 , 3.2 ; P = 0.13 ) . There were no significant differences between HFO and BiPAP in dyspnea NRS ( P = 0.14 ) and MBS ( P = 0.47 ) . Oxygen saturation improved with HFO ( 93 % vs. 99 % ; P = 0.003 ) , and respiratory rate had a nonstatistically significant decrease with both interventions ( HFO -3 , P = 0.11 ; BiPAP -2 , P = 0.11 ) . No significant adverse effects were observed . CONCLUSION HFO and BiPAP alleviated dyspnea , improved physiologic parameters , and were safe . Our results justify larger r and omized controlled trials to confirm these findings Purpose To evaluate the efficiency , safety and outcome of high flow nasal cannula oxygen ( HFNC ) in ICU patients with acute respiratory failure . Methods Pilot prospect i ve monocentric study . Thirty-eight patients were included . Baseline demographic and clinical data , as well as respiratory variables at baseline and various times after HFNC initiation during 48 h , were recorded . Arterial blood gases were measured before and after the use of HFNC .  Noise and discomfort were monitored along with outcome and need for invasive mechanical ventilation . Results HFNC significantly reduced the respiratory rate , heart rate , dyspnea score , supraclavicular retraction and thoracoabdominal asynchrony , and increased pulse oxymetry . These improvements were observed as early as 15 min after the beginning of HFNC for respiratory rate and pulse oxymetry . PaO2 and PaO2/FiO2 increased significantly after 1 h HFNC in comparison with baseline ( 141 ± 106 vs. 95 ± 40 mmHg , p = 0.009 and 169 ± 108 vs. 102 ± 23 , p = 0.036 ; respectively ) . These improvements lasted throughout the study period . HFNC was used for a mean duration of 2.8 days and a maximum of 7 days . It was never interrupted for intolerance . No nosocomial pneumonia occurred during HFNC . Nine patients required secondary invasive mechanical ventilation . Absence of a significant decrease in the respiratory rate , lower oxygenation and persistence of thoracoabdominal asynchrony after HFNC initiation were early indicators of HFNC failure . Conclusions HFNC has a beneficial effect on clinical signs and oxygenation in ICU patients with acute respiratory failure . These favorable results constitute a prerequisite to launching a r and omized controlled study to investigate whether HFNC  reduces intubation in these patients BACKGROUND : Acute dyspnea and hypoxemia are 2 of the most common problems in the emergency room . Oxygen therapy is an essential supportive treatment to correct these issues . In this study , we investigated the physiologic effects of high-flow nasal oxygen cannula ( HFNC ) compared with conventional oxygen therapy ( COT ) in subjects with acute dyspnea and hypoxemia in the emergency room . METHODS : A prospect i ve r and omized comparative study was conducted in the emergency department of a university hospital . Forty subjects were r and omized to receive HFNC or COT for 1 h. The primary outcome was level of dyspnea , and secondary outcomes included change in breathing frequency , subject comfort , adverse events , and rate of hospitalization . RESULTS : Common causes of acute dyspnea and hypoxemia were congestive heart failure , asthma exacerbation , COPD exacerbation , and pneumonia . HFNC significantly improved dyspnea ( 2.0 ± 1.8 vs 3.8 ± 2.3 , P = .01 ) and subject comfort ( 1.6 ± 1.7 vs 3.7 ± 2.4 , P = .01 ) compared with COT . No statistically significant difference in breathing frequency was found between the 2 groups at the end of the study . HFNC was well tolerated , and no serious adverse events were found . The rate of hospitalization in the HFNC group was lower than in the COT group , but there was no statistically significant difference ( 50 % vs 65 % , P = .34 ) . CONCLUSIONS : HFNC improved dyspnea and comfort in subjects presenting with acute dyspnea and hypoxemia in the emergency department . HFNC may benefit patients requiring oxygen therapy in the emergency room BACKGROUND : Non-intubated critically ill patients are often treated by high-flow oxygen for acute respiratory failure . There is no current recommendation for humidification of oxygen devices . METHODS : We conducted a prospect i ve r and omized trial with a final crossover period to compare nasal airway caliber and respiratory comfort in patients with acute hypoxemic respiratory failure receiving either st and ard oxygen therapy with no humidification or heated and humidified high-flow oxygen therapy ( HHFO2 ) in a medical ICU .  Nasal airway caliber was measured using acoustic rhinometry at baseline , after 4 and 24 hours ( H4 and H24 ) , and 4 hours after crossover ( H28 ) . Dryness of the nose , mouth , and throat was auto-evaluated and assessed blindly by an otorhinolaryngologist . After the crossover , the subjects were asked which system they preferred . RESULTS : Thirty subjects completed the protocol and were analyzed . Baseline median oxygen flow was 9 and 12 L/min in the st and ard and HHFO2 groups , respectively ( P = .21 ) . Acoustic rhinometry measurements showed no difference between the 2 systems . The dryness score was significantly lower in the HHFO2 group at H4 ( 2 vs 6 , P = .007 ) and H24 ( 0 vs 8 , P = .004 ) . During the crossover period , dryness increased promptly after switching to st and ard oxygen and decreased after switching to HHFO2 ( P = .008 ) . Sixteen subjects ( 53 % ) preferred HHFO2 ( P = .01 ) , especially those who required the highest flow of oxygen at admission ( P = .05 ) . CONCLUSIONS : Upper airway caliber was not significantly modified by HHFO2 , compared to st and ard oxygen therapy , but HHFO2 significantly reduced discomfort in critically ill patients with respiratory failure . The system is usually preferred over st and ard oxygen therapy BACKGROUND : The effectiveness of noninvasive ventilation ( NIV ) after extubation in preventing post-extubation respiratory failure is still controversial . METHODS : We conducted a prospect i ve , multicenter r and omized controlled study involving patients on mechanical ventilation for > 48 hours who tolerated a 2-hour spontaneous breathing trial and were subsequently extubated . The patients were r and omized to NIV or st and ard medical therapy .  Re-intubation rate within 72 hours was the primary outcome measure . Multivariable logistic regression analysis was used to determine predictors for extubation failure . RESULTS : We r and omized 406 patients to either NIV ( no. = 202 ) or st and ard medical therapy ( no. = 204 ) . The 2 groups had similar baseline clinical characteristics . There were no differences in extubation failure ( 13.2 % in control and 14.9 % in  NIV ) , intensive care unit or hospital mortality . Cardiac failure was a more common cause of extubation failure in control than in NIV . There was no difference in rapid shallow breathing index ( RSBI ) in extubation failure patients between control ( 80 ) and NIV ( 73 ) . When using data from all patients , we found Acute Physiology and Chronic Health Evaluation ( APACHE II ) scores ( odds ratio [ OR ] 1.13 , 95 % CI 1.07–1.20 , P < .001 ) , maximal inspiratory pressure ( OR 1.04 , 95 % CI 1.00–1.08 , P = .03 ) , and RSBI ( OR 1.03 , 95 % CI 1.02–1.05 , P < .001 ) to be predictors of extubation failure . Abundant secretions were the most common reason ( 35.1 % ) for extubation failure identified by attending physicians . CONCLUSIONS : Preventive use of NIV after extubation in patients who passed spontaneous breathing trial did not show benefits in decreasing extubation failure rate or the mortality rate Purpose Nasal continuous positive airway pressure ( nCPAP ) is currently the gold st and ard for respiratory support for moderate to severe acute viral bronchiolitis ( AVB ) . Although oxygen delivery via high flow nasal cannula ( HFNC ) is increasingly used , evidence of its efficacy and safety is lacking in infants . Methods A r and omized controlled trial was performed in five pediatric intensive care units ( PICUs ) to compare 7 cmH2O nCPAP with 2 L/kg/min oxygen therapy administered with HFNC in infants up to 6 months old with moderate to severe AVB . The primary endpoint was the percentage of failure within 24 h of r and omization using prespecified criteria . To satisfy noninferiority , the failure rate of HFNC had to lie within 15 % of the failure rate of nCPAP . Secondary outcomes included success rate after crossover , intubation rate , length of stay , and serious adverse events . Results From November 2014 to March 2015 , 142 infants were included and equally distributed into groups . The risk difference of −19 % ( 95 % CI −35 to −3 % ) did not allow the conclusion of HFNC noninferiority ( p = 0.707 ) . Superiority analysis suggested a relative risk of success 1.63 ( 95 % CI 1.02–2.63 ) higher with nCPAP . The success rate with the alternative respiratory support , intubation rate , duration s of noninvasive and invasive ventilation , skin lesions , and length of PICU stay were comparable between groups . No patient had air leak syndrome or died . Conclusion In young infants with moderate to severe AVB , initial management with HFNC did not have a failure rate similar to that of nCPAP . This clinical trial was recorded in the National Library of Medicine registry ( NCT 02457013 ) OBJECTIVE : Compare the short-term benefit of high-flow nasal cannula ( HFNC ) with non-rebreathing mask in terms of change in dyspnea , physiologic variables , and patient comfort in subjects after endotracheal extubation . METHODS : A r and omized crossover study was conducted in a 10-bed respiratory care unit in a university hospital . Seventeen mechanically ventilated subjects were r and omized after extubation to either Protocol A ( applied HFNC for 30 min , followed by non-rebreathing mask for another 30 min ) or Protocol B ( applied non-rebreathing mask for 30 min , followed by HFNC for another 30 min ) . The level of dyspnea , breathing frequency , heart rate , blood pressure , oxygen saturation , and patient comfort were recorded . The results were expressed as mean ± SD , frequency , or percentage . Categorical variables were compared by chi-square test or Fisher exact test , and continuous variables were compared by dependent or paired t test . Statistical significance was defined as P < .05 . RESULTS : Seventeen subjects were divided into 2 groups : 9 subjects in Protocol A and 8 subjects in Protocol B. The baseline characteristics and physiologic parameters before extubation were not significantly different in each protocol . At the end of study , HFNC indicated less dyspnea ( P = .04 ) and lower breathing frequency ( P = .009 ) and heart rate ( P = .006 ) compared with non-rebreathing mask . Most of the subjects ( 88.2 % ) preferred HFNC to non-rebreathing mask . CONCLUSIONS : HFNC can improve dyspnea and physiologic parameters , including breathing frequency and heart rate , in extubated subjects compared with conventional oxygen therapy . This device may have a potential role for use after endotracheal extubation RATIONALE Oxygen is commonly administered after extubation . Although several devices are available , data about their clinical efficacy are scarce . OBJECTIVES To compare the effects of the Venturi mask and the nasal high-flow ( NHF ) therapy on PaO2/FiO2SET ratio after extubation . Secondary endpoints were to assess effects on patient discomfort , adverse events , and clinical outcomes . METHODS R and omized , controlled , open-label trial on 105 patients with a PaO2/FiO2 ratio less than or equal to 300 immediately before extubation . The Venturi mask ( n = 52 ) or NHF ( n = 53 ) were applied for 48 hours postextubation . MEASUREMENTS AND MAIN RESULTS PaO2/FiO2SET , patient discomfort caused by the interface and by symptoms of airways dryness ( on a 10-point numerical rating scale ) , interface displacements , oxygen desaturations , need for ventilator support , and reintubation were assessed up to 48 hours after extubation . From the 24th hour , PaO2/FiO2SET was higher with the NHF ( 287 ± 74 vs. 247 ± 81 at 24 h ; P = 0.03 ) . Discomfort related both to the interface and to airways dryness was better with NHF ( respectively , 2.6 ± 2.2 vs. 5.1 ± 3.3 at 24 h , P = 0.006 ; 2.2 ± 1.8 vs. 3.7 ± 2.4 at 24 h , P = 0.002 ) . Fewer patients had interface displacements ( 32 % vs. 56 % ; P = 0.01 ) , oxygen desaturations ( 40 % vs. 75 % ; P < 0.001 ) , required reintubation ( 4 % vs. 21 % ; P = 0.01 ) , or any form of ventilator support ( 7 % vs. 35 % ; P < 0.001 ) in the NHF group . CONCLUSIONS Compared with the Venturi mask , NHF results in better oxygenation for the same set FiO2 after extubation . Use of NHF is associated with better comfort , fewer desaturations and interface displacements , and a lower reintubation rate . Clinical trial registered with www . clinical trials.gov ( NCT 01575353 ) Objectives : Tracheal intubation of ICU patients is frequently associated with severe hypoxemia . Although noninvasive ventilation reduces desaturation during intubation of severely hypoxemic patients , it does not allow for per-procedure oxygenation and has not been evaluated in mild-to-moderate hypoxemic patients for whom high-flow nasal cannula oxygen may be an alternative . We sought to compare pre- and per-procedure oxygenation with either a nonrebreathing bag reservoir facemask or a high-flow nasal cannula oxygen during tracheal intubation of ICU patients . Design : Prospect i ve quasi-experimental before-after study ( Clinical Trials.gov : NCT01699880 ) . Setting : University hospital medico-surgical ICU . Patients : All adult patients requiring tracheal intubation in the ICU were eligible . Interventions : In the control ( before ) period , preoxygenation was performed with a nonrebreathing bag reservoir facemask and in the change of practice ( after ) period , with high-flow nasal cannula oxygen . Measurements and Main Results : Primary outcome was median lowest SpO2 during intubation , and secondary outcomes were SpO2 after preoxygenation and number of patients with saturation less than 80 % . One hundred one patients were included .  Median lowest SpO2 during intubation were 94 % ( 83–98.5 ) with the nonrebreathing bag reservoir facemask versus 100 % ( 95–100 ) with high-flow nasal cannula oxygen ( p < 0.0001 ) . SpO2 values at the end of preoxygenation were higher with high-flow nasal cannula oxygen than with nonrebreathing bag reservoir facemask and were correlated with the lowest SpO2 reached during the intubation procedure ( r = 0.38 , p < 0.0001 ) . Patients in the nonrebreathing bag reservoir facemask group experienced more episodes of severe hypoxemia ( 2 % vs 14 % , p = 0.03 ) . In the multivariate analysis , preoxygenation with high-flow nasal cannula oxygen was an independent protective factor of the occurrence of severe hypoxemia ( odds ratio , 0.146 ; 95 % CI , 0.01–0.90 ; p = 0.037 ) . Conclusions : High-flow nasal cannula oxygen significantly improved preoxygenation and reduced prevalence of severe hypoxemia compared with nonrebreathing bag reservoir facemask . Its use could improve patient safety during intubation PURPOSE The purpose of the study is to describe early predictors and to develop a prediction tool that accurately identifies the need for  mechanical ventilation ( MV )  in pneumonia patients with hypoxemic acute respiratory failure ( ARF ) treated with high-flow nasal cannula ( HFNC ) .  MATERIAL S AND METHODS This is a 4-year prospect i ve observational 2-center cohort study including patients with severe pneumonia treated with HFNC .  High-flow nasal cannula failure was defined as need for MV .  ROX index was defined as the ratio of pulse oximetry/fraction of inspired oxygen to respiratory rate . RESULTS One hundred fifty-seven patients were included , of whom 44 ( 28.0 % ) eventually required  MV  ( HFNC failure ) . After 12 hours of HFNC treatment , the ROX index demonstrated the best prediction accuracy ( area under the receiver operating characteristic curve 0.74 [ 95 % confidence interval , 0.64 - 0.84 ] ; P<.002 ) . The best cutoff point for the ROX index was estimated to be 4.88 . In the Cox proportional hazards model , a ROX index greater than or equal to 4.88 measured after 12 hours of HFNC was significantly associated with a lower risk for MV  ( hazard ratio , 0.273 [ 95 % confidence interval , 0.121 - 0.618 ] ; P=.002 ) , even after adjusting for potential confounding . CONCLUSIONS In patients with ARF and pneumonia , the ROX index can identify patients at low risk for HFNC failure in whom therapy can be continued after 12 hours In this study , we evaluated the performance of a humidified nasal high-flow system ( Optiflow ™ , Fisher and Paykel Healthcare ) by measuring delivered FiO2 and airway pressures . Oxygraphy , capnography and measurement of airway pressures were performed through a hypopharyngeal catheter in healthy volunteers receiving Optiflow ™ humidified nasal high flow therapy at rest and with exercise . The study was conducted in a non- clinical experimental setting . Ten healthy volunteers completed the study after giving informed written consent . Participants received a delivered oxygen  fraction of 0.60 with gas flow rates of 10 , 20 , 30 , 40 and 50 l/minute in r and om order . FiO2 , FEO2 , FECO2 and airway pressures were measured . Calculation of FiO2 from FEO2 and FECO2 was later performed . Calculated FiO2 approached 0.60 as gas flow rates increased above 30 l/minute during nose breathing at rest . High peak inspiratory flow rates with exercise were associated with increased air entrainment . Hypopharyngeal pressure increased with increasing delivered gas flow rate . At 50 l/minute the system delivered a mean airway pressure of up to 7.1 cmH2O . We believe that the high gas flow rates delivered by this system enable an accurate inspired oxygen fraction to be delivered . The positive mean airway pressure created by the high flow increases the efficacy of this system and may serve as a bridge to formal positive pressure systems Purpose Patients with a body mass index ( BMI ) ≥30 kg/m2 experience more severe atelectasis following cardiac surgery than those with normal BMI and its resolution is slower . This study aim ed to compare extubation of patients post-cardiac surgery with a BMI ≥30 kg/m2 onto high-flow nasal cannulae ( HFNC ) with  st and ard care to determine whether HFNC could assist in minimising post-operative atelectasis and improve respiratory function . Methods In this r and omised controlled trial , patients received HFNC or st and ard oxygen therapy post-extubation . The primary outcome was atelectasis on chest X-ray . Secondary outcomes included oxygenation , respiratory rate ( RR ) , subjective dyspnoea , and failure of allocated treatment . Results One hundred and fifty-five patients were r and omised , 74 to control , 81 to HFNC . No difference was seen between groups in atelectasis scores on Days 1 or 5 ( median scores = 2 , p = 0.70 and p = 0.15 , respectively ) . In the 24-h post-extubation , there was no difference in mean PaO2/FiO2 ratio ( HFNC 227.9 , control 253.3 , p = 0.08 ) , or RR ( HFNC 17.2 , control 16.7 , p = 0.17 ) . However , low dyspnoea levels were observed in each group at 8 h post-extubation , median ( IQR ) scores were 0 ( 0–1 ) for control and 1 ( 0–3 ) for HFNC ( p = 0.008 ) . Five patients failed allocated treatment in the control group compared with three in the treatment group [ Odds ratio 0.53 , ( 95 % CI 0.11 , 2.24 ) , p = 0.40 ] . Conclusions In this study , prophylactic extubation onto HFNC post-cardiac surgery in patients with a BMI ≥30 kg/m2 did not lead to improvements in respiratory function . Larger studies assessing the role of HFNC in preventing worsening of respiratory function and intubation are required INTRODUCTION : High-flow nasal cannula ( HFNC ) can deliver heated and humidified gas ( up to 100 % oxygen ) at a maximum flow of 60 L/min via nasal prongs or cannula . The aim of this study was to assess the short-term physiologic effects of HFNC . Inspiratory muscle effort , gas exchange , dyspnea score , and comfort were evaluated . METHODS : Twelve subjects admitted to the ICU for acute hypoxemic respiratory failure were prospect ively included . Four study sessions were performed . The first session consisted of oxygen therapy given through a high-FIO2 , non-rebreathing face mask . Recordings were then obtained during periods of HFNC and CPAP at 5 cm H2O in r and om order , and final measurements were performed during oxygen therapy delivered via a face mask . Each of these 4 periods lasted ∼20 min . RESULTS : Esophageal pressure signals , breathing pattern , gas exchange , comfort , and dyspnea were measured . Compared with the first session , HFNC reduced inspiratory effort ( pressure-time product of 156.0 [ 119.2–194.4 ] cm H2O × s/min vs 204.2 [ 149.6–324.7 ] cm H2O × s/min , P < .01 ) and breathing frequency ( P < .01 ) . No significant differences were observed between HFNC and CPAP for inspiratory effort and breathing frequency . Compared with the first session , PaO2/FIO2 increased significantly with HFNC ( 167 [ 157–184 ] mm Hg vs 156 [ 110–171 ] mm Hg , P < .01 ) . CPAP produced significantly greater PaO2/FIO2 improvement than did HFNC . Dyspnea improved with HFNC and CPAP , but this improvement was not significant . Subject comfort was not different across the 4 sessions . CONCLUSIONS : Compared with conventional oxygen therapy , HFNC improved inspiratory effort and oxygenation . In subjects with acute hypoxemic respiratory failure , HFNC is an alternative to conventional oxygen therapy . ( Clinical Trials.gov registration NCT01056952 . IMPORTANCE Studies of mechanically ventilated critically ill patients that combine population s that are at high and low risk for reintubation suggest that conditioned high-flow nasal cannula oxygen therapy after extubation improves oxygenation compared with conventional oxygen therapy . However , conclusive data about reintubation are lacking . OBJECTIVE To determine whether high-flow nasal cannula oxygen therapy is superior to conventional oxygen therapy for preventing reintubation in mechanically ventilated patients at low risk for reintubation . DESIGN , SETTING , AND PARTICIPANTS Multicenter r and omized clinical trial conducted between September 2012 and October 2014 in 7 intensive care units ( ICUs ) in Spain . Participants were 527 adult critical patients at low risk for reintubation who fulfilled criteria for planned extubation . Low risk for reintubation was defined as younger than 65 years ; Acute Physiology and Chronic Health Evaluation II score less than 12 on day of extubation ; body mass index less than 30 ; adequate secretions management ; simple weaning ; 0 or 1 comorbidity ; and absence of heart failure , moderate-to-severe chronic obstructive pulmonary disease , airway patency problems , and prolonged mechanical ventilation . INTERVENTIONS Patients were r and omized to undergo either high-flow or conventional oxygen therapy for 24 hours after extubation . MAIN OUTCOMES AND MEASURES The primary outcome was reintubation within 72 hours , compared with the Cochran-Mantel-Haenszel χ2 test . Secondary outcomes included postextubation respiratory failure , respiratory infection , sepsis and multiorgan failure , ICU and hospital length of stay and mortality , adverse events , and time to reintubation . RESULTS Of 527 patients ( mean age , 51 years [ range , 18 - 64 ] ; 62 % men ) , 264 received high-flow therapy and 263 conventional oxygen therapy . Reintubation within 72 hours was less common in the high-flow group ( 13 patients [ 4.9 % ] vs 32 [ 12.2 % ] in the conventional group ; absolute difference , 7.2 % [ 95 % CI , 2.5 % to 12.2 % ] ; P = .004 ) . Postextubation respiratory failure was less common in the high-flow group ( 22/264 patients [ 8.3 % ] vs 38/263 [ 14.4 % ] in the conventional group ; absolute difference , 6.1 % [ 95 % CI , 0.7 % to 11.6 % ] ; P = .03 ) . Time to reintubation was not significantly different between groups ( 19 hours [ interquartile range , 12 - 28 ] in the high-flow group vs 15 hours [ interquartile range , 9 - 31 ] in the conventional group ; absolute difference , -4 [ 95 % CI , -54 to 46 ] ; P = .66 ] . No adverse effects were reported . CONCLUSIONS AND RELEVANCE Among extubated patients at low risk for reintubation , the use of high-flow nasal cannula oxygen compared with conventional oxygen therapy reduced the risk of reintubation within 72 hours . TRIAL REGISTRATION clinical trials.gov Identifier : NCT01191489
Purpose : We conducted a systematic review and meta- analysis of r and omized controlled trials ( RCTs ) to evaluate the effect of  high-flow nasal cannula ( HFNC ) on reintubation in adult patients .