Post-traumatic stress disorder after weaning from prolonged mechanical ventilation Proportional assist ventilation with load-adjustable gain factors in critically ill patients: comparison with pressure support Safety and efficacy of a fully closed-loop control ventilation (IntelliVent-ASV®) in sedated ICU patients with acute respiratory failure: a prospective randomized crossover study Replacement of fentanyl infusion by enteral methadone decreases the weaning time from mechanical ventilation: a randomized controlled trial Automatic versus manual pressure support reduction in the weaning of post-operative patients: a randomised controlled trial Weaning children from mechanical ventilation with a computer-driven protocol: a pilot trial Automatic “Respirator/Weaning” with Adaptive Support Ventilation: The Effect on Duration of Endotracheal Intubation and Patient Management Effects of patient-triggered automatic switching between mandatory and supported ventilation in the postoperative weaning period What is the daily practice of mechanical ventilation in pediatric intensive care units? A multicenter study Injurious ventilatory strategies increase cytokines and c-fos m-RNA expression in an isolated rat lung model. A multicenter randomized trial of computer-driven protocolized weaning from mechanical ventilation. Adaptive support ventilation for faster weaning in COPD: a randomised controlled trial A randomized trial of automated versus conventional protocol-driven weaning from mechanical ventilation following coronary artery bypass surgery. Predicting 3-day and 7-day outcomes of weaning from mechanical ventilation. Mandatory Minute Volume Weaning in Patients with Pulmonary Pathology Ventilation and Weaning Practices in Australia and New Zealand Methods for combining randomized clinical trials: strengths and limitations. Automatic control of pressure support for ventilator weaning in surgical intensive care patients. Delirium as a predictor of long-term cognitive impairment in survivors of critical illness A computer-controlled ventilator weaning system. A clinical trial. The impact of delirium in the intensive care unit on hospital length of stay Depressive disorders during weaning from prolonged mechanical ventilation A randomized, controlled trial of protocol-directed versus physician-directed weaning from mechanical ventilation. Computer‐driven automated weaning reduces weaning duration in difficult‐to‐wean patients Post-traumatic stress disorder after critical illness requiring general intensive care Evaluation of fully automated ventilation: a randomized controlled study in post-cardiac surgery patients Weaning Automation with Adaptive Support Ventilation: A Randomized Controlled Trial in Cardiothoracic Surgery Patients Adaptive Support Ventilation for Fast Tracheal Extubation after Cardiac Surgery: A Randomized Controlled Study Implications of extubation delay in brain-injured patients meeting standard weaning criteria. Memory, delusions, and the development of acute posttraumatic stress disorder-related symptoms after intensive care A randomised, controlled trial of conventional versus automated weaning from mechanical ventilation using SmartCare™/PS Adaptive support ventilation for complete ventilatory support in acute respiratory distress syndrome: a pilot, randomized controlled trial. Weaning children from mechanical ventilation with a computer-driven system (closed-loop protocol): A pilot study* [Comparison of computer-driven weaning and physician-directed weaning from mechanical ventilation: a randomized prospective study]. Computerized decision support for mechanical ventilation of trauma induced ARDS: results of a randomized clinical trial. Characteristics and outcomes in adult patients receiving mechanical ventilation: a 28-day international study. Wean earlier and automatically with new technology (the WEAN study). A multicenter, pilot randomized controlled trial. [Comparison of SmartCare and spontaneous breathing trials for weaning old patients with chronic obstructive pulmonary diseases].
Purpose Weaning from prolonged mechanical ventilation may be associated with mental discomfort . It is not known whether such discomfort is linked with the development of post-traumatic stress disorder ( PTSD ) . Accordingly , we investigated whether PTSD occurs in patients after weaning from prolonged ventilation .  We also determined whether administering a question naire would identify patients at risk for developing PTSD . Methods A prospect i ve longitudinal study of patients transferred to a long-term acute-care hospital for weaning from prolonged ventilation  was undertaken : 72 patients were studied 1 week after weaning , and 41 patients were studied again 3 months later . An experienced psychologist conducted a structured clinical interview 3 months after weaning to establish a diagnosis of PTSD . To assess for the presence of PTSD-related symptoms , the post-traumatic stress syndrome ( PTSS-10 ) question naire was administered 1 week after weaning and 3 months later . Results The psychologist diagnosed PTSD in 12 % of patients 3 months after ventilator weaning . Patients who developed PTSD were more likely to have a previous history of psychiatric disorders ( P < 0.02 ) . A PTSS-10 score > 20 one week after weaning reliably identified patients who were diagnosed with PTSD 3 months later : sensitivity 1.0 ; specificity 0.76 ; area under the receiver-operating characteristic curve 0.91 . Conclusion PTSD was diagnosed in 12 % of patients who were weaned from prolonged ventilation . A PTSS-10 score > 20 one week after weaning identified patients diagnosed with PTSD 3 months later . This finding suggests that a simple question naire administered before hospital discharge can identify patients at risk for developing PTSD Objectives It is not known if proportional assist ventilation with load-adjustable gain factors ( PAV+ ) may be used as a mode of support in critically ill patients . The aim of this study was to examine the effectiveness of sustained use of PAV+ in critically ill patients and compare it with pressure support ventilation ( PS ) . Design and setting R and omized study in the intensive care unit of a university hospital . Methods A total of 208 critically ill patients mechanically ventilated on controlled modes for at least 36 h and meeting certain criteria were r and omized to receive either PS  ( n = 100 ) or  PAV+ ( n = 108 ) . Specific written algorithms were used to adjust the ventilator setting s in each mode . PAV+ or PS was continued for 48 h unless the patients met pre-defined criteria either for switching to controlled modes ( failure criteria ) or for breathing without ventilator assistance . Results Failure rate was significantly lower in PAV+ than that in PS ( 11.1 vs. 22.0 % , P = 0.040 , OR 0.443 , 95 % CI 0.206–0.952 ) . The proportion of patients exhibiting major patient – ventilator dyssynchronies at least during one occasion and after adjusting the initial ventilator setting s , was significantly lower in PAV+ than in PS ( 5.6 vs. 29.0 % , P < 0.001 , OR 0.1 , 95 % CI 0.06–0.4 ) . The proportion of patients meeting criteria for unassisted breathing did not differ between modes . Conclusions PAV+ may be used as a useful mode of support in critically ill patients . Compared to PS , PAV+ increases the probability of remaining on spontaneous breathing , while it considerably reduces the incidence of patient – ventilator asynchronies Purpose IntelliVent-ASV ® is a development of adaptive support ventilation ( ASV ) that automatically adjusts ventilation and oxygenation parameters . This study assessed the safety and efficacy of IntelliVent-ASV ® in se date d intensive care unit ( ICU ) patients with acute respiratory failure . Methods This prospect i ve r and omized crossover comparative study was conducted in a 12-bed ICU in a general hospital . Two periods of 2 h of ventilation in r and omly applied ASV or IntelliVent-ASV ® were compared in 50 se date d , passively ventilated patients . Tidal volume ( VT ) , respiratory rate ( RR ) , inspiratory pressure ( PINSP ) , SpO2 and ETCO2 were continuously monitored and recorded breath by breath . Mean values over the 2-h period were calculated . Respiratory mechanics , plateau pressure ( PPLAT ) and blood gas exchanges were measured at the end of each period . Results There was no safety issue requiring premature interruption of IntelliVent-ASV ® . Minute ventilation ( MV ) and VT decreased from 7.6 ( 6.5–9.5 ) to 6.8 ( 6.0–8.0 ) L/min ( p < 0.001 ) and from 8.3 ( 7.8–9.0 ) to 8.1 ( 7.7–8.6 ) mL/kg PBW ( p = 0.003 ) during IntelliVent-ASV ® as compared to ASV . PPLAT and FiO2 decreased from 24 ( 20–29 ) to 20 ( 19–25 ) cmH2O ( p = 0.005 ) and from 40 ( 30–50 ) to 30 ( 30–39 ) % ( p < 0.001 ) during IntelliVent-ASV ® as compared to ASV . RR , PINSP , and PEEP decreased as well during IntelliVent-ASV ® as compared to ASV . Respiratory mechanics , pH , PaO2 and PaO2/FiO2 ratio were not different but PaCO2 was slightly higher during IntelliVent-ASV ® as compared to ASV . Conclusions In passive patients with acute respiratory failure , IntelliVent-ASV ® was safe and able to ventilate patients with less pressure , volume and FiO2 while producing the same results in terms of oxygenation Introduction Patients undergoing mechanical ventilation ( MV ) are frequently administered prolonged and /or high doses of opioids which when removed can cause a withdrawal syndrome and difficulty in weaning from MV . We tested the hypothesis that the introduction of enteral methadone during weaning from sedation and analgesia in critically ill adult patients on MV would decrease the weaning time from MV . Methods A double-blind r and omized controlled trial was conducted in the adult intensive care units ( ICUs ) of four general hospitals in Brazil . The 75 patients , who met the criteria for weaning from MV and had been using fentanyl for more than five consecutive days , were r and omized to the methadone ( MG ) or control group ( CG ) . Within the first 24 hours after study enrollment , both groups received 80 % of the original dose of fentanyl , the MG received enteral methadone and the CG received an enteral placebo . After the first 24 hours , the MG received an intravenous ( IV ) saline solution ( placebo ) , while the CG received IV fentanyl . For both groups , the IV solution was reduced by 20 % every 24 hours . The groups were compared by evaluating the MV weaning time and the duration of MV , as well as the ICU stay and the hospital stay . Results Of the 75 patients r and omized , seven were excluded and 68 were analyzed : 37 from the MG and 31 from the CG . There was a higher probability of early extubation in the MG , but the difference was not significant ( hazard ratio : 1.52 ( 95 % confidence interval ( CI ) 0.87 to 2.64 ; P = 0.11 ) . The probability of successful weaning by the fifth day was significantly higher in the MG ( hazard ratio : 2.64 ( 95 % CI : 1.22 to 5.69 ; P < 0.02 ) . Among the 54 patients who were successfully weaned ( 29 from the MG and 25 from the CG ) , the MV weaning time was significantly lower in the MG ( hazard ratio : 2.06 ; 95 % CI 1.17 to 3.63 ; P < 0.004 ) . Conclusions The introduction of enteral methadone during weaning from sedation and analgesia in mechanically ventilated patients result ed in a decrease in the weaning time from MV Introduction Reduction of automatic pressure support based on a target respiratory frequency or m and atory rate ventilation ( MRV ) is available in the Taema-Horus ventilator for the weaning process in the intensive care unit ( ICU ) setting . We hypothesised that MRV is as effective as manual weaning in post-operative ICU patients . Methods There were 106 patients selected in the post-operative period in a prospect i ve , r and omised , controlled protocol . When the patients arrived at the ICU after surgery , they were r and omly assigned to either : traditional weaning , consisting of the manual reduction of pressure support every 30 minutes , keeping the respiratory rate/tidal volume ( RR/TV ) below 80 L until 5 to 7 cmH2O of pressure support ventilation ( PSV ) ; or automatic weaning , referring to MRV set with a respiratory frequency target of 15 breaths per minute ( the ventilator automatically decreased the PSV level by 1 cmH2O every four respiratory cycles , if the patient 's RR was less than 15 per minute ) . The primary endpoint of the study was the duration of the weaning process . Secondary endpoints were levels of pressure support , RR , TV ( mL ) , RR/TV , positive end expiratory pressure levels , FiO2 and SpO2 required during the weaning process , the need for reintubation and the need for non-invasive ventilation in the 48 hours after extubation . Results In the intention to treat analysis there were no statistically significant differences between the 53 patients selected for each group regarding gender ( p = 0.541 ) , age ( p = 0.585 ) and type of surgery ( p = 0.172 ) . Nineteen patients presented complications during the trial ( 4 in the PSV manual group and 15 in the MRV automatic group , p < 0.05 ) . Nine patients in the automatic group did not adapt to the MRV mode . The mean ± sd ( st and ard deviation ) duration of the weaning process was 221 ± 192 for the manual group , and 271 ± 369 minutes for the automatic group ( p = 0.375 ) . PSV levels were significantly higher in MRV compared with that of the PSV manual reduction ( p < 0.05 ) . Reintubation was not required in either group . Non-invasive ventilation was necessary for two patients , in the manual group after cardiac surgery ( p = 0.51 ) . Conclusions The duration of the automatic reduction of pressure support was similar to the manual one in the post-operative period in the ICU , but presented more complications , especially no adaptation to the MRV algorithm . Trial Registration Trial registration number : IS RCT Purpose Duration of weaning from mechanical ventilation  is decreased with the use of written protocol s in adults . In children , the use of written protocol s has not had such an impact . Methods and measurements We conducted a single-center trial to assess the feasibility of conducting a multicenter r and omized clinical trial comparing the duration of weaning from mechanical ventilation  in those managed by a computer-driven explicit protocol versus usual care .  Mechanically ventilated children aged between 2 and 17 years on pressure support and not receiving inotropes were included . After r and omization , children were weaned either by usual care ( n = 15 ) that was characterized by no protocol ized decisions by attending physicians , or by a computer-driven protocol ( Smartcare/PS ™ , Drager Medical ) ( n = 15 ) . Weaning duration until first extubation was the primary outcome . For comparison , a Mann – Whitney U test was employed ( p < 0.05 ) . Results Patients characteristics at inclusion were similar . The median duration of weaning was 21 h ( range 3–142 h ) in the SmartCare/PS ™ group and 90 h ( range 4–552 h ) in the usual care group , p = 0.007 . The rate of reintubation within 48 h after extubation and the rate of noninvasive ventilation after extubation in the SmartCare/PS ™ and usual care groups were 2/15 versus 1/15 and 2/15 versus 2/15 , respectively . Conclusions A pediatric r and omized trial on mechanical ventilation with a computerized protocol in North America is feasible . A computer-driven protocol that also manages children younger than 2 years old would help to decrease the number of PICU admissions screened in a multicentre trial on this topic Adaptive support ventilation ( ASV ) provides an automatic adaptation of the ventilator setting s to patient ’s passive and active respiratory mechanics . In a r and omized controlled study , we evaluated automatic respiratory weaning in ASV for early tracheal extubation after cardiac surgery . Eligible patients were assigned to either an ASV protocol or a st and ard one consisting of synchronized intermittent ventilation followed by pressure support .  Eighteen patients completed the ASV protocol , and 16 completed the st and ard one . There were no differences between groups in perioperative characteristics , lengths of tracheal intubation and intensive care unit stay , and ventilatory variables , except less peak inspiratory pressure during the initial phase in ASV ( 17.5 ± 0.8 versus 22.2 ± 0.8 cm H2O ; P < 0.01 ) . ASV patients required fewer ventilatory setting s manipulations ( 2.4 ± 0.7 versus 4.0 ± 0.8 manipulations per patient ; P < 0.05 ) and endured less high-inspiratory pressure alarms ( 0.7 ± 2.4 versus 2.9 ± 3.0 ; P < 0.05 ) . These results suggest that in this specific population of patients , automation of postoperative ventilation with ASV result ed in an outcome similar to the control group . The internal logic of the new device result ed in less manipulation of the setting and alarms that could simplify respiratory management Objective : To compare two ventilator setting s in the postoperative weaning period . Patient-triggered automatic switching between controlled ventilation and supported spontaneous breathing ( Automode , AM ) was compared to synchronised intermittent m and atory ventilation ( SIMV ) with stepwise manual adjustment of m and atory frequency according to the breathing activity . Design : Prospect i ve clinical investigation . Setting : Eighteen-bed intensive care unit in a university hospital . Patients : Forty postoperative patients with healthy lungs who had undergone brain tumour surgery . Interventions : R and omisation either to the AM or SIMV weaning procedure after entering the ICU . Measurements and results : Total weaning time and number of manipulations on the ventilator were observed . Cardiocirculatory and respiratory parameters were measured consecutively at five points during the weaning period . No significant differences were seen for cardiocirculatory parameters , airway pressures and oxygenation between the two groups . There was a trend to shorter weaning times  with AM ( 136±46 min vs 169±68 min , n.s . ) , the average number of manipulations on the ventilator was lower ( 0.55±0.69 vs 5.05±1.19 , p<0.001 ) and arterial partial pressure of carbon dioxide ( PaCO2 ) levels showed fewer variations in the late phase of the weaning period ( 39.5±3.1 vs 38.3±7.2 , p<0.001 for differences in variance ) . Conclusions : Automatic , patient-triggered switching between controlled and supported mode of ventilation can be used for postoperative weaning of neurosurgical patients with healthy lungs . Compared to a SIMV weaning procedure , fewer manipulations on the ventilator are necessary and individual adaptation of ventilation seems to be more accurate Objective To describe the daily practice of mechanical ventilation ( MV ) , and secondarily , its outcome in pediatric intensive care units ( PICUs ) . Design Prospect i ve cohort of infants and children who received MV for at least 12 h. Setting Thirty-six medical surgical PICUs . Patients All consecutive patients admitted to the PICUs during 2-month period . Measurements and main results Of the 1893 patients admitted , 659 ( 35 % ) received MV for a median time of 4 days ( 25th percentile , 75 % : 2 , 6 ) . Median of age was 13 months ( 25th percentile , 75 % : 5 , 48 ) . Common indications for MV were acute respiratory failure ( ARF ) in 72 % of the patients , altered mental status in 14 % of the patients , and ARF on chronic pulmonary disease in 10 % of the patients . Median length of stay in the PICUs was 8 days ( 25th percentile , 75 % : 5 , 13 ) . Overall mortality rate in the PICUs was 15 % ( confidence interval 95 % : 13–18 ) for the entire population , 50 % ( 95 % CI : 25–74 ) in patients who received MV because of acute respiratory distress syndrome , 24 % ( 95 % CI : 16–35 ) in patients who received MV for altered mental status and 16 % ( 95 % CI : 9–29 ) in patients who received MV for ARF on chronic pulmonary disease . Conclusion One in every 3 patients admitted to the PICUs requires ventilatory support .. The ARF was the most common reason for MV , and survival of unselected infants and children receiving MV for more than 12 h was 85 % We examined the effect of ventilation strategy on lung inflammatory mediators in the presence and absence of a preexisting inflammatory stimulus . 55 Sprague-Dawley rats were r and omized to either intravenous saline or lipopolysaccharide ( LPS ) . After 50 min of spontaneous respiration , the lungs were excised and r and omized to 2 h of ventilation with one of four strategies : ( a ) control ( C ) , tidal volume ( Vt ) = 7 cc/kg , positive end expiratory pressure ( PEEP ) = 3 cm H2O ; ( b ) moderate volume , high PEEP ( MVHP ) , Vt = 15 cc/kg ; PEEP = 10 cm H2O ; ( c ) moderate volume , zero PEEP ( MVZP ) , Vt = 15 cc/kg , PEEP = 0 ; or ( d ) high volume , zero PEEP ( HVZP ) , Vt = 40 cc/kg , PEEP = 0 . Ventilation with zero PEEP ( MVZP , HVZP ) result ed in significant reductions in lung compliance . Lung lavage levels of TNFalpha , IL-1beta , IL-6 , IL-10 , MIP-2 , and IFNgamma were measured by ELISA . Zero PEEP in combination with high volume ventilation ( HVZP ) had a synergistic effect on cytokine levels ( e.g. , 56-fold increase of TNFalpha versus controls ) . Identical end inspiratory lung distention with PEEP ( MVHP ) result ed in only a three-fold increase in TNFalpha , whereas MVZP produced a six-fold increase in lavage TNFalpha . Northern blot analysis revealed a similar pattern ( C , MVHP < MVZP < HVZP ) for induction of c-fos mRNA . These data support the concept that mechanical ventilation can have a significant influence on the inflammatory/anti-inflammatory milieu of the lung , and thus may play a role in initiating or propagating a local , and possibly systemic inflammatory response RATIONALE AND OBJECTIVES Duration of weaning from mechanical ventilation  may be reduced by the use of a systematic approach . We assessed whether a closed-loop knowledge-based algorithm introduced in a ventilator to act as a computer-driven weaning protocol can improve patient outcomes as compared with usual care . METHODS AND MEASUREMENTS We conducted a multicenter r and omized controlled study with concealed allocation to compare usual care for weaning with computer-driven weaning . The computerized protocol included an automatic gradual reduction in pressure support , automatic performance of spontaneous breathing trials ( SBT ) , and generation of an incentive message when an SBT was successfully passed . One hundred forty-four patients were enrolled before weaning initiation . They were r and omly allocated to computer-driven weaning or to physician-controlled weaning according to local guidelines . Weaning duration until successful extubation and total duration of ventilation were the primary endpoints . MAIN RESULTS Weaning duration was reduced in the computer-driven group from a median of 5 to 3 d ( p=0.01 ) and total duration of mechanical ventilation from 12 to 7.5 d ( p=0.003 ) . Reintubation rate did not differ ( 23 vs. 16 % , p=0.40 ) . Computer-driven weaning also decreased median intensive care unit ( ICU ) stay duration from 15.5 to 12 d ( p=0.02 ) and caused no adverse events . The amount of sedation did not differ between groups . In the usual care group , compliance to recommended modes and to SBT was estimated , respectively , at 96 and 51 % . CONCLUSIONS The specific computer-driven system used in this study can reduce mechanical ventilation duration and ICU length of stay , as compared with a physician-controlled weaning process Adaptive support ventilation ( ASV ) is a closed-loop ventilation mode that can act both as pressure support ventilation ( PSV ) and pressure-controlled ventilation . Weaning with ASV shows promising results , mainly in post-cardiac surgery patients . The aim of the present r and omised controlled study was to test the hypothesis that weaning with ASV could reduce the weaning duration in patients with chronic obstructive pulmonary disease ( COPD ) when compared with PSV . From among 435 COPD patients admitted to the intensive care unit ( ICU ) during a 20-month period , 97 were enrolled . Patients were assigned at r and om to either ASV or PSV as a weaning mode . Compared with PSV , ASV provided shorter weaning times ( median 24 ( interquartile range 20–62 ) h versus 72 ( 24–144 ) h , p=0.041 ) with similar weaning success rates ( 35 out of 49 for ASV and 33 out of 48 for PSV ) . Length of stay in the ICU was also shorter with ASV but the difference was not statistically significant . This study suggests that ASV may be used in the weaning of COPD patients with the advantage of shorter weaning times . Further studies are needed to investigate the role and potential advantages of ASV in the weaning period of different patient groups OBJECTIVE The Siemens servo 300 A ventilator has an automode function that allows automated weaning of patients from mechanical ventilation . Spontaneous breathing triggers the ventilator . After two spontaneously triggered breaths , the ventilator automatically changes from m and atory mechanical ventilation to spontaneous ventilation . If spontaneous breathing or triggering does not occur , the Siemens servo 300 A ventilator changes from spontaneous ventilation back to m and atory mechanical ventilation . We compared the effects of automated versus conventional protocol -driven weaning on the time until extubation in patients undergoing coronary artery bypass graft ( CABG ) surgery . In addition , we studied the effects of the mode of weaning on hemodynamic and physiologic parameters . METHODS Twenty consecutive male patients without respiratory disease scheduled for CABG at the University Hospital of Regensburg were entered into the study . Patients were r and omized to postoperative ventilation with the Siemens 300 A/automode ventilator ( group A , n = 10 ) or with the Siemens 300 ventilator ( group B , n = 10 ) . All patients were weaned from ventilation according to a st and ardized protocol . RESULTS On average , patients in group A were younger and had lower pulmonary artery pressure ( PAP ) and higher cardiac output compared to patients in group B. However , patients in group A had longer ischemic and bypass times compared to patients in group B. Postoperative use of analgesia and sedation were similar in both groups . Time from tracheal intubation until extubation was 2 h shorter in patients assigned to automode ventilation compared to patients assigned to conventional ventilation ( mean time group A 7.9 h , group B 10.0 h ; p = 0.069 ) . Peak airway pressure was reduced by 2 cm H2O at the beginning of spontaneous ventilation in group A compared to group B. After extubation , cardiac index showed a greater increase in patients assigned to group A compared to those in group B. CONCLUSIONS Automode ventilator weaning trended toward more rapid extubation than did conventional protocol -driven ventilation in conjunction with a st and ardized weaning protocol . Physiologic and hemodynamic factors were better in patients using automode ventilation compared to patients using conventional ventilation . Automode ventilation was well tolerated and did not induce significant adverse effects OBJECTIVE To determine the correlation of acute physiology and chronic health evaluation ( APACHE ) II score and various weaning indexes ( WIs ) with 3- and 7-day weaning outcomes . DESIGN Prospect i ve , observational . SETTING The medical ICU of a teaching , urban hospital . METHODS The study included 118 adults referred for weaning from mechanical ventilation ( MV ) .  Critical care physicians , critical care nurses , and respiratory care practitioners were asked to predict whether it would take < or =3 days , 4 to 7 days , or > or = 8 days to wean each patient from MV . The WIs and APACHE II scores were measured or calculated . The causes of respiratory failure , the duration of MV before initiating weaning assessment , and the 3- and 7-day weaning outcomes were obtained . Significance was set at p<0.05 . RESULTS The most common causes of respiratory failure were pneumonia ( 38 cases ) and acute exacerbation of COPD ( 29 cases ) . Fifty-seven patients ( 48 % ) were successfully weaned from MV within 3 days of weaning assessment , and 67 ( 57 % ) were weaned within 7 days . The percentages of correct prediction of 3-day weaning outcome by critical care physicians , critical care nurses , and respiratory care practitioners were 64 % , 62 % , and 59 % , respectively ; for 7-day weaning outcome , 60 % , 64 % , and 58 % , respectively . The successfully weaned groups had significantly lower APACHE II scores and higher maximal inspiratory pressures than the unsuccessfully weaned ( failure ) groups . There were no significant differences between the two groups for the remaining indexes , including rapid shallow breathing , dynamic compliance , static compliance , spontaneous respiratory rate , and the ratio of PaO2 to the fraction of inspired oxygen . CONCLUSIONS The overall severity of illness as assessed by APACHE II score correlates better with 3- and 7-day weaning outcome than the published WIs This study evaluates m and atory minute volume ( MMV ) weaning in patients with pulmonary pathology . When weaning criteria were fulfilled , 22 patients were r and omised to MMV and 18 to a control intermittent m and atory ventilation ( IMV ) group . With IMV weaning the ventilator rate was decreased by two breaths per minute at 3 - 4 hourly intervals during daylight hours . In the MMV group a target of 75 % of the ventilator minute volume was set . All weans were considered complete four hours after the cessation of mechanical support , and were deemed successful if no further ventilation was required . The success rate was 86 % in the IMV and 89 % in the MMV group . MMV weaning was rapid ( 4.75 + 1.5 hrs ) and proved less dem and ing on the ICU staff by providing a safe trial of spontaneous respiration , while retaining the facility for partial ventilation Using a one-day prospect i ve point prevalence design , this study aim ed to characterise the current practice of mechanical ventilation and weaning in Australian and New Zeal and intensive care units . During 2005 , a bi-national one-day survey of 55 intensive care units found the point-prevalence of mechanical ventilation to be 284/491(58 % ) . Common modes used were synchronised intermittent m and atory ventilation with pressure support , pressure support ventilation ( each 116/284 , 41 % ) and pressure-control modes ( 48/284 , 17 % ) . Relative to volume-control modes , pressure-control was more frequently used for patients with respiratory disease ( odds ratio 4.7 , 95 % confidence interval 2.4 to 9.2 , P < 0.001 ) or greater severity of illness ( odds ratio 1.7 , 95 % confidence interval 1.1 to 2.6 , P=0.01 , per five-point increment in the maximum sequential organ failure score ) . Excluding cardiothoracic surgery patients , the Kaplan-Meier estimated median total ventilation duration was 1.9 days ( interquartile range 0.8 to 6.8 days ) . Apart from 24/255 ( 9.4 % ) patients who received only  pressure support ventilation  , weaning methods ( attempted in 255 patients , 29 prior deaths ) included : change to  pressure support ventilation ( 186/255 , 73 % ) , T-piece ( 31/255 , 12 % ) or other methods ( 14/255 , 5.5 % ) . The point prevalence of mechanical ventilation  was greater than comparable international studies . Australian and New Zeal and intensive care unit ventilatory practice s are similar , but differ substantially from published international survey results , due to a near absence of assist/control , prominent use of pressure-control modes and a preference for pressure support ventilation weaning as opposed to T-piece Methods for combining data from several studies exist and appear to be quite useful . None satisfactorily addresses the question of what studies should be combined . This issue is the most serious method ological limitation . Even studies with statistically significant interaction might still be combined if the effect were in the same direction . Thus , substantial scientific input is required as to what criteria must be met by each potential study . Much can be learned from combining or pooling data but it must be done cautiously . Pooling exercises do not replace well design ed prospect i ve clinical trials . Efforts for establishing basic design criteria to allow for multicentre and multicountry trials to be more easily combined might be useful . RATIONALE Despite its ability to reduce overall ventilation time , protocol -guided weaning from mechanical ventilation is not routinely used in daily clinical practice . Clinical implementation of weaning protocol s could be facilitated by integration of knowledge-based , closed-loop controlled protocol s into respirators . OBJECTIVES To determine whether automated weaning decreases overall ventilation time compared with weaning based on a st and ardized written protocol in an unselected surgical patient population . METHODS In this prospect i ve controlled trial patients ventilated for longer than 9 hours were r and omly allocated to receive either weaning with automatic control of pressure support ventilation ( automated-weaning group ) or weaning based on a st and ardized written protocol ( control group ) using the same ventilation mode . The primary end point of the study was overall ventilation time . MEASUREMENTS AND MAIN RESULTS Overall ventilation time ( median [ 25th and 75th percentile ] ) did not significantly differ between the automated-weaning ( 31 [ 19 - 101 ] h ; n = 150 ) and control groups ( 39 [ 20 - 118 ] h ; n = 150 ; P = 0.178 ) . Patients who underwent cardiac surgery ( n = 132 ) exhibited significantly shorter overall ventilation times in the automated-weaning ( 24 [ 18 - 57 ] h ) than in the control group ( 35 [ 20 - 93 ] h ; P = 0.035 ) . The automated-weaning group exhibited shorter ventilation times until the first spontaneous breathing trial ( 1 [ 0 - 15 ] vs. 9 [ 1 - 51 ] h ; P = 0.001 ) and a trend toward fewer tracheostomies ( 17 vs. 28 ; P = 0.075 ) . CONCLUSIONS Overall ventilation times did not significantly differ between weaning using automatic control of pressure support ventilation and weaning based on a st and ardized written protocol . Patients after cardiac surgery may benefit from automated weaning . Implementation of additional control variables besides the level of pressure support may further improve automated-weaning systems . Clinical trial registered with www . clinical trials.gov ( NCT 00445289 ) Objective : To test the hypothesis that duration of delirium in the intensive care unit is an independent predictor of long-term cognitive impairment  after critical illness requiring mechanical ventilation . Design : Prospect i ve cohort study . Setting : Medical intensive care unit in a large community hospital in the United States . Patients : Mechanically ventilated medical intensive care unit patients who were assessed daily for delirium while in the intensive care unit and who underwent comprehensive cognitive assessment s 3 and 12 mos after discharge . Measurements and Main Results : Of 126 eligible patients , 99 survived ≥3 months after critical illness ; long-term cognitive outcomes were obtained for 77 ( 78 % ) patients . Median age was 61 yrs , 51 % were admitted with sepsis/acute respiratory distress syndrome , and median duration of delirium was 2 days . At 3-mo and 12-mo follow-up , 79 % and 71 % of survivors had cognitive impairment , respectively ( with 62 % and 36 % being severely impaired ) . After adjusting for age , education , preexisting cognitive function , severity of illness , severe sepsis , and exposure to sedative medications in the intensive care unit , increasing duration of delirium was an independent predictor of worse cognitive performance — determined by averaging age-adjusted and education-adjusted T-scores from nine tests measuring seven domains of cognition — at 3-mo ( p = .02 ) and 12-mo follow-up ( p = .03 ) . Duration of mechanical ventilation , alternatively , was not associated with long-term cognitive impairment ( p = .20 and .58 ) . Conclusions : In this study of mechanically ventilated medical intensive care unit patients , duration of delirium ( which is potentially modifiable ) was independently associated with long-term cognitive impairment , a common public health problem among intensive care unit survivors . ( Crit Care Med 2010 ; The purpose of this study was to determine if a computer-directed weaning system could wean patients with complex medical problems from mechanical ventilation and appropriately respond to signs of respiratory failure more effectively than traditional physician-directed weaning methods . In a prospect i ve , r and omized , controlled study , we tested the system in 15 patients who had required prolonged mechanical ventilation and met predetermined weaning tests . Patients were r and omly assigned to one of two groups : ( 1 ) automatic , computer-directed weaning or ( 2 ) physician-controlled weaning . The computer-directed system decreased or increased the synchronized intermittent m and atory ventilation rate and pressure support ( PS ) based on predetermined limits of patient respiratory rate ( RR ) and tidal volume ( TV ) . Pulse oximeter oxygen saturation was monitored , and alarms were triggered by an oxygen saturation of < 90 percent . In the physician control group , weaning progressed with SIMV rate and PS reduction , as judged appropriate by the physician . Nine patients were assigned to the computer group ; six patients were assigned to the control group . The average patient age was 64.8 + /- 14.9 years for the computer group , 65.2 + /- 22.7 years for the control group . The average time on mechanical ventilation prior to weaning was 13.4 + /- 7.8 days for the computer group and 14.5 + /- 11.1 days for the control group . Seven of the nine computer group patients weaned within 48 h of the study , with an average time to wean of 18.7 + /- 5.9 h. All seven were breathing spontaneously 48 h after weaning . Two of the six control group patients weaned within 48 h of the study , with an average time of 25.6 + /- 5.6 h. Both patients who weaned were placed back on mechanical ventilation within 30 h. The number of arterial blood gas sample s drawn during the study was 1.4 + /- 0.7 for the computer group , 7.2 + /- 4.3 for the control group . The number of minutes per hour outside acceptable limits of RR > 30 , RR < 8 , or TV < 5 ml/kg was 3.2 + /- 2.8 min for the computer group and 6.6 + /- 4.1 min for the control group . The study suggests that use of the computer-directed weaning system results in fewer arterial blood gas sample s , shorter weaning times , and less time spent outside acceptable RR and TV parameters Abstract . Study objective : To determine the relationship between delirium in the intensive care unit ( ICU ) and outcomes including length of stay in the hospital . Design : A prospect i ve cohort study . Setting : The adult medical ICU of a tertiary care , university-based medical center . Participants : The study population consisted of 48 patients admitted to the ICU , 24 of whom received mechanical ventilation .  Measurements : All patients were evaluated for the development and persistence of delirium on a daily basis by a geriatric or psychiatric specialist with expertise in delirium assessment using the Diagnostic Statistical Manual IV ( DSM-IV ) criteria of the American Psychiatric Association , the reference st and ard for delirium ratings . Primary outcomes measured were length of stay in the ICU and hospital . Results : The mean onset of delirium was 2.6 days ( S.D.±1.7 ) , and the mean duration was 3.4±1.9 days . Of the 48 patients , 39 ( 81.3 % ) developed delirium , and of these 29 ( 60.4 % ) developed the complication while still in the ICU . The duration of delirium was associated with length of stay in the ICU ( r=0.65 , P=0.0001 ) and in the hospital ( r=0.68 , P<0.0001 ) . Using multivariate analysis , delirium was the strongest predictor of length of stay in the hospital ( P=0.006 ) even after adjusting for severity of illness , age , gender , race , and days of benzodiazepine and narcotic drug administration . Conclusions : In this patient cohort , the majority of patients developed delirium in the ICU , and delirium was the strongest independent determinant of length of stay in the hospital . Further study and monitoring of delirium in the ICU and the risk factors for its development are warranted Purpose Patients who require mechanical ventilation  are at risk of emotional stress because of total dependence on a machine for breathing . The stress may negatively impact ventilator weaning and survival . The purpose of this study was to determine whether depressive disorders in patients being weaned from prolonged mechanical ventilation  are linked to weaning failure and decreased survival . Methods A prospect i ve study of 478 consecutive patients transferred to a long-term acute care hospital for weaning from prolonged ventilation  was undertaken . A clinical psychologist conducted a psychiatric interview to assess for the presence of depressive disorders . Results Of the 478 patients , 142 had persistent coma or delirium and were unable to be evaluated for depressive disorders . Of the remaining 336 patients , 142 ( 42 % ) were diagnosed with depressive disorders . In multivariate analysis , co-morbidity score [ odds ratio ( OR ) , 1.23 ; P = 0.007 ] , functional dependence before the acute illness ( OR , 1.70 , P = 0.03 ) and history of psychiatric disorders ( OR , 3.04 , P = 0.0001 ) were independent predictors of depressive disorders . The rate of weaning failure was higher in patients with depressive disorders than in those without such disorders ( 61 vs. 33 % , P = 0.0001 ) , as was mortality ( 24 vs. 10 % , P = 0.0008 ) . The presence of depressive disorders was independently associated with mortality ( OR , 4.3 ; P = 0.0002 ) ; age ( OR , 1.06 ; P = 0.001 ) and co-morbidity score ( OR , 1.24 ; P = 0.02 ) also predicted mortality . Conclusion Depressive disorders were diagnosed in 42 % of patients who were being weaned from prolonged ventilation . Patients with depressive disorders were more likely to experience weaning failure and death OBJECTIVE To compare a practice of protocol -directed weaning from mechanical ventilation implemented by nurses and respiratory therapists with traditional physician-directed weaning . DESIGN R and omized , controlled trial . SETTING Medical and surgical intensive care units in two university-affiliated teaching hospitals . PATIENTS Patients requiring mechanical ventilation ( n = 357 ) . INTERVENTIONS Patients were r and omly assigned to receive either protocol -directed ( n = 179 ) or physician-directed ( n = 178 ) weaning from mechanical ventilation . MEASUREMENTS AND MAIN RESULTS The primary outcome measure was the duration of mechanical ventilation from tracheal intubation until discontinuation of mechanical ventilation . Other outcome measures included need for reintubation , length of hospital stay , hospital mortality rate , and hospital costs . The median duration of mechanical ventilation was 35 hrs for the protocol -directed group ( first quartile 15 hrs ; third quartile 114 hrs ) compared with 44 hrs for the physician-directed group ( first quartile 21 hrs ; third quartile 209 hrs ) . Kaplan-Meier analysis demonstrated that patients r and omized to protocol -directed weaning had significantly shorter duration s of mechanical ventilation compared with patients r and omized to physician-directed weaning ( chi 2 = 3.62 , p = .057 , log-rank test ; chi 2 = 5.12 , p = .024 , Wilcoxon test ) . Cox proportional-hazards regression analysis , adjusting for other covariates , showed that the rate of successful weaning was significantly greater for patients receiving protocol -directed weaning compared with patients receiving physician-directed weaning ( risk ratio 1.31 ; 95 % confidence interval 1.15 to 1.50 ; p = .039 ) . The hospital mortality rates for the two treatment groups were similar ( protocol -directed 22.3 % vs. physician-directed 23.6 % ; p = .779 ) . Hospital cost savings for patients in the protocol -directed group were $ 42,960 compared with hospital costs for patients in the physician-directed group . CONCLUSION Protocol -guided weaning of mechanical ventilation , as performed by nurses and respiratory therapists , is safe and led to extubation more rapidly than physician-directed weaning Background Weaning difficulties occur in 31 % of total intubated patients , and result in prolonged weaning duration . A computer‐driven automated weaning system can perform a spontaneous breathing trial ( SBT ) automatically and display a message when the trial is successfully passed . Such a system might have a beneficial effect on difficult‐to‐wean patients . The aim of this study was to examine whether the computer‐driven automated weaning system can accelerate discontinuation of mechanical ventilation and improve outcomes in difficult‐to‐wean patients . Methods This r and omized controlled study included 39 difficult‐to‐wean patients who failed their first spontaneous breathing trial . Before initiating weaning , eligible patients were r and omly allocated to wean by computer‐driven automated weaning system ( CDW group , n=19 ) or a physician‐controlled local protocol ( PW group , n=20 ) . Weaning duration , defined as the time from inclusion until first extubation , was the primary endpoint . Secondary endpoints were total duration of mechanical ventilation , the length of intensive care unit ( ICU ) stay , the number of reintubations , the mortality rate in the ICU , the number of noninvasive ventilations , the number of complications in the ICU , and the number of ventilator‐associated pneumonia cases . Results The weaning duration was reduced with the computer‐driven weaning as compared with the usual protocol ( median 29.0 hours vs. 45.5 hours , P=0.044 ) . Total duration of mechanical ventilation and duration of the ICU stay did not differ between the CDW and PW groups . There was no difference in the number of reintubations between the CDW and PW groups ( 3 and 4 patients , P=0.732 ) . The study groups showed comparable numbers of tracheostomy , selfextubations , ventilator‐associated pneumonia , and non‐invasive ventilation . Mortality in the ICU was similar in the CDW and the PW groups ( 21.1 % vs. 20.0 % , P=0.935 ) . Conclusion The computer‐driven automated weaning system can reduce weaning duration in difficult‐to‐wean patients as compared with a physician‐controlled weaning protocol Objective To determine the incidence and severity of symptoms related to the diagnosis of post-traumatic stress disorder ( PTSD ) in a cohort of general ICU patients . Design A prospect i ve cohort study 3 months after general ICU discharge . Setting A general ICU in a teaching hospital in northern Scotl and . Patients and participants Seventy-eight ICU survivors of general ICU . Interventions Patients were contacted 3 months after ICU discharge and asked to complete a telephone assessment of the Davidson Trauma Scale .  Measurements and results The median score was 8 , with 22 % recording a score of at least 27 and 14 % meeting the full diagnostic criteria for PTSD . The overall score was not correlated with sex , ICU length of stay , or APACHE II score but was inversely correlated with age and directly correlated with length of mechanical ventilation . The overall score was also related to the patient reporting having visited a GP or a mental health professional for psychological distress previous to ICU . Conclusions We found a high incidence of symptoms consistent with PTSD 3 months after ICU discharge in this general ICU cohort . This was associated with younger patients and those who visited their GP or a mental health professional complaining of psychological symptoms . Further research and a greater liaison between ICU staff and family practitioners and mental health practitioners is required to better identify individuals at risk and reduce psychological morbidity in this group Purpose Discrepancies between the dem and and availability of clinicians to care for mechanically ventilated patients can be anticipated due to an aging population and to increasing severity of illness . The use of closed-loop ventilation provides a potential solution . The aim of the study was to evaluate the safety of a fully automated ventilator . Methods We conducted a r and omized controlled trial comparing automated ventilation ( AV ) and protocol ized ventilation ( PV ) in 60 ICU patients after cardiac surgery . In the PV group , tidal volume , respiratory rate , FiO2 and positive end-expiratory pressure ( PEEP ) were set according to the local hospital protocol based on currently available guidelines . In the AV group , only sex , patient height and a maximum PEEP level of 10 cmH2O were set . The primary endpoint was the duration of ventilation within a “ not acceptable ” range of tidal volume . Zones of optimal , acceptable and not acceptable ventilation were based on several respiratory parameters and defined a priori . Results The patients were assigned equally to each group , 30 to PV and 30 to AV . The percentage of time within the predefined zones of optimal , acceptable and not acceptable ventilation were 12 % , 81 % , and 7 % respectively with PV , and 89.5 % , 10 % and 0.5 % with AV ( P < 0.001 ) . There were 148 interventions required during PV compared to only 5 interventions with AV ( P < 0.001 ) . Conclusion Fully AV was safe in hemodynamically stable patients immediately following cardiac surgery . In addition to a reduction in the number of interventions , the AV system maintained patients within a predefined target range of optimal ventilation Background : Adaptive support ventilation ( ASV ) is a microprocessor-controlled mode of mechanical ventilation that switches automatically from controlled ventilation to assisted ventilation and selects ventilatory setting s according to measured lung mechanics . Methods : In a r and omized controlled trial , non – fast-track coronary artery bypass grafting patients ' lungs were ventilated with ASV or pressure-controlled/pressure-support ventilation ( control ) to compare time until tracheal extubation , duration of controlled ventilation versus assisted ventilation , and ventilation characteristics . Results : One hundred twenty-eight consecutive patients were r and omized . ASV patients had their tracheas extubated after median 16.4 and interquartile range 12.5–20.8 hr , and control patients after 16.3 ( 13.7–19.3 ) hr , respectively ( P = 0.97 ) . The percentage of time patients were on assisted ventilation ( expressed as the median percentage of total duration of ventilation ) was 43 % ( 28%–67 % ) in the ASV group and 52 % ( 33%–75 % ) in the control group ( P < 0.05 ) . However , the number of switches from controlled to assisted ventilation was higher in the ASV group ( 43.0 [ 14.0–74.0 ] ) than in the control group ( 4.0 [ 2.0–9.0 ] ) ( P < 0.001 ) . In ASV patients , mean tidal volumes were significantly larger during controlled ventilation than in control patients ( 8.6 ± 0.8 mL/kg predicted body weight vs 7.1 ± 1.4 mL/kg predicted body weight ; P = 0.05 ) , and no differences in tidal volumes were found during assisted ventilation . Conclusion : Weaning automation with ASV is feasible and safe in non – fast-track coronary artery bypass grafting patients .  Time until tracheal extubation with ASV equals time until tracheal extubation with st and ard weaning and allows for frequent ( automatic ) switches between controlled and assisted ventilation Background Adaptive support ventilation ( ASV ) is a microprocessor-controlled mode of mechanical ventilation that maintains a predefined minute ventilation with an optimal breathing pattern ( tidal volume and rate ) by automatically adapting inspiratory pressure and ventilator rate to changes in the patient ’s condition . The aim of the current study was to test the hypothesis that a protocol of respiratory weaning based on ASV could reduce the duration of tracheal intubation after uncomplicated cardiac surgery ( “ fast-track ” surgery ) . Methods A group of patients being given ASV ( group ASV ) was compared with a control group ( group control ) in a r and omized controlled study . After coronary artery bypass grafting during general anesthesia with midazolam and fentanyl  , patients were r and omly assigned to group ASV or group control . Both protocol s were divided into three predefined phases , and weaning progressed according to arterial blood gas and clinical criteria . In phase 1 , ASV mode was set at 100 % of the theoretical value of volume/minute in group ASV , and synchronized intermittent m and atory ventilation mode was used in group control . When spontaneous breathing occurred , ASV setting was reduced by 50 % of minute ventilation ( phase 2 ) and again by 50 % ( phase 3 ) , and the trachea was extubated . In group control , the ventilator was switched to 10 cm H2O inspiratory pressure support ( phase 2 ) , then to 5 cm H2O ( phase 3 ) until extubation . Results Forty-nine patients were enrolled . Sixteen patients completed the ASV protocol , and 20 the st and ard protocol ; 7 patients were excluded in group ASV and 6 in group control according to explicit , predefined criteria . There were no differences between groups in perioperative characteristics or in the doses of sedation . The primary outcome of the study , that is , the duration of tracheal intubation , was shorter in group ASV than in group control ( median [ quartiles ] : 3.2 [2.5–4.6]vs . 4.1 [ 3.1–8.6 ] h;P < 0.02 ) . Fewer arterial blood analyses were performed in group ASV ( median number [ quartiles ] : 3 [3–4]vs . 4 [ 3–6 ] ) , suggesting that fewer changes in the setting s of the ventilator were required in this group . Conclusions A respiratory weaning protocol based on ASV is practicable ; it may accelerate tracheal extubation and simplify ventilatory management in fast-track patients after cardiac surgery . The evaluation of potential advantages of the use of such technology on patient outcome and re source utilization deserves further studies We hypothesized that variation in extubating brain injured patients would affect the incidence of nosocomial pneumonia , length of stay , and hospital charges . In a prospect i ve cohort of consecutive , intubated brain-injured patients , we evaluated daily : intubation status , spontaneous ventilatory parameters , gas exchange , neurologic status , and specific outcomes listed above . Of 136 patients , 99 ( 73 % ) were extubated within 48 h of meeting defined readiness criteria . The other 37 patients ( 27 % ) remained intubated for a median 3 d ( range , 2 to 19 ) . Patients with delayed extubation developed more pneumonias ( 38 versus 21 % , p < 0.05 ) and had longer intensive care unit ( median , 8.6 versus 3.8 d ; p < 0.001 ) and hospital ( median , 19.9 versus 13.2 d ; p = 0.009 ) stays . Practice variation existed after stratifying for differences in Glasgow Coma Scale scores ( 10 versus 7 , p < 0.001 ) at time of meeting readiness criteria , particularly for comatose patients . There was a similar reintubation rate . Median hospital charges were $ 29,057.00 higher for extubation delay patients ( p < 0.001 ) . This study does not support delaying extubating patients when impaired neurologic status is the only concern prolonging intubation . A r and omized trial of extubation at the time brain-injured patients fulfill st and ard weaning criteria is justifiable Objective To examine prospect ively the relationship between memories of intensive care ( ICU ) and levels of anxiety after ICU discharge , the stability of these memories with time , and their relationship to the development of acute posttraumatic stress disorder (PTSD)-related symptoms . Design Case series cohort assessed by interview at 2 and 8 wks after ICU discharge . Setting District general hospital ( serving a population of 350,000 ) general intensive care unit . Patients  Memories of ICU and anxiety levels  were studied in 45 patients after ICU discharge . Thirty patients were examined again at 8 wks to assess memory stability and development of acute PTSD-related symptoms . Measurements and Main Results St and ardized interviews and question naires were used to assess memory for ICU , anxiety , and depression 2 wks after ICU discharge . In addition , PTSD-related symptoms and panic were assessed 8 wks after ICU discharge . A total of 33 of 45 patients had delusional memories from ICU at 2 wks ; nine of the patients with delusional memories had no factual memories , and these patients had higher anxiety levels 2 wks after ICU discharge ( p < .0001 ) . Thirty patients had paired assessment s at 2 and 8 wks . Those patients who had no factual recall of ICU but had delusional memories at 2 wks scored highly for PTSD-related symptoms and panic attacks at 8 wks ( p = .023 and .014 , respectively ) . The only predictors of possible acute PTSD-related symptoms at the 8-wk assessment were trait anxiety ( p = .006 ) and having delusional memories without recall of factual events in the ICU at 2 wks ( p < .0001 ) . Only delusional memories were retained over time , whereas the recall of factual events in the ICU declined . Conclusions We propose that the development of acute PTSD-related symptoms may be related more to recall of delusions alone . This study suggests that even relatively unpleasant memories for real events during critical illness may give some protection from anxiety and the later development of PTSD-related symptoms when memories of delusions are prominent Objective Preliminary assessment of an automated weaning system ( SmartCare ™ /PS ) compared to usual management of weaning from mechanical ventilation performed in the absence of formal protocol s. Design and setting A r and omised , controlled pilot study in one Australian intensive care unit . Patients A total of 102 patients were equally divided between SmartCare/PS and Control . Interventions The automated system titrated pressure support , conducted a spontaneous breathing trial and provided notification of success ( “ separation potential ” ) . Measurements and results The median time from the first identified point of suitability for weaning commencement to the state of “ separation potential ” using SmartCare/PS was 20 h ( interquartile range , IQR , 2–40 ) compared to 8 h ( IQR 2–43 ) with Control ( log-rank P = 0.3 ) . The median time to successful extubation was 43 h ( IQR 6–169 ) using SmartCare/PS and 40 ( 14–87 ) with Control ( log-rank P = 0.6 ) . Unadjusted , the estimated probability of reaching “ separation potential ” was 21 % lower ( 95 % CI , 48 % lower to 20 % greater ) with SmartCare/PS compared to Control . Adjusted for other covariates ( age , gender , APACHE II , SOFAmax , neuromuscular blockade , corticosteroids , coma and elevated blood glucose ) , these estimates were 31 % lower ( 95 % CI , 56 % lower to 9 % greater ) with SmartCare/PS . The study groups showed comparable rates of reintubation , non-invasive ventilation post-extubation , tracheostomy , sedation , neuromuscular blockade and use of corticosteroids . Conclusions Substantial reductions in weaning duration previously demonstrated were not confirmed when the SmartCare/PS system was compared to weaning managed by experienced critical care specialty nurses , using a 1:1 nurse-to-patient ratio . The effect of SmartCare/PS may be influenced by the local clinical organisational context .Descriptor28 . Mechanical ventilation : weaning BACKGROUND AND OBJECTIVE Low tidal volume ventilation has been shown to improve survival in acute respiratory distress syndrome ( ARDS ) .  Adaptive support ventilation ( ASV ) , a closed-loop ventilatory mode , can minimize the work of breathing , and thus potentially improve the outcomes in ARDS . The aim of this pilot , r and omized clinical trial was to compare the outcomes of ASV versus volume-cycled ventilation ( VCV ) in ARDS . METHODS Patients with ARDS were r and omly allocated to either ASV or VCV . The primary outcomes were duration of mechanical ventilation , new-onset organ dysfunction and hospital length of stay . The secondary outcomes were ease of use of the ventilator mode ( assessed using the visual analogue scale ( VAS ) ) , number of daily arterial blood gas analyses , daily requirements of sedative and neuromuscular blockers , and mortality . RESULTS Forty-eight patients ( 28 males , 20 females ) with ARDS were r and omized to receive either ASV ( n = 23 ) or VCV ( n = 25 ) during the study period . The baseline characteristics were almost similar in the two groups . The duration of mechanical ventilation , delta sequential organ failure assessment scores , intensive care unit and hospital stay were comparable in the two groups . The mortality  ( VCV-36 % vs ASV-34.7 % ) , ease of use of mechanical ventilation , daily midazolam and vecuronium doses , and the number of arterial blood gas analyses performed were also similar in the two groups . CONCLUSIONS There was no significant difference in the outcomes of patients with ARDS ventilated with either VCV or ASV in this study Objective : To evaluate the applicability , tolerance , and efficacy of a closed-loop protocol to wean children from mechanical ventilation . Design : Prospect i ve single-center pilot study . Setting : Tertiary care university hospital . Patients : Twenty mechanically ventilated children aged between 1 and 17 yrs , with a body weight ≥10 kg , no inotropes , and no heavy sedation . Interventions : Patients were weaned in pressure support mode by a closed-loop computerized protocol ( closed-loop protocol ) that interprets clinical data in real time and controls pressure support levels . Measurements and Main Results : The closed-loop protocol applicability and tolerance were evaluated . The efficacy of this protocol was evaluated by comparing the duration of mechanical ventilation with a historical group of 20 patients weaned with a clinician-decision protocol . The closed-loop protocol successfully decreased pressure support ventilation in 16 children , recommended separation from the ventilator in 14 children , and did not cause any serious adverse events . Mechanical ventilation duration was 5.1 ± 4.2 days in the closed-loop group and 6.7 ± 11.5 days ( mean ± sd ) in the clinician-decision group ( p = .33 ) with no difference in the need for reintubation or noninvasive mechanical ventilation ( one of 20 and four of 20 , respectively ; p = .20 ) . Conclusions : A closed-loop protocol was successfully used to wean children from mechanical ventilation . Further studies are required to assess the impact of this novel therapeutic strategy on the length of mechanical ventilation OBJECTIVE To evaluate if the computer-driven weaning ( CDW ) with a closed-loop knowledge-based system introduced in a ventilator is superior to physician-directed weaning ( PDW ) in difficult-to-wean patients in the intensive care unit ( ICU ) . METHODS Sixty-two difficult-to-wean patients were r and omized into 2 groups : weaning with Smart Care/PS ( SC group , n = 32 ) or with synchronize intermittent m and atory ventilation add positive support ventilation ( SP group , n = 30 ) . In the SC group , the automated system titrated pressure support , conducted a spontaneous breathing trial and provided notification of success ( separation potential ) . In the SP group , weaning from ventilators was carried out by gradually decreasing respiratory support . The length of mechanical ventilation and stay in ICU , the rate of ventilator-associated pneumonia ( VAP ) , the retubing rate in 48 h , manual ventilator setting changes before extubation were compared between the 2 groups . RESULTS In the SC group , the weaning time was ( 49 + /- 13 ) h , ( 67 + /- 37 ) h , and ( 254 + /- 96 ) h , respectively in patients with neuromuscular diseases , for post-operative respiratory support and patients with respiratory diseases ; while in the SP group , the weaning time was ( 223 + /- 38 ) h , ( 106 + /- 34 ) h and ( 502 + /- 91 ) h , respectively ; the difference between the 2 groups being statistically significant ( chi(2 ) = 8.33 , 4.77 , 4.43 , all P < 0.05 ) . The time of stay in ICU was ( 9.0 + /- 1.7 ) d and ( 7.3 + /- 1.9 ) d in the SC group for patients with neuromuscular diseases and patients with post-operative respiratory support , respectively , while that was ( 20.8 + /- 5.1 ) d and ( 14.6 + /- 1.7 ) d in the SP group , respectively . Time of stay in ICU was significantly shorter in the SC group ( chi2 = 6.74 , 7.68 , both P < 0.05 ) . The number of manual ventilator setting changes was ( 5 + /- 1 ) times in the SC group , significantly less than that of the SP group ( 13 + /- 3 , t = 2.73 , P < 0.05 ) . There were no significant differences between the SC and the SP groups in the rate of re-intubation , the rate of tracheotomy , the incidence of pneumothorax , the incidence of VAP and the incidence of subcutaneous emphysema . CONCLUSION The CDW method used in patients with difficult weaning from ventilators was shown to shorten the weaning time , reduce stay in ICU , and decrease the need for manual adjustment of ventilators BACKGROUND Variability and logistic complexity of mechanical ventilatory support of acute respiratory distress syndrome , and need to st and ardize care among all clinicians and patients , led University of Utah/LDS Hospital physicians , nurses , and engineers to develop a comprehensive computerized protocol . This bedside decision support system was the basis of a multicenter clinical trial ( 1993 - 1998 ) that showed ability to export a computerized protocol to other sites and improved efficacy with computer- versus physician-directed ventilatory support . The Memorial Hermann Hospital Shock Trauma intensive care unit ( ICU ) ( Houston , TX ; a Level I trauma center and teaching affiliate of The University of Texas Houston Medical School ) served as one of the 10 trial sites and recruited two thirds of the trauma patients . Results from the trauma patient subgroup at this site are reported to answer three questions : Can a computerized protocol be successfully exported to a trauma ICU ? Was ventilator management different between study groups ? Was patient outcome affected ? METHODS Sixty-seven trauma patients were r and omized at the Memorial Hermann Shock Trauma ICU site . " Protocol " assigned patients had  ventilatory support directed by the bedside respiratory therapist using the computerized protocol . " Non protocol " patients were managed by physician orders . RESULTS Of the 67 trauma patients r and omized , 33 were protocol ( age 40 + /- 3 ; Injury Severity Score [ ISS ] 26 + /- 3 ; 73 % blunt ) and 34 were non protocol ( age 38 + /- 2 ; ISS 25 + /- 2 ; 76 % blunt ) . For the protocol group , the computerized protocol was used 96 % of the time of ventilatory support and 95 % of computer-generated instructions were followed by the bedside respiratory therapist . Outcome measures ( i.e. , survival , ICU length of stay , morbidity , and barotrauma ) were not significantly different between groups . Fio2 > or = 0.6 and Pplateau > or = 35 cm H2O exposures were less for the protocol group . CONCLUSION A computerized protocol for bedside decision support was successfully exported to a trauma center , and effectively st and ardized mechanical ventilatory support of trauma-induced acute respiratory distress syndrome without adverse effect on patient outcome CONTEXT The outcome of patients receiving mechanical ventilation for particular indications has been studied , but the outcome in a large number of unselected , heterogeneous patients has not been reported . OBJECTIVE To determine the survival of patients receiving mechanical ventilation  and the relative importance of factors influencing survival . DESIGN , SETTING , AND SUBJECTS Prospect i ve cohort of consecutive adult patients admitted to 361 intensive care units who received mechanical ventilation for more than 12 hours between March 1 , 1998 , and March 31 , 1998 . Data were collected on each patient at initiation of mechanical ventilation and daily throughout the course of mechanical ventilation for up to 28 days . MAIN OUTCOME MEASURE All-cause mortality during intensive care unit stay . RESULTS Of the 15 757 patients admitted , a total of 5183 ( 33 % ) received mechanical ventilation  for a mean ( SD ) duration of 5.9 ( 7.2 ) days . The mean ( SD ) length of stay in the intensive care unit was 11.2 ( 13.7 ) days . Overall mortality rate in the intensive care unit was 30.7 % ( 1590 patients ) for the entire population , 52 % ( 120 ) in patients who received ventilation because of acute respiratory distress syndrome , and 22 % ( 115 ) in patients who received ventilation for an exacerbation of chronic obstructive pulmonary disease . Survival of unselected patients receiving mechanical ventilation for more than 12 hours was 69 % . The main conditions independently associated with increased mortality were ( 1 ) factors present at the start of mechanical ventilation ( odds ratio [ OR ] , 2.98 ; 95 % confidence interval [ CI ] , 2.44 - 3.63 ; P<.001 for coma ) , ( 2 ) factors related to patient management ( OR , 3.67 ; 95 % CI , 2.02 - 6.66 ; P<.001 for plateau airway pressure > 35 cm H(2)O ) , and ( 3 ) developments occurring over the course of mechanical ventilation ( OR , 8.71 ; 95 % CI , 5.44 - 13.94 ; P<.001 for ratio of PaO(2 ) to fraction of inspired oxygen < 100 ) . CONCLUSION Survival among mechanically ventilated patients depends not only on the factors present at the start of mechanical ventilation , but also on the development of complications and patient management in the intensive care unit RATIONALE Automated weaning has not been compared with a paper-based weaning protocol in North America . OBJECTIVES We conducted a pilot r and omized trial comparing automated weaning with protocol ized weaning in critically ill adults to evaluate clinician compliance and acceptance of the weaning and sedation protocol s , recruitment , and impact on outcomes . METHODS From August 2007 to October 2009 , we enrolled critically ill adults requiring more than 24 hours of mechanical ventilation and at least partial reversal of the condition precipitating respiratory failure at nine Canadian intensive care units . We r and omized patients who tolerated at least 30 minutes of pressure support and either failed or were not yet ready to undergo a spontaneous breathing trial to automated or protocol ized weaning .  Both groups used pressure support , included spontaneous breathing trials , used a common positive end-expiratory pressure-FI(O(2 ) ) chart , sedation protocol , and criteria for extubation , reintubation , and noninvasive ventilation . MEASUREMENTS AND MAIN RESULTS We recruited 92 patients ( 49 automated , 43 protocol ized ) over 26 months .  Adherence to assigned weaning protocol s and extreme sedation scale scores fell within prespecified thresholds . Combined physician-respiratory therapist and nurse acceptance scores of the study weaning and sedation protocol s , respectively , were not significantly different . Automated weaning patients had significantly shorter median times to first successful spontaneous breathing trial ( 1.0 vs. 4.0 d ; P < 0.0001 ) , extubation ( 3.0 vs. 4.0 d ; P = 0.02 ) , and successful extubation ( 4.0 vs. 5.0 d ; P = 0.01 ) , and underwent fewer tracheostomies and episodes of protracted ventilation . CONCLUSIONS Compared with a st and ardized protocol , automated weaning was associated with promising outcomes that warrant further investigation . Minor protocol modifications may increase compliance , facilitate recruitment , and enhance feasibility . Clinical trial registered with www.controlled-trials.com ( IS RCT N43760151 ) OBJECTIVE To compare the outcome of the SmartCare and spontaneous breathing trials ( SBT ) for weaning old patients with chronic obstructive pulmonary diseases ( COPD ) . METHODS Thirty-eight COPD patients were enrolled in Department of Respiratory Medicine on the South Building , General Hospital of People 's Liberation Army from January , 2003 to April , 2005 . They mechanically ventilated for at least 3 d ( age : 70 - 91 year , average : 83.3 + /- 4.3 ) , r and omly assigned to receive SmartCare ( SC group , n = 13 ) or  SBT ( SBT group , n = 25 ) . All patients were considered clinical ly and biologically stable , and therefore ready to be weaned from mechanical ventilation . In SC group , patients were ventilated with an inspiratory pressure ( IPAP ) support adjusted to achieve pH value > or = 7.35 , saturation of oxygen in arterial blood ( SaO2 ) > or = 90 % , respiratory frequency ( RR ) > or = 10 and < or = 30 breaths/min , and fraction of inspired oxygen ( FiO2 ) < or = 45 % . In SBT group , the patients were placed in a weaning protocol utilizing increasing duration of spontaneous breathing . The following data were recorded at weaning : the acute physiology and chronic health evaluation II ( APACHE II ) score , arterial blood gases under mechanical ventilation , serum calcium , magnesium , and phosphorus , the days of ventilation before weaning and the duration of weaning . The patients of both groups were considered as successfully weaned when they were able to tolerate at least 48 consecutive hours of spontaneous breathing . Failure was defined in a patient who died during the weaning process or who still needed mechanical ventilation after at least 40 consecutive days of weaning . RESULTS No significant differences were found between the groups at the onset of weaning from mechanical ventilation regarding APACHE II , serum albumin , calcium , magnesium , phosphorus , partial pressure of carbon dioxide in arterial blood ( PaCO2 ) , and the days of mechanical ventilation ( t = 0.834 , 0.696 , 1.384 , 0.682 , 0.467 , 0.816 , 0.384 , all P > 0.05 ) . The pH value of the SBT group ( 7.45 + /- 0.05 ) was higher than the SC group ( 7.40 + /- 0.04 , t = 3.263 , P < 0.05 ) . Although patients in the SC group spent less time in weaning than those in the SBT group , the difference was not significant [ ( 8.54 + /- 2.09 ) , ( 13.32 + /- 2.19 ) d for the SC and SBT groups , respectively , t = 1.320 , P = 0.251 ] . The 7-d weaning success rate was greater in the SC group than the SBT group ( 77 % , 40 % , chi(2 ) = 4.677 , P = 0.031 ) . No significant difference was found in 14-d weaning success rate ( 77 % , 64 % in the SC and SBT groups , chi(2 ) = 0.661 , P = 0.416 ) . Fewer arterial blood analyses were performed in the SC group ( 3.5 + /- 3.1 , 6.6 + /- 3.7 , t = 2.710 , P = 0.011 ) . CONCLUSION The SmartCare is better than SBT in weaning patients with COPD within 7 days
BACKGROUND Automated closed loop systems may improve adaptation of mechanical support for a patient 's ventilatory needs and facilitate systematic and early recognition of their ability to breathe spontaneously and the potential for discontinuation of ventilation .
This review was originally published in 2013 with an up date published in 2014 .
OBJECTIVES The primary objective for this review was to compare the total duration of weaning from  mechanical ventilation , defined as the time from study r and omization to successful extubation ( as defined by study authors ) , for critically ill ventilated patients managed with an automated weaning system versus no automated weaning system ( usual care ) .
Secondary objectives for this review were to determine differences in the duration of ventilation , intensive care unit ( ICU ) and hospital lengths of stay ( LOS ) , mortality , and adverse events related to early or delayed extubation with the use of automated weaning systems compared to weaning in the absence of an automated weaning system .