Intraoperative Patient Warming using Radiant Warming or Forced-air Warming during Long Operations Effects of a Circulating-water Garment and Forced-air Warming on Body Heat Content and Core Temperature The Efficacy of a Resistive Heating Under-Patient Blanket Versus a Forced-Air Warming System: A Randomized Controlled Trial Core and thenar skin temperature variation during prolonged abdominal surgery: comparison of two sites of active forced air warming Comparison of Forced-air Warming and Radiant Heating during Transurethral Prostatic Resection under Spinal Anaesthesia Factors associated to the development of hypothermia in the intraoperative period. A randomised controlled trial of the electric heating pad vs forced‐air warming for preventing hypothermia during laparotomy Warming by resistive heating maintains perioperative normothermia as well as forced air heating. Resistive-Heating and Forced-Air Warming Are Comparably Effective Thermo-wrap technology preserves normothermia better than routine thermal care in patients undergoing off-pump coronary artery bypass and is associated with lower immune response and lesser myocardial damage. Water warming garment versus forced air warming system in prevention of intraoperative hypothermia during liver transplantation: a randomized controlled trial [ISRCTN32154832] Preliminary evaluation of the Arctic Sun temperature-controlling system during off-pump coronary artery bypass surgery. Relative Efficiency of Two Warming Devices during Laparoscopic Cholecystectomy Influence of body core temperature on blood loss and transfusion requirements during off-pump coronary artery bypass grafting: a comparison of 3 warming systems. Comparison of two convective warming systems during major abdominal and orthopedic surgery Comparison of Two Different Temperature Maintenance Strategies during Open Abdominal Surgery: Upper Body Forced-air Warming versus Whole Body Water Garment Comparison of a Radiant Patient Warming Device with Forced Air Warming during Laparoscopic Cholecystectomy A Randomized Controlled Trial of the Arctic Sun® Temperature Management System Versus Conventional Methods for Preventing Hypothermia During Off-Pump Cardiac Surgery Resistive-Polymer Versus Forced-Air Warming: Comparable Efficacy in Orthopedic Patients A new thermoregulation system for maintaining perioperative normothermia and attenuating myocardial injury in off-pump coronary artery bypass surgery. Hypothermia during laparotomy can be prevented by locally applied warm water and pulsating negative pressure. Randomized non-inferiority trial of the vitalHEAT™ Temperature Management System vs the Bair Hugger® warmer during total knee arthroplasty Comparison of forced‐air warming and electric heating pad for maintenance of body temperature during total knee replacement Temperature management during off-pump coronary artery bypass graft surgery: a randomized clinical trial on the efficacy of a circulating water system versus a forced-air system. Comparison of Three Warming Devices for the Prevention of Core Hypothermia and Post-Anaesthesia Shivering
Forced-air warming is the most commonly used and effective method of active warming . A new radiant warming device ( Suntouch ™ , Fisher and Paykel ) may provide an alternative when the skin surface available for warming is limited . We conducted a r and omized controlled trial to compare the efficacy of the Suntouch ™ radiant warmer and forced-air warming . With ethics committee approval , 60 surgical patients having procedures anticipated to be more than two hours in duration were recruited . Patients were r and omized to either radiant warming or forced-air warming . All intravenous fluids were warmed but prewarming was not used . The final intraoperative core temperatures ( ° C ) for the radiant warming and forced-air warming groups were 36.0±0.5 and 36.4±0.6 ( P=0.002 ) respectively . No other patient variables were significantly different . The Suntouch ™ is not as effective as the forced air warming for intraoperative warming during long surgical procedures . The device may be useful when forced-air warming is not possible Background : Forced-air warming is sometimes unable to maintain perioperative normothermia . Therefore , the authors compared heat transfer , regional heat distribution , and core rewarming of forced-air warming with a novel circulating-water garment . Methods : Nine volunteers were each evaluated on two r and omly ordered study days . They were anesthetized and cooled to a core temperature near 34 ° C . The volunteers were subsequently warmed for 2.5 h with either a circulating-water garment or a forced-air cover . Overall , heat balance was determined from the difference between cutaneous heat loss ( thermal flux transducers ) and metabolic heat production ( oxygen consumption ) . Average arm and leg ( peripheral ) tissue temperatures were determined from 18 intramuscular needle thermocouples , 15 skin thermal flux transducers , and “ deep ” h and and foot thermometers . Results : Heat production ( approximately 60 kcal/h ) and loss ( approximately 45 kcal/h ) were similar with each treatment before warming . The increases in heat transfer across anterior portions of the skin surface were similar with each warming system ( approximately 65 kcal/h ) . Forced-air warming had no effect on posterior heat transfer , whereas circulating-water transferred 21 ± 9 kcal/h through the posterior skin surface after a half hour of warming . Over 2.5 h , circulating water thus increased body heat content 56 % more than forced air . Core temperatures thus increased faster than with circulating water than forced air , especially during the first hour , with the result that core temperature was 1.1 ° ± 0.7 ° C greater after 2.5 h ( P < 0.001 ) . Peripheral tissue heat content increased twice as much as core heat content with each device , but the core-to-peripheral tissue temperature gradient remained positive throughout the study . Conclusions : The circulating-water system transferred more heat than forced air , with the difference result ing largely from posterior heating . Circulating water rewarmed patients 0.4 ° C/h faster than forced air . A substantial peripheral-to-core tissue temperature gradient with each device indicated that peripheral tissues insulated the core , thus slowing heat transfer BACKGROUND : We compared temperature changes in patients undergoing hip replacement during warming  with a resistive heating blanket or air-forced system . METHODS : Fifty-six patients were enrolled . Patients were r and omly allocated to the “ forced-air group ” ( forced-air system ) or to the “ heating-blanket group ” ( resistive heating under-patient blanket ) . RESULTS : Baseline tympanic temperatures were 36.0 ± 0.6 ° C in the forced-air group and 36.1 ± 0.4 ° C in the heating-blanket group ( P > 0.05 ) . At the end of surgery tympanic temperatures were 35.3 ± 0.5 ° C in the forced-air group and 35.1 ± 0.6 ° C in the heating-pad group ( P > 0.05 ) . CONCLUSIONS : We demonstrated that , using either a resistive heating-blanket or forced-air warming systems , patients ended surgery in mild hypothermia after elective total hip replacement , but without significant differences between these two warming devices Background : This study was design ed to compare the efficacy of two different sites of active forced air warming , upper body or lower body , to maintain normothermia ; and their respective effect on thenar skin temperature in relation to the accelerographic monitoring of neuromuscular blockade during long‐lasting abdominal surgery Forced-air warming is commonly used to warm patients intraoperatively , but may not achieve normothermia during a short procedure . Comparative trials of a new radiant warming device in general anaesthesia ( Suntouch ™ , Fisher and Paykel , Auckl and , New Zeal and ) have had conflicting results . We conducted a r and omized controlled trial to compare the efficacy and thermal comfort of the Suntouch ™ radiant warmer and forced-air warming in patients at high risk of hypothermia during neuraxial blockade . With ethics committee approval , 60 patients having transurethral resection of the prostate under spinal were r and omized to either radiant warming or forced-air warming . All intravenous and irrigation fluids were warmed but pre-warming was not used . The final intraoperative rectal temperatures for the radiant warming and forced-air warming groups were 36.1 ° C and 36.4 ° C respectively ( P=0.03 ) . A large proportion of patients in both groups ( 46 % and 33 % respectively , P=0.3 ) were hypothermic ( < 36 ° C ) on arrival in the post-anaesthesia care unit . No other patient variables were significantly different . Neither warming device reliably prevented hypothermia , although forced-air warming was slightly superior This study aim ed to assess factors associated to body temperature changes intraoperatively in patients undergoing elective surgery . A prospect i ve study including 70 patients was carried out in a charity hospital . A data collection instrument was developed and its face and content validity was established . The variables measured were operating room temperature and humidity and patient body temperature at different times . In the multivariate linear regression , the variables type of anesthesia , duration of anesthesia , body mass index , and operating room temperature were directly associated to mean body temperature . Nurses are responsible for planning and implementing effective interventions that can contribute to minimize costs and most importantly reduce hypothermia complications A r and omised controlled trial was conducted to compare the efficacy of upper body forced‐air warming ( Bair Hugger ™ , Augustine Medical model 500/OR , Prairie , MN ) with that of an electric heating pad ( Operatherm 202 , KanMed , Bromma , Sweden ) for maintenance of intra‐operative body temperature in 60 patients undergoing laparotomy under general anaesthesia .  The nasopharyngeal temperature was recorded throughout the operative period . The mean ( SD ) final temperatures were 36.2 ( 0.4 ) ° C with forced‐air warming and 35.5 ( 1.0 ) ° C with electric heating pad ( p < 0.01 ) . Upper body forced‐air warming is more effective than the heating pad for maintenance of body temperature during laparotomy BACKGROUND Even mild perioperative hypothermia is associated with several severe adverse effects . Resistive heating has possible advantages compared with other active warming systems because it can heat several fields independently . To assess this new warming system , we measured core temperature in patients during surgery who were warmed with circulating water mattresses , forced air covers or resistive heating covers . METHODS Twenty-four patients undergoing laparoscopic cholecystectomy were r and omly assigned to ( i ) circulating water mattress ( 38 degrees C ) , ( ii ) forced air warming ( set to ' medium ' ) or ( iii ) carbon-fibre resistive warming ( 38 degrees C ) . Warming was applied throughout anaesthesia and surgery . The groups were compared using one-way ANOVA and Student-Newman-Keuls tests . RESULTS Confounding factors were similar among the groups . Core temperatures in each group decreased for 20 min , but subsequently increased in the forced air and resistive heating groups . There was no significant difference between the forced air and resistive heating groups at any time . In contrast , core temperature in the circulating water group continued to decrease . Consequently , core temperature in the circulating water group was significantly lower than in the other groups 30 min after anaesthetic induction and at later times . CONCLUSIONS Resistive heating maintains core body temperature as well as forced air heating and both are better than circulating water . Resistive heating offers the advantage of adjustable heating pods Serious adverse outcomes from perioperative hypothermia are well documented . Consequently , intraoperative warming has become routine . We thus evaluated the efficacy of a novel , nondisposable carbon-fiber resistive-heating system .  Twenty-four patients undergoing open abdominal surgery lasting approximately 4 h were r and omly assigned to warming with 1 ) a full-length circulating water mattress set at 42 ° C , 2 ) a lower-body forced-air cover with the blower set on high , or 3 ) a three-extremity carbon-fiber resistive-heating blanket set to 42 ° C . Patients were anesthetized with a combination of continuous epidural and general anesthesia .  All fluids were warmed to 37 ° C , and ambient temperature was kept near 22 ° C . Core ( tympanic membrane ) temperature changes among the groups were compared by using factorial analysis of variance and Scheffe[Combining Acute Accent ] F tests ; results are presented as means ± SD . Potential confounding factors did not differ significantly among the groups . In the first 2 h of surgery , core temperature decreased by 1.9 ° C ± 0.5 ° C in the circulating-water group , 1.0 ° C ± 0.6 ° C in the forced-air group , and 0.8 ° C ± 0.2 ° C in the resistive-heating group . At the end of surgery , the decreases were 2.0 ° C ± 0.8 ° C in the circulating-water group , 0.6 ° C ± 1.0 ° C in the forced-air group , and 0.5 ° C ± 0.4 ° C in the resistive-heating group . Core temperature decreases were significantly greater in the circulating-water group at all times after 150 elapsed minutes ; however , temperature changes in the forced-air and resistive-heating groups never differed significantly . Even during major abdominal surgery , resistive heating maintains core temperature as effectively as forced air . IMPLICATION S : Efficacy was similar for forced-air and resistive heating , and both maintained intraoperative core temperature far better than circulating-water mattresses . We thus conclude that even during major abdominal surgery , resistive heating maintains core temperature as effectively as forced air OBJECTIVE Perioperative hypothermia might be detrimental to the patient undergoing off-pump coronary artery bypass surgery . We assessed the efficacy of the Allon thermoregulation system ( MTRE Advanced Technologies Ltd , Or-Akiva , Israel ) compared with that of routine thermal care in maintaining normothermia during and after off-pump coronary artery bypass surgery . METHODS Patients undergoing off-pump coronary artery bypass surgery were perioperatively and r and omly warmed with the 2 techniques  ( n = 45 per group ) . Core temperature , hemodynamics , and troponin I , interleukin 6 , interleukin 8 , and interleukin 10 blood levels were assessed . RESULTS The mean temperature of the patients in the Allon thermoregulation system group ( AT group ) was significantly ( P < .005 ) higher than that of the patients receiving routine thermal care ( the RTC group ) ; less than 40 % of the latter reached 36 degrees C compared with 100 % of the former . The cardiac index was higher and the systemic vascular resistance was lower ( P < .05 ) by 16 % and 25 % , respectively , in the individuals in the AT group compared with in the individuals in the RTC group during the 4 postoperative hours . End-of-surgery interleukin 6 levels and 24-hour postoperative troponin I levels were significantly ( P < .01 ) lower in the patients in the AT group than in the RTC group . The RTC group 's troponin levels closely correlated with their interleukin 6 levels at the end of the operation ( R = 0.51 , P = .002 ) . CONCLUSIONS Unlike routine thermal care , the Allon thermoregulation system maintains core normothermia in more than 80 % of patients undergoing off-pump coronary artery bypass surgery . Normothermia is associated with better cardiac and vascular conditions , a lower cardiac injury rate , and a lower inflammatory response . The close correlation between the increased interleukin 6 and troponin I levels in the routine thermal care group indicates a potential deleterious effect of lowered temperature on the patient 's outcome Background The authors compared two strategies for the maintenance of intraoperative normothermia  during orthotopic liver transplantation ( OLT ) : the routine forced-air warming system and the newly developed , whole body water garment . Methods In this prospect i ve , r and omized and open-labelled study , 24 adult patients were enrolled in one of two intraoperative temperature management groups during OLT . The water-garment group ( N = 12 ) received warming with a body temperature ( esophageal ) set point of 36.8 ° C . The forced air-warmer group ( N = 12 ) received routine warming therapy using upper- and lower-body forced-air warming system .  Body core temperature ( primary outcome ) was recorded intraoperatively and during the two hours after surgery in both groups . Results The mean core temperatures during incision , one hour after incision and during the skin closing were significantly higher ( p < 0.05 , t test with Bonferroni corrections for the individual tests ) in the water warmer group compared to the control group ( 36.7 ± 0.1 , 36.7 ± 0.2 , 36.8 ± 0.1 vs 36.1 ± 0.4 , 36.1 ± 0.4 , 36.07 ± 0.4 ° C , respectively ) . Moreover , significantly higher core temperatures were observed in the water warmer group than in the control group during the placement of cold liver allograft ( 36.75 ± 0.17 vs 36.09 ± 0.38 ° C , respectively ) and during the allograft reperfusion period ( 36.3 ± 0.26 vs 35.52 ± 0.42 ° C , respectively ) . In addition , the core temperatures immediately after admission to the SICU ( 36.75 ± 0.13 vs 36.22 ± 0.3 ° C , respectively ) and at one hr ( 36.95 ± 0.13 vs 36.46 ± 0.2 ° C , respectively ) were significantly higher in the water warmer group , compared to the control group , whereas the core temperature did not differ significantly afte two hours in ICU in both groups . Conclusions The investigated water warming system results in better maintenance of intraoperative normothermia than routine air forced warming applied to upper- and lower body BACKGROUND Maintaining normothermia during off-pump coronary artery bypass ( OPCAB ) surgery is a challenge not met by currently available medical devices and strategies . The purpose of this study was to determine the efficacy of a new thermoregulatory device , the A rct ic Sun temperature-controlling circulating fluid adhesive pad system , in preventing hypothermia during OPCAB surgery . METHODS Thirteen consenting patients undergoing OPCAB had their temperature managed using the A rct ic Sun system . They were matched with 23 consenting control OPCAB patients whose temperature was maintained with st and ardized , conventional therapy ( elevated ambient operating room temperature , warmed intravenous fluids , and a convective forced air warming system placed under the surgical drapes ) . Nasopharyngeal temperature ( recorded at 1-minute intervals ) was compared between the two groups by analysis of both the time and area under the curve for a temperature less than 36 degrees C. RESULTS Multivariate linear regression analysis revealed that the average amount of hypothermia in the A rct ic Sun group was significantly less than in the control group , both for time spent less than 36 degrees C ( 20.7 vs 121.3 minutes , p = 0.0004 ) and for area under the curve less than 36 degrees C ( 11.8 degrees C vs 78.1 degrees C x minutes , p = 0.0001 ) . CONCLUSIONS The A rct ic Sun temperature-controlling system is more effective than conventional warming methods in preventing hypothermia during OPCAB surgery Intraoperative hypothermia is a known consequence of general anaesthesia .  Forced air warming devices are commonly used to prevent hypothermia in anaesthesia , but there are limited data on the use of radiant warming devices . Previous trials comparing the efficacy of forced air and radiant warming devices have reported discordant results . The current study evaluated the efficacy of these devices during elective laparoscopic cholecystectomy , where surgery was expected to last > 60 minutes . Twenty-nine patients were r and omised to either a forced air warming device ( Warm-touch ™ ; group 1 , n=15 ) or a radiant warming device applied to the face ( Sun-touch ™ ; group 2 , n=14 ) . All fluids were given via a st and ardised fluid warmer set at 41 ° C . Oesophageal temperature was measured every 15 minutes until the end of the procedure . Between-group , over-time temperatures and interaction were analysed using a linear mixed model . Statistical significance was ascribed at P ≤0.05 . The median ( range ) time of surgery was 90 ( 60 to 180 ) minutes . Mean ( SD ) oesophageal temperatures  in the Warm-touch and Sun-touch groups were at 15 minutes 36.2 (0.30) ° C and 36.2 (0.57) ° C , and at 90 minutes 36.2 (0.44) ° C and 35.9 (0.29) ° C respectively . There was no statistically significant temperature difference between groups ( P=0.69 ) or over time ( P=0.61 ) , and no interaction between time and treatment group ( P=0.97 ) . Postoperative headache was recorded in four Sun-touch and no Warm-touch patients ( P=0.04 ) . No difference in the  efficacy of the Sun-touch warming device compared with the Warm-touch was demonstrated . Operational-mode side-effects may limit the use of the Sun-touch device BACKGROUND The aim of this prospect i ve r and omized trial was to evaluate the efficacy of 3 intraoperative warming systems ( Warm-Touch , Thermamed SmartCare OP system , and Allon 2001 ) on maintenance of normothermia and to investigate their effects on perioperative bleeding and transfusion requirements in patients undergoing off-pump coronary artery bypass grafting . METHODS With institutional approval/patient informed consent , 90 patients presenting for elective multiple off-pump coronary artery bypass grafting were r and omly assigned to 1 of the 3 warming systems . Active warming was started after the induction of anesthesia . Perioperative transfusion was based on international guidelines . Body core temperature was recorded every 30 minutes during operation . Perioperative blood loss , autotransfusion , and allogenic transfusions were recorded . Analysis of variance was performed with post hoc Scheffé tests and chi 2 tests . RESULTS Normothermia could be sufficiently maintained during operation by the Allon 2001 only . Final body core temperature was 34.7 degrees C + /- 0.9 degrees C ( Warm-Touch ) , 35.6 degrees C + /- 0.8 degrees C ( Thermamed SmartCare OP ) , and 36.5 degrees C + /- 0.4 degrees C ( Allon 2001 ; P < .001 , Warm-Touch vs Thermamed SmartCare OP , Warm-Touch vs Allon 2001 , and Thermamed SmartCare OP vs Allon 2001 ) . Perioperative blood loss was 2683 + /- 1049 mL ( Warm-Touch ) , 2300 + /- 788 mL ( Thermamed SmartCare OP ) , and 1497 + /- 497 mL ( Allon 2001 ; P = .195 , Warm-Touch vs Thermamed SmartCare OP ; P < .001 , Warm-Touch vs Allon 2001 ; P = .001 , Thermamed SmartCare OP vs Allon 2001 ) . Transfusion requirements were 1097 + /- 874 mL ( Warm-Touch ) , 986 + /- 744 mL ( Thermamed SmartCare OP ) , and 431 + /- 387 mL ( Allon 2001 ; P = .838 , Warm-Touch vs Thermamed SmartCare OP ; P = .003 , Warm-Touch vs Allon 2001 ; P = .013 , Thermamed SmartCare OP vs Allon 2001 ) . Free of allogenic transfusion were 15 ( 51.7 % ; Warm-Touch ) , 18 ( 60 % ; Thermamed SmartCare OP ) , and 24 ( 82.8 % ; Allon 2001 ) patients ( P = .037 ) . CONCLUSIONS The goal of normothermia during off-pump coronary artery bypass grafting was best achieved by the Allon system . With this concept , overall blood loss and transfusion requirements were reduced , hence indicating improved quality of perioperative care Purpose : Convective warming is routinely employed to maintain perioperative normothermia . However , due to differences in nozzle temperature and air flow of the power units , there are clinical ly relevant differences in heat transfer among convective warming systems . The purpose of this study was to evaluate the use of a quieter , convective warming system ( WarmAir , sound pressure level 49 dba , air flow 35 cfm ) . The WarmAir system was compared to the st and ard , higher air flow system ( Bair Hugger Model 750 , sound pressure level 55 dba , air flow 48 cfm ) with regards to temperature outcome . Methods : Patients undergoing general anesthesia for major abdominal and orthopedic surgery were r and omized into one of two groups : WarmAir  or  Bair Hugger . Both groups received an upper body , convective blanket using coverage appropriate for the given surgical procedure . Convective warming , at the high setting , was started after prepping and draping , and distal esophageal or nasopharyngeal temperature was measured intraoperatively . Sublingual temperature was measured preoperatively and on admission to the postanesthesia care unit . Results : The WarmAir ( n=89 ) and Bair Hugger ( n=95 ) groups were similar with respect to age , gender , body mass index , ASA status , fluid balance , and duration of surgery . There was no difference in temperature outcomes between groups . In the WarmAir group , preoperative , lowest intraoperative , end of surgery , and postanesthesia care unit admission temperatures were ( means ±SD ) ; 36.3±0.5 , 35.4±1.1 , 36.4±0.7 , and 36.4±0.6 ° C , respectively . Corresponding temperatures in the Bair Hugger group were ; 36.3±0.6 , 35.6±1.0 , 36.5±0.6 , and 36.4±0.5 ° C , respectively . Conclusion : Despite differences in heating characteristics , both convective warming systems were effective in maintaining perioperative normothermia in patients undergoing major abdominal and orthopedic surgery . Therefore , choice of warming system is dependent on other factors such as ergonomics and cost . RésuméObjectif : Le chauffage par convection est habituellement utilisé pour maintenir la normothermie périopératoire . Toutefois , en raison de différences au niveau de la température du bec et du débit d’air des blocs d’alimentation , il existe des différences significatives d’un point de vue clinique quant au transfert de chaleur lorsque l’on compare différents systèmes de chauffage par convection . L’objectif de cette étude était d’évaluer l’utilisation d’un système de chauffage par convection plus silencieux ( WarmAir , niveau de pression acoustique 49 dba , débit d’air 35 cfm ) . Le système WarmAir a été comparé au système st and ard , avec un débit d’air plus élevé ( Bair Hugger Model 750 , niveau de pression acoustique 55 dba , débit d’air 48 cfm ) , en ce qui a trait au niveau de la température atteinte . Méthode : Des patients subissant une anesthésie générale lors . de chirurgies abdominales ou orthopédiques majeures ont été r and omisés en deux groupes : WarmAir ou Bair Hugger . Les deux groupes ont reçu une couverture chauffante pour le haut du corps couvrant une surface adaptée à l’intervention chirurgicale en question . Le chauffage par convection , au niveau de réglage le plus élevé , a été débuté après le badigeonnage et la pose des champs , et la température oesophagienne distale ou naso-pharyngée a été mesurée pendant l’opération . La température sublinguale a été mesurée avant l’opération et lors de l’admission à la salle de réveil . Résultats : Les groupes WarmAir ( n=89 ) et Bair Hugger ( n=95 ) étaient semblables au niveau de l’âge , du sexe , de l’indice de masse corporelle , de l’état physique selon l’ASA , de l’hydratation et de la durée de la chirurgie . Il n’y a pas eu de différences dans les températures atteintes entre les deux groupes . Dans le groupe WarmAir , les températures préopératoire , au plus bas pendant l’opération , à la fin de la chirurgie et à l’admission à la salle de réveil étaient de ( moyennes ±ET ) : 36,3±0,5 , 35,4±1,1 , 36,4±0,7 , et 36,4±0,6 ° C , respectivement . Les températures correspondantes . dans le groupe Bair Hugger étaient de : 36,3±0,6 , 35,6±1,0 , 36,5±0,6 , et 36,4±0,5 ° C , respectivement . Conclusion : Malgré des différences dans les caractéristiques de chauffage , les deux systèmes de chauffage par convection à l’étude ont été efficaces pour maintenir la normothermie périopératoire chez les patients subissant des chirurgies abdominales et orthopédiques majeures . Dès lors , le choix d’un système de chauffage dépend d’autres facteurs tels que l’ergonomie et le coût Background A new system has been developed that circulates warm water through a whole body garment worn by the patient during surgery . In this study the authors compared two different strategies for the maintenance of intraoperative normothermia . One strategy used a new water garment warming system that permitted active warming of both the upper and lower extremities and the back . The other strategy used a single ( upper body ) forced-air warming system . Methods In this prospect i ve , r and omized study , 53 adult patients were enrolled in one of two intraoperative temperature management groups during open abdominal surgery with general anesthesia . The water-garment group ( n = 25 ) received warming with a body temperature ( rectal ) set point of 36.8 ° C . The forced-air – warmer group ( n = 28 ) received routine warming therapy using upper body forced-air warming system ( set on high ) . The ambient temperature in the operating room was maintained constant at approximately 20 ° C . Rectal , distal esophageal , tympanic , forearm , and fingertip temperatures were recorded perioperatively and during 2 h after surgery . Extubated patients in both groups were assessed postoperatively for shivering , use of additional warming devices , and subjective thermal comfort . Results The mean rectal and esophageal temperatures at incision , 1 h after incision , at skin closure , and immediately postoperatively were significantly higher ( 0.4–0.6 ° C ) in the group that received water-garment warming when compared with the group that received upper body forced-air warming . The calculated 95 % confidence intervals for the above differences in core temperatures were 0.7–0.1 , 0.8–0.2 , 0.8–0.2 , and 0.9–0.1 , retrospectively . In addition , 14 and 7 % of patients in the control upper body forced-air group remained hypothermic ( < 35.5 ° C ) 1 and 2 h after surgery , respectively . No core temperature less than 35.5 ° C was observed perioperatively in any of the patients from the water-garment group . A similar frequency of the thermal stress events ( shivering , use of additional warming devices , subjective thermal discomfort ) was observed after extubation in both groups during the 2 h after surgery . Conclusions The investigated water warming system , by virtue of its ability to deliver heat to a greater percentage of the body , results in better maintenance of intraoperative normothermia that does forced-air warming applied only to the upper extremities , as is common practice The importance of maintaining a patient 's core body temperature during anaesthesia to reduce the incidence of postoperative complications has been well documented . The st and ard practice of this institution is the use of a forced air device for intraoperative warming . The purpose of this study was to compare this st and ard with an alternative warming device using a radiant heat source which only heated the face . This prospect i ve , r and omized controlled trial compared the efficacy of two methods of intraoperative warming : the BairHugger ™ ( Augustine Medical , U.S.A. ) forced air device and the SunTouch ™ ( Fisher & Paykel Healthcare , N.Z. ) radiant warmer during laparoscopic cholecystectomy in 42 female patients . Oesophageal core temperatures were recorded automatically on to computer during operations using st and ardised anaesthesia , intravenous infusions and draping . The study failed to show any statistical or clinical difference between the two patient groups in terms of mean core temperature both intraoperatively ( P=0.42 ) and in the recovery period ( P=0.54 ) . Mean start to end core temperature differences were marginly lower in the radiant group ( 0.08 ° C ) but not statistically or clinical ly significantly different . Given some of the drawbacks with forced air systems , such as the expense of the single use blanket , this new radiant warming device offers an alternative method of active warming with advantages in terms of cost and possible application to a wide variety of surgical procedures In this trial we compared the hypothermia avoidance abilities of the A rct ic Sun ® Temperature Management System ( a servo-regulated system that circulates temperature-controlled water through unique energy transfer pads adherent to the patient ’s body ) with conventional temperature control methods . Patients undergoing off-pump coronary artery bypass ( OPCAB ) surgery were r and omized to either the A rct ic Sun System alone ( AS group ) or conventional methods ( control group ; increased room temperature , heated IV fluids , convective forced air warming system ) for the prevention of hypothermia ( defined by a temperature < 36 ° C ) . The AS group had nasopharyngeal temperature servo-regulated to a target of 36.8 ° C . Temperature was recorded throughout the operative period and comparisons were made between groups for both the time and area under the curve ( AUC ) for a temperature < 36 ° C ( AUC<36 ° C ) . Twenty-nine patients ( AS group = 14 , control group = 15 ) were studied . The AS group had significantly less hypothermia than the control group , both for duration of time < 36 ° C ( 2.5 [ 0–22 ] min , median [ interquartile range ] AS group versus 118 [ 49–192 ] min , control group ; P = 0.0008 ) as well as for AUC<36 ° C ( 0.3 [ 0–2.2 ] ° C × min , AS group versus 17.1 [ 3.6–173.4 ] ° C × min , control group ; P = 0.002 ) . The A rct ic Sun Temperature Management System significantly reduced intraoperative hypothermia during OPCAB surgery . Importantly , this was achieved in the absence of any other temperature modulating techniques , including the use of IV fluid warming or increases in the ambient operating room temperature BACKGROUND : Several adverse consequences are caused by mild perioperative hypothermia . Maintaining normothermia with patient warming systems , today mostly with forced air ( FA ) , has thus become a st and ard procedure during anesthesia . Recently , a polymer-based resistive patient warming system was developed . We compared the efficacy of a widely distributed FA system with the resistive-polymer ( RP ) system in a prospect i ve , r and omized clinical study . METHODS : Eighty patients scheduled for orthopedic surgery were r and omized to either FA warming ( Bair Hugger warming blanket # 522 and blower # 750 , Arizant , Eden Prairie , MN ) or RP warming ( Hot Dog Multi-Position Blanket and Hot Dog controller , Augustine Biomedical , Eden Prairie , MN ) . Core temperature , skin temperature ( head , upper and lower arm , chest , abdomen , back , thigh , and calf ) , and room temperature ( general and near the patient ) were recorded continuously . RESULTS : After an initial decrease , core temperatures increased in both groups at comparable rates ( FA : 0.33 ° C/h ± 0.34 ° C/h ; RP : 0.29 ° C/h ± 0.35 ° C/h ; P = 0.6 ) . There was also no difference in the course of mean skin and mean body ( core ) temperature . FA warming increased the environment close to the patient ( the workplace of anesthesiologists and surgeons ) more than RP warming ( 24.4 ° C ± 5.2 ° C for FA vs 22.6 ° C ± 1.9 ° C for RP at 30 minutes ; PAUC < 0.01 ) . CONCLUSION : RP warming performed as efficiently as FA warming in patients undergoing orthopedic surgery BACKGROUND Most patients undergoing coronary artery bypass surgery  demonstrate perioperative mild-to-moderate hypothermia ( < 36 degrees C ) . Patients undergoing off-pump coronary artery bypass ( OPCAB ) grafting  may become even more severely hypothermic for want of cardiopulmonary bypass rewarming . One consequence is increased circulating catecholamine levels that induce an elevated systemic vascular resistance ( SVR ) , which causes a subsequent deterioration in cardiac output . MATERIAL S AND METHODS We assessed the ability of the Allon thermoregulatory ( AT ) system to maintain normothermia and its impact on hemodynamics and myocardial function in patients undergoing OPCAB surgery .  In this study , the first 60 of 120 suitable patients were assigned to AT ( n = 40 ) or routine thermal care ( RTC ) ( n = 20 ) . Core body temperature , cardiac index ( CI ) , SVR , and cardiac-specific troponin I ( cTnI ) were analyzed perioperatively for patients in both groups . RESULTS Core body temperature was significantly higher in the AT group ( from 36.1 degrees C + /- 0.5 degrees C at induction of anesthesia to 37 degrees C + /- 0.5 degrees C during surgery ) than in the RTC group ( from 35.8 degrees C + /- 0.4 degrees C to 35.2 degrees C + /- 0.8 degrees C , respectively ; P < .01 ) . SVR was significantly lower , and CI was greater ( at comparable time points ) , whereas cTnI levels in the AT group were lower than in the RTC group from the end of surgery until 24 hours postoperatively ( 7.4 + /- 17.7 g/L versus 31.9 + /- 47.4 g/L ; P = .03 ) . These findings indicate the possibility for less ischemic damage sustained intraoperatively in the AT group . CONCLUSIONS Maintenance of perioperative normothermia ( 36.5 degrees C-37.5 degrees C ) during OPCAB procedures can be efficiently achieved with the Allon thermoregulation system . The system was found to be superior to other routinely used methods of temperature maintenance . Benefits may include lowering afterload ( as expressed by reduced SVR ) , an improved CI , and attenuation of myocardial injury ( as assessed by cTnI levels ) BACKGROUND Conflicting results have been obtained when using heat and constant negative pressure applied to the arm to induce re-warming in patients with mild hypothermia due to surgery . We hypothesized that pulsating negative pressure would increase skin blood flow and thus heat transfer . The purpose of this study was to compare a new method of applying heat and pulsating negative pressure to the skin with conventional forced-air warming for preventing perioperative hypothermia . METHODS Twenty patients undergoing prolonged laparotomy for gastric surgery were r and omized into two groups . One group ( SM ) received hospital st and ard method : forced-air warming , 43 degrees C ( Bair Hugger ) on the thoracic and upper arm surface . The other group ( NM ) received the new method : warm water and pulsating negative pressure treatment applied in a transparent acrylic cylinder ( 50 x 16 cm ) on one arm . The cylinder was circulated with water at 42.5 degrees C , leaving an air pocket inside the device . Pulsating pressure between 0 and -40 mm Hg was generated in the air pocket inside the cylinder . RESULTS Two groups of 10 patients were studied . Warming was started shortly after induction of general anaesthesia . The two methods performed similarly during the first 60 min , with a mean 0.7 degrees decrease in core temperature . The tympanic temperature curve in NM group then increased and returned to baseline ( 37 degrees C ) by 120 min . The temperature of SM group increased more slowly , reaching 36 degrees C by 120 min ( P < 0.05 ) . CONCLUSION Warm water and pulsating negative pressure was significantly better at treating hypothermia during laparotomy than forced-air warming Purpose Intraoperative and postoperative hypothermia occur commonly ; mild hypothermia ( 34–36 ° C ) is associated with adverse events . The use of perioperative warming devices has become routine , but currently available active warming devices may be limited in certain circumstances . The vitalHEAT ™ Temperature Management System provides conductive warming ( circulating warm water ) around a single extremity together with a vacuum that is applied to the limb . In this r and omized trial , we tested the hypothesis that the vitalHEAT ™ system is non-inferior to the Bair Hugger ® during unilateral total knee arthroplasty . Methods Physical status I – III patients who were ≥18 yr-old were eligible to participate . The patients were r and omly assigned to the vitalHEAT ™ system ( n = 30 ) or to Bair Hugger ® ( n = 25 ) warming . Intraoperative and first recovery room temperatures were recorded in both groups . Results The baseline characteristics of the groups were similar . In terms of the primary outcome measure , i.e. , sublingual temperature measured within 10 min of recovery room arrival , the vitalHEAT ™ system did not meet the criterion for non-inferiority . Specifically , the confidence interval for the difference between means included the non-inferiority margin ( −0.5 ° C ) . In terms of the secondary measures , i.e. , intraoperative esophageal temperatures , the vitalHEAT ™ system also underperformed compared with the Bair Hugger ® . Conclusions The vitalHEAT ™ system may have advantages over convective warming systems because it requires a much smaller body surface area ; however , in this study of warming during total knee arthroplasty , it underperformed when compared with the Bair Hugger ® , especially around and after the time of tourniquet release . Clinical trial registration number : NCT00711867.RésuméObjectifL’hypothermie peropératoire et postopératoire est courante ; l’hypothermie légère ( 34 - 36 ° C ) est associée à des événements indésirables . Le recours à des appareils de réchauffement périopératoires est entré dans la pratique courante , mais les appareils de réchauffement actif actuellement disponibles sur le marché pourraient avoir des limites dans certaines circonstances . Le Système de gestion de la température vitalHEAT ™ procure un réchauffement par conduction ( circulation d’eau chaude ) autour d’un seul membre avec un vide et est appliqué au membre . Dans cette étude r and omisée , nous avons testé l’hypothèse que le système vitalHEAT ™ est non inférieur au Bair Hugger ® pendant une arthroplastie totale du genou unilatérale . MéthodeLes patients de statut physique I-III de ≥ 18 ans étaient admissibles à l’étude . Les patients ont été r and omisés à être réchauffés soit avec le système vitalHEAT ™ ( n = 30 ) ou avec le Bair Hugger ® ( n = 25 ) . Les températures ambiantes peropératoire et de la première salle de réveil ont été enregistrées dans les deux groupes . RésultatsLes caractéristiques de base des groupes étaient semblables . En termes de mesure du critère d’évaluation principal , soit la température sublinguale mesurée dans les 10 premières minutes suivant l’arrivée en salle de réveil , le système vitalHEAT ™ n’a pas répondu au critère de non-infériorité . Plus spécifiquement , l’intervalle de confiance pour la différence entre les moyennes comprenait une marge de non-infériorité ( -0,5 ° C ) . Du point de vue des mesures secondaires , soit les températures oesophagiennes peropératoires , le système vitalHEAT ™ a également été sous-performant par rapport au Bair Hugger ® . Conclusion Le système vitalHEAT ™ pourrait avoir des avantages par rapport aux systèmes de réchauffement par convection étant donné qu’il nécessite une surface corporelle bien plus petite ; toutefois , dans cette étude du réchauffement pendant une arthroplastie totale du genou , ce système a été sous-performant comparativement au Bair Hugger ® , particulièrement au moment du dégonflement du garrot et après . Numéro d’enregistrement de l’étude clinique : NCT00711867 We conducted a r and omised controlled trial to compare the efficacy of forced‐air warming ( Bair Hugger ™ , Augustine Medical model 500/OR , Prairie , MN ) with that of an electric heating pad ( Operatherm 202 , KanMed , Sweden ) for maintenance of intra‐operative body temperature in 60 patients undergoing total knee replacement under combined spinal‐epidural anaesthesia .  Intra‐operative tympanic and rectal temperatures and verbal analogue score for thermal comfort were recorded . There were no differences in any measurements between the two groups , with mean ( SD ) final rectal temperatures of 36.8 ( 0.4 ) ° C with forced‐air warming and 36.9 ( 0.4 ) ° C with the electric pad . The heating pad is as effective as forced‐air warming for maintenance of intra‐operative body temperature OBJECTIVE The aim of this study was to evaluate the performance of a new temperature management system specifically design ed for cardiac surgery ( Allon ThermoWrapping Thermoregulation System ; MTRE Advanced Technologies Ltd , Or Akiva , Israel ) using a circulating-water garment and to compare it with a conventional forced-air cover system in order to determine whether it could reduce the incidence of perioperative hypothermia during off-pump coronary artery bypass graft ( OPCAB ) surgery . DESIGN Prospect i ve , r and omized . SETTING University , tertiary care hospital . PARTICIPANTS Thirty-one patients undergoing primary OPCAB surgery . INTERVENTIONS Patients undergoing OPCAB surgery were r and omized into the new thermoregulation system , Allon ( study group , n = 15 ) , and the st and ard forced-air system , Bair Hugger ( Sterile Cardiac Access blanket Model 645 ; Augustine SA , Berne , Switzerl and ) ( control group , n = 16 ) . MEASUREMENTS AND MAIN RESULTS Rectal temperature was recorded each 30 minutes during surgery and at intensive care unit arrival . Patients in the study group had higher temperatures than the control group at all time points , and the difference reached statistical significance after 2 hours of surgery . Moreover , fewer patients in the study group suffered perioperative hypothermia ( defined as rectal temperature < 36 degrees C ) than the control group ( 2/15 patients ( 13.3 % ) in the study group v 13/16 ( 81.3 % ) in the control group [ p = 0.0006 ] ) . No difference in other outcomes was noted . None of the patients died in the hospital . There were no adverse events reported . CONCLUSIONS The circulating-water garment , Allon ThermoWrapping Thermoregulation System , maintained normothermia during OPCAB surgery better than forced-air systems , especially after the first 2 hours of surgery , and it was not associated with surgical field disturbance The efficacy of forced air warming with a surgical access blanket in preventing a decrease in core temperature during anaesthesia and post-anaesthesia shivering ( PAS ) was compared with two widely used interventions comprising forced air warming combined with an upper body blanket , and a circulating water mattress , in a prospect i ve , r and omized double-blind study . A total of 90 patients undergoing total abdominal hysterectomy were studied , 30 in each group .  Core temperature was measured 15 , 30 , 45 , 60 , 90 and 120 min after induction of anaesthesia . PAS was evaluated every 5 min after emergence from anaesthesia over a period of 1 h. Core temperature fell in all three groups compared with the baseline , but forced air warming using a surgical access blanket was more effective than the other warming methods in ameliorating the temperature decrease . The surgical access blanket was also superior to the circulating water mattress in reducing PAS
This study analyzed the evidence available in the literature concerning the effectiveness of different active cutaneous warming systems to prevent  intraoperative hypothermia .