title: Perioperative normothermia to reduce the incidence of surgical-wound infection and shorten hospitalization. Study of Wound Infection and Temperature Group. Mild hypothermia increases blood loss and transfusion requirements during total hip arthroplasty Forced-Air Warming Decreases Vasodilator Requirement After Coronary Artery Bypass Surgery Warming by resistive heating maintains perioperative normothermia as well as forced air heating. [The effect of intraoperative warming on patient core temperature]. Forced-air warming and fluid warming minimize core hypothermia during abdominal surgery. A prospective, randomized study of cardiopulmonary bypass temperature and blood transfusion. Preoperative combined with intraoperative skin-surface warming avoids hypothermia caused by general anesthesia and surgery. Aggressive Warming Reduces Blood Loss During Hip Arthroplasty Influence of body core temperature on blood loss and transfusion requirements during off-pump coronary artery bypass grafting: a comparison of 3 warming systems. [Prevention of intraoperative hypothermia in children]. Leg Warming Minimizes Core Hypothermia During Abdominal Surgery Effects of Mild Hypothermia on Blood Coagulation in Patients Undergoing Elective Plastic Surgery A Randomized Controlled Trial of the Arctic Sun® Temperature Management System Versus Conventional Methods for Preventing Hypothermia During Off-Pump Cardiac Surgery The impact of warming on pain and wound healing after hernia surgery: a preliminary study. Active warming of critically ill trauma patients during intrahospital transfer: A prospective, randomized trial Effects of preoperative warming on the incidence of wound infection after clean surgery: a randomised controlled trial Perioperative hypothermia and postoperative opioid requirements Forced‐air surface warming versus oesophageal heat exchanger in the prevention of peroperative hypothermia What are the Most Important Risk Factors for a Patient’s Developing Intraoperative Hypothermia? Supplemental perioperative oxygen to reduce the incidence of surgical-wound infection. Prevention of Intraoperative Hypothermia by Preoperative Skin-Surface Warming The Effect of Forced Air Warming on Postoperative Oxygen Consumption and Temperature in Elective Orthopaedic Surgery Unintentional Hypothermia Is Associated with Postoperative Myocardial Ischemia
abstract: BACKGROUND Mild perioperative hypothermia , which is common during major surgery , may promote surgical-wound infection by triggering thermoregulatory vasoconstriction , which decreases subcutaneous oxygen tension . Reduced levels of oxygen in tissue impair oxidative killing by neutrophils and decrease the strength of the healing wound by reducing the deposition of collagen . Hypothermia also directly impairs immune function . We tested the hypothesis that hypothermia both increases susceptibility to surgical-wound infection and lengthens hospitalization . METHODS Two hundred patients undergoing colorectal surgery were r and omly assigned to routine intraoperative thermal care ( the hypothermia group ) or additional warming ( the normothermia group ) . The patient 's anesthetic care was st and ardized , and they were all given cefam and ole and metronidazole . In a double-blind protocol , their wounds were evaluated daily until discharge from the hospital and in the clinic after two weeks ; wounds containing culture-positive pus were considered infected . The patients ' surgeons remained unaware of the patients ' group assignments . RESULTS The mean ( + /- SD ) final intraoperative core temperature was 34.7 + /- 0.6 degrees C in the hypothermia group and 36.6 + /- 0.5 degrees C in the normothermia group ( P < 0.001 ) Surgical-wound infections were found in 18 of 96 patients assigned to hypothermia ( 19 percent ) but in only 6 of 104 patients assigned to normothermia ( 6 percent , P = 0.009 ) . The sutures were removed one day later in the patients assigned to hypothermia than in those assigned to normothermia ( P = 0.002 ) , and the duration of hospitalization was prolonged by 2.6 days ( approximately 20 percent ) in hypothermia group ( P = 0.01 ) . CONCLUSIONS Hypothermia itself may delay healing and predispose patients to wound infections . Maintaining normothermia intraoperatively is likely to decrease the incidence of infectious complications in patients undergoing colorectal resection and to shorten their hospitalizations BACKGROUND In-vitro studies indicate that platelet function and the coagulation cascade are impaired by hypothermia . However , the extent to which perioperative hypothermia influences bleeding during surgery remains unknown . Accordingly , we tested the hypothesis that mild hypothermia increases blood loss and allogeneic transfusion requirements during hip arthroplasty . METHODS Blood loss and transfusion requirements were evaluated in 60 patients undergoing primary , unilateral total hip arthroplasties who were r and omly assigned to normothermia ( final intraoperative core temperature 36.6 [ 0.4 ] degrees C ) or mild hypothermia ( 35.0 [ 0.5 ] degrees C ) .  Crystalloid , colloid , scavenged red cells , and allogeneic blood were administered by strict protocol . FINDINGS Intra- and postoperative blood loss was significantly greater in the hypothermic patients : 2.2 ( 0.5 ) L vs 1.7 ( 0.3 ) L , p < 0.001 ) . Eight units of allogeneic packed red cells were required in seven of the 30 hypothermic patients , whereas only one normothermic patient required a unit of allogeneic blood ( p < 0.05 for administered volume ) . A typical decrease in core temperature in patients undergoing hip arthroplasty will thus augment blood loss by approximately 500 mL. INTERPRETATION The maintenance of intraoperative normothermia reduces blood loss and allogeneic blood requirements in patients undergoing total hip arthroplasty Postoperative hypothermia is common and associated with adverse hemodynamic consequences , including adrenergically mediated systemic vasoconstriction and hypertension . Hypothermia is also a known predictor of dysrhythmias and myocardial ischemia in high-risk patients . We describe a prospect i ve , r and omized trial design ed to test the hypothesis that forced-air warming ( FAW ) provides improved hemodynamic variables after coronary artery bypass graft . After institutional review board approval and written informed consent , 149 patients undergoing coronary artery bypass graft were r and omized to receive postoperative warming with either FAW ( n = 81 ) or a circulating water mattress ( n = 68 ) . Core temperature was measured at the tympanic membrane . A weighted mean skin temperature was calculated . Heart rate , mean arterial blood pressure , central venous pressure , cardiac output , and systemic vascular resistance were monitored for 22 h postoperatively . Mean arterial blood pressure was maintained by protocol between 70 and 80 mm Hg by titration of nitroglycerin and sodium nitroprusside . The two groups had similar demographic characteristics . Tympanic and mean skin temperatures were similar between groups on intensive care unit admission . During postoperative rewarming , tympanic temperature was similar between groups , but mean skin temperature was significantly greater in the FAW group ( P < 0.05 ) . Heart rate , mean arterial pressure , central venous pressure , cardiac output , and systemic vascular resistance were similar for the two groups . The percent of patients requiring nitroprusside to achieve the hemodynamic goals was less ( P < 0.05 ) in the FAW group . In conclusion , aggressive cutaneous warming with FAW results in a higher mean skin temperature and a decreased requirement for vasodilator therapy in hypothermic patients after cardiac surgery . This most likely reflects attenuation of the adrenergic response or opening of cutaneous vascular beds as a result of surface warming . Implication s Forced-air warming after cardiac surgery decreases the requirement for vasodilator drugs and may be beneficial in maintaining hemodynamic variables within predefined limits 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 OBJECTIVE To investigate the influence of using fluid warming and forced-air warming system on  patient core temperature , blood loss , blood transfusion , extubation time , and postoperative shivering .  METHODS Forty ASA ( American Society of Anesthesiologists ' Physical Status ) I-II patients , aged 21 - 69 years , scheduled for elective abdominal surgery under general anesthesia , were enrolled in the study . The patients were premedicated with intramuscular dolantin 50 mg and atropine 0.5 mg . Anesthesia was induced with midazolam 1 mg , fentanyl 50 - 100 microg and propofol 1.5 - 2.0 mg/kg . Tracheal intubation was facilitated with vecuronium 1 mg and succinylcholine 1.5 - 2.0 mg/kg . The patients were mechanically ventilated and anesthesia was maintained with isoflurane 1.5 - 2.0 % , 50 % N2O in oxygen and intermittent iv boluses of fentanyl ( total dose 5 - 6 microg/kg ) . Vecuronium was used for muscle relaxation during maintenance of anesthesia . The patients were r and omly divided into 2 groups : control group ( n = 20 ) and warming group ( n = 20 ) . In both groups , the patients were covered with surgery blanket . In the warming group , patients were additionally warmed with fluid warming device and forced-air warming system during the operation . The core temperature was recorded every 20 minutes during the operation , as well as the blood loss , blood transfusion , extubation time and postoperative shivering . RESULTS The core temperature at the end of the surgery was ( 36.4 + /- 0.4 ) degrees C in the warming group and ( 35.3 + /- 0.5 ) degrees C in the control group . The difference was statistically significant ( t = 7.547 , P < 0.001 ) . There was no significant difference of blood loss and blood transfusion between two groups . The extubation time was significantly shorter in the warming group [ ( 18 + /- 6 ) vs ( 26 + /- 10 ) min , t = -3.364 , P = 0.002 ] . 6 patients shivered postoperatively in the control group and none in the warming group ( chi2 = 7.059 , P = 0.008 ) . CONCLUSION Fluid warming system and forced-air warming system can effectively maintain normothermia during the surgery and then help to reduce the extubation time and postoperative shivering OBJECTIVE To evaluate the effect of intraoperative combined forced-air warming and fluid warming system on  patient 's core temperature , blood loss , transfusion dem and , extubation time , and incidence of postoperative shivering . METHODS Forty patients with American Society of Anesthesiologists physical status I and II , aged 18 - 70 years , scheduled for elective abdominal surgery were r and omly assigned to receive intraoperative warming from a forced-air blanket and fluid warming system or conventional cotton blanket , 20 in each group . The core temperature was recorded every 20 minutes during the operation , as well as the blood loss , blood transfusion , extubation time , and incidence of postoperative shivering . RESULTS The core temperature at the end of the surgery in the warming group was significantly different from that in the control group ( 36.4 + /- 0.4 degrees C vs. 35.3 + /- 0.5 degrees C , P < 0.001 ) . Application of intraoperative warming significantly shortened the time between the end of the surgery and extubation ( P < 0.01 ) . Postoperative shivering occurred in 30 % of the patients in the control group compared to no patient in the warming group ( P < 0.01 ) . CONCLUSION Active warming with air-forced blanket and fluid warming system provides sufficient heat to prevent hypothermia during abdominal surgery BACKGROUND We hypothesized that normothermic cardiopulmonary bypass ( CPB ) would be associated with decreased blood loss and allogeneic transfusion requirements relative to hypothermic CPB . METHODS After obtaining institutional review board approval and informed patient consent , we conducted a prospect i ve , r and omized study of 79 patients undergoing CPB for a primary cardiac operation at normothermic ( 37 degrees C ) ( n = 44 ) or hypothermic temperature ( 25 degrees C ) ( n = 35 ) .  Blood loss and transfusion requirements in the operating room and for the first 24 hours in the intensive care unit were determined . A paired t test and rank sum tests were used . A p value of less than 0.05 was considered significant . RESULTS The normothermic and hypothermic CPB groups did not differ in demographic variables , CPB or cross-clamp duration , heparin sodium or protamine sulfate dose , prothrombin time , or thromboelastogram results . There were no differences between the two CPB groups in blood loss or transfusion requirements . CONCLUSIONS We found that when there was no difference in duration of CPB , normothermic and hypothermic CPB groups demonstrated similar blood loss and transfusion requirements even though other studies have shown hypothermia induces platelet dysfunction and alters the activity of the coagulation cascade STUDY OBJECTIVES To evaluate the effects of intraoperative skin-surface warming with and without 1 hour of preoperative warming , in preventing intraoperative hypothermia , and postoperative hypothermia , and shivering , and in offering good conditions to early tracheal extubation . DESIGN Prospect i ve , r and omized , blind study . SETTING Teaching hospital . PATIENTS 30 ASA physical status I and II female patients scheduled for elective abdominal surgery . INTERVENTIONS Patients received st and ard general anesthesia . In 10 patients , no special pre caution s were taken to avoid hypothermia . Ten patients were su bmi tted to preoperative and intraoperative active warming . Ten patients were only warmed intraoperatively . MEASUREMENTS AND MAIN RESULTS Temperatures were recorded at 15-minute intervals . The patients who were warmed preoperatively and intraoperatively had core temperatures significantly more elevated than the other patients during the first two hours of anesthesia . All patients warmed intraoperatively were normothermic only at the end of the surgery . The majority of the patients warmed preoperatively and intraoperatively or intraoperatively only were extubated early , and none had shivering . In contrast , five unwarmed patients shivered . CONCLUSIONS One hour of preoperative warning combined with intraoperative skin-surface warming , not simply intraoperative warming alone , avoided hypothermia caused by general anesthesia during the first two hours of surgery . Both methods prevented postoperative hypothermia and shivering and offered good conditions for early tracheal extubation We evaluated the effects of aggressive warming and maintenance of normothermia on  surgical blood loss and allogeneic transfusion requirement . We r and omly assigned 150 patients undergoing total hip arthroplasty with spinal anesthesia to  aggressive warming ( to maintain a tympanic membrane temperature of 36.5 ° C ) or conventional warming ( 36 ° C ) . Autologous and allogeneic blood were given to maintain a priori design ated hematocrits . Blood loss was determined by a blinded investigator based on sponge weight and scavenged cells ; postoperative loss was determined from drain output . Results were analyzed on an intention-to-treat basis . Average intraoperative core temperatures were warmer in the patients assigned to aggressive warming ( 36.5 ° ± 0.3 ° vs 36.1 ° ± 0.3 ° C , P < 0.001 ) . Mean arterial pressure was similar in each group preoperatively , but was greater intraoperatively in the conventionally warmed patients : 86 ± 12 vs 80 ± 9 mm Hg , P < 0.001 . Intraoperative blood loss was significantly greater in the conventional warming ( 618 mL ; interquartile range , 480–864 mL ) than the aggressive warming group ( 488 mL ; interquartile range , 368–721 mL;P = 0.002 ) , whereas postoperative blood loss did not differ in the two groups . Total blood loss during surgery and over the first two postoperative days was also significantly greater in the conventional warming group ( 1678 mL ; interquartile range , 1366–1965 mL ) than in the aggressively warmed group ( 1,531 mL ; interquartile range , 1055–1746 mL , P = 0.031 ) . A total of 40 conventionally warmed patients required 86 units of allogeneic red blood cells , whereas 29 aggressively warmed patients required 62 units ( P = 0.051 and 0.061 , respectively ) . We conclude that aggressive intraoperative warming reduces blood loss during hip arthroplasty . Implication s Aggressive warming better maintained core temperature ( 36.5 ° vs 36.1 ° C ) and slightly decreased intraoperative blood pressure . Aggressive warming also decreased blood loss by approximately 200 mL. Aggressive warming may thus , be beneficial in patients undergoing hip arthroplasty 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 UNLABELLED Children are very sensible to the occurrence of  intraoperative hypothermia ( HT )  ( core temperature < or = 36.0 degrees C ) during general anaesthesia because their regulation capacity is less effective than in adults and due to a large skin-surface area compared with their body mass . We compared the efficacy of different heating devices to prevent HT in children during surgery . METHODS With approval of the local ethics committee 50 children between one and seven years , scheduled for peripheral surgery lasting at least 2 hours were included in this study . Anaesthesia was st and ardized in all patients . Patients were r and omly divided into 5 groups . In group 1 , in addition to the usual cotton blankets , room temperature was elevated to 27 - 28 degrees C. In group 2 , room temperature was maintained at 27 - 28 degrees C , and the patients were additionally wrapped into an aluminum blanket . In group 3 , elevated room temperature was combined with a convective heating blanket . Patients in group 4 were warmed with an aluminum blanket , while the room temperature was maintained at 22 degrees C. In group 5 , room temperature was maintained at 22 degrees C and patients were warmed with a convective heating device ( Tab . 1 ) . Room and core body temperature ( tympanon membrane ) were continuously measured . ANOVA and Fisher 's exact Test ( significance level : p < 0.05 ) were performed for the statistical analysis of the results . RESULTS The demographic data of all 5 groups , the infused fluid volume and the anaesthetic technique were similar . There were no significant differences concerning age , height and weight of the pediatric patients ( Tab . 2 ) . The core temperature decreased by -1.7 degrees C in group 1 . In group 4 core temperature decreased by -1.6 degrees C. Using a convective warming system in normal ambient temperature ( group 5 ) core temperature increased by 0.2 degree C and was as effective in the prevention of HT as group 2 . A significant increase in core temperature occurred in group 3 + 0.7 degree C ( Tab . 3 and Fig. 1 ) . DISCUSSION OR temperature seems to be a critical factor influencing heat loss . Increasing OR temperature and covering with cotton sheets was not effective in preventing the heat loss . Increasing room temperature in combination with aluminum sheets is one alternative to prevent HT . Our study shows that the use of a convective warming device prevents HT during a 2-hour surgery in young children even at a OR temperature of about 22 degrees C. In conclusion , in pediatric patients the use of a convective heating system proved to be an effective alternative to room heating The efficacy of leg skin warming in preventing hypothermia and shivering was evaluated in two separate prospect i ve , r and omized trials in patients undergoing abdominal surgery . In the first trial , 22 patients were r and omized to receive no hypothermia prevention ( control group ) or active warming with an electric warming blanket ( electric blanket group ) . In the second trial 33 patients were r and omized to receive no hypothermia prevention ( control group ) or forced-air warming ( Bair Hugger ® group ) or forced-air warming with insulation of the air blanket from the environment ( insulated Bair Hugger ® group ) . The core and skin temperatures were measured and changes in body heat content calculated . In the first trial , core temperature was 34.6 ± 0.3 ° C at the end of surgery in the control group vs 36.4 ± 0.1 ° C in the electric warming blanket group ( P < 0.001 ) . Shivering occurred in nine control patients and in one warmed patient ( P < 0.05 ) . In the second trial , core temperature was 35.1 ± 0.2 ° C at the end of surgery in the control group , 36.3 ± 0.1 ° C in the Bair Hugger ® group ( P < 0.01 ) and 37.1 ± 0.1 ° C in the insulated Bair Hugger ® group ( P < 0.01 versus control ; P < 0.05 versus Bair Hugger ® ) . Shivering occurred in one patient of each warmed group and in seven of the control group ( P < 0.05 ) . Skin-surface warming limited to the legs provides sufficient heat ( ranging 34 to 43 watts ) to counterbalance heat losses during abdominal surgery Background : The aim of this prospect i ve , controlled study was to evaluate the effects on coagulation function of active patient warming during elective plastic surgery . Methods : Seventy-six patients undergoing elective plastic surgery ( additive and reductive mastoplasty , rhinoplasty , and liposuction )  were either covered with st and ard sterile drapes ( control group , n = 38 ) or actively warmed during surgery with countercurrent fluid warming and forced-air skin warming ( treatment group , n = 38 ) . Complete evaluation of the coagulation activity was performed 1 hour before general anesthesia was induced and then at the end of surgery . Results : Although no differences in preoperative core temperature were observed ( 36.0 ± 0.5 ° C in the control group and 36.1 ± 0.4 ° C in the treatment group ; p = 0.12 ) , core temperature was lower at the end of surgery in the control group ( 34 ± 1.0 ° C ) than in the treatment group ( 36 ± 0.6 ° C ) ( p = 0.0005 ) . No differences in prothrombin time and fibrinogen plasma concentrations were observed between the two groups . At the end of surgery , control group patients showed significantly larger activated partial thromboplastin times ( 36.8 ± 3.5 seconds ) and bleeding times ( 8.1 ± 1.6 minutes ) as compared with patients maintained normothermic during surgery ( 34.0 ± 2.9 seconds and 4.3 ± 1.1 minutes ; p = 0.0005 and p = 0.0005 , respectively ) . Conclusion : Actively maintaining intraoperative normothermia allows patients to maintain normal coagulation function during elective plastic surgery lasting longer than 2 hours , potentially reducing the occurrence of bleeding-related complications after plastic surgery 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 OBJECTIVE To determine whether the application of warmth  after hernia surgery reduces pain and aids wound healing . METHOD Forty-five patients were recruited and r and omised to receive either no warming;two hours of warming immediately after surgery ; or seven days of warming . RESULTS Postoperative pain scores were significantly lower after two hours of warming immediately after surgery compared with the non-warmed patients ( p<0.05 ) . Pain scores were lower on each of the first seven postoperative days in the warmed groups compared with the non-warmed subjects . Patients in the warmed groups also had lower ASEPSIS wound scores . CONCLUSION Warming may allow wounds to heal with fewer complications . In addition , warming for only two hours immediately after surgery may provide similar benefits to seven days of warming ZusammenfassungHintergrundHypothermia ist ein oft beobachtbares Phänomen bei Traumapatienten während der Akutversorgung . Bekannte Komplikationen einer akzidentellen Hypothermie sind Wundheilungsstörungen , kardiale Komplikationen , hämodynamische Instabilität , Defizite i m Immunsystem und vermehrter Blutverlust . In der folgenden Studie verglichen wir passiv gewärmte vs. aktiv gewärmte Patienten auf dem Transport von einer Intensivstation zum CT . Method enDreißig Intensivpatienten wurden r and omisiert zur einer aktiv gewärmten Gruppe , abgedeckt mit einer Carbonfiberwärmedecke ( 42 ° C ) während des gesamtem Transport und zur einer passiv gewärmten Gruppe , die mit einer ausgeschalteten Carbonfiberdecke versorgt waren . In beiden Gruppen waren die Carbonfiberdecke mit konventionellen Wolldecken abgedeckt . Es wurden die Vitalparameter und die Körpertemperaturen gemessen . ErgebnisseDie Ausgangs date n der Patienten waren in beiden Gruppen vergleichbar . Die Ausgangstemperatur in Gruppe A war 36,4 ° C±0,2 ° C und blieb stabil bei 36,4 ° C±01 ° C , die Temperatur in Gruppe B startete bei 36,4 ° C±0,2 ° C und sank statistisch signifikant auf 34,7 ° C±0,6 ° C.SchlussfolgerungenDie Hypothermie ist ein gängiges Problem , wenn Patienten wegen der diagnostischen Maßnahme einen innerklinischen Transport benötigen . Das aktive Wärmen dieser Patienten während des Transports kann die Körpertemperatur stabil normotherm halten . We können daher zur Erhaltung der Normothermia das aktive Wärmen von Patienten während eines Transports empfehlen . Summary Objective Hypothermia in trauma victims is a frequently observed phenomenon in acute care . Known complications of hypothermia are impaired wound healing , cardiac complications , hemodynamic instability , impaired immune function and increased blood loss . We compared active warming versus passive warming in hypothermia in critical-care patients undergoing intrahospital transfer from ICU to computer tomography ( CT ) . Methods Thirty critically ill patients were r and omized either to an actively warmed group , covered with a carbon-fiber heating blanket ( set to 42 ° C ) during the entire transport including the time spent in the CT , or to a passively warmed group , covered with a carbon-fiber heating blanket ( switched off ) during the entire transport and in the CT . The carbon-fiber blanket was covered with a conventional wool blanket in both groups . Vital parameters and core temperatures were recorded . Results Patients ’ characteristics and vital parameters were similar in each treatment group . Initial average core temperature in group A was 36.4 ° C±0.2 ° C and remained stable at 36.4 ° C±0.1 ° C ; core temperature in group B started at 36.4 ° C±0.2 ° C but decreased to 34.7 ° C±0.6 ° C . Conclusions Hypothermia is common when critically ill trauma patients require intrahospital transport for diagnostic procedures . Resistive heating during intrahospital transport kept the core temperature stable and assured normothermia in all actively warmed patients . We therefore recommend active warming for critically ill trauma patients during intrahospital transport BACKGROUND Wound infection after clean surgery is an expensive and often underestimated cause of patient morbidity , and the benefits of using prophylactic antibiotics have not been proven . Warming patients during colorectal surgery has been shown to reduce infection rates . We aim ed to assess whether warming patients before short duration , clean surgery would have the same effect . METHODS 421 patients having clean ( breast , varicose vein , or hernia ) surgery were r and omly assigned to either a non-warmed ( st and ard ) group or one of two warmed groups ( local and systemic ) . We applied warming for at least 30 min before surgery . Patients were followed up and masked outcome assessment s made at 2 and 6 weeks . FINDINGS Analysis was done on an intention-to-treat basis . We identified 19 wound infections in 139 non-warmed patients ( 14 % ) but only 13 in 277 who received warming ( 5 % ; p=0.001 ) . Wound scores were also significantly lower ( p=0.007 ) in warmed patients . There was no significant difference in the development of haematomas or seromas after surgery but the non-warmed group were prescribed significantly more postoperative antibiotics ( p=0.002 ) . INTERPRETATION Warming patients before clean surgery seems to aid the prevention of postoperative wound infection . If applied according to the manufacturers guidelines these therapies have no known side-effects and might , with the support of further studies , provide an alternative to prophylactic antibiotics in this type of surgery Background and objective Hypothermia may alter the disposition of opioids . Because opioids are commonly used as analgesics in the postoperative period , it is of clinical interest to clarify whether perioperatively developed hypothermia affects postoperative opioid requirements . Methods Fifty-nine patients undergoing subtotal hysterectomy were prospect ively r and omized and either treated intraoperatively with forced air warming , or served as controls covered with conventional blankets without active warming . Both groups received postoperative patient-controlled analgesia with the opioid ketobemidone .  Total analgesic requirements , dem and s , analgesic requirements over 6-h intervals and pain scores were measured for 48 h. Core temperature at the tympanic membrane and ambient room temperature were measured during the perioperative period . Results There were no postoperative differences in analgesic requirements or pain intensity between normothermic and hypothermic patients . Patients treated with warm air had an up to 1 ° C higher core temperature from 0.5 h after anaesthesia induction until almost 2 h postoperatively . The actively warmed patients also had a lower intraoperative blood loss than the hypothermic patients ( 186 ± 27 mL vs. 308 ± 47 mL;P < 0.05 ) . Conclusion In a clinical setting , opioid requirements do not seem to be affected by mild postoperative hypothermia after lower abdominal surgery Background : In a prospect i ve , r and omized , placebo‐controlled study we investigated the efficacy of 2 different heating methods in 24 patients undergoing abdominal surgery of at least 2 h expected duration Anesthesiologists attempt to maintain perioperative normothermia for surgical patients . We surveyed clinical anesthesiologists and physician research ers and asked them to prioritize risk factors for a patient to develop  intraoperative hypothermia .  The question naire included 41 factors associated with changes in patient temperature identified during a computerized literature search . We asked respondents to estimate the relative importance of each risk factor on a 10-point scale . The survey was mailed to two groups : 1 ) 180 anesthesiologists ( n = 84 respondents ) r and omly selected from the 1999 American Society of Anesthesiologists Members Directory and to 2 ) 24 physician research ers ( n = 12 respondents ) in thermoregulation . Research ers rated the following to be the most important risk factors for hypothermia ( in sequence ) : neonates , a low ambient operating room temperature , burn injuries , general anesthesia with neuraxial anesthesia , geriatric patients , low temperature of the patient before induction , a thin body type , and large blood loss . The results for the clinician group were similar , because the median differences between the groups ’ results were two or fewer units for all items . The risk factors identified to be most important can now be further evaluated in clinical trials to develop a multivariate predictive tool for calculating a patient ’s a priori risk for developing hypothermia BACKGROUND Destruction by oxidation , or oxidative killing , is the most important defense against surgical pathogens and depends on the partial pressure of oxygen in contaminated tissue . An easy method of improving oxygen tension in adequately perfused tissue is to increase the concentration of inspired oxygen . We therefore tested the hypothesis that the supplemental administration of oxygen during the perioperative period decreases the incidence of wound infection . METHODS We r and omly assigned 500 patients undergoing colorectal resection  to receive 30 percent or 80 percent inspired oxygen during the operation and for two hours afterward . Anesthetic treatment was st and ardized , and all patients received prophylactic antibiotic therapy . With use of a double-blind protocol , wounds were evaluated daily until the patient was discharged and then at a clinic visit two weeks after surgery . We considered wounds with culture-positive pus to be infected . The timing of suture removal and the date of discharge were determined by the surgeon , who did not know the patient 's treatment-group assignment . RESULTS Arterial oxygen saturation was normal in both groups ; however , the arterial and subcutaneous partial pressure of oxygen was significantly higher in the patients given 80 percent oxygen than in those given 30 percent oxygen . Among the 250 patients who received 80 percent oxygen , 13 ( 5.2 percent ; 95 percent confidence interval , 2.4 to 8.0 percent ) had surgical-wound infections , as compared with 28 of the 250 patients given 30 percent oxygen ( 11.2 percent ; 95 percent confidence interval , 7.3 to 15.1 percent ; P=0.01 ) . The absolute difference between groups was 6.0 percent ( 95 percent confidence interval , 1.2 to 10.8 percent ) . The duration of hospitalization was similar in the two groups . CONCLUSIONS The perioperative administration of supplemental oxygen is a practical method of reducing the incidence of surgical-wound infections Background : Intraoperative hypothermia initially results from internal redistribution of heat facilitated by anesthesia-induced vasodilatlon . Preinductlon skin-surface warming minimizes postinduction hypothermia in anesthetized volunteers . However , its efficacy might be reduced in surgical situations , because of multiple sources of heat loss . Methods : Intraoperative core and mean skin temperatures were measured during total hip arthroplasty in 16 patients , r and omly assigned to be covered preoperatlvely with a warming blanket for ≥90 min ( prewarmed group ) or not covered ( unwarmed group ) . Results : During the first hour of anesthesia , core temperature decreased more than twice as much in the unwarmed group ( −0.7 ± 0.1 ° C ; mean ± SE ) than in the prewarmed patients ( −0.3 ± 0.1 ° C ) . At the end of surgery , core temperature was 36.3 ± 0.1 ° C in the prewarmed group and 35.2 ± 0.2 ° C in the unwarmed group . During recovery , seven patients obviously shivered in the unwarmed group and none in the prewarmed group . Conclusions : Preanesthetic skin-surface warming reduces the initial postinductlon hypothermia in surgical patients , preventing intraoperative hypothermia and postoperative shivering even for procedures lasting 3 h or longer Actively warming  patients during surgery is considered the best method of preventing inadvertent hypothermia . In order to investigate the effect of forced air warming on postoperative oxygen consumption , we studied 26 patients undergoing orthopaedic surgery  using a prospect i ve , r and omized trial design . We measured oxygen consumption , carbon dioxide production , temperature , thermal comfort and pain scores . Apart from intraoperative temperature , there were no significant differences in these measurements between the two groups . This study demonstrated the gradual heat gain and also the potential for hyperthermia from pre- and intraoperative forced air warming . We conclude that forced air warming is not necessary for moderate duration non-body-cavity surgery if effective preinduction covering of patients and minimal surgical exposure is achieved Background Hypothermia occurs commonly during surgery and can be associated with increased metabolic dem and s during rewarming in the postoperative period . Although cardiac complications remain the leading cause of morbidity after anesthesia and surgery , the relationship between unintentional hypothermia and myocardial ischemia during the perioperative period has not been studied . Methods One hundred patients undergoing lower extremity vascular reconstruction received continuous Hotter monitoring throughout the first 24 h postoperatively . Myocardial ischemia was determined by a cardiologist masked to clinical variables . The patient 's sublingual temperature on arrival at the intensive care unit immediately after the surgical procedure was used to divide the patients into two groups : hypothermic ( temperature , < 35 ° C ; n = 33 ) and normothermic ( temperature , ≤ 35 ° C ; n = 67 ) . The relationship between unintentional hypothermia and myocardial ischemia occurring during the first postoperative day was evaluated by univariate and multivariate analyses . Results A greater percentage of patients had electrocardiographic changes consistent with myocardial ischemia in the hypothermic group ( 36 % , 12 of 33 ) compared with those in the normothermic group ( 13 % , 9 of 67 , P = 0.008 ) . Preoperative risk factors for perioperative cardiac morbidity were similar between the two groups , except for patient age . The mean age was 70 ± 2 yr and 62 ± 1 yr in the hypothermic and normothermic groups , respectively ( P = 0.001 ) . When subgroup and multivariate analyses were used to adjust for differences in age , temperature remained an independent predictor of ischemia ( odds ratio , 1.82 per degree Celsius ; 95 % confidence interval , 1.09–3.02 ) . The incidence of postoperative angina was greater in the hypothermic group ( 18 % , 6 of 33 ) than in the normothermic group ( 1.5 % , 1 of 67 , P = 0.002 ) . The incidence of PaO2 < 80 mmHg in the arterial blood was greater in the hypothermic group ( 52 % , 17 of 33 ) than in the normothermic group ( 30 % , 20 of 67 , P = 0.03 ) . Conclusions Unintentional hypothermia is associated with myocardial ischemia , angina , and PaO2 < 80 mmHg during the early postoperative period in patients undergoing lower extremity vascular surgery
target: In the fixed effect model , the warming group had significantly less pain and lower incidence of wound infection , compared with the no-warming group .
  In the r and om effect model , the warming group was also associated with lower risk of post-anesthetic shivering .
  Both in the r and om and the fixed effect models , the warming group was associated with significantly less blood loss .
  Perioperative warming of surgical patients is effective in reducing postoperative wound pain , wound infection and shivering .
  Systemic warming of the surgical patient is also associated with less perioperative blood loss through preventing hypothermia-induced coagulopathy .
background: OBJECTIVE The objective of this review was to systematic ally analyze the trials on the effectiveness of perioperative warming in surgical patients .