Mild Perioperative Hypothermia Research Articles

Inadvertent perioperative hypothermia and surgical site infections after liver resection

BackgroundIn the overall surgical population, inadvertent perioperative hypothermia has been associated with an increased incidence of surgical site infection (SSI). However, recent clinical trials did not validate this notion. This study aimed to investigate the potential correlation between inadvertent perioperative hypothermia and SSIs following liver resection. MethodsThis retrospective cohort study included all consecutive patients who underwent liver resection between January 2019 and December 2021 at the First Affiliated Hospital, Zhejiang University School of Medicine. Perioperative temperature managements were implemented for all patients included in the analysis. Estimated propensity score matching (PSM) was performed to reduce the baseline imbalances between the normothermia and hypothermia groups. Before and after PSM, univariate analyses were performed to evaluate the correlation between hypothermia and SSI. Multivariate regression analysis was performed to determine whether hypothermia was an independent risk factor for postoperative transfusion and major complications. Subgroup analyses were performed for diabetes mellitus, age > 65 years, and major liver resection. ResultsAmong 4000 patients, 2206 had hypothermia (55.2%), of which 150 developed SSI (6.8%). PSM yielded 1434 individuals in each group. After PSM, the hypothermia and normothermia groups demonstrated similar incidence rates of SSI (6.3% vs. 7.0%, P = 0.453), postoperative transfusion (13.3% vs. 13.7%, P = 0.743), and major complications (9.0% vs. 10.1%, P = 0.309). Univariate regression analysis revealed no significant effects of hypothermia on the incidence of SSI in the group with the highest hypothermia exposure [odds ratio (OR) = 1.25, 95% confidence interval (CI): 0.84-1.87, P = 0.266], the group with moderate exposure (OR = 1.00, 95% CI: 0.65-1.53, P = 0.999), or the group with the lowest exposure (OR = 1.11, 95% CI: 0.73-1.65, P = 0.628). The subgroup analysis revealed similar results. Regarding liver function, patients in the hypothermia group demonstrated lower γ-glutamyl transpeptidase (37 vs. 43 U/L, P = 0.001) and alkaline phosphatase (69 vs. 72 U/L, P = 0.016). However, patients in the hypothermia group exhibited prolonged activated partial thromboplastin time (29.2 vs. 28.6 s, P < 0.01). ConclusionsIn our study of patients undergoing liver resection, we found no significant association between mild perioperative hypothermia and SSI. It might be due to the perioperative temperature managements, especially active warming measures, which limited the impact of perioperative hypothermia on the occurrence of SSI.

Coagulation under Mild Hypothermia Assessed by Thromboelastometry

Introduction: While previous studies have shown a significant impact of extreme hypo- and hyperthermia on coagulation, effects of much more frequently occurring perioperative mild hypothermia are largely unknown. This study therefore aimed to analyze the effects of mild hypothermia using rotational thromboelastometry in vitro. Materials and Methods: Twelve healthy volunteers were included in this study. Standard thromboelastometric tests (EXTEM, INTEM, FIBTEM) were used to evaluate coagulation in vitro at 39, 37, 35.5, 35, and 33°C. Beyond standard thromboelastometric tests, we also evaluated the effects of mild hypothermia on the TPA-test (ClotPro, Enicor GmbH, Munich, Germany), a new test which aims to detect fibrinolytic capacity by adding tissue plasminogen activator to the sample. Data are presented as the median with 25/75th percentiles. Results: Extrinsically activated coagulation (measured by EXTEM) showed a significant increase in clot formation time (CFT; 37°C: 90 s [81/105] vs. 35°C: 109 s [99/126]; p = 0.0002), while maximum clot firmness (MCF) was not significantly reduced. Intrinsically activated coagulation (measured by INTEM) also showed a significant increase in CFT (37°C: 80 s [72/88] vs. 35°C: 94 s [86/109]; p = 0.0002) without significant effects on MCF. Mild hypothermia significantly increased both the lysis onset time (136 s [132/151; 37°C] vs. 162 s [141/228; 35°C], p = 0.0223) and lysis time (208 s [184/297; 37°C] vs. 249 s [215/358; 35°C]; p = 0.0259). Conclusion: This demonstrates that even under mild hypothermia coagulation is significantly altered in vitro. Perioperative temperature monitoring and management are greatly important and can help to prevent mild hypothermia and its adverse effects. Further investigation and in vivo testing of coagulation under mild hypothermia is needed.

Therapeutic Effect of Perioperative Mild Hypothermia on Postoperative Neurological Outcomes in Patients with Acute Stanford Type A Aortic Dissection.

Postoperative patients of acute Stanford type A aortic dissection (AAAD) often experience complications consisting of nervous system injury. Mild hypothermia therapy has been proven to provide the therapeutic effect of cerebral protection. We aimed to investigate the therapeutic effects of perioperative mild hypothermia on postoperative neurological outcomes in patients with AAAD. A prospective randomized controlled study was conducted on adult patients undergoing aortic dissection surgery between February 2017 and December 2017. Patients in the treatment group underwent mild hypothermia (34° to 35°C) immediately after surgery, and in the conventional therapy group, patients were rewarmed to normal body temperature (36° to 37°C). Postoperative time to regain consciousness, postoperative serum neuron-specific enolase (NSE) and S-100β levels, cerebral tissue oxygen saturation, presence of delirium or permanent neurological dysfunction, intensive care unit (ICU) and hospital stay duration, and 28-day mortality were compared. We enrolled 55 patients who underwent AAAD surgery and were randomly allocated into to 2 groups, 27 patients in the treatment group and 28 patients in the conventional therapy group. Compared with the conventional therapy group, postoperative time to regain consciousness was much shorter for patients in the mild hypothermia group (12.65 hours, interquartile range [IQR] 8.28 to 23.82, versus 25.80 hours, IQR 14.00 to 59.80; P = .02), and the rate of regaining consciousness in 24 hours after surgery was much higher (74.07% versus 46.42%; P = .037). At the same time, the ICU stay of patients in the mild hypothermia therapy group was significantly shorter than that in the conventional therapy group (5.53 ± 3.13 versus 9.35 ± 8.76 days; P = .038). Cerebral tissue oxygen saturation, incidence of delirium or permanent neurological dysfunction, duration of hospital stay, and 28-day mortality showed no statistical difference. Postoperative serum NSE and S-100β levels increased compared with preoperative baseline values in both groups (P < .05), and the serum NSE levels of patients in the mild hypothermia therapy was significantly lower than the conventional therapy group 1 hour (P = .049) and 6 hours (P = .04) after surgery. There was no difference in the chest drainage volume or shivering between the 2 groups 24 hours after surgery. Perioperative mild hypothermia therapy is able to significantly reduce brain cell injury and shorten the postoperative time to regain consciousness, thus improving the neurological prognosis of patients with AAAD.

Preoperative patient preparation in enhanced recovery pathways.

Enhanced recovery pathways are a novel approach focused on enhancing the care of surgical patients. “Prehabilitation” is the term applied to any intervention administered before surgery to reduce surgery-related morbidity, decrease the length of hospital stay, expedite the return of organ function, and facilitate the patient's return to normal life. A PubMed search was performed with the following key words: enhanced recovery, preoperative preparation, cessation of smoking and euvolemia. The results from this Pubmed search revealed that female patients may have higher levels of anxiety than male patients. Intensive smoking and alcohol cessation 6–8 weeks before elective surgery may reduce the incidence of postoperative morbidity. Preoperative exercise can be effective for reducing the postoperative complications like pulmonary complications and shortening the length of hospital stay. It is safe to allow patients to drink clear fluids up until 2 h before elective surgery (Level II evidence). Perioperative normoglycemia is the single most important factor to prevent surgical site infection. Intermittent pneumatic compression devices and low molecular weight heparin are effective in preventing postoperative thromboembolism. No advantage is gained by preoperative mechanical bowel preparation in elective colorectal surgery. The goal of preoperative fluid management is for the patient to arrive in the operating room in a hydrated and euvolemic state. Mild perioperative hypothermia may promote surgical wound infection by triggering thermoregulatory vasoconstriction, which decreases subcutaneous oxygen tension.

Mild Perioperative Hypothermia and Myocardial Injury: A Retrospective Cohort Analysis

We tested the primary hypothesis that final intraoperative esophageal temperature is associated with increased odds of a composite of in-hospital all-cause mortality and myocardial injury within 7 days after noncardiac surgery. Secondary exposures were time-weighted average intraoperative temperature and area <37°C threshold. Myocardial injury was defined by postoperative fourth-generation troponin T ≥0.03 ng/mL apparently due to cardiac ischemia. Data were extracted for inpatients who had noncardiac surgery with general anesthesia at the Cleveland Clinic between 2012 and 2015. All had esophageal temperature monitoring and routine postoperative troponin monitoring. We estimated the confounder-adjusted association between final intraoperative esophageal temperature and the collapsed composite with multivariable logistic regression. We similarly estimated associations with time-weighted average intraoperative temperature and area <37°C. Two thousand two hundred ten patients were included. Nearly all final esophageal temperatures were 36°C-37°C. Ninety-seven patients (4.4%) had myocardial injury, and 7 (0.3%) died before discharge. Final intraoperative core temperature was not associated with the collapsed composite: odds ratio, 0.91 (95% confidence interval, 0.68-1.24) per 1°C decrease. Similarly, neither of the secondary exposures was associated with the composite outcome. We did not observe an association between mild perioperative hypothermia and mortality or myocardial injury in adults having noncardiac surgery. However, the range of final intraoperative temperatures was small and largely restricted to the normothermic range (36°C-37°C). Trials are needed to further assess the effect of temperature on myocardial injury.

Perioperative hypothermia: a preventable complication

Hypothermia is a common and yet preventable complication from general anaesthesia.1 Although regarded by many as an inconsequential complication, mild perioperative hypothermia is associated with an increased risk of wound...

Control of body temperature and immune function in patients undergoing open surgery for gastric cancer.

The influence of mild perioperative hypothermia on the immune function and incidence of postoperative wound infections has been suggested, but the specific mechanism is unclear. This study aimed to analyze the body temperature, immune function, and wound infection rates in patients receiving open surgery for gastric cancer. Body temperature was controlled in each patient using one of four different methods: wrapping limbs, head and neck; insulated blankets; warming infusion fluids and insulated blankets; and warming fluids without insulated blankets. One hundred patients were randomly divided into four groups of 25 patients each, and every group received a different intraoperative treatment for maintaining normal body temperature. Nasopharyngeal and rectal temperatures, transforming growth factor beta (TGF-β), interleukin 10 (IL-10) levels, and cluster of differentiation (CD)3+T and CD4+/CD25+ regulatory T cell (Treg) counts were measured before surgery and at 2 and 4 hours postoperatively. Patients were evaluated at one week after surgery for signs of infection. Intraoperative body temperature and measures of immune function varied significantly between the four groups, with the largest temperature changes observed in the group in which only the limbs were wrapped in cotton pads to control the body temperature. The lowest temperature change (i.e., close to normal temperature) and cytokine response after surgery were observed in the group in which infusion fluids and transfused blood (if needed) were heated to 37℃, peritoneal irrigation fluid was heated to 37℃, and an insulation blanket was heated to 39℃ and placed under the patient. No intergroup differences were found in the infection rates at one week after surgery. In conclusion, body temperature variation during surgery affects the immune function of patients, and maintaining body temperature close to normal results in the least variation of immune function.

The impact of mild peri-operative hypothermia on the effectiveness of tranexamic acid in total hip arthroplasty.

Surgical patients experience inadvertent hypothermia as a result of anaesthesia-induced thermoregulatory impairment. Previous studies have found that hypothermia is associated with increased blood loss and transfusion requirements. This study examined the incidence of hypothermia in patients undergoing total hip arthroplasty (THA), whether hypothermia is associated with increased blood loss, and whether any such association is modified by tranexamic acid (TXA) administration. An observational prospective study was performed in 941 consecutive patients undergoing elective THA, with and without intra-operative administration of TXA. The presence of hypothermia on post-anaesthesia care unit admission was determined, and the post-operative bleeding index calculated. Transfusions and complications were documented. The incidence of peri-operative inadvertent hypothermia was 84.2%. TXA was administered to 751 (79.8%) patients. The bleeding index was 2.6 (95% confidence interval [CI] 2.6-2.7) in patients treated with TXA and 3.1 (95% CI 2.8-3.4) in patients who did not receive TXA (p = 0.012). Mild hypothermia did not have a significant impact on the bleeding index (difference, -0.4; 95% CI, -1.1 to +0.2; p = 0.190), nor on the effectiveness of TXA (difference, 0.4; 95% CI, -0.3 to +1.1; p = 0.250). The incidence of hypothermia in our THA population was high, despite peri-operative air warming. However, mild hypothermia was not significantly associated with increased blood loss and did not reduce the effectiveness of TXA.

The impact of perioperative hypothermia on plastic surgery outcomes: a multivariate logistic regression of 1062 cases.

Perioperative hypothermia has been associated with increased rates of infection, prolonged recovery time, and coagulopathy. The authors assessed the impact of hypothermia on patient outcomes after plastic surgery and analyzed the impact of prewarming on postoperative outcomes. The medical charts of 1062 patients who underwent complex plastic surgery typically lasting at least 1 hour were reviewed. Hypothermia was defined as a temperature at or below 36°C. Postoperative complication data were collected for outcomes including infection, delayed wound healing, seroma, hematoma, dehiscence, deep venous thrombosis, and overall wound problems. Odds ratios (ORs) were estimated from 3 multivariate logistic regression models of hypothermia and one model of body contouring procedures that included prewarming as a parameter. Perioperative hypothermia was not a significant predictor of wound problems (OR = 0.83; P = .28). In the stratified regression model, hypothermia did not significantly impact wound problems. The regression model measuring the interaction between hypothermia and operating time did not show a significantly increased risk of wound problems. Prewarming did not significantly affect perioperative hypothermia (P = .510), and in the model of body contouring procedures with prewarming as a categorical variable, massive weight loss was the most significant predictor of wound complications (OR = 2.57; P = .003). Prewarming did not significantly affect outcomes (OR = 1.49; P = .212). Based on univariate and multivariate models in our study, mild perioperative hypothermia appears to be independent of wound complications. LEVEL OF EVIDENCE 4: Risk.

Temperature monitoring: the consequences and prevention of mild perioperative hypothermia

Homeothermic species require a nearly constant internal body temperature. Significant deviations from “normal” internal temperature cause the metabolic function to deteriorate. Usually, the human thermoregulatory system maintains a core body temperature within 0.2°C of normal, near 37°C. Hypothermia results from exposure to cold, or exposure combined with drugs or illness that decrease thermoregulatory efficacy. Exposure to a cold operating room environment during anaesthesia and surgery commonly combines with anaesthetic-induced inhibition of thermoregulation to produce hypothermia. The prevention and management of temperature-related complications is expedited by an understanding of both normal and druginfluenced thermoregulation. Keywords : mild perioperative hypothermia; consequences; prevention

Effects of mild perioperative hypothermia on cellular immune function in patients undergoing surgery for rectal cancer

Objective To investigate the effects of mild pefioperative hypothermia on cellular immune function in patients undergoing surgery for rectal cancer.Methods Fifty ASA Ⅰ or Ⅱ patients aged 30-64 yr undergoing surgery for rectal cancer were randomly divided into 2 groups ( n =25 each):mild hypothermia group and normal body temperature group.Anesthesia was induced with midazolam,fentanyl,etomidate and vecuronium and maintained with propofol,remifentanil and vecuronium.The patients were mechanically ventilated after tracheal intubation.PET CO2 was maintained at 35-45 mm Hg.The venous blood samples were taken from peripheral vein at 1 h before anesthesia (T1 ),at the end of operation (T2),at 24 h after operation (T3),and on 7th day after operation (T4) to measure the serum Th1 and Th2 cytokines levels and Th1/Th2 cytokines balance was observed.Results Compared with the baseline value at T1,the serum Th2 cytokines level was significantly decreased and Th1/Th2 ratio was significantly increased at T4 in normal body temperature group,and the serum Th1 cytokines level and Th1/Th2 ratio were significantly decreased and the serum Th2 cytokines level was significantly increased at T2.3 in mild hypothermia group ( P ＜ 0.05).Compared with normal body temperature group,the serum Th1 cytokines level and Th1/Th2 ratio were significantly decreased and the serum Th2 cytokines level was significantly increased at T2-4 in mild hypothermia group ( P ＜ 0.05).Conclusion Mild perioperative hypothermia can depress cellular immune function in patients undergoing surgery for rectal cancer. Key words: Hypothermia; Rectal neoplasms; Immunity,cellular; Thl cells; Th2 cells

The effect of rapidly infused intravenous room temperature fluids in occurrence of perioperative mild hypothermia

The effect of rapidly infused intravenous room temperature fluids in occurrence of perioperative mild hypothermia

Resistive-Polymer Versus Forced-Air Warming: Comparable Efficacy in Orthopedic Patients

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 standard 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 prospective, randomized clinical study. Eighty patients scheduled for orthopedic surgery were randomized 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. After an initial decrease, core temperatures increased in both groups at comparable rates (FA: 0.33 degrees C/h +/- 0.34 degrees C/h; RP: 0.29 degrees C/h +/- 0.35 degrees 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 degrees C +/- 5.2 degrees C for FA vs 22.6 degrees C +/- 1.9 degrees C for RP at 30 minutes; P(AUC) <0.01). RP warming performed as efficiently as FA warming in patients undergoing orthopedic surgery.

Resistive Polymer Versus Forced-Air Warming: Comparable Heat Transfer and Core Rewarming Rates in Volunteers

Mild perioperative hypothermia increases the risk of several severe complications. Perioperative patient warming to preserve normothermia has thus become routine, with forced-air warming being used most often. In previous studies, various resistive warming systems have shown mixed results in comparison with forced-air. Recently, a polymer-based resistive patient warming system has been developed. We compared the efficacy of a standard forced-air warming system with the resistive polymer system in volunteers. Eight healthy volunteers participated, each on two separate study days. Unanesthetized volunteers were cooled to a core temperature (tympanic membrane) of 34 degrees C by application of forced-air at 10 degrees C and a circulating-water mattress at 4 degrees C. Meperidine and buspirone were administered to prevent shivering. In a randomly designated order, volunteers were then rewarmed (until their core temperatures reached 36 degrees C) with one of the following active warming systems: (1) forced-air warming (Bair Hugger warming cover #300, blower #750, Arizant, Eden Prairie, MN); or (2) polymer fiber resistive warming (HotDog whole body blanket, HotDog standard controller, Augustine Biomedical, Eden Prairie, MN). The alternate system was used on the second study day. Metabolic heat production, cutaneous heat loss, and core temperature were measured. Metabolic heat production and cutaneous heat loss were similar with each system. After a 30-min delay, core temperature increased nearly linearly by 0.98 (95% confidence interval 0.91-1.04) degrees C/h with forced-air and by 0.92 (0.85-1.00) degrees C/h with resistive heating (P = 0.4). Heating efficacy and core rewarming rates were similar with full-body forced-air and full-body resistive polymer heating in healthy volunteers.

The Effects of Mild Perioperative Hypothermia on Blood Loss and Transfusion Requirement

Survey of Anesthesiology: October 2008 - Volume 52 - Issue 5 - p 238 doi: 10.1097/01.SA.0000318617.83351.b9

Intraoperative Hypothermia and Blood Loss: Are Antifibrinolytic Exposure and Variations in Anesthetic Technique Possible Confounders?

Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. yiandoc@hotmail.comI read with great interest the excellent article by Dr. Rajagopalan et al. 1detailing their meta-analysis to investigate the relation between mild perioperative hypothermia, blood loss, and transfusion. Their analysis demonstrated that mild hypothermia increases blood loss by approximately 16% and increases the risk for transfusion by approximately 22%.My first question to the authors is whether perioperative antifibrinolytic exposure has confounded the results of the meta-analysis. For example, tranexamic acid was used in the one cardiac study that did not show increased blood loss or transfusion due to hypothermia.2Was antifibrinolytic therapy a major confounder across studies included in the meta-analysis? Does antifibrinolytic exposure explain the studies that documented no increased bleeding or transfusion risk due to mild hypothermia?My second question to the authors is whether these negative studies are confounded by hemostatic variations in anesthetic technique, such as induced hypotension and/or regional anesthesia.3,4I congratulate Dr. Rajagopalan et al. on their excellent article that has further highlighted the importance of perioperative euthermia. I look forward to their comments.Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. yiandoc@hotmail.com

The Effects of Mild Perioperative Hypothermia on Blood Loss and Transfusion Requirement

Anesthetic-induced hypothermia is known to reduce platelet function and impair enzymes of the coagulation cascade. The objective of this meta-analysis and systematic review was to evaluate the hypothesis that mild perioperative hypothermia increases surgical blood loss and transfusion requirement. The authors conducted a systematic search of published randomized trials that compared blood loss and/or transfusion requirements in normothermic and mildly hypothermic (34-36 degrees C) surgical patients. Results are expressed as a ratio of the means or relative risks and 95% confidence intervals (CI); P < 0.05 was considered statistically significant. Fourteen studies were included in analysis of blood loss, and 10 in the transfusion analysis. The median (quartiles) temperature difference between the normothermic and hypothermic patients among studies was 0.85 degrees C (0.60 degrees C versus 1.1 degrees C). The ratio of geometric means of total blood loss in the normothermic and hypothermic patients was 0.84 (0.74 versus 0.96), P = 0.009. Normothermia also reduced transfusion requirement, with an overall estimated relative risk of 0.78 (95% CI 0.63, 0.97), P = 0.027. Even mild hypothermia (<1 degree C) significantly increases blood loss by approximately 16% (4-26%) and increases the relative risk for transfusion by approximately 22% (3-37%). Maintaining perioperative normothermia reduces blood loss and transfusion requirement by clinically important amounts.

Perioperative Hypothermie

Mild perioperative hypothermia is a common complication of anesthesia and surgery associated with several adverse effects including impaired wound healing and more frequently leads to wound infections. Perioperative hypothermia affects the hemostasis and various immune functions and therefore interferes with the initial phases of the wound healing process. Furthermore, perioperative hypothermia contributes to wound complications by inhibition of deposition of collagen and prolongation of postoperative catabolism. Wound complications prolong hospitalization and substantially increase medical costs. Thus, maintaining normothermia perioperatively is essential to reduce the number of wound complications.

Warming of Intravenous Fluids Prevents Hypothermia During Off-Pump Coronary Artery Bypass Graft Surgery

Even mild perioperative hypothermia (34 degrees -36 degrees C) can cause numerous adverse outcomes, including morbid cardiac events, coagulopathy with increased blood loss, and a decreased resistance to surgical wound infection. The purpose of this study was to evaluate the effect of fluid warming on preventing hypothermia during off-pump coronary artery bypass (OPCAB) surgery. A prospective randomized clinical study. A tertiary care university hospital. Forty patients undergoing OPCAB procedures. Patients were randomized into control (n = 20) and Hotline (n = 20) groups. In the Hotline group, all intravenous fluids were warmed to 41 degrees C by using 2 Hotline (SIMS Inc, Rockland, MD) systems. All patients (control and Hotline groups) were managed with standardized institutional practice by using a combination of increased ambient operating room temperature (to 25 degrees C) and the use of a warmed water mattress (38 degrees C). Temperatures were recorded every hour after the induction of anesthesia at the pulmonary artery, nasopharynx, rectum, and bladder. In the Hotline group, temperatures were maintained or increased. In the control group, temperatures gradually decreased. There were no significant differences between the 2 groups in hemodynamic parameters, serum catecholamine concentrations, duration of intensive care unit stay, or duration of ward stay. The results show that the warming of intravenous fluids by using the Hotline system prevents decreases in systemic temperatures during OPCAB surgery.

Instructions for Obtaining Journal CME Credit

Anesthesiology's journal-based CME program is open to all readers. Members of the American Society of Anesthesiologists participate at a preferred rate, but you need not be an ASA member or a journal subscriber to take part in this CME activity. Please complete the following steps:The American Society of Anesthesiologists is approved by the Accreditation Council for Continuing Medical Education (ACCME) to sponsor continuing medical education programs for physicians.The American Society of Anesthesiologists designates this educational activity for a maximum of 1 AMA PRA Category 1 Credit ™. Physicians should only claim credit commensurate with the extent of their participation in the activity.Purpose: The focus of the journal-based CME program, and the articles chosen for the program, is to educate readers on current developments in the science and clinical practice of the specialty of Anesthesiology.Target Audience: Physicians and other medical professionals whose medical specialty is the practice of anesthesia.Learning Objectives: After reading this article, participants should have a better understanding of some of the factors contributing to surgical site infections and what anesthesiologists can do to reduce this complication.Authors –William J. Mauermann, M.D., and Edward C. Nemergut, M.D. Grants or research support: None Consultantships or honoraria: None The article authored by Drs. Mauermann and Nemergut was supported solely from institutional and/or departmental sources.Question Writer –Peter L. Bailey, M.D. Dr. Bailey has no grants, research support, or consultant positions, nor does he receive any honoraria from outside sources, which may create conflicts of interest concerning this CME program.Based on the article by Mauermann and Nemergut entitled “The anesthesiologist's role in the prevention of surgical site infections”http://content.wkhealth.com/linkback/openurl/trusted?issn=0003-3022&amp;volume=105&amp;issue=2&amp;spage=413&amp;part=fulltextin the August issue of Anesthesiology, choose the one correct answer for each question:1. Which of the following statements concerning surgical site infections is most likely true?A. They account for the vast majority of all hospital-acquired infections.B. They become established within a few hours of contamination.C. They typically present later than 48 hours after surgery.D. They are not related to surgical technique.2. Compared to normothermia (37 ± 0.3 °C), mild perioperative hypothermia (34–36 °C) is most likely to be associated withA. A decrease in cardiac complicationsB. Improved intraoperative hemostasisC. An increase in surgical site infectionsD. Shorter hospital length of stay3. Compared to normothermia (37 ± 0.3 °C), mild perioperative hypothermia (34–36 °C) is associated with all of the following except A. A greater degree of subcutaneous tissue vasoconstrictionB. Delayed postoperative food intakeC. A greater incidence of surgical site infectionsD. Earlier collagen deposition in surgical wounds4. Which of the following statements is most likely true?A. Decreased subcutaneous tissue oxygen tensions are associated with surgical site infections.B. Hypothermia enhances the killing of bacteria by neutrophils.C. Hypothermia decreases nitrogen loss.D. Subcutaneous tissue oxygen requirements are high.5. Which of the following statements concerning glucose and the risk for surgical site infections is most likely true?A. Hyperglycemia increases surgical site infections only in diabetic patients.B. Hyperglycemia decreases immune defense mechanisms against infection.C. Keeping glucose levels less than 250 mg/dl eliminates the increased risk of infection associated with hyperglycemia.D. Hyperglycemia is not associated with an increase in mortality in hospitalized patients.6. Which of the following statements concerning preoperative antibiotic prophylaxis for surgical site infections is most likely true?A. Prophylaxis should target as many pathogens as possible.B. Prophylaxis with a cephalosporin is not adequate for surgery requiring gram-negative and anaerobic coverage.C. Patients reporting any reaction to penicillin should not receive a cephalosporin.D. The most effective time for antibiotic administration is within 1 hour prior to skin incision.