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1 Infection Prevention Division Essentials EDU Learning Program UNINTENDED HYPOTHERMIA: THE IMPORTANCE OF MAINTAINING NORMOTHERMIA Disclosure Sponsored by Arizant Healthcare Inc., a 3M company 3M Health Care is a provider approved by the California Board of Registered Nursing Registered nurse participants can receive up to 1.0 contact hour upon course completion Presented by Linda West Clinical Specialist Arizant Healthcare Inc. 3M Infection Prevention Division Introduction Perioperative hypothermia is defined as any core temperature less than 36.0 C (96.8 F) 1-3 Inadvertent perioperative hypothermia is considered a frequent, preventable complication of surgery Unless preventative measures are taken, inadvertent hypothermia occurs in 50% to 90% of surgical patients 1 Research shows that even mild hypothermia can result in significant negative outcomes 1

2 Introduction The induction of anesthesia can cause a drop in patient core temperature of up to 1.6 C on average within the first hour 2 Even mild hypothermia can lead to adverse outcomes and additional costs 3 mp ( C) Δ Core Tem Characteristic Patterns of General Anesthesia-Induced Hypothermia 1hr -1.6 C Elapsed Time (h) Adapted from: Sessler, Anesth, 2000 Course Objectives Explain how the body s thermoregulation system works Define unintended perioperative hypothermia Define and explain the principle mechanisms of heat loss in the surgical patient Identify adverse patient outcomes associated with unintended perioperative hypothermia Identify areas where cost savings can be recognized by maintaining normothermia Review the effectiveness of currently available warming modalities Explain the benefit of prewarming to help prevent unintended perioperative hypothermia Attest Sterile U Network THE THERMOREGULATION SYSTEM Presentation Title 2

3 Normothermia Normothermia: the body s ideal thermal state Core temperature: C (98.6 F) Temperature gradient: 2-4 C between the core and periphery 37 o C periphery 2-4 o C cooler Hypothalamus The hypothalamus regulates the body s core temperature 3-4 Thermoreceptors are used by the hypothalamus to respond to temperature 3-4 Thermoreceptors are located in: 3-4 Skin Spinal cord Brain Deep central tissues Hypothalamus Behavioral Changes to Body Temperature Behavioral changes to temperature are prompted by thermal discomfort 3 Responses may include: 3 Adding or removing clothing Adjusting ambient temperature Moving to cooler or warmer areas 3

4 Surgical Patients Response to Body Temperature Anesthetized surgical patients: Cannot regulate temperature through behavior changes Rely on body s thermoregulation system - and clinician intervention - to regulate temperature Interthreshold Range Interthreshold range: 3 Acceptable limits of core body temperature Body s response to cold: 3 Vasoconstriction NST Shivering Body s response to heat: 3 Vasodilation Sweating Interthreshold Range Vasoconstriction NST Vasodilation Shivering Sweating 33 C 35 C 37 C 39 C 41 C Attest Sterile U Network FACTORS CAUSING UNINTENDED HYPOTHERMIA Presentation Title 4

5 Primary Causes of Perioperative Hypothermia Unintended Hypothermia: Any core temperature <36 C (96.8 F) 1-3 Primary causes of perioperative hypothermia include: 2-3 Administration of anesthetic drugs leading to temperature redistribution General anesthesia Regional anesthesia Cold O.R. temperatures Exposed body cavities Infusion of cold fluids and blood General Anesthesia Patients cannot regulate their core temperature to the optimal set point under general anesthesia 3 Inability to rely on behavioral responses Rely on autonomic thermoregulation system to respond Anesthetic agents inhibit the autonomic system by: 3 Reducing metabolism Depressing hypothalamus Metabolic Heat Production 40-year-old (70kg) patient 5 Awake: 70 kilocalories heat/hour Anesthetized: 42 kilocalories 80-year-old (70kg) patient 5 Awake: 60 kilocalories heat/hour Anesthetized: 38 kilocalories ries/hr Kilocalor Metabolic Heat Production Awake Year-Old 80-Year-Old Anesthetized Adapted from: Morrison, International Anesthesiology Clinics,

6 Anesthesia-Impaired Response to Temperature The hypothalamic response to regulate temperature is degraded 3 Interthreshold range widens to 4 C 3 Anesthetized patients get warmer or colder before thermoregulatory responses are triggered 3 Vasoconstriction NST Shivering Anesthesia-Impaired Response to Temperature Vasodilation 33 C 35 C 37 C 39 C 41 C Hypothermia <36.0 C Sweating Heat Redistribution Characteristic Patterns of General Anesthesia-Induced Hypothermia An average core temperature drop of 1.6 C can occur in the first hour of general anesthesia 2 81% from core-to-peripheral heat redistribution known as redistribution temperature drop 2 C) Δ Core Temp ( 2 Characteristic Patterns of General Anesthesia-Induced Hypothermia hr -1.6 C Elapsed Time (h) Adapted from: Sessler, Anesth,

7 Phases of Unplanned Hypothermia 0 Phase I: Rapid decrease in core temperature 2-1 Phase II: Slow, linear decline in Δ Core Temp ( C) temperature 2-2 Phase III: Temperature plateau 2-3 1hr Elapsed Time (h) Adapted from: Sessler, Anesth, 2000 Regional Anesthesia Similar process of hypothermia as compared to general anesthesia 3 Central and peripheral thermoregulatory functions impaired 3 Nerve blocks prevent normal responses and disrupt nerve conduction 3 Skin temperatures in blocked areas misjudged by thermoreceptors 3 Regional Anesthesia Patients often feel warmer due to incorrect perceptions of thermoreceptors in blocked areas 3 Hypothermia is frequently undetected in patients under regional anesthesia because: 3 Core temperatures are not monitored as frequently Patients do not typically express feelings of thermal discomfort 7

8 Cold Environment Heat loss exacerbated by cold environment in most O.R.s O.R. temperatures are C ( F) Heat moves from warmer to colder object or area Surgical Procedure Heat loss due to surgical procedure During prep and surgery, large areas of skin are exposed to the cold O.R. Surgical incisions exposing internal organs also contribute Additional Causes of Heat Loss Additional causes of unplanned perioperative hypothermia may include: Length of surgery Blood and fluid loss Wet skin preps Anesthesia is the primary cause of unintended hypothermia in surgical patients 8

9 Mechanisms of Heat Transfer Radiation 4 Heat loss to cold environment Convection 4 Heat loss from body surface into air currents Conduction 4 Heat loss due to contact with another object Evaporation 3-4 Heat loss from moisture on the body s surface changing from a liquid to a gaseous state Attest Sterile U Network EFFECTS OF UNINTENDED HYPOTHERMIA Presentation Title Adverse Effects of Unintended Hypothermia There are many documented adverse effects of unintended hypothermia including: 6 Wound infection Myocardial ischemia and cardiac disturbances Coagulopathy Prolonged and altered drug effect Increased mortality Shivering and thermal discomfort Delayed emergence from anesthesia 9

10 SSIs and Normothermia Improving patient safety and reducing surgical complications, such as SSIs, are an important focus for healthcare Maintaining normothermia has been identified as a key contributor to reducing SSIs by various organizations The Numbers are Staggering Hospital infections, including SSIs, are the fourth largest killer in the U.S., claiming more lives than AIDS, breast cancer and traffic accidents combined 7 SSIs may result in yearly medical costs of $1 to $10 billion 8 Patients who acquire SSIs are more likely to be: 9 Readmitted to the hospital Admitted to the ICU Two times more likely to die Surgical Wound Infections Hypothermic colorectal surgical patients with mild hypothermia have: 10 20% 15% 10% 5% 0% Hypothermic 10 Infection Rate Length of Hospital Stay Normothermic Days Patients with wound infections Patients without wound infections Adapted from: Kurz et al., New Engl J Med, 1996 Adapted from: Kurz et al., New Engl J Med,

11 Myocardial Ischemia and Cardiac Disturbances Hypothermia contributes to an increase in morbid myocardial events and ventricular tachycardia % 60% 6.0% 5.0% 4.0% 3.0% 2.0% 1.0% 0.0% Morbid Cardiac Events Hypothermic Normothermic % 8.0% 6.0% 4.0% 2.0% 0.0% Ventricular Tachycardia Hypothermic Normothermic 11 Adapted from: Frank et al., JAMA, 1997 Adapted from: Frank et al., JAMA, 1997 Coagulopathy Blood loss is higher in hypothermic patients during surgery and 1000 postoperatively Even a core temperature drop of <2 C was found to 400 increase blood loss by mL (1 unit) 12 0 ml End of Surgery Blood Loss 12 Hypothermic Normothermic Adapted from: Schmied et al., The Lancet, 1996 Coagulopathy Increased allogeneic blood required for hypothermic patients12, 14 Hypothermia may: 12 Impair platelet function Reduce clotting Increase fibrinolysis Units of Blood Allogeneic Blood Required Hypothermic Normothermic Adapted from: Schmied et al., The Lancet,

12 Prolonged and Altered Drug Effect Drug metabolism is reduced by hypothermia Vecuronium, a neuromusclar 60 blocking agent, was found to 50 have an average duration of: ±4 minutes in normothermic 30 patients 20 62±8 minutes in hypothermic patients s Minutes 10 0 Duration of Action of 15 Vecuronium Hypothermic Normothermic Adapted from: Heier et al., Anesth, 1991 Increased Mortality Increase in morbidity and mortality rates postoperatively 16 The mortality rate for the hypothermia group was 12.1% versus a rate of 1.5% for the normothermic group % 12.0% 10.0% 8.0% 6.0% 4.0% 2.0% 0.0% Mortality Rate 16 Hypothermic Normothermic Adapted from: Bush et al., J Vasc Surg, 1995 Shivering Shivering occurs in 40-60% of unwarmed patients recovering from general anesthesia 3,10 Some patients have expressed the feelings of thermal discomfort and shivering to be more significant than post-surgical pain 3 It is rare to see intense shivering postanesthetically in patients with normothermic temperatures 6 12

13 Thermal Comfort A study by Fossum, et al found that: Thermal comfort is greater in actively warmed patients 17 No actively warmed patients verbalized being cold 17 66% reported most comfortable on a comfort scale Warmth is the top nursing concern, followed by pain management and position 18 Maintaining normothermia is important clinically and as a means of increasing patient comfort10, Delayed Emergence from Anesthesia Hypothermic patients need an average of 90 minutes longer in PACU vs. normothermic patients 14 Maintaining normothermia is likely to decrease PACU time % Not Fit for Discharge 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Normothermic Recovery from Anesthesia Hypothermic Time (min) Adapted from: Lenhardt et al., Anesth, 1997 Attest Sterile U Network MAINTAINING NORMOTHERMIA: OUTCOMES AND ECONOMICS Presentation Title 13

14 Benefits of Normothermia Studies have suggested that maintaining normothermia may yield positive results such as: 19 Reduction in the use of blood products Shortened length of stay Decreased ICU time Reduced rate of wound infection Decreased likelihood of myocardial infarction Lower mortality rates Meta-Analysis Results Meta-Analysis Results 19 Cost Savings Range Blood products $227 - $344 Hospital stay $1,534 - $4,602 ICU time $105 - $314 Wound infections $549 - $1,697 Myocardial infarction $68 - $90 Mechanical ventilation $16 - $26 Mortality Undefined Total Per Patient Savings $2,495 - $7,073 Adapted from: Mahoney, Odom, AANA Journal, 1999 UK Clinical Practice Guideline UK Clinical Practice Guideline Consequences 20 Unit cost (GBP) Unit cost (USD) Surgical wound infection (minor surgery) 950 $1,508 Surgical wound infection (major surgery) 3858 $6,125 Transfusion 244 $387 Morbid cardiac event (ischemia) 2024 $3,213 Morbid cardiac event (cardiac arrest) 2021 $3,208 Morbid cardiac event (myocardial infarction) 1674 $2,658 Mechanical ventilation 1144 $1,816 Pressure ulcer 1064 $1,689 PACU length of stay per hour 44 $70 Hospital length of stay per hour 275 $437 Adapted from: NICE, Clinical Practice Guideline, GBP= USD (1/26/11) Source: 14

15 Attest Sterile U Network HOW TO MAINTAIN NORMOTHERMIA Presentation Title Modalities for Warming There are a variety of warming modalities: 21 Heated humidifiers Heated moisture exchangers Warm cotton blankets Thermal drapes Circulating water mattresses Electric conductive pads and covers Forced-air warming Fluid warming GOAL: Maintain patient core temperature ( 36 C) Active Warming vs. Passive Warming It is important to understand the differences between active warming and passive warming Active warming is the active application of heat, i.e. forced-air warming or conductive warming Passive warming uses insulative techniques, i.e. cotton blankets or surgical drapes Active warming with forced-air warming is referenced as the standard of care for managing perioperative normothermia

16 ) ) Relative Effectiveness Forced-air warming is the most effective method Effects of Warming Methods on for maintaining Mean Body normothermia Temperature ody Change in Mean Bo Temperature ( C) Hours Adapted from: Sessler, Anesth Clin N Am, 1994 Airway Heating and Humidification Less than 10% of heat is lost through the respiratory tract, making airway heating minimally i ody Change in Mean Bo Temperature ( C) effective 6, Relative Effectiveness: The Effects of Warming Methods on Mean Body Temperature Hours Adapted from: Sessler, Anesth Clin N Am, 1994 Cotton Blankets Cotton blankets are passive insulators they do not provide active warming 26 Heat from a warmed cotton blanket is quickly lost to its surroundings 26 Patient heat loss is virtually identical with warmed and unwarmed cotton blankets 26 16

17 ) Conductive Warming There are various conductive warming methods such as: Circulating water mattresses Warm water garments Resistive electric covers Heated pads Conductive modalities are designed to be in direct contact with the patient s skin to improve heat transfer from the device to the patient Heat is provided where there is surface-to-surface contact Circulating Water Mattresses Heat moves from warm mattress to colder body with surface-to-surface contact 21 Heat transfer effectiveness is limited to: 22 The relatively small body surface area in contact with the mattress Surface contact areas that are typically poorly perfused Combination of heat and pressure can increase potential for thermal injury ody Change in Mean Bo Temperature ( C) Relative Effectiveness: The Effects of Warming Methods on Mean Body Temperature Hours Adapted from: Sessler, Anesth Clin N Am, 1994 Resistive-Electric Modalities Recent studies on the effectiveness of resistiveelectric warming modalities versus forced-air warming have found: Combined use of two resistive-electric blankets (both over-the-body and under-the-body) produced non-inferior core temperature results after elective orthopedic surgery when compared to a single forced-air warming upper body blanket. 27 Patients warmed with a forced-air full body blanket were re-warmed two times faster than a resistive-electric full body warming blanket following major maxillary tumor surgery

18 Forced-Air Warming Effective due to convection and radiation Heat transfer is due to the gentle dispersion of warmed air across the patient s skin Forced-air blankets transfer more heat while operating at a relatively low temperature Forced-air warming has been found to be the most effective warming therapy3,10, 21-24, Forced-Air Warming Forced-air warming provides effective warming therapy, even when only 50% of the patient s body surface is covered during surgery Patient Core Temperature ( C) Forced-Air Warming Control End Time (min) 29 Adapted from: Camus et al., Anesth Analg, 1993 Forced-Air Warming Effectiveness In a study by Ouellette: 30 Patient with forced-air warming maintained temperatures 36.2 C Temperatures were maintained even with <50% patient body surface covered ture (C) Patient Temperat Outcomes of Warming Modalities 30 Start 30 min. 60 min. 90 min. End Forced-air warming Humidifier Space blanket Humidistat Control Adapted from: Ouellette, J AANA,

19 Advances in Forced-Air Warming Systems Under-the-body blankets are a recent advance in forced-air warming systems Under-the-body blankets are used during procedures requiring full-access to the patient, or where traditional over-the-body blankets cannot be used Forced-Air Warming: Clinical Evidence Nearly 170 studies published on the safety and effectiveness Including >60 randomized controlled trials Forced-air warming is the only patient warming modality with peer-reviewed clinical outcomes data proving effectiveness in maintaining normothermia resulting in a reduction of SSIs 10 Facts about Forced-Air Warming A summary of clinical evidence: Numerous studies show forced-air warming does not increase bacterial contamination of O.R.s Huang, et al. found a decrease in bacterial count at the surgical site when forced-air warming was used 37 Olmsted, et al. found forced-air warming had no negative effects on air quality in the O.R. 38 Single-use, disposable blankets reduce the risk of crosscontamination No infection has ever been linked to the use of a forced-air warming system 19

20 Fluid Warming Helps prevent hypothermia as an adjunct warming therapy Generally does not transfer enough heat to increase patient temperature 21 Prevents additional patient cooling caused by cold blood or IV solutions 21 Fluid Warming Infusing cold fluids can produce hypothermia in surgical patients 21 Each liter of fluid infused at ambient temperature (or blood at 4 C) can decrease the mean body temperature by about 0.25 C 21 in Mean Body erature ( C) Change Tempe Fluid Temperature 21 Fluid at 38 C Administrated Fluids (L) Adapted from: Sessler, Anesth Clin N Am, 1994 Water Bath vs. Dry Heat Fluid Warming Systems Water Bath Fluid Warming Systems Use warm water to transfer heat Water has been identified as a potential source of nosocomial pathogens 40 Potential source of bacteria growth when not properly maintained 41 Dry Heat Fluid Warming Systems Use warming cassettes inserted between metal warming plates Eliminate potential a source of nosocomial pathogens because no water is used 20

21 Attest Sterile U Network PREWARMING Presentation Title Definition of Prewarming Prewarming is the application of heat prior to surgery for the purpose of increasing the total heat content of the body Prewarming can increase the temperature of the periphery, which means that the temperature gradient within the body s core is reduced Prewarming and Heat Redistribution Core temperature drop happens too quickly for active warming to compensate during the first hour following anesthesia induction 42 emp ( C) 2 Characteristic Patterns of General Anesthesia-Induced Hypothermia C -2 In essence, the ability to 1hr maintain normothermia in the -3 O.R. depends on the length of surgery and the time required to re-warm following temperature drop 42 Elapsed Time (h) Adapted from: Sessler, Anesth, 2000 Δ Core Te

22 Prewarming Benefits minutes of prewarming with forced-air warming can bank heat in the periphery and reduce or eliminate redistribution temperature drop 42 It is not possible to clinically warm patients with warmed I.V. fluids alone 21 Prewarming with active forced-air warming is the only practical way to offset redistribution temperature drop Attest Sterile U Network QUALITY IMPROVEMENTS: PATIENT NORMOTHERMIA AND SSI Presentation Title Focus on SSI Reduction Surgical site infections (SSI) are costly and prevalent 90-day costs of $86,833 per patient with an SSI, while surgeries without adverse events average just $18, Preventing each infection can result in a reduced length of hospital stay of up to one week, and savings of $3,151 on average 9 SSIs represent 40% of all hospital-acquired infections in surgical patients 44 22

23 Normothermia and SSI Reduction There is no longer a question whether maintenance of normal core body temperature is important for decreasing the incidence of SSI; the answer is unequivocally yes Barie, PS. Surgical Site Infections: Epidemiology and Prevention. Surgical Infections. Vol 3, Supplement 2002; S-9 S-21. Best Practices for Preventing SSIs Clipping Remove hair appropriately Antibiotics Use prophylactic p antibiotics appropriately Temperature Maintain normothermia Sugar Maintain glucose control Rationale for Normothermia Measures Scientific literature is strong The practice gaps are substantial Effective management is inexpensive, low risk, and easy to implement The most commonly used warming systems are remarkably safe There are few, if any, anesthetic interventions that have been proven to so markedly improve the outcome of surgery with so little effort, risk, and cost, making this a nearly ideal area for performance measurement and improvement Hannenberg A, Sessler DI. Improving Perioperative Temperature Management. Anesth Analg. 2008;107:

24 Normothermia: An Important Topic JC CMS SCIP CDC Patient Normothermia IHI WHO ASPAN ASA AORN Proven Method of Warming Forced-air warming is included in pay-forperformance quality measures Forced-air warming is the standard of care in preventing unintended hypothermia and its consequences 22-25, CMS SCIP-Infection-10 Perioperative Temperature Management Measure 51 Numerator Active warming used intraoperatively OR At least one temp 36.0 C within 30 minutes immediately before or 15 minutes immediately after anesthesia end time Denominator All patients undergoing surgical procedures under general or neuraxial anesthesia of 60 minutes or longer 24

25 CMS SCIP-Infection-10 Perioperative Temperature Management Measure 51 What this means for facilities: 1. Warming more patients regardless of age 2. Warming more procedures* regardless of complexity 3. Ensuring normothermia Normothermia is the goal *Excludes cardiac bypass procedures Attest Sterile U Network CONCLUSION Presentation Title Conclusion Perioperative hypothermia is defined as any core temperature less than 36.0 C (96.8 F) 1-3 Inadvertent perioperative hypothermia is considered a frequent, preventable complication of surgery Unless preventative measures are taken, inadvertent hypothermia occurs in 50% to 90% of surgical patients 1 Research shows that even mild hypothermia can result in significant negative outcomes 25

26 Course Objectives Explain how the body s thermoregulation system works Define unintended perioperative hypothermia Define and explain the principle mechanisms of heat loss in the surgical patient Identify adverse patient outcomes associated with unintended perioperative hypothermia Identify areas where cost savings can be recognized by maintaining normothermia Review the effectiveness of currently available warming modalities Explain the benefit of prewarming to help prevent unintended perioperative hypothermia Infection Prevention Division Attest Sterile U Network Questions? Presentation Title References 1. Young V, Watson M. Prevention of Perioperative Hypothermia in Plastic Surgery. Aesthetic Surgery Journal. 2006; Sessler, DI. Perioperative Heat Balance. Anesth. 2000;92: Sessler DI. Current concepts: Mild Perioperative Hypothermia. New Engl J Med. 1997; 336(24): Guyton AC, Hall JE. Textbook of Medical Physiology. 10 th Ed Morrison RC. Hypothermia in the elderly. International Anesthesiology Clinics (2): Sessler DI, Kurz A. Mild Perioperative Hypothermia. Anesthesiology News. October 2008: Return to Previous Slide 7. Kohn L, Corrigan J, Donaldson M. To err is human: building a safer health system. Washington DC: Institute of Medicine, National Academy Press, Perencevich EN, Sands KE, Cosgrove SE, Guadagnoli E, Meara E, Platt R. Health and economic impact of surgical site infections diagnosed after hospital discharge. Emerging Infectious Diseases, 2003 Feb. 9. Kirkland KB, Briggs JP, Trivette SL, Wilkinson WE, Sexton DJ. The impact of surgical-site infections in the 1990s: attributable mortality, excess length of hospitalization, and extra costs. Infection Control Hospital Epidemiology, 1999;20: Kurz A, Sessler DI, et al. Perioperative Normothermia to Reduce the Incidence of Surgical-Wound Infection and Shorten Hospitalization. New Engl J Med. 1996;334: Frank SM, Fleisher LA, Breslow MJ, et al. Perioperative maintenance of normothermia reduces the incidence of morbid cardiac events. JAMA. 1997;277: Schmied H, Kurz A, et al. Mild hypothermia increases blood loss and transfusion requirements during total hip arthroplasty. The Lancet. 1996;347(8997): Rajagopalan S, et al. The Effects of Mild Perioperative Hypothermia on Blood Loss and Transfusion Requirement. Anesth. 2008; 108: Lenhardt R, Marker E, Goli V, et al. Mild Intraoperative Hypothermia Prolongs Postanesthetic Recovery. Anesth. 1997; 87(6): Heier T, Caldwell JE, Sessler DI, et al. Mild Intraoperative Hypothermia Increases Duration of Action and Spontaneous Recovery of Vecuronium Blockade during Nitrous Oxide-Isoflurane Anesthesia in Humans. Anesth. 1991;74(5):

27 References 16. Bush H Jr., Hydo J, Fischer E, et al. Hypothermia during elective abdominal aortic aneurysm repair: The high price of avoidable morbidity. J Vasc Surg. 1995;21(3): Fossum S, Hays J, Henson MM. A Comparison Study on the Effects of Prewarming Patients in the Outpatient Surgery Setting. J PeriAnesth Nurs. 2001;16(3): Wilson L, Kolcaba K. Practical Application of Comfort Theory in the Perianesthesia Setting. J PeriAnesth Nurs. 2004;19(3): Mahoney CB, Odom J. Maintaining intraoperative normothermia: A meta-analysis of outcomes with costs. AANA Journal. 1999;67(2): National Collaborating Centre for Nursing and Supportive Care commissioned by National Institute for Health and Clinical Excellence. Clinical Practice Guideline: The management of inadvertent perioperative hypothermia in adults. April Sessler DI. Consequences and treatment of perioperative hypothermia. Anesth Clin N Am. 1994;12(3): Hynson JM, Sessler DI. Intraoperative warming therapies: a comparison of three devices. J Clin Anesth. 1992; 4: Return to Previous Slide 23. Kurz A, Kurz M, Poeschl G, et al. Forced-Air Warming Maintains Intraoperative Normothermia Better Than Circulating-Water Mattresses. Anesth Analg. 1993;77(1): Borms S, Engelen S, Himpe D, et al. Bair Hugger Forced-Air Warming Maintains Normothermia More Effectively Than Thermo-Lite Insulation. J Clin Anesth. 1994;6: Brauer A, Pacholik L, et al. Conductive Heat Exchange with a Gel-Coated Circulating Water Mattress. Anesth Analg. 2004;99: Sessler DI, Schroeder M. Heat Loss in Humans Covered with Cotton Hospital Blankets. Anesth Analg. 1993; No. 1: Nguyen HH, et al. A New Underbody Resistive Warming Device vs. Forced Air Warming to Prevent Perioperative Hypothermia. ASA abstracts, A Plattner O, et al. Comparison of Forced-Air and a New Resistive Warming Device for Intraoperative Rewarming. ASA abstracts, A Camus Y, Delva E, et al. Leg Warming Minimizes Core Hypothermia During Abdominal Surgery. Anesth Analg. 1993;77: Ouellette RG. Comparison of four intraoperative warming devices. J AANA (4): Zink RS, Iaizzo PA. Convective warming therapy does not increase the risk of wound contamination in the operating room. Anesth Analg. 1993; 76(1): Hall AC, Teenier T. Bair Hugger does not increase microbial contamination in the Operating Room. 1991; PGA poster presentation. 33. Moretti B, et al. Active warming systems to maintain perioperative normothermia in hip replacement surgery: a therapeutic aid or a vector of infection? The Journal of Hospital Infection. 2009; 73: References Return to Previous Slide 34. Memarzadeh F. Active warming systems to maintain perioperative normothermia in hip replacement surgery. J Hosp Infect (2010), doi: /j.jhin Miyazaki H, Sato M, Okazaki K. Forced-air warmer did not increase the risk of contamination caused by interference of clean airflow. Anesth. 2007;107:A Sharp RJ, et al. Do warming blankets increase bacterial counts in the operating field in a laminar-flow theatre? J Bone Joint Sur. B2002; 84-B: Huang JK, Shah EF, Vinodkumar N, Hegarty MA, Greatorex RA. The Bair Hugger patient warming system in prolonger vascular surgery: an infection risk? Crit Care. 2003;7:R Olmsted RN, Kulpmann R, Schlautmann B. (2010, October). Effect of Forced-Air Warming on Operating Theatre Air Quality: assessment using submicron particle release. Poster session presented at the 7 th International Conference of the Hospital Infection Society. Liverpool, U.K.*This study was funded in part by Arizant Healthcare. 39. Sladen RN. Thermal Regulation in Anesthesia and Surgery. ASA Refresher Courses in Anesthesiology. Ed. Paul G. Barash, Burns S. A continued threat. Managing Infection Control. August 2003, pp Burns S. An investigation of surgical infections reveals a fluid warmer as a reservoir for bacteria. American Journal of Infection Control. 1999; 27(2): Sessler DI, Schroeder M, Merrifield B, et al. Optimal duration and temperature of prewarming. Anesth. 1995: 82(3): Agency for Healthcare Research and Quality. Impact of Medical Errors on 90-day Costs and Outcomes: An Examination of Surgical Patients. Health Services Research; July Institute for Healthcare Improvement. Getting Started Kit: Prevent Surgical Site Infections Barie, PS. Surgical Site Infections: Epidemiology and Prevention. Surgical Infections. Vol 3, Supplement 2002; S-9 S Hannenberg A, Sessler DI. Improving Perioperative Temperature Management. Anesth Analg : US Centers for Medicare and Medicaid Services. Specifications manual for the national hospital inpatient quality measures US Centers for Medicare and Medicaid Services physician quality reporting initiative measure specifications manual for claims and registry reporting of individual measures Sessler SI, Moayeri A. Skin-surface warming: heat flux and central temperature. Anesth. 1990; 73: Giesbrecht GG, Ducharme MB, McGuire JP. Comparison of forced-air patient warming systems for perioperative use. Anesth. 1995; 80: Specifications Manual for National Hospital Inpatient Quality Measures Discharges (4Q09) through (1Q10) 27