Background Inadvertent hypothermia is common in patients undergoing surgical procedures with a reported prevalence of perioperative hypothermia ranging from 50% to 90%. Hypothermia within the perioperative environment may have many undesired physiological effects that are associated with postoperative morbidity. There are different options for treating and/or preventing hypothermia within the adult perioperative environment, which include active and passive warming methods. This systematic review was undertaken to provide comprehensive evidence on the most effective strategies for prevention and management of inadvertent hypothermia in the perioperative environment.
Objective The objective of this review was to identify the most effective methods for the treatment and/or preventions of hypothermia in intraoperative or postoperative patients.
Inclusion criteria Adult patients ≥18 years of age, who underwent any type of surgery were included in this review. Types of interventions included were any type of linen or cover, aluminium foil wraps, forced-air warming devices, radiant warming devices and fluid warming devices. This review considered all identified prospective studies that used a clearly described process for randomisation, and/or included a control group. The primary outcome of interest was change in core body temperature.
Review methods Two independent reviewers assessed methodological validity of papers selected for retrieval and any disagreements were resolved through discussion.
Results Nineteen studies with a combined 1451 patients who underwent different surgical procedures were included in this review. Meta-analysis was not possible. Forced-air warming in pregnant women scheduled for caesarean delivery under regional anaesthesia prevented maternal and foetal hypothermia. Intravenous and irrigating fluids warmed (38–40°C) to a temperature higher than that of room temperature by different fluid warming devices (both dry and water heated) proved significantly beneficial to patients in terms of stable haemodynamic variables, and higher core temperature at the end of the surgery.
Water garment warmer was significantly (P < 0.05) effective than forced-air warming in maintaining intraoperative normothermia in orthotopic liver transplantation patients. Extra warming with forced air compared to routine thermal care was effective in reducing the incidence of surgical wound infections and postoperative cardiac complications.
Passive warming with reflective heating blankets or elastic bandages wrapped around the legs tightly were found to be ineffective in reducing the incidence or magnitude of hypothermia.
Conclusion There are significant benefits associated with forced-air warming. Evidence supports commencement of active warming preoperatively and monitoring it throughout the intraoperative period. Single strategies such as forced-air warming were more effective than passive warming; however, combined strategies, including preoperative commencement, use of warmed fluids plus forced-air warming as other active strategies were more effective in vulnerable groups (age or durations of surgeries).
Implications for practice • Use active warming strategies
• Commence warming preoperatively
• In extended surgeries or aged patients use multiple active warming strategies
• Warm fluids designated for intraoperative administration
• Consider pharmacotherapeutic strategies in preference to no treatment/prevention
Implications for research Future research should focus on large, high quality randomised controlled trials looking at long-term clinical outcomes, operating temperature forced-air warming devices, different body sites and percentage of body coverage area of active warming.