Warttig Sheryl, Alderson Phil, Campbell Gillian, Smith Andrew F
National Institute for Health and Care Excellence, Level 1A, City Tower, Piccadilly Plaza, Manchester, UK, M1 4BD.
Cochrane Database Syst Rev. 2014 Nov 20;2014(11):CD009892. doi: 10.1002/14651858.CD009892.pub2.
Inadvertent postoperative hypothermia (a drop in core body temperature to below 36°C) occurs as an effect of surgery when anaesthetic drugs and exposure of the skin for long periods of time during surgery result in interference with normal temperature regulation. Once hypothermia has occurred, it is important that patients are rewarmed promptly to minimise potential complications. Several different interventions are available for rewarming patients.
To estimate the effectiveness of treating inadvertent perioperative hypothermia through postoperative interventions to decrease heat loss and apply passive and active warming systems in adult patients who have undergone surgery.
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Issue 2), MEDLINE (Ovid SP) (1956 to 21 February 2014), EMBASE (Ovid SP) (1982 to 21 February 2014), the Institute for Scientific Information (ISI) Web of Science (1950 to 21 February 2014) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL), EBSCO host (1980 to 21 February 2014), as well as reference lists of articles. We also searched www.controlled-trials.com and www.clincialtrials.gov.
Randomized controlled trials of postoperative warming interventions aiming to reverse hypothermia compared with control or with each other.
Three review authors identified studies for inclusion in this review. One review author extracted data and completed risk of bias assessments; two review authors checked the details. Meta-analysis was conducted when appropriate by using standard methodological procedures as expected by The Cochrane Collaboration.
We included 11 trials with 699 participants. Ten trials provided data for analysis. Trials varied in the numbers and types of participants included and in the types of surgery performed. Most trials were at high or unclear risk of bias because of inappropriate or unclear randomization procedures, and because blinding of assessors and participants generally was not possible. This may have influenced results, but it is unclear how the results may have been influenced. Active warming was found to reduce the mean time taken to achieve normothermia by about 30 minutes in comparison with use of warmed cotton blankets (mean difference (MD) -32.13 minutes, 95% confidence interval (CI) -42.55 to -21.71; moderate-quality evidence), but no significant difference in shivering was noted. Active warming was found to reduce mean time taken to achieve normothermia by almost an hour and a half in comparison with use of unwarmed cotton blankets (MD -88.86 minutes, 95% CI -123.49 to -54.23; moderate-quality evidence), and people in the active warming group were less likely to shiver than those in the unwarmed cotton blanket group (Relative Risk=0.61 95% CI= 0.42 to 0.86; low quality evidence). There was no effect on mean temperature difference in degrees celsius at 60 minutes (MD=0.18°C, 95% CI=-0.10 to 0.46; moderate quality evidence), and no data were available in relation to major cardiovascular complications. Forced air warming was found to reduce time taken to achieve normothermia by about one hour in comparison to circulating hot water devices (MD=-54.21 minutes 95% CI= -94.95, -13.47). There was no statistically significant difference between thermal insulation and cotton blankets on mean time to achieve normothermia (MD =-0.29 minutes, 95% CI=-25.47 to 24.89; moderate quality evidence) or shivering (Relative Risk=1.36 95% CI= 0.69 to 2.67; moderate quality evidence), and no data were available for mean temperature difference or major cardiovascular complications. Insufficient evidence was available about other comparisons, adverse effects or any other secondary outcomes.
AUTHORS' CONCLUSIONS: Active warming, particularly forced air warming, appears to offer a clinically important reduction in mean time taken to achieve normothermia (normal body temperature between 36°C and 37.5°C) in patients with postoperative hypothermia. However, high-quality evidence on other important clinical outcomes is lacking; therefore it is unclear whether active warming offers other benefits and harms. High-quality evidence on other warming methods is also lacking; therefore it is unclear whether other rewarming methods are effective in reversing postoperative hypothermia.
术后意外低体温（核心体温降至36°C以下）是手术的一种影响，麻醉药物以及手术期间皮肤长时间暴露会干扰正常体温调节。一旦发生低体温，迅速复温以尽量减少潜在并发症非常重要。有几种不同的复温干预措施可供选择。
评估通过术后干预减少热量散失以及对成年手术患者应用被动和主动保暖系统来治疗围手术期意外低体温的有效性。
我们检索了Cochrane对照试验中心注册库（CENTRAL）（2014年第2期）、MEDLINE（Ovid SP）（1956年至2014年2月21日）、EMBASE（Ovid SP）（1982年至2014年2月21日）、科学信息研究所（ISI）科学网（1950年至2014年2月21日）以及护理及相关健康文献累积索引（CINAHL）、EBSCOhost（1980年至2014年2月21日），以及文章的参考文献列表。我们还检索了www.controlled-trials.com和www.clinicaltrials.gov。
旨在逆转低体温的术后保暖干预措施与对照或相互之间比较的随机对照试验。
三位综述作者确定纳入本综述的研究。一位综述作者提取数据并完成偏倚风险评估；两位综述作者检查细节。在适当情况下，按照Cochrane协作网预期的标准方法程序进行荟萃分析。
我们纳入了11项试验，共699名参与者。10项试验提供了分析数据。试验纳入的参与者数量和类型以及所进行的手术类型各不相同。由于随机化程序不当或不明确，并且评估者和参与者通常无法设盲，大多数试验存在高偏倚风险或偏倚风险不明确。这可能影响了结果，但不清楚结果可能受到了怎样的影响。与使用加温棉毯相比，主动保暖被发现可使达到正常体温的平均时间缩短约30分钟（平均差（MD）-32.13分钟，95%置信区间（CI）-42.55至-21.71；中等质量证据），但寒战方面未发现显著差异。与使用未加温棉毯相比，主动保暖被发现可使达到正常体温的平均时间缩短近一个半小时（MD -88.86分钟，95% CI -123.49至-54.23；中等质量证据），并且主动保暖组的人寒战的可能性低于未加温棉毯组（相对风险=0.61，95% CI= 0.42至0.86；低质量证据）。60分钟时摄氏度的平均温差无影响（MD=0.18°C，95% CI=-0.10至0.46；中等质量证据），并且没有关于主要心血管并发症的数据。与循环热水设备相比，发现强制空气加温可使达到正常体温的时间缩短约一小时（MD=-54.21分钟，95% CI= -94.95，-13.47）。在达到正常体温的平均时间（MD =-0.29分钟，95% CI=-25.47至24.89；中等质量证据）或寒战方面（相对风险=1.36，95% CI= 0.69至2.67；中等质量证据）隔热与棉毯之间无统计学显著差异，并且没有关于平均温差或主要心血管并发症的数据。关于其他比较、不良反应或任何其他次要结局的证据不足。
主动保暖，尤其是强制空气加温，似乎能使术后低体温患者达到正常体温（36°C至37.5°C之间的正常体温）的平均时间在临床上显著缩短。然而，缺乏关于其他重要临床结局的高质量证据；因此不清楚主动保暖是否还有其他益处和危害。关于其他保暖方法的高质量证据也缺乏；因此不清楚其他复温方法是否能有效逆转术后低体温。
