Hypothermia for traumatic head injury
Editorial Group: Cochrane Injuries Group
Published Online: 15 APR 2009
Assessed as up-to-date: 6 APR 2009
Copyright © 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
How to Cite
Sydenham E, Roberts I, Alderson P. Hypothermia for traumatic head injury. Cochrane Database of Systematic Reviews 2009, Issue 2. Art. No.: CD001048. DOI: 10.1002/14651858.CD001048.pub4.
- Publication Status: New search for studies and content updated (no change to conclusions)
- Published Online: 15 APR 2009
Hypothermia has been used in the treatment of head injury for many years. Encouraging results from small trials and laboratory studies led to renewed interest in the area and some larger trials.
To estimate the effect of mild hypothermia for traumatic head injury on mortality and long-term functional outcome complications.
We searched the Cochrane Injuries Group Specialised Register, Current Controlled Trials MetaRegister of trials, Zetoc, ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED) and Conference Proceedings Citation Index-Science (CPCI-S), CENTRAL (The Cochrane Library), MEDLINE and EMBASE. We handsearched conference proceedings and checked reference lists of all relevant articles. The search was last updated in April 2009.
Randomised controlled trials of hypothermia to a maximum of 35ºC for at least 12 consecutive hours versus control in patients with any closed traumatic head injury requiring hospitalisation. Two authors independently assessed all trials.
Data collection and analysis
Data on death, Glasgow Outcome Scale and pneumonia were sought and extracted, either from published material or by contacting the investigators. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each trial on an intention-to-treat basis.
We found 23 trials with a total of 1614 randomised patients. Twenty-one trials involving 1587 patients reported data on deaths. There were fewer deaths in patients treated with hypothermia than in the control group (OR 0.85, 95% CI 0.68 to 1.06). Nine trials with good allocation concealment showed no decrease in the likelihood of death with hypothermia compared with the control group (OR 1.11, 95% CI 0.82 to 1.51). In both cases the result was not statistically significant. Twenty-one trials involving 1587 patients reported data on unfavourable outcomes (death, vegetative state or severe disability). Patients treated with hypothermia were less likely to have an unfavourable outcome than those in the control group (OR 0.77, 95% CI 0.62 to 0.94). Nine trials with good allocation concealment showed patients treated with hypothermia were less likely to have an unfavourable outcome than those in the control group, but the reduction was small and non-significant (OR 0.93, 95% CI 0.70 to 1.23). Hypothermia treatment was associated with a slight increase in the odds of pneumonia (OR 1.35, 95% CI 0.95 to 1.91) but there was a reduction in pneumonia for trials with good allocation concealment (four trials analysed separately, 306 patients, OR 0.84, 95% CI 0.52 to 1.35) although in both cases the results are not statistically significant.
There is no evidence that hypothermia is beneficial in the treatment of head injury. Hypothermia may be effective in reducing death and unfavourable outcomes for traumatic head injured patients, but significant benefit was only found in low quality trials. Low quality trials have a tendency to overestimate the treatment effect. The high quality trials found no decrease in the likelihood of death with hypothermia, but this finding was not statistically significant and could be due to the play of chance. Hypothermia should not be used except in the context of a high quality randomised controlled trial with good allocation concealment.
Plain language summary
Hypothermia (body temperature cooling) for traumatic head injury
This review includes twenty-three randomised controlled trials involving 1614 patients with traumatic head injury. In each trial, the patients were randomly divided into two groups: one group remained at normal body temperature, and the other group was cooled to a maximum of 35 degrees Celsius (or 95 degrees Fahrenheit) for at least 12 consecutive hours. Cooling could be of the whole body (e.g. with a blanket with circulating cold water), or just the head (e.g. with a helmet with circulating cold water). Information on death, disability, and pneumonia were evaluated for each trial.
The review authors found that fewer people died or became severely disabled if they were treated with hypothermia, but this finding may be due to chance. It was also found that patients given hypothermia were more likely to develop pneumonia, and some patients died from pneumonia, but the increased risk of pneumonia could also be due to chance.
Some of the trials included in the review were of low methodological quality. Low quality trials have a tendency to overestimate the effect of a treatment. In this review, the lower quality trials showed hypothermia treatment to be somewhat effective in reducing death and disability among patients with head injury. However, the good quality trials showed no decrease in the likelihood of death with hypothermia treatment and a reduced likelihood of pneumonia. Some of the findings in this review are therefore contradictory, and this is probably due to the inclusion of data from low quality trials.
The review authors conclude that there is no evidence that hypothermia is beneficial in the treatment of head injury. Most of the positive and negative effects found may be due to chance. Hypothermia should not be used except in the context of a randomised controlled trial with good allocation concealment.
我們搜尋了Cochrane Injuries Group Specialised Register, Current Controlled Trials MetaRegister of trials, Zetoc, ISI Web of Science: Science Citation Index Expanded (SCIEXPANDED)以及Conference Proceedings Citation IndexScience (CPCIS), CENTRAL (The Cochrane Library), MEDLINE 以及 EMBASE。我們手查了會議的議程並且檢查了所有相關論文的參考文獻。最後一次搜尋的更新在2009年4月。
分別從發表的文章或接觸研究者取得資料，搜尋及擷取的資料包括死亡率、昏迷指數和肺炎比率。Odds ratios 與 95%信賴區間由 intentiontotreat 的基礎計算出。
我們找了總共包括 1094位隨機分配患者的23個臨床試驗。其中有21個臨床試驗報告了死亡資料，這些試驗總共包含1587位患者。其中相較於對照組，低溫治療的患者死亡較少(OR 0.85, 95% CI 0.68 to 1.06)。而具有較好分配遮蔽的9個試驗顯示，相較於對照組，低溫治療並沒有降低死亡的可能性(OR 1.11, 95% CI 0.82 to 1.51)。結果在統計上並無明顯差異.21個臨床試驗包含1587位患者顯示出不好的結果(死亡率,植物人或嚴重失能). 相較於控制組,低溫治療的病人較不會有不好的結果(OR 0.77, 95% CI 0.62 to 0.94). 相較於對照組，具有較好分配遮蔽的9個試驗顯示低溫治療的病人較不會有不好的結果,但降低的比率小且不明顯(OR 0.93, 95% CI 0.70 to 1.23). 低溫治療可能與肺炎風險稍微增加有關(OR 1.35, 95% CI 0.95 to 1.91), 但在較好分配遮蔽的試驗顯示低溫治療會降低肺炎風險(四個試驗306個病人個別分析,OR 0.84, 95% CI 0.52 to 1.35), 雖然結果在統計上並無明顯差異.
治療性低體溫對頭部創傷的病人 這篇回顧性文獻包括的23個臨床試驗1614位頭部創傷患者.每一個臨床試驗,患者隨機分配成兩個族群:一群維持正常體溫,另一群輕微低溫控制到攝氏35度C(華氏95度F)並且至少持續12小時.低溫控制可達全身(有著冰水循環的毯子)或只有頭部低溫控制(有著冰水循環的頭盔). 評估每一個臨床試驗的死亡率,失能與肺炎發生率.這篇回顧性文獻作者發現少數病患因治療性低體溫而導致死亡或嚴重失能,但可能是因為機率的關係.此外也發現治療性低體溫的病患較有可能發生肺炎且有些病患死於肺炎但這種增加的風險也有可能是因為機率的關係. 這篇回顧性文獻中,包含某些低方法學品質 的臨床試驗,低品質的試驗可能會高估治療效果.文獻中,低品質的試驗對於頭部創傷患者顯示出治療性低體溫對於降低死亡率與失能可能有效.然而,高品質的試驗發現治療性低體溫並不會降低死亡與肺炎的可能性. 這篇回顧性文獻中的某些發現是矛盾的,這可能是由於包含低品質臨床試驗所致. 回顧性文獻作者總結:沒有證據顯示治療性低體溫對頭部創傷的病人有益處.大部分正面或負面的效果皆可能是因為機率的關係. 除了在有較好分配遮蔽的臨床隨機試驗文章,一般而言,治療性低體溫不被建議使用.