Scolaris Content Display Scolaris Content Display

Study flow diagram.
Figures and Tables -
Figure 1

Study flow diagram.

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all 37 included studies.
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Figure 2

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all 37 included studies.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.Note: blank spaces in risk of bias table indicate that the relevant outcome was not reported by study authors
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Figure 3

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Note: blank spaces in risk of bias table indicate that the relevant outcome was not reported by study authors

Funnel plot of comparison 1: Therapeutic cooling versus no cooling, outcome: 1.1 Mortality.
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Figure 4

Funnel plot of comparison 1: Therapeutic cooling versus no cooling, outcome: 1.1 Mortality.

Comparison 1 Therapeutic cooling versus no cooling, Outcome 1 Mortality.
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Analysis 1.1

Comparison 1 Therapeutic cooling versus no cooling, Outcome 1 Mortality.

Comparison 1 Therapeutic cooling versus no cooling, Outcome 2 Unfavourable outcome.
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Analysis 1.2

Comparison 1 Therapeutic cooling versus no cooling, Outcome 2 Unfavourable outcome.

Comparison 1 Therapeutic cooling versus no cooling, Outcome 3 Pneumonia.
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Analysis 1.3

Comparison 1 Therapeutic cooling versus no cooling, Outcome 3 Pneumonia.

Comparison 2 Therapeutic cooling versus no cooling: by duration, Outcome 1 Mortality.
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Analysis 2.1

Comparison 2 Therapeutic cooling versus no cooling: by duration, Outcome 1 Mortality.

Comparison 2 Therapeutic cooling versus no cooling: by duration, Outcome 2 Unfavourable outcome.
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Analysis 2.2

Comparison 2 Therapeutic cooling versus no cooling: by duration, Outcome 2 Unfavourable outcome.

Comparison 2 Therapeutic cooling versus no cooling: by duration, Outcome 3 Pneumonia.
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Analysis 2.3

Comparison 2 Therapeutic cooling versus no cooling: by duration, Outcome 3 Pneumonia.

Comparison 3 Therapeutic cooling versus no cooling: by length of follow‐up, Outcome 1 Mortality.
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Analysis 3.1

Comparison 3 Therapeutic cooling versus no cooling: by length of follow‐up, Outcome 1 Mortality.

Comparison 3 Therapeutic cooling versus no cooling: by length of follow‐up, Outcome 2 Unfavourable outcome.
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Analysis 3.2

Comparison 3 Therapeutic cooling versus no cooling: by length of follow‐up, Outcome 2 Unfavourable outcome.

Summary of findings for the main comparison. Hypothermia for traumatic brain injury

Hypothermia for traumatic brain injury

Patient or population: patients with traumatic brain injury
Settings: hospitals; in Australia, Canada, China, Czech Republic, Germany, Japan, Malaysia, New Zealand, UK, USA
Intervention: hypothermia versus normothermia

Outcomes

No of Participants
(studies)

Quality of the evidence
(GRADE)

Comments

Mortality at end of follow‐up

2944
(32 studiesa)

⊕⊝⊝⊝
very lowb

Data not combined in meta‐analysis. Visual inspection of data showed variation in differences of effect not explained by subgroup analysis

Unfavourable outcome at end of follow‐up

2620
(27 studiesc)

⊕⊝⊝⊝
very lowd

Data not combined in meta‐analysis. Visual inspection of data showed variation in differences of effect not explained by subgroup analysis

Pneumonia

693
(14 studiese)

⊕⊕⊝⊝
lowf

Data not combined in meta‐analysis. Visual inspection of data showed variation in differences of effect

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

aWe identified 33 studies that reported data for mortality, with comparable data available for 32 studies
bFew studies had sufficiently described random sequence generation and concealment; downgraded one level for study limitations. Some inconsistencies between studies, not explained by per protocol subgroup analyses; downgraded one level for inconsistency. Some differences in study population between studies; Andrews 2015 included participants with less severe head injury, and with a longer delay in treatment; downgraded one level for indirectness.
cWe identified 29 studies that reported data for unfavourable outcome, with comparable data available for 26 studies.
dFew studies had sufficiently described random sequence generation and concealment; downgraded one level for study limitations. Some inconsistencies between studies not explained by per protocol subgroup analyses and we noted a moderate level of statistical heterogeneity; downgraded two levels for inconsistency. Some differences in study population between studies; Andrews 2015 included participants with less severe head injury, and with a longer delay in treatment; downgraded one level for indirectness.
eWe identified 14 studies that reported data for pneumonia, with comparable data available for 12 studies.
fSome inconsistencies between studies, not explained by per protocol subgroup analyses; downgraded one level for inconsistency. Some differences in study population between studies; Andrews 2015 included participants with less severe head injury, and with a longer delay in treatment; downgraded one level for indirectness.

Figures and Tables -
Summary of findings for the main comparison. Hypothermia for traumatic brain injury
Comparison 1. Therapeutic cooling versus no cooling

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Mortality Show forest plot

32

Odds Ratio (M‐H, Fixed, 95% CI)

Subtotals only

2 Unfavourable outcome Show forest plot

27

Odds Ratio (M‐H, Fixed, 95% CI)

Subtotals only

3 Pneumonia Show forest plot

12

Odds Ratio (M‐H, Fixed, 95% CI)

Subtotals only

Figures and Tables -
Comparison 1. Therapeutic cooling versus no cooling
Comparison 2. Therapeutic cooling versus no cooling: by duration

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Mortality Show forest plot

32

Odds Ratio (M‐H, Fixed, 95% CI)

Totals not selected

1.1 24 hours

4

Odds Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

1.2 More than 24 hours

28

Odds Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

2 Unfavourable outcome Show forest plot

26

Odds Ratio (M‐H, Fixed, 95% CI)

Totals not selected

2.1 24 hours

3

Odds Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.2 More than 24 hours

23

Odds Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

3 Pneumonia Show forest plot

12

Odds Ratio (M‐H, Fixed, 95% CI)

Totals not selected

3.1 24 hours

2

Odds Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

3.2 More than 24 hours

10

Odds Ratio (M‐H, Fixed, 95% CI)

0.0 [0.0, 0.0]

Figures and Tables -
Comparison 2. Therapeutic cooling versus no cooling: by duration
Comparison 3. Therapeutic cooling versus no cooling: by length of follow‐up

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Mortality Show forest plot

32

Risk Ratio (IV, Fixed, 95% CI)

Totals not selected

1.1 One month

13

Risk Ratio (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

1.2 Three months

6

Risk Ratio (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

1.3 Six months

14

Risk Ratio (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

1.4 Twelve months or more

7

Risk Ratio (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2 Unfavourable outcome Show forest plot

26

Risk Ratio (IV, Fixed, 95% CI)

Totals not selected

2.1 Three months

9

Risk Ratio (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.2 Six months

15

Risk Ratio (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2.3 Twelve months

6

Risk Ratio (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

Figures and Tables -
Comparison 3. Therapeutic cooling versus no cooling: by length of follow‐up