Adelson 2005 HYPO 2.

Methods	Randomised controlled trial, parallel group
Participants	Total number of participants: 27 Baseline characteristics: Therapeutic cooling Age: mean (SD) 7.17 (± 6.64) years Type of injury (closed/open): closed GCS on admission: mean (SD) 6.42 (± 1.2) No cooling Age: mean (SD) 5.6 (± 5.23) years Type of injury (closed/open): closed GCS on admission: mean (SD) 6.23 (± 1.2) Inclusion criteria: children 0 to 214 months of age, with non‐penetrating head injury, GCS ≤ 8, within 24 hours of admission Exclusion criteria: normal initial CT scan, penetrating brain injury, brain death on admission to emergency department, failure to obtain informed consent 24 hours from admission, uncorrectable coagulopathy (PT/PTT > 16/40 seconds), hypotensive episode for > 5 minutes defined as SBP < fifth percentile for age Country: USA Setting: hospital (single centre)
Interventions	Therapeutic cooling Number of participants: 14 Method of cooling: surface cooling using a hypothermia/heating blanket. Sedation and paralysis induced to prevent shivering Target temperature: 32 to 33 °C Time of cooling: < 6 hours Duration of cooling: 48 hours Rewarming details: after 48 hours, passive warming, 1 °C every 3 to 4 hours until 36.5 °C reached. Initiation of warming not stopped due to intracranial hypotension but slowed at times due to elevations in ICP Site of temperature measurement: rectal No cooling Number of participants: 13 Method of temperature management: participants were passively warmed if their initial presenting core temperature was < 36 °C Target temperature: 36.5 to 37.5 °C
Outcomes	Outcomes measured in study: mortality, ventricular arrhythmias, delayed intracranial haemorrhage, intraabdominal/thoracic bleeding, coagulopathy infection (pneumonia), GOS, Infant Health Questionnaire, Vineland Adaptive Behaviour scale, ICP, other secondary clinical outcomes
Notes	Funding/declarations of interest: National Institute of Health grant, General Clinical Research Centre at Children's Hospital of Pittsburgh grant Study dates: August 2001 to December 2003 Note: HYPO 2 was a single‐centre trial set up later due to recruitment issues in HYPO 1, but running in parallel to HYPO 1 with a different inclusion criteria. All other methods and outcomes were the same as HYPO 1
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as randomised and stratification done by age of child at time of injury. No additional details
Allocation concealment (selection bias)	Unclear risk	Insufficient details provided
Blinding of participants and personnel (performance bias): mortality	Low risk	Not possible to blind personnel; unlikely to influence performance
Blinding of participants and personnel (performance bias): GOS	Unclear risk	Not possible to blind personnel; unclear if this would influence performance
Blinding of participants and personnel (performance bias): pneumonia	Unclear risk	Not possible to blind personnel; unclear if this would influence performance
Blinding of outcome assessment (detection bias): mortality; pneumonia	Low risk	Lack of blinding unlikely to influence outcome assessment
Blinding of outcome assessment (detection bias): GOS	Low risk	Neurocognitive tests (GOS) were performed by the site neuropsychologist or technician who were blinded to the therapeutic intervention
Incomplete outcome data (attrition bias) All outcomes	Low risk	Low for mortality and pneumonia. Small loss of follow‐up at 3 and 6 months for GOS data, not reported by treatment groups.
Selective reporting (reporting bias)	Unclear risk	Clinical trials registration or pre‐published protocol not reported. Insufficient information to make judgement
Other bias	Low risk	No other sources of bias identified