Xie 2007.

Methods	Randomised but no evidence of blinding.
Participants	60 patients 24 hours after head injury (confirmed with C/T or MRI) and with GCS between 3 and 12. No major chest or abdominal trauma or disease.
Interventions	Standard neurosurgical care including ICP control, neurosurgical procedures and antibiotics. Addition of HBOT at between 2 and 2.5 ATA for 70 to 80 minutes daily for 10 days.
Outcomes	Glasgow Coma Score.
Notes	Main purpose of the study was to document changes in the serum level of the inflammatory marker, C‐reactive protein.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described in the paper: "All the subjects were randomly divided ...with 30 in each group".
Allocation concealment (selection bias)	Unclear risk	Not described in the paper.
Blinding (performance bias and detection bias) All outcomes	High risk	No apparent blinding.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Data were complete.
Selective reporting (reporting bias)	High risk	Authors signalled 'effectiveness of therapy' as an outcome but this is not given in the paper.
Other bias	Low risk	No other obvious potential source of bias.

ATA ‐ Atmospheres Absolute 
 GCS ‐ Glasgow Coma Score 
 GOS ‐ Glasgow Outcome Score 
 HBOT ‐ Hyperbaric Oxygen Therapy