Lång 2018.

Methods	RCT
Participants	Sample size: 65 (experimental 38, control 27) Sex (male): experimental 82%, control 85% Age: experimental 45, control 43 Country: Finland Setting: mechanically ventilated adults with traumatic brain disease admitted to the ICU Disease severity score: APACHE II score median 22 Inclusion criteria Isolated non‐penetrating TBI or adults with multiple trauma with TBI with GCS 8 or less (inclusive), expected need for intubation and mechanical ventilation > 24 hours Recruitment within 18 hours after admission to ICU Time from TBI < 36 hours Informed consent from next of kin Exclusion criteria Age < 18 or > 65 years Anticipated brain death in 12 hours or otherwise moribund adults expected to die in 24 hours Expected need for mechanical ventilation < 24 hours Insufficient oxygenation assessed by a clinician Adults with multiple trauma with brain injury and severe abdominal, thoracic, or pelvic injury possibly affecting oxygenation No consent Insufficient oxygenation with the treatment modality of the lower oxygenation group (PaO2 < 13 kPa or SpO2 < 95% with FiO2 of 0.40 and PEEP of 10) Oxygenation failure probable during ICU care Penetrating TBI Suspected pregnancy (perform urinary or serological pregnancy test if suspected)
Interventions	Experimental: FiO2 of 0.70. Categorized by us as using a high target in the experimental group Control: FiO2 of 0.40. Categorized by us as using a low target in the control group Co‐intervention: not specified Duration: maximum 14 days
Outcomes	Laboratory markers during the first 3 days Pulmonary function (PaO2/FiO2 ratio, ARDS, atelectasis, pneumonia) Length of mechanical ventilation Length of ICU stay Length of hospital stay Death Extended Glasgow Outcome Scale
Notes	Email sent 6 December 2018 to Dr Lång and a reply was received. It was unclear how the trial was funded. According to protocol, the trial was supported by Kuopio University Hospital.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Stated that the trial was randomized, but the method of sequence generation was not described
Allocation concealment (selection bias)	Low risk	Sealed, opaque envelopes
Blinding of participants and personnel (performance bias) All outcomes	High risk	Open‐label
Blinding of outcome assessment (detection bias) All outcomes	High risk	Only the neurologist assessing the neurological outcomes was blinded.
Incomplete outcome data (attrition bias) All outcomes	High risk	8% were lost to follow‐up, and allocation groups were not specified in the publication. The number of participants lost to follow‐up in each group was clarified by email.
Selective reporting (reporting bias)	Low risk	The trial was registered prior to randomization (NCT01201291), however quality of life is not reported; however trial authors are planning to publish these results.
Other bias	High risk	Unplanned trial stop