Hasegawa 2002.

Methods	Randomised clinical trial.
Participants	Country: Japan. Number randomised: 80. Post‐randomisation drop‐out: 1 (1.3%) (see notes). Mean age: 65 years. Females: not stated. Major liver resections: 26 (32.9%). Cirrhotic livers: 35 (44.3%). Inclusion criteria: Liver resection for the removal of tumours. Exclusion criteria: Severe pulmonary dysfunction (< 70% vital capacity or FEV1/FVC < 60%).
Interventions	Participants were randomly assigned to two groups. Group 1: hypoventilation (n = 40) (see notes). Group 2: control (n = 40). Further details of intervention and control: Intervention: hypoventilation (4 ml/kg tidal volume; respiratory rate 15/min) only during clamping. Control: Ventilation at 10 ml/kg tidal volume; respiratory rate 10/min. Other details Vascular occlusion: intermittent PTC. Method of parenchymal transection: clamp crush or CUSA. Management of raw surface: not stated. Other co‐interventions to decrease blood loss: none reported.
Outcomes	The outcome measures were mortality, transfusion requirements, peri‐operative morbidity, hospital stay, blood loss, and liver function tests.
Notes	One patient from intervention group who did not undergo liver resection was excluded from analysis. Attempts to contact the authors in November 2008 were unsuccessful.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: This information was not available.
Allocation concealment (selection bias)	Unclear risk	Comment: This information was not available.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: This information was not available.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: This information was not available.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: There was one post‐randomisation drop‐out. This patient did not undergo liver resection. This was not due to the treatment effect.
Selective reporting (reporting bias)	High risk	Comment: Important outcomes such as liver failure were not reported.
Free of vested interest bias?	Unclear risk	Comment: This information was not available.