Ge 2013.

Methods	RCT with parallel groups Approved by the ethics committee and informed consent obtained Site: Ningbo 6th Hospital, Ningbo Zhjiang, China Setting: hospital Dates of data collection: July 2011 to February 2012
Participants	60 participants aged 70–85 years, ASA class II or III, undergoing spinal fusion
Interventions	Treatment group: tidal volume 6 mL/kg, rate 12˜18/min, inspiratory/expiratory ratio 1:2, PEEP 10 cmH2O mechanical ventilation and alveolar recruitment performed once every 15 min (n = 30) Control group: tidal volume 12 mL/kg, rate 12/min and inspiratory/expiratory ratio 1:2 (n = 30)
Outcomes	Relevant to this review Pneumonia at day 1 after surgery Others pH, PaO2, PaCO2, PaO2/FiO2, alveolo‐arterial oxygen diffusion coefficient, heart rate, systolic and diastolic arterial blood pressure and central venous pressure Atelectasia
Notes	Funding: unspecified Declaration of interest: not mentioned Volume per body weight: predicted body weight: men: 50 + 0.91 × height – 152.4; women: 45.5 + 0.91 × height – 152.4 Information for this trial was extracted by Shumming Pan and Yuhua‐Gao
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomly assigned, from Shumming Pan and judged as "randomized controlled trial:" by Yuhua‐Gao from page 82.
Allocation concealment (selection bias)	Unclear risk	Unclear The allocation method allowed the record staff to know the treatment allocation of the next participant to be enrolled in the study.
Blinding of participants and personnel (performance bias) All outcomes	High risk	The allocation method allowed the record staff to know the treatment allocation of the next participant to be enrolled in the study.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	This study did not describe whether the outcome assessor was blinded to the intervention.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No participant selected for this study dropped out
Selective reporting (reporting bias)	Low risk	All the measurements stated in the methods section were included in the results.
Other bias	Unclear risk	No clear definition for pneumonia (possible inclusion of bronchitis or other pulmonary complications)