Schellongowski 2007.

Methods	Phase 2 study: cross‐over trial (3‐treatment, 2‐sequence, 5‐period design), with continuous rotation (passive washout) between all treatments Method of analysis: Friedman test for differences between body positions and Dunn's multiple comparison post‐test for pairs of time points
Participants	12 mechanically ventilated adults with ARF due to ALI or ARDS diagnosed within 96 hours of inclusion (ARDS defined, based on guidelines from the American European Consensus Conference) Other inclusion criteria: decision to treat participant with CLRT within 48 hours of inclusion, haemodynamic stability during rotation over maximal angle at least 12 hours before inclusion Sex (M/F) 10/2, median age 54 years (range 22 to 81 years) Median PEEP 10 mbar (range 6 to 15 mbar), median Vt 556 mL (range 326 to 756 mL) with time‐cycled pressure‐controlled mode Diagnosis: pneumonia (n = 11), near drowning causing ARDS (n = 1), 7 of 12 had sepsis Severity of illness: median APACHE II 17 (range 7 to 37), median SAPS II 46 (range 31 to 85), median Murray lung injury score 2.63 (range 2 to 3.5) Termination criteria: haemodynamic or respiratory instability (defined as sustained decline in BP necessitating vasopressor therapy or dose rate increase of vasopressor and/or decline in SaO2 measured by pulse oximetry < 88%) Setting: ICU of University Hospital, Vienna, Austria (location of study authors)
Interventions	Steep left lateral and steep right lateral positions for 30 minutes, supine position (S1, S2, S3) for 10 minutes. Note: full cycle of continuous rotation for 8 minutes after all treatments, except S3 Sequences/groups S1(baseline),L, S2, R, S3  S1(baseline),R, S2, L, S3
Outcomes	Pulmonary gas exchange (SaO2, P/F ratio, SvO2) and haemodynamics (MABP, CI) measures at 10, 20 and 30 minutes for steep lateral positions, and at 10 minutes for all supine positions Other co‐primary outcomes reported but not relevant for this review were pulmonary shunt fraction, PaCO2 and respiratory mechanics measures (Vt, PIP, PEEP, static compliance)
Standard management	All ventilation settings kept unchanged during data collection. FiO2 set to achieve SaO2 of 92% to 96%, PEEP (increments of 2 mbar between 5 and 20 mbar) set to maintain FiO2 ≤ 0.6 and SaO2 > 91%, frequency set to keep PaCO2 < 60 torr and to avoid dynamic hyperinflation, PIP kept to lowest level to apply Vt of approx 8 mL/kg body weight, haemodynamics stabilized by adequate volume substitution to keep PCWP of 12 to 15 torr and vasopressors if necessary. All participants received continuous infusion of analgo‐sedation (midazolam and sufentanil and/or ketamine) and sedation titrated to achieve Ramsay sedation score of 5 and to suppress spontaneous breathing. No muscle relaxants given
Position description	62 degrees static lateral rotation, Rotorest KCl Medisus bed paused in supine position for 10 minutes (baseline), then paused in each body position of interest during data collection. No further descriptions except continuous rotation for 1 hour before phase 2 study protocol
Washout period	Not described Comment: continuous lateral rotation of the whole body along its longitudinal axis from 1 lateral position to the other, with maximum angle of 124 degrees (full cycle for 8 minutes) between body positions (i.e. passive washout period without data collection)
Notes	No sample size calculation described CI determination by intermittent thermodilution technique Pressure transducers fixed to moveable portion of kinetic system close to the participant to guarantee that the position of the tip was always at the level of the left atrium, with pressure transducers zeroed to mid‐axillary level Results table (Table 3) stated 'measured values' with ± symbol only Comments: Summary statistics ambiguous (unclear whether mean and SD were intended, all baseline measures were reported in median and non‐parametric statistical tests were conducted). Data transformation possibly required for meta‐analysis. However, no extractable lateral position data because of unit of analysis error. Supine position order not randomized; therefore, comparison between each lateral position and supine position not valid for extraction
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described Quotation: "patients were randomized to stop either in left or right steep position first"
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not described
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Not described Comment: objective outcome measures taken from real‐time physiological monitoring systems, ABG and mixed venous gas analyser; therefore, lack of outcome assessor blinding unlikely to bias results
Incomplete outcome data (attrition bias) All outcomes	Low risk	10 participants completed the study, with 2 withdrawals during phase 2 study as termination criteria met (SaO2 < 80% in left lateral position, concomitant decrease in BP, Vt and compliance). Numerator for each reported outcome was not stated; unclear whether data points were missing and how missing data were handled within the analysis (Friedman test) Comment: missing data points, if present, unlikely to bias within‐subject differences
Selective reporting (reporting bias)	Unclear risk	No explanation was given as to why non‐parametric statistical analysis (Friedman test) was conducted for continuous data. Primary endpoints for pulmonary gas exchange were unclear; P/F ratio was reported within results and analysis but was not mentioned within the methods section, whereas, SaO2 and mixed venous gases were indicated as measures at each time point but were not reported within the results or analysis Comment: unclear whether pulmonary gas exchange measures were selectively reported Furthermore, P/F ratio results within a line graph appear to be misleading. P/F ratios were presented sequentially from S1 to right lateral to S2 to left lateral to S3 (at each time point for each period (treatment) for each individual). However, half the group was rotated to the left lateral position (L) in the second period (first lateral position); therefore, sequence and changes between body positions were not accurately represented graphically
Other bias	Unclear risk	Non‐uniform unbalanced cross‐over design. Sequence effects and treatment‐by‐period interactions not reported Comments: unclear whether sequence effects, period effects or treatment‐by‐period interactions were a source of bias. If carryover effects were present, they were unlikely to be equally applied across treatments because of lack of balance and uniformity. Carryover effects may be due to short active washout and continuous rotation during passive washout period. Possibly insufficient washout before and after data collection. Overall, unclear risk of carryover bias Possible intervention bias for comparisons between supine and lateral positions due to unequal period duration and numbers of measures taken within each period (comparisons not equivalent)