Physiologic, clinical and safety outcomes associated with prone positioning during mechanical ventilation
| Outcome | No. of patients or events | Measure of effect* | I2 value, % |
|---|---|---|---|
| Oxygenation (Pao2/Fio2 ratio)† | No. of patients | Ratio of means (95% CI) | |
| Day 1 | 1283 | 1.36 (1.25–1.47) | 49 |
| Day 2 | 1171 | 1.29 (1.21–1.37) | 27 |
| Day 3 | 933 | 1.25 (1.18–1.31) | 0 |
| Clinical and safety outcomes | No. of events, n/N | Risk ratio (95% CI) | |
| Ventilator-associated pneumonia | 368/1561 | 0.89 (0.71–1.13) | 0 |
| Pressure ulcers | 818/1765 | 1.27 (1.16–1.40) | 0 |
| Obstruction of endotracheal tube | 200/1847 | 1.60 (1.27–2.02) | 0 |
| Unplanned extubation or dislodgement of endotracheal tube‡ | 211/2309 | 1.08 (0.78–1.48) | 16 |
| Unplanned removal of central or arterial lines | 59/886 | 1.49 (0.42–5.27) | 67 |
| Dislodgement of thoracostomy tube | 17/886 | 3.14 (1.02–9.69) | 0 |
| Pneumothorax | 95/1663 | 0.84 (0.57–1.25) | 0 |
| Cardiac arrest | 211/1527 | 0.73 (0.39–1.38) | 76 |
Note: CI = confidence interval, Pao2/Fio2 ratio = ratio of partial pressure of arterial oxygen to fraction of inspired oxygen.
↵* Random-effects models were used for all analyses.
↵† We measured effect on oxygenation by comparing the mean Pao2/Fio2 ratio in the prone group to the closest available recorded measurement in the supine group. If more than one measurement was taken, we chose the measurement closest to the end of the session of prone positioning on that day.
↵‡ One trial (14) included all dislodgements of endotracheal tubes, not just unplanned extubations. When we excluded the results of this trial from the meta-analysis, the risk ratio for unplanned extubation was 0.86 (95% CI 0.62–1.20; I2 = 0%; 9 trials, 1471 patients, 129 events).