. Author manuscript; available in PMC: 2019 Aug 16.

Published in final edited form as: Anaesthesia. 2017 Sep 11;72(11):1334–1343. doi: 10.1111/anae.14039

Table 4.

The odds ratio (OR) for postoperative respiratory complications in patients receiving pressure-controlled ventilation compared with volume-controlled ventilation, according to pre-defined sub-groups of ventilatory pressures and susceptibility to complications. Values are number (proportion).

	Pressure vs. Volume		Sub-group vs. Sub-group
Variable and sub-group	OR (95%CI)	p value	RRR (95%CI)	p value
PEEP
< 5 (n = 39,015)	1.40 (1.26–1.55)	< 0.001	1.17 (1.02–1.33)	0.023
≥ 5 (n = 70,344)	1.20 (1.11-–1.31)	< 0.001
ASA
< 3 (n = 75,098)	1.29 (1.16–1.43)	< 0.001	1.06 (0.89–1.16)	0.82
≥ 3 (n = 34,261)	1.27 (1.17–1.37)	< 0.001
SPORC
< 7 (n = 106,407)	1.28 (1.20–1.37)	< 0.001	1.00 (0.79–1.27)	1
≥ 7 (n = 106,407) ≥ 7 (n = 2952)	1.28 (1.03–1.62)	0.029
Tidal volume
< 12 ml.kg^–1 (n = 105,012)	1.32 (1.23–1.41)	< 0.001	1.22 (0.95–1.57)	0.11
≥ 12 ml.kg^–1 (n = 4348)	1.08 (0.85–1.37)	0.536
Driving pressure
< 19 cmH₂O (n = 77,424)	1.37 (1.27–1.48)	< 0.001	1.18 (1.07–1.30)	0.016
≥ 19 cmH₂O (n = 31,936)	1.16 (1.04–1.30)	0.011

ASA, ASA physical status; RRR, relative risk ratio; PEEP, positive end-expiratory pressure; SPORC, Score for Prediction of Postoperative Respiratory Complications [21].