Nine RCTs (n=1,292) were included in the review.
The quality scores of the included studies ranged from 3 to 7 out of 10. Adequate randomisation methods were reported in 3 studies, allocation concealment in one, and the avoidance of potentially influential cointerventions in five. All studies had baseline comparability of the treatment groups but none used blinding or intention-to-treat analysis.
VAP developed in 19.2% of the patients. No significant difference between the treatment groups was found (RD -0.01, 95% CI: -0.05, 0.03), based on 9 RCTs. There was no evidence of statistical heterogeneity. Trial quality was not found to significantly affect this result.
There was no significant difference in overall mortality between the treatment groups: 23.2% in the CES group versus 22.5% in the OES group (RD -0.01, 95% CI: -0.04, 0.05), based on 5 RCTs. There was no evidence of statistical heterogeneity. Trial quality was not found to significantly affect this result.
Duration of ventilation was significantly reduced in the OES group compared with CES (WMD 0.64, 95% CI: 0.21, 1.06), based on 4 studies. One study was shown to substantially contribute to the overall estimate (93%). Trial quality was not found to significantly affect this result. No difference between the
treatment groups was found for length of stay in the intensive care unit (WMD -0.90 days, 95% CI: -5.61, 3.81), based on 2 RCTs. There was no evidence of statistical heterogeneity. Hospital length of stay was not reported in any of the included studies.