Association of intraoperative hypotension with postoperative morbidity and mortality: systematic review and meta-analysis

Abstract

Background: Intraoperative hypotension, with varying definitions in literature, may be associated with postoperative complications. The aim of this meta-analysis was to assess the association of intraoperative hypotension with postoperative morbidity and mortality.

Methods: MEDLINE, Embase and Cochrane databases were searched for studies published between January 1990 and August 2018. The primary endpoints were postoperative overall morbidity and mortality. Secondary endpoints were postoperative cardiac outcomes, acute kidney injury, stroke, delirium, surgical outcomes and combined outcomes. Subgroup analyses, sensitivity analyses and a meta-regression were performed to test the robustness of the results and to explore heterogeneity.

Results: The search identified 2931 studies, of which 29 were included in the meta-analysis, consisting of 130 862 patients. Intraoperative hypotension was associated with an increased risk of morbidity (odds ratio (OR) 2.08, 95 per cent confidence interval 1.56 to 2.77) and mortality (OR 1.94, 1.32 to 2.84). In the secondary analyses, intraoperative hypotension was associated with cardiac complications (OR 2.44, 1.52 to 3.93) and acute kidney injury (OR 2.69, 1.31 to 5.55). Overall heterogeneity was high, with an I2 value of 88 per cent. When hypotension severity, outcome severity and study population variables were added to the meta-regression, heterogeneity was reduced to 50 per cent.

Conclusion: Intraoperative hypotension during non-cardiac surgery is associated with postoperative cardiac and renal morbidity, and mortality. A universally accepted standard definition of hypotension would facilitate further research into this topic.

Fig. 1

PRISMA diagram showing the selection of articles for review

Fig. 2

Forest plot of all included studies A random-effects model was used for all meta-analyses. Odds ratios (ORs) are shown with 95 per cent confidence intervals. *Units for mean arterial pressure (MAP) are mmHg. MI, myocardial infarction; SBP, systolic BP; SSI, surgical-site infection.

Fig. 3

Funnel plot of all included studies Egger’s test for funnel asymmetry: z=1.62, P=0.106.

Fig. 4

Meta-regression: bubble plot visually demonstrating a relationship between severity of hypotension and odds ratios found in the 29 included studies Each bubble represents the odds ratio for an included study. The size of each bubble corresponds with the study weight attributed in the meta-analysis. The regression line denotes the best fit with 95 per cent confidence intervals.