Intraoperative hypotension and the risk of postoperative adverse outcomes: a systematic review.

Abstract

Intraoperative hypotension is a common side effect of general anesthesia and might lead to inadequate organ perfusion. However, the relationship between hypotension during non-cardiac surgery and unfavorable results is not clear.

Methods: We searched in PubMed, Embase, Web of Science and CINAHL, classified the quality of retrieved articles according to the STROBE and CONSORT criteria. The strengths of association from high-quality studies were classified into end-organ specific injury risks: acute renal failure (ARF), myocardial injury, stroke and overall organ injury risks for various arterial blood pressure thresholds.

Results: We present an overview of 42 articles on reported associations between various intraoperative hypotension and their associations with postoperative adverse outcomes after non-cardiac surgery. High risks of end-organ injury were reported for prolonged exposure (> 10 min) to mean blood pressures (MBP) <80 mmHg and for shorter durations <70 mmHg. Reported risks increase with increased durations for MBP <65-60 mmHg or for any exposure <55-50 mmHg.

Conclusions: The reported associations suggest that organ injury might occur when MBP decreases <80 mmHg for> 10 min, and that this risk increases with the progressive decrease in blood pressure. Given the retrospective observational design of the studies reviewed, reflected by large variability in patient characteristics, hypotension definitions and outcomes, solid conclusions cannot be obtained about what blood pressure and under what circumstances are really dangerous. We provide recommendations for the design of future studies.