Duration and magnitude of blood pressure below cerebral autoregulation threshold during cardiopulmonary bypass is associated with major morbidity and operative mortality

Authors: Ono M, Brady K, Easley RB, Brown C, Kraut M, Gottesman RF, Hogue CW Jr.

OBJECTIVES: Optimizing blood pressure using near-infrared spectroscopy monitoring has been suggested to ensure organ perfusion during cardiac surgery. Near-infrared spectroscopy is a reliable surrogate for cerebral blood flow in clinical cerebral autoregulation monitoring and might provide an earlier warning of malperfusion than indicators of cerebral ischemia. We hypothesized that blood pressure below the limits of cerebral autoregulationduring cardiopulmonary bypass would be associated with major morbidity and operative mortality after cardiac surgery.

METHODS: Autoregulation was monitored during cardiopulmonary bypass in 450 patients undergoing coronary artery bypass grafting and/or valve surgery. A continuous, moving Pearson's correlation coefficient was calculated between the arterial pressure and low-frequency near-infrared spectroscopy signals and displayed continuously during surgery using a laptop computer. The area under the curve of the product of the duration and magnitude of blood pressure below the limits of autoregulation was compared between patients with and without major morbidity (eg, stroke, renal failure, mechanical lung ventilation >48 hours, inotrope use >24 hours, or intra-aortic balloon pump insertion) or operative mortality.

RESULTS: Of the 450 patients, 83 experienced major morbidity or operative mortality. The area under the curve of the product of the duration and magnitude of blood pressure below the limits of autoregulation was independently associated with major morbidity or operative mortality after cardiac surgery (odds ratio, 1.36; 95% confidence interval, 1.08-1.71; P = .008).

CONCLUSIONS: Blood pressure management during cardiopulmonary bypass using physiologic endpoints such as cerebral autoregulationmonitoring might provide a method of optimizing organ perfusion and improving patient outcomes from cardiac surgery.

Full text and source: The journal of thoracic and cardiovascular surgery

Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

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