Duration and magnitude of blood pressure below cerebral autoregulation threshold during cardiopulmonary bypass is associated with major morbidity and operative mortality.
OBJECTIVE
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 autoregulation during 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 autoregulation monitoring might provide a method of optimizing organ perfusion and improving patient outcomes from cardiac surgery.
Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Md.
Masahiro
M
Ono
Department of Pediatrics and Anesthesiology, Baylor College of Medicine, Texas Children's Hospital, Houston, Tex.
Kenneth
K
Brady
Department of Pediatrics and Anesthesiology, Baylor College of Medicine, Texas Children's Hospital, Houston, Tex.
R Blaine
RB
Easley
Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Md.
Charles
C
Brown
Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Md.
Michael
M
Kraut
Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Md.
Rebecca F
RF
Gottesman
Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Md. Electronic address: chogue2@jhmi.edu.
Charles W
CW
Hogue
D000368:Aged; D019540:Area Under Curve; D001794:Blood Pressure; D002315:Cardiopulmonary Bypass / Q000009:adverse effects* / Q000401:mortality*; D002560:Cerebrovascular Circulation; D001026:Coronary Artery Bypass / Q000009:adverse effects* / Q000401:mortality*; D005260:Female; D006351:Heart Valves / Q000601:surgery*; D006706:Homeostasis; D017052:Hospital Mortality; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D015999:Multivariate Analysis; D016017:Odds Ratio; D011183:Postoperative Complications / Q000401:mortality* / Q000628:therapy; D011237:Predictive Value of Tests; D012307:Risk Factors; D019265:Spectroscopy, Near-Infrared; D013997:Time Factors; D016896:Treatment Outcome
CABG; CBF; COx; CPB; MAP; MMOM; NIRS; cardiopulmonary bypass; cerebral blood flow; cerebral oximetry index; coronary artery bypass grafting; major morbidity and operative mortality; mean arterial pressure; near-infrared spectroscopy; rScO(2); regional cerebral oxygen saturation