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Original Investigation
May 22, 2019

Effect of Targeting Mean Arterial Pressure During Cardiopulmonary Bypass by Monitoring Cerebral Autoregulation on Postsurgical Delirium Among Older Patients: A Nested Randomized Clinical Trial

Author Affiliations
  • 1Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
  • 2Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland
  • 3Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
  • 4School of Medicine, New York University, New York
  • 5Medical Student, School of Medicine, Tufts University, Medford Massachusetts
  • 6Department of Radiology, Massachusetts General Hospital, Boston
  • 7Department of Cardiovascular Surgery, Saitama Medical Center, Jichi Medical University, Saitama, Japan
  • 8Division of Cardiac Surgery, Department of Surgery, Penn State University Hershey Medical Center, Hershey, Pennsylvania
  • 9Department of Anesthesiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
  • 10Bluhm Cardiovascular Institute, Department of Anesthesiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
JAMA Surg. Published online May 22, 2019. doi:10.1001/jamasurg.2019.1163
Key Points

Question  Does targeting mean arterial pressure during cardiopulmonary bypass by monitoring cerebral autoregulation reduce the incidence of delirium compared with usual care?

Findings  In this nested randomized clinical trial of 199 participants, the incidence of delirium (excluding coma) was significantly greater in the usual care group (53%) than in the group in which mean arterial pressure was targeted using cerebral autoregulation monitoring (38%).

Meaning  Targeting mean arterial pressure during cardiopulmonary bypass using cerebral autoregulation monitoring may reduce the incidence of post–cardiac surgery delirium.

Abstract

Importance  Delirium occurs in up to 52% of patients after cardiac surgery and may result from changes in cerebral perfusion. Using intraoperative cerebral autoregulation monitoring to individualize and optimize cerebral perfusion may be a useful strategy to reduce the incidence of delirium after cardiac surgery.

Objective  To determine whether targeting mean arterial pressure during cardiopulmonary bypass (CPB) using cerebral autoregulation monitoring reduces the incidence of delirium compared with usual care.

Design, Setting, and Participants  This randomized clinical trial nested within a larger trial enrolled patients older than 55 years who underwent nonemergency cardiac surgery at a single US academic medical center between October 11, 2012, and May 10, 2016, and had a high risk for neurologic complications. Patients, physicians, and outcome assessors were masked to the assigned intervention. A total of 2764 patients were screened, and 199 were eligible for analysis in this study.

Intervention  In the intervention group, the patient’s lower limit of cerebral autoregulation was identified during surgery before CPB. On CPB, the patient’s mean arterial pressure was targeted to be greater than that patient’s lower limit of autoregulation. In the control group, mean arterial pressure targets were determined according to institutional practice.

Main Outcomes and Measures  The main outcome was any incidence of delirium on postoperative days 1 through 4, as adjudicated by a consensus expert panel.

Results  Among the 199 participants in this study, mean (SD) age was 70.3 (7.5) years and 150 (75.4%) were male. One hundred sixty-two (81.4%) were white, 26 (13.1%) were black, and 11 (5.5%) were of other race. Of 103 patients randomized to usual care, 94 were analyzed, and of 102 patients randomized to the intervention 105 were analyzed. Excluding 5 patients with coma, delirium occurred in 48 of the 91 patients (53%) in the usual care group compared with 39 of the 103 patients (38%) in the intervention group (P = .04). The odds of delirium were reduced by 45% in patients randomized to the autoregulation group (odds ratio, 0.55; 95% CI, 0.31-0.97; P = .04).

Conclusions and Relevance  The results of this study suggest that optimizing mean arterial pressure to be greater than the individual patient’s lower limit of cerebral autoregulation during CPB may reduce the incidence of delirium after cardiac surgery, but further study is needed.

Trial Registration  ClinicalTrials.gov identifier: NCT00981474.

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