ABSTRACT
OBJECTIVE: To determine the effect of arterial normobaric hyperoxia during cardiopulmonary bypass (CPB) on postoperative neurocognitive function. The authors hypothesized that arterial hyperoxia during CPB is associated with neurocognitive decline at 6 weeks after cardiac surgery. DESIGN: Retrospective study of patients undergoing cardiac surgery with CPB. SETTING: A university hospital. PARTICIPANTS: One thousand eighteen patients undergoing coronary artery bypass graft (CABG) or CABG + valve surgery with CPB who previously had been enrolled in prospective cognitive trials. INTERVENTIONS: A battery of neurocognitive measures was administered at baseline and 6 weeks after surgery. Anesthetic and surgical care was managed as clinically indicated. MEASUREMENTS AND MAIN RESULTS: Arterial hyperoxia was assessed primarily as the area under the curve (AUC) for the duration that PaO2 exceeded 200 mmHg during CPB and secondarily as the mean PaO2 during bypass, as a PaO2 = 300 mmHg at any point and as AUC>150 mmHg. Cognitive change was assessed both as a continuous change score and a dichotomous deficit rate. Multivariate regression accounting for age, years of education, baseline cognition, date of surgery, baseline postintubation PaO2, duration of CPB, and percent change in hematocrit level from baseline to lowest level during CPB revealed no significant association between hyperoxia during CPB and postoperative neurocognitive function. CONCLUSIONS: Arterial hyperoxia during CPB was not associated with neurocognitive decline after 6 weeks in cardiac surgical patients.
Subject(s)
Cardiac Surgical Procedures/adverse effects , Cardiac Surgical Procedures/methods , Cardiopulmonary Bypass/adverse effects , Cardiopulmonary Bypass/methods , Cognition Disorders/etiology , Cognition Disorders/psychology , Hyperoxia/blood , Hyperoxia/psychology , Postoperative Complications/psychology , Aged , Female , Heart Valves/surgery , Humans , Learning/physiology , Male , Middle Aged , Neuropsychological Tests , Oxygen/blood , Retrospective StudiesABSTRACT
BACKGROUND: Postoperative neurocognitive decline occurs frequently. Although predictors of cognitive injury have been well examined, factors that modulate recovery have not. We sought to determine the predictors of cognitive recovery after initial injury following cardiac surgery. METHODS: Two hundred eighty-one patients previously enrolled in cognitive studies who experienced cognitive decline 6 weeks after cardiac surgery were retrospectively evaluated. Eligible patients completed a battery of neurocognitive measures and quality-of-life assessments at baseline, 6 weeks, and 1 year after surgery. Factor analysis was conducted to calculate the cognitive index (CI), a unified, continuous measure of cognitive function. Cognitive recovery was defined as 1-year CI greater than baseline CI. Potential predictors of cognitive recovery including patient characteristics, quality-of-life factors, comorbidities, medications, and intraoperative variables were assessed with multivariable regression modeling; P<0.05 was considered significant. RESULTS: Of the 229 patients in our final data set, 103 (45%) demonstrated cognitive recovery after initial decline in CI at 6 weeks. Multivariable analyses revealed that more education (odds ratio [OR] 1.332 [1.131-1.569], P<0.001), baseline CI (OR 0.987 [0.976-0.998], P=0.02), less decline in CI at 6 weeks (OR 1.044 [1.014-1.075], P=0.004), and greater activities of daily living at 6 weeks (OR 0.891 [0.810-0.981], P=0.02) were significant predictors of cognitive recovery. CONCLUSION: Cognitive recovery occurred in approximately one half of the cardiac surgical patients experiencing early decline. The association between cognitive recovery and Instrumental Activities of Daily Living scores at 6 weeks merits further investigation as it is the only potentially modifiable predictor of recovery.
