Nitric oxide index is not a predictor of cognitive dysfunction following laparotomy

Study Objective: To determine the associations between postoperative cognitive dysfunction (POCD) and plasma concentrations of stable nitric oxide products [nitric oxide index (NOi)]. Design: Prospective study. Setting: Academic hospital. Patients: 28 ASA physical status I, II, and III physical status patients undergoing major non-cardiac surgery. Interventions: Cognitive assessment was performed preoperatively and postoperatively at 4 days (early) and 6 weeks (late). Measurements: Serial measurements of plasma NOi were recorded. Main Results: Early POCD with a deficit in one cognitive domain was present in 18 patients (64%), and in 8 patients (28%) with deficits in two or more cognitive domains. Late POCD was evident in three patients (20%) who had a deficit in one domain. Eight patients were lost to late follow-up. There was no difference in baseline or subsequent serum concentrations of NOi between those who showed early and late POCD and those who showed no POCD. Conclusion: Factors other than nitric oxide-mediated injury is responsible for POCD following major non-cardiac surgery.