Postoperative cognitive deficit after cardiopulmonary bypass with preserved cerebral oxygenation: a prospective observational pilot study

Abstract

BackgroundNeurologic deficits after cardiac surgery are common complications. Aim of this prospective observational pilot study was to investigate the incidence of postoperative cognitive deficit (POCD) after cardiac surgery, provided that relevant decrease of cerebral oxygen saturation (cSO2) is avoided during cardiopulmonary bypass.MethodscSO2 was measured by near infrared spectroscopy in 35 patients during cardiopulmonary bypass. cSO2 was kept above 80% of baseline and above 55% during anesthesia including cardiopulmonary bypass. POCD was tested by trail making test, digit symbol substitution test, Ray's auditorial verbal learning test, digit span test and verbal fluency test the day before and 5 days after surgery. POCD was defined as a decline in test performance that exceeded - 20% from baseline in two tests or more. Correlation of POCD with lowest cSO2 and cSO2 - threshold were determined explorative.ResultsPOCD was observed in 43% of patients. Lowest cSO2 during cardiopulmonary bypass was significantly correlated with POCD (p = 0.015, r2 = 0.44, without Bonferroni correction). A threshold of 65% for cSO2 was able to predict POCD with a sensitivity of 86.7% and a specificity of 65.0% (p = 0.03, without Bonferroni correction).ConclusionsDespite a relevant decrease of cerebral oxygen saturation was avoided in our pilot study during cardiopulmonary bypass, incidence of POCD was comparable to that reported in patients without monitoring. A higher threshold for cSO2 may be needed to reduce the incidence of POCD.

Cerebral oxygen saturation after multiple perioperative influential factors predicts the occurrence of postoperative cognitive dysfunction

“…Fudickar et al [ 38 ] use minimum ScO 2 to predict the occurrence of POCD, but only found week predictive performance (AUC = 0.61), while we found that ScO 2 after multiple influential factors had better discriminatory power for POCD. ScO 2 less than 50 % or decrease 20 % from baseline during carotid endarterectomy indicated focal cerebral ischemia [ 39 ], and were commonly regarded as safe limits of ScO 2 and chosen as the low limits in the present study.…”

Cerebral and tissue oximetry

“…It has been reported that a 5% to 15% decrement in rScO 2 from baseline on the side ipsilateral to carotid cross-clamping has a 44% to 100% sensitivity and 44% to 100% specificity for predicting changes in CBF velocity as measured by transcranial Doppler, EEG slowing, or changes in SSEPs. [51–55] These studies have limitations such as small sample size. One of the largest studies to date, which involved almost 600 patients who underwent CEA under general anesthesia, found that a 11.7% decrease from baseline in rScO 2 had a sensitivity of 75% and a specificity of 77% for detecting neurological complications [66].…”

Postoperative Neurocognitive Dysfunction in Patients Undergoing Cardiac Surgery after Remote Ischemic Preconditioning: A Double-Blind Randomized Controlled Pilot Study

“…Sample size calculation was estimated in previous studies investigating POCD by Hudetz et al [21] and by our own group [17], [22]. We assumed that the incidence of POCD could be reduced from 30% in the control group to 20% in the RIPC group, and we added 50% of the patients enrolled in the study.…”