Objective: To explore the relationship of postoperative cognitive dysfunction (POCD) in one-lung ventilation (OLV) patients and regional cerebral oxygen saturation (rSO2).
Methods: Twenty-nine male and twenty-one female cases of OLV received thoracic surgery, with American Standards Association (ASA) physical status being at Grades I-III. Neuropsychological tests were performed on the day before operation and 7 d after operation, and there was an intraoperative continuous monitoring of rSO2. The values of rSO2 before anesthesia induction (t1), at the beginning of OLV (t2), and at the time of OLV 30 min (t3), OLV 60 min (t4), the end of OLV (t5), and the end of surgery (t6) were recorded. The intraoperative average of rSO2 , the intraoperative minimum value of rSO2 (rSO(2, min)), and the reduced maximum percentage of rSO2 (rSO(2, %max)) when compared with the baseline value were calculated. The volume of blood loss, urine output, and the amount of fluid infusion was recorded.
Results: A total of 14 patients (28%) in the 50 cases suffered from POCD. The values of mini-mental state examination (MMSE), the digit span and the digit symbol on the 7th day after the operation for POCD in OLV patients were found to be significantly lower than those before the operation (P<0.05). The values of MMSE and vocabulary fluency scores were significantly lower than those in the non-POCD group (P<0.05). The values of rSO2 in the POCD group of OLV patients at t2 and t3 and the values of rSO2 in the non-POCD group at t2 were found to be significantly higher than those at t1 (P<0.05). The values of rSO(2, %max) in the POCD group were significantly higher than those in the non-POCD group (P<0.05). When the value of rSO(2, %max) is more than 10.1%, it may act as an early warning index for cognitive function changes.
Conclusions: POCD after OLV may be associated with a decline in rSO2.
Keywords: One-lung ventilation; Postoperative cognitive dysfunction; Regional cerebral oxygen saturation.