Cognitive dysfunction after general versus regional anesthesia assessed by event-related potentials

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Postoperative cognitive dysfunction has been reported after a variety of noncardiac surgical procedures, especially in elderly patients. We hypothesized that the risk of postoperative cognitive dysfunction might be different with regional compared with general anesthesia.

Patients and methods

A total of 60 patients (25 men, 35 women) aged over 60 years and classified as belonging to grades I and II according to the American Society of Anesthesiologists (ASA) undergoing elective total knee replacement or dynamic hip screw orthopedic operations were included into this study. They were classified into two groups: 30 patients anesthetized generally and 30 patients anesthetized regionally. The hemodynamic parameters (O2 saturation, heart rate, and blood pressure) were recorded preoperatively, intraoperatively, and postoperatively. The cognitive function was measured by P300 waves preoperatively and within 1 week postoperatively.


In the general anesthesia group, there was a statistically significant decrease in the O2 saturation and increase in the heart rate postoperatively compared with preoperatively (control). However, in the regional anesthesia group, there was no such difference. There was a statistically significant postoperative increase in the P300 latency (ms) (349±10) in comparison with the preoperative readings (335±15) in the general anesthesia group. However, in the regional anesthesia group, there was no such difference.


General anesthesia may produce cognitive dysfunction in elderly patients, as detected by a statistically significant delay in the P300 wave latency postoperatively. Therefore, an epidural anesthesia is a better choice for total knee replacement and dynamic hip screw operations for achieving less cognitive dysfunction and less hospital stay.

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