Increased incidence of postoperative cognitive dysfunction 24 hr after minor surgery in the elderly

Postoperative cognitive dysfunction (POCD) is evident in 26% of elderly patients seven days after major non-cardiac surgery. Despite the growing popularity of day surgery, the influence of anesthetic techniques on next day POCD has not been investigated. Therefore, we evaluated the incidence of POCD and changes in serum markers of neuronal damage (S-100ss protein and Neuron-Specific Enolase), 24 hr after single-agent propofol or sevoflurane anesthesia in elderly patients undergoing minor surgery.

Patients (n = 30, mean age 73, range 65-86 yr) coming for cystoscopy or hysteroscopy, were randomized, in an observer-blind design, to receive either single-agent propofol or sevoflurane anesthesia. Changes in neuropsychological tests (the Stroop test and the modified Word-Recall Test), 24 hr postoperatively were compared with age-matched control subjects (n = 15) using Z-score analysis. Changes in S-100beta protein and Neuron-Specific Enolase levels were also documented.

POCD was present in 7/15 [47% (95% confidence interval (CI) 21 to 72%)] patients who received propofol and 7/15 [47% (95% CI 21 to 72%)] patients who received sevoflurane, compared with 1/15 [7% (95% CI 6 to 19%)] control patients, P = 0.03. S-100beta protein and Neuron-Specific Enolase levels were not significantly different in anesthetized patients postoperatively compared with preoperative values.

The incidence of POCD in elderly patients on the first day after minor surgery is higher than previously reported for seven days after major surgery, and is increased after both propofol and sevoflurane anesthesia, compared with age-matched controls. S-100beta protein and Neuron-Specific Enolase levels were unaffected by anesthetic technique.