Influence of thiopental and propofol on postoperative cognitive recovery in the elderly patient undergoing general anesthesia

Abstract

Study Objective: To assess mental and psychomotor recovery following induction of anesthesia with thiopental or propofol in elderly patients undergoing general anesthesia. Design: Randomized, prospective, double-blind study. Setting: Large referral hospital. Patients: 40 elderly patients ASA physical status I-III (>65 years) undergoing abdomino-pelvic surgery with an estimated surgical time of at least 90 minutes. Interventions: All patients received combined epidural-general anesthesia. After establishing a T 6 sensory blockade, patients were randomized to receive either thiopental or propofol for induction of general anesthesia. The induction drug was slowly titrated until loss of eyelash reflex was noted. Thereafter, all patients received desflurane (2% to 3% end-tidal) and 70% nitrous oxide (N 2O) in oxygen for maintenance of general anesthesia. To facilitate tracheal intubation, intravenous alfentanil 10 μg/kg and atracurium 0.4 mg/kg were administered. Perioperative analgesia was maintained with epidural bupivacaine. Measurements and Main Results: A digit substitution test (DSST) and shape-sorter test, as well as patient-generated 100-mm visual analog score (VAS; 0 = minimal and 100 = maximal) for anxiety, sleepiness, and coordination, were performed during the preanesthetic interview, on postanesthesia care unit admission, and at 15, 45, 90, and 120 minutes thereafter. To induce loss of consciousness, either thiopental 2.5 ± 1.0 mg/kg or propofol 1.6 ± 0.6 mg/kg was administered. The mean anesthetic time was 109 ± 30 minutes and 114 ± 38 minutes for the thiopental and propofol groups, respectively. Emergence, extubation, and orientation times, as well as time to follow commands, were unaffected by patient randomization. Similarly, the DSST and shape-sorter tests, in addition to the patient-generated VAS for pain, anxiety, and coordination, were similar among groups. However, irrespective of treatment modality, return to baseline digit substitution and shape-sorter scores were significantly delayed (p < 0.01). Conclusion: When compared to thiopental, propofol does not facilitate improved cognitive recovery in geriatric patients undergoing prolonged surgery.