Impairment of sustained attention after major gynaecological surgery

The sustained attention to response task (SART) test is a sensitive indicator of deficits in sustained attention and is simple to perform. Sustained attention is impaired for a short period after minor surgery under general anaesthesia but the magnitude and duration of this effect after major surgery is unknown. We used the SART test to investigate deficits in sustained attention in patients undergoing major surgery under general anaesthesia.

The SART test was completed before surgery and at 24, 48 and 72 h postoperatively by 20 ASA I-II female patients (mean age 48.6 yr) undergoing total abdominal hysterectomy under general anaesthesia. It was also completed by 20 age-matched female controls at similar time intervals to evaluate the effect of repeated test performance.

There was a significant (P < 0.05) interaction between the groups in number of errors made (a measure of sustained attention deficit). The number of errors decreased in control subjects on repeated performance of the SART test but remained unchanged in patients undergoing total abdominal hysterectomy. The differences between groups remained significant after 72 h (P < 0.05). Patients' overall response times slowed significantly at 24-48 h (P < 0.05), but this recovered by 72 h after surgery. In contrast, overall response times in the control group tended to accelerate on repeated performance of the SART.

The results of this study suggest that 72 h following major surgery patients have deficits in sustained attention compared with controls. Control subjects demonstrated a marked learning effect on repeated test performance compared with patients.