Background and Goal of Study: The recovery of patients after general anaesthesia is usually measured using clinical signs and scores (1,2). There is a lack of objective measurement methods, which can be used in clinical routine. The aim of this study was to evaluate the existing psychological methods for measurement of cognitive recovery in patients after general anaesthesia in ambulatory setting.
Materials and Methods: Each of 113 patients scheduled for ambulatory gynaecological surgery underwent 3 standard psychological tests before (T1), 15 minutes after the surgery (T2) and on discharge from the recovery room (T3). Wechsler memory scale (test 1, attention and short-term memory), d2 - test (test 2, concentration) and computer-based 4-choice-reaction time (4CRT, test 3, psychomotor function) as well as Postanesthesia Discharge Scoring System (PADSS) were used.
The same test battery was used in 51 healthy female volunteers. The results of 3 tests were compared at T1, T2 and T3 using Bonferroni-adjusted Student's t-test for paired data.
Results and Discussion: In patients, the short-term memory and concentration (tests 1 und 2) decreased, the 4CRT (test 3) increased at T2 vs. T1 and T2 vs. T3 (p< 0.01). At T3 the parameters of test 1 and test 3 reached the preoperative level T1, in test 2 the concentration increased at T3 as compared to T1 (p< 0.001) due to learning effect. PADSS increased from 8 (T2) to 10 (T3) (median, p< 0.001). Healthy volunteers demonstrated the clear learning effect in all 3 tests through the course of the study (p< 0.01).
Conclusion(s): All 3 tested methods, being more sensitive than PADSS, can measure the recovery of cognitive function in patients after general anaesthesia, although the computer-based 4CRT seems to be the most convenient in clinical routine.
1. Aldrete & Kroulik. Anesth Analg 1970;49:924-34.
2. Chung. Can J Anaest 1995;42:1056-8.