RECOVERY OF PSYCHOMOTOR AND COGNITIVE FUN CTIONS AFTER ANESTHESIA WITH PROPOFOL ALFENTANIL AND THIOPENTONE ISOFLURANE ALFENTANIL

Recent changes in the medical system have resulted in a significant in crease of ambulatory surgical procedures. Therefore, a safe and short postoperative recovery period and, especially, the full recovery of co mplex psychological function after general anaesthesia have become inc reasingly important. In the present study we investigated the recovery of psychomotor and cognitive function after general anaesthesia with propofol/alfentanil and thiopentone/isoflurane/alfentanil. Patients an d methods. Institutional approval and informed consent was obtained in 40 female ASA I or II patients undergoing diagnostic laparoscopy. As oral premedication the patients received chloracepat (10-20 mg) 45 min before the start of anaesthesia. Anaesthesia was induced in group I w ith propofol (2.5 mg/kg) and maintained with propofol (6-12 mg/kg/h)/a lfentanil (0.05 mg/kg) and 50% N2O in O2. The patients of group II rec eived thiopentone (5 mg/kg) for induction and isoflurane (0.5-1.5 vol% )/alfentanil (0.05 mg/kg) and 50% N2O in O2 for maintenance of general anaesthesia. In particular we measured the following parameters: (1) The recovery time, defined as the interval between the termination of the anaesthetic and the patient's correct recall of her birth date. (2 ) The choice reaction times to optical stimuli (red or green light), w hich was used as a parameter for attention and psychomotor function. ( 3) The score in the ''Zahlen-Verbindung-Test'' in which the patients h ad to connect numbers from 1 to 90 in correct order. This is also a pa rameter to quantify attention and psychomotor function. (4) The digit span which is a value derived from the number of correctly reproduced digits from a list presented to the patients. It is a measure of numer ical memory. (5) The Munich Verbal Learning Test, which is the German version of the California Verbal Learning Test. It represents the numb er of correctly reproduced words from a previously presented list and is a measure of the verbal memory. (6) The Wisconsin Card Sorting Test , which serves to test the ability to plan and act and to form terms a nd concepts. (7) The State-Trait Anxiety Inventory, to quantify state anxiety. (8) Pain score, using a visual analogue scale. The tests were performed at four measurement points: the day before the operation an d 30, 60, and 240 min after recovery. The ''Zahlen-Verbindungs-Tests'' , the digit span and the Munich Verbal Learning Test were presented in four parallel forms to minimize learning effects. For statistical ana lysis of the data the Wilcoxon test was employed within groups and the Mann-Whitney test between groups. Results. The groups were comparable in age, weight, height and level of education. No significant differe nce was found between them in operation or anaesthesia time or in the total dosage of alfentanil. Recovery time in the propofol group was, a t 10 min, significantly shorter than in the isoflurane group, with 16 min. Choice reaction times were significantly increased 30 min after r ecovery from anaesthesia in both groups. In the propofol group they re turned to normal after 60 min, whereas in the isoflurane group signifi cant increases could be observed even 240 min after recovery from the anaesthetic. Choice reaction times were significantly longer in the is oflurane group than in the propofol group 60 min and 240 min after ana esthesia. In the ''Zahlen-Verbindungs-Test'' the patients showed signi ficantly worse results 30 min and 60 min after anaesthesia. The propof ol group tended to be better than the isoflurane group, but the differ ence did not reach statistical significance. Also in the digit span, t he scores were significantly lower 30 min after recovery from the anae sthetic. Here again the propofol group tended to be a little better th an the isoflurane group 30 min, 60 min and 240 min after anaesthesia. In the Munich Verbal Learning Test both groups had lower scores 30 min and 60 min, the isoflurane group also 240 min, after recovery. The sc ores were significantly lower in the isoflurane group than in the prop ofol group 60 min and 240 min after recovery. No differences between t he groups could be found in the Wisconsin Card Sorting Test. The posto perative state anxiety was significantly lower in the propofol group t han in the isoflurane group. No differences between the groups could b e found in the pre- and post-operative pain scores. Conclusions. Recov ery time was shorter in the propofol group than in the isoflurane grou p. The propofol group showed less postoperative impairment of psychomo tor function than the isoflurane group. The propofol group showed bett er post-operative numerical and verbal memorisation. After anaesthesia with propofol patients seemed to be in a better mood state, with less state anxiety. These results seem to be important not only with regar d to the patient's subjective well-being, but also with regard to the patient's safety especially after ambulatory surgical procedures.