TOTAL INTRAVENOUS ANESTHESIA IN GERIATRIC SURGERY - S-(-KETAMINE VS ALFENTANIL())

In this prospective, randomized study, two regimens of total intraveno us anaesthesia (TIVA), with propofol and S(+)-ketamine (S-ketammine) a nd with propofol and alfentanil, were compared with reference to endoc rine stress response, circulatory effects and recovery. Methods. The i nvestigation was conducted in two groups of 20 ASA I-III patients over 60 years of age who were scheduled for endoprothetic orthopaedic surg ery. After oral premedication with midazolam, patients received a TIVA with body-weight-adjusted doses of propofol, and S-ketamine or alfent anil as the analgesic component. For CPPV (PEEP 5 mbar), air and oxyge n (F1O2 33%) were used, For muscle relaxation, patients of both groups received vecuronium in body-weight-adjusted doses. Blood samples were taken through a central venous line at seven time points before induc tion of anaesthesia and on the first morning after the operation also for analysis of epinephrine, norepinephrine (by HPLC/ECD), and ADH, AC TH and cortisol (by RIA). In additon, SAP, HR, arterial oxygen saturat ion, recovery from anaesthesia and side effects were observed. Results . The two groups had comparable group mean values for age (S-ketamine group 71 years, alfentanilgroup 70 years), other biometric data, and d uration of anaesthesia and operation (Table 1). Plasma levels of epine phrine, norepinephrine (Table 2, Fig.1), ADH (Table 2, Fig.2) ACTH and cortisol (Table 2, Fig.3) were higher in the S-ketamine-group (P<0.05 ) owing to the intraoperative course of these endocrine parameters. Be fore induction, and on the first morning after the operation, levels w ere comparable between the groups. 5 min after the induction of anaest hesia, SAP and HR (Table 3) were significantly lower in the alfentanil group (P=0.001). Recovery from anaesthesia (orientation with respect to person and location) was faster in the alfentanil group (16 vs 39 m in, P=0.001). An arterial oxygen saturation below 90% was observed in 7 patients in the S-ketamine- and 13 patients in the alfentanilgroup ( P=0.03). Four patients with S-ketamine reported dreams, and 1 dream wa s judged negative. Postoperative emesis was found in 6 patients in the S-ketaminegroup and 12 patients in the alfentanilgroup (P=0.03). All patients said they would agree to undergo the same anaesthetic techniq ue again. Conclusions. Considerable differences were found in the endo crine stress response of the two groups. With respect to endocrine res ponse and circulation, TIVA with propofol and S-ketamine had sympathom imetic properties with positive circulatory effects and led to moderat e endocrine stimulation, This should be kept in mind in patients with hypotension, hypothyrosis, or adrenocortical insufficiency; because '' eustress'' might be beneficial in this group of patients. On the other hand, TIVA with propofol and alfentanil showed sympatholytic properti es, with negative circulatory effects and a remarkable reduction of en docrine stress response. This might be beneficial in patients with hyp ertension and states of endocrine hyperfunction, Both regimens were ac companied by such typical side effects as dreams, delayed recovery, re duced ventilation, and emesis, which should also be considered.