[Anesthesia procedures--postoperative effects]

The perioperative morbidity and mortality is mainly influenced by the type and duration of surgery as well as the patient's preoperative state of health. Anesthesia per se, however, may also result in severe perioperative (patho) physiological changes, which may be both desired (e.g. analgesia, vasodilation in vascular surgery) or detrimental (e.g. hypothermia, ventilatory depression) and which may differ depending on the anesthetic technique used (e.g. general anesthesia vs. regional anesthesia). Yet, all anaesthetic techniques have in common, that their effects are not limited to the duration of the surgical intervention, but may expand far into the postoperative period. Therefore, many trials have been performed in the past aiming to compare the impact of different anesthetic techniques on the incidence of postoperative techniques, no significant advantage of one or the other technique has been identified up to now with respect to postoperative mortality or severe morbidity. This finding may be due to at least three factors. 1) Many side-effects related to anesthesia--due to close postoperative monitoring--are detected and treated early in the postoperative phase (e.g. in the recovery room), thereby preventing serious complications.2) Postoperative mortality related exclusively to anesthesia probably is so low, that huge patient numbers would be required to demonstrate any significant differences between different techniques. 3) Besides the factor 'anesthesia', many other factors contribute to the anesthesia related morbidity and mortality (e.g. the factor 'anesthetist') which are hardly quantified. The fact that clear advantages for a single technique have not yet been demonstrated must not, however, result in anesthetic 'nihilism'. Rather there may be good reasons in the individual patient (e.g. lack of a recovery room), to prefer a certain anesthetic technique or drug over another, in order to lower the individual risk of anesthesia. Whether the use of a certain technique-e.g. spinal or epidural anesthesia-may contribute to a reduction of specific postoperative surgical complications (e.g. rate of reocclusion subsequent to peripheral vascular surgery) is presently under investigation.