[Tramadol infusion anesthesia with the substitution of enflurane and various nitrous oxide concentrations].

The synthetic opioid tramadol was given to 40 patients during surgery according to a fixed, calculated infusion scheme. Anesthesia was started with thiopental and the patients were given different nitrous oxide concentrations via a semi-open system (group 1: 60%, group 2: 75%). The aim of this study was to clarify whether this anaesthetic procedure is practicable or whether it has grave disadvantages in comparison with the anesthesia models used so far. Furthermore we wanted to clarify whether under this infusion scheme the proportion of N2O in the inspiratory mixture is sufficient or whether higher concentrations are required. In 24 of 40 patients analgesia or the depth of anaesthesia was insufficient so that additional enflurane application was necessary. Postoperative respiratory depression in three patients had to be treated with naloxone. The advantages of this procedure are the safe and easy practicability, absence of significant changes in the haemodynamic parameters, good postoperative response of the patients and postoperative pain relief as well as the low incidence of postoperative side effects such as nausea, vomiting and CO2-retention.