Methohexital/Alfentanil - Thiopental/Alfentanil zur totalen intravenösen Anästhesie für die direkte Laryngoskopie unter 100 % O₂-Injektorbeatmung

Zusammenfassung

In der vorliegenden Studie werden Methohexital und Thiopental als intravenöses Narkotikum per Dauerinfusion bei operativen Eingriffen unter der Verwendung der Jetventilation mit reinem Sauerstoff verglichen. 40 Patienten wurden randomisiert auf die Methohexital- (n = 20) und die Thiopentalgruppe (n = 20) verteilt. Am Abend vor der Operation wurden psychometrische Tests durchgeführt und die Patienten erhielten eine standardisierte Prämedikation. Die Narkose wurde mit 2 mg Alcuronium, 1 mg Alfentanil, 1,4 mg/kg KG Methohexital beziehungsweise 5 mg/kg KG Thiopental sowie 1,4 mg/kg KG Succinylcholin eingeleitet. Direkt vor Beginn der Laryngoskopie erhielten die Patienten 2-4 mg Alfentanil. Die Muskelrelaxation wurde durch eine Succinylinfusion unter relaxometrischer Kontrolle aufrechterhalten. Methohexital beziehungsweise Thiopental wurden nach klinischen Gesichtspunkten als Infusion weitergegeben.

Summary

For the direct laryngoscopy and microscopic examination of the larynx with exploratory excision and polpectomy using low frequency jet-ventilation with 100 % oxygen we used total intravenous anaesthesia with a strong acting opioid and a barbiturate. Because the achievement of sufficient reflexes and a high degree of vigilance postoperatively are to be aimed, Methohexitone (M) and Thiopentone (T) were investigated in the regard of the suppression of vigilance in the postoperative period. 40 patients were randomly assigned to the group M (n = 20) or T (n = 20). The evening before operation, an intelligence test and a syndrom-short-test (SST) were performed for the measurement of attention and memory (functional psychosis). The patients received 2 mg Flunitrazepam orally and transdermal Scopolamin. On the day of operation the patients received 1 mg Lormetazepam orally for premedication. Anaesthesia was induced with 2 mg Alcuronium, 1 mg Alfentanil, 1.4 mg/kg Body-weight M respectively 5 mg/kg Bodyweight T and 1.4mg/kg Bodyweight Succinylcholin. Immediately before laryngoscopy the patients received 2-4 mg Alfentanil. Muscle relaxation was achieved by an infusion with Succinylcholin using relaxometry. Methohexitone respectively Thiopentone were administered by infusion depending on clinical signs indicating insufficient anaesthesia. The following parameters were measured: Blood pressure, heart rate, duration of operation and anaesthesia, parameters of vigilance 30, 60 and 120 minutes after operation (SST) and the ability of performance. The groups were comparable with respect to all data except the parameters of vigilance. The patients receiving M were significantly more vigilant 30 min., 60 min. (SST) and 120 min (SST) after the end of anaesthesia than patients receiving T (p = 0,01). The results show that both methods can be used for direct laryngoscopy using total intravenous anaesthesia and jet-ventilation. Methohexitone should be prefered to Thiopentone because the patients achieve a high degree of vigilance significantly earlier than the patients receiving Thiopentone. The reason for these results are the better hepatic extraction rate and the shorter half life time of Methohexitone.