[Elimination of the obturator reflex as a specific indication for dilute solutions of etidocaine. A study of the suitability of a local anesthetic for reflex elimination in the 3-in-1 block technic].

Abstract

Direct stimulation of the obturator nerve by the electroresectoscope during transurethral resection of tumors in lateral bladder regions is possible under regional or general anaesthesia without muscle relaxation. The resulting obturator reflex may lead to perforation of the bladder. Two different regional techniques can be used to interrupt the obturator reflex arc: (1) separate block of the obturator nerve; or (2) the "3-in-1 block" (Winnie). In the present study elimination of the obturator reflex was carried out by "3-in-1 block" with diluted solutions of etidocaine in 55 cases. Venous plasma levels of etidocaine were measured in 9 patients after application of etidocaine 0.5% (unilateral 30 ml and bilateral 60 ml). Samples were taken 10, 20, 30, 40, 60, and 120 min after the "3-in-1 block". RESULTS. The "3-in-1 block" with diluted etidocaine produced excellent motor block of the obturator nerve. Clinical side effects did not occur. Plasma peak levels reached 2.2 micrograms/ml; the protein binding rate was 85%-95%. DISCUSSION. Elimination of the obturator reflex is the only specific motor nerve block in anesthesia. Diluted etidocaine solutions seem to be adequate: irrespective the technique used for eliminating the reflex, diluted etidocaine produces a good effect and permits a dosage reduction compared with other local anesthetics. It is possible to block the obturator nerve bilaterally by "3-in-1 block" or unilaterally by "3-in-1 block" in combination with epidural analgesia within the recommended dose limits.