[Anesthesia with oral ketamine]. / Anesthésie par la kétamine orale.

ABSTRACT

Oral ketamine (7.5 mg X kg-1) was used to induce general anaesthesia in fourty seven young women undergoing voluntary abortion. Additional anaesthesia was necessary eight times because pre operative consciousness remained normal, and nine times because of important intra operative reactions. A majority (78.8%) of patients appreciated this technique of anaesthesia. Absence of narcosis (17%) and intra operative analgesia (23%) and frequency of post operative nightmares may require some modifications of the method.

ABSTRACT

PIP Ketamine was administered to 47 women aged 14-41 years who were about to undergo induced abortions. The patients received 2.5 mg of lorazepam 2 hours before the operation and 7.5 mg/kg of ketamine diluted in orange juice or water 45 minutes before. In all cases, sleep and transfer to the operating table were accomplished in calm and semidarkness. Intravenous tubes were inserted and .02 mg/kg of atropine sulfate was administered. Patients considered still conscious were given intravenous injections of ketamine 1 mg/kg. Perioperative evaluation of the quality of anesthesia was done using a 4-level scale based on reactions to stimuli. Ketamine .5 mg/kg was administered intravenously each time significant reactions were obtained. 45 minutes after oral ketamine administration, 8 patients were still conscious and received additional anesthesia. 9 of the 39 patients asleep at the preoperative evaluation required additional anesthesia during the procedure. The immediate postoperative period was calm in all cases, even though some patients later reported having had disagreeable hallucinations. 46.8% had vomiting. The frequency of vomiting declined from 54.4% to 28.8% when pure water was substituted for orange juice as the vector for the preoperative oral ketamine. Correct responses to simple questions were obtained an average of 12.4 minutes postoperatively, but all patients had periods of somnolence lasting 4.8 hours on average. 15 had partial recollections of the surgery. 78.8% of the patients stated that the anesthesia used was excellent or good. 8.5% felt it was average, and 10.6% felt it was poor. Very few publications mention oral use of ketamine. The failure rates of 17% during the preoperative evaluation and 23% during the operation were not negligible and were probably due to the very low bioavailability of ketamine administered orally and the variability of digestive absorption of ketamine from 1 subject to another. The method appears to be appropriate for use in induced abortions, but better management is required to reduce failure rates and control side effects of vomiting and disagreeable postoperative hallucinations.