Ketamine is a unique anesthetic drug that provides analgesia, hypnosis, and amnesia with minimal respiratory and cardiovascular depression. Because of its sympathomimetic properties it would seem to be an excellent choice for patients with depressed ventricular function in cardiac surgery. However, its use has not gained widespread acceptance in adult cardiac surgery patients, perhaps due to its perceived negative psychotropic effects. Despite this limitation, it is receiving renewed interest in the United States as a sedative and analgesic drug for critically ill-patients.
The effects of hypnosis, acupuncture and analgesic drugs on the subjective experience of pain and on objective neurophysiological parameters were investigated. Pain was produced by brief electric stimuli on the wrist. Pain challengers were: hypnosis (induced by two different video tapes), acupuncture (at specific and unspecific loci, with and without electrical stimulation of the needles), morphine and ketamine. Evaluation of clinical parameters included the subjective experience of pain intensity, blood pressure, puls, temperature, psychosomatic symptoms and side effects.
The interaction of intramuscularly injected ketamine and its N-demethylated metabolite (metabolite I) with halothane was evaluated in rats. Five, 10, 20, or 50 mg/kg of ketamine alone or 20, 50, or 100 mg/kg of metabolite I alone produced less than 10 minutes of hypnosis. However, halothane anesthetic requirement (i.e., MAC) was depressed in a dose-dependent fashion as much as 56% 1-2 hours and as much as 14% 5-6 hours after injection of ketamine, 50 mg/kg, im.
The Journal of Pharmacology and Experimental Therapeutics
Four pharmacologic actions of intravenous ketamine (30 mg/kg) were studied in the rat. To elucidate the mechanism(s) terminating the pharmacologic effects, animals were pretreated with ketamine and agents anticipated to modify hepatic microsomal metabolism, including phenobarbital and SKF 525A.
Eighty-five patients ranging from 12 h to 7 years of age were included in this study. In the first group 35 cases received ketamine, gallamine and oxygen for surgery on the great vessels. Ketamine provided satisfactory analgesia and amnesia. Heart rate did not change significantly. Gallamine gave additional safety in the prevention of bradycardia. One hundred per cent oxygen increased oxygen saturation and made more oxygen available for the tissues. The combination secured favorable conditions even in cases of sevre right to left shunt.
Probenecid increases plasma ketamine levels in mice concurrently with an enhancement of duration of loss of righting reflex. The magnitude of these changes is directly related to the dose of ketamine and intervals between administration of compounds. Plasma levels of anesthetic are similar for all animals upon termination of hypnosis.
The mechanism which normally affects distribution of blood flow through unventilated areas of the lung is hypoxic pulmonary vasoconstriction; this acts to divert the blood to well ventilated alveoli, resulting in a better ratio of ventilation to perfusion. Several reports have focused attention on the reduction or abolition of this reflex in the unventilated lung by most of the volatile anaesthetic agents used in clinical practice. This response was not abolished by the intravenous anaesthetic agents.
The upper oesophageal sphincter can prevent regurgitation of oesophageal contents into the pharynx following gastrooesophageal reflux in the awake patient. Upper oesophageal sphincter pressure was recorded with a Dent sleeve after hypnosis with midazolam (n = 7) and also during the rapid intravenous induction of anaesthesia with thiopentone (n = 16) or ketamine (n = 7). Thiopentone decreased mean (SD) sphincter pressure from an awake value of 43 (19) to 9 (7) mmHg (p less than 0.001) and midazolam from 38 (25) to 7 (3) mmHg (p less than 0.02).
BACKGROUND: Midazolam, if used with ketamine for induction and maintenance of anesthesia, may attenuate hyperdynamic circulatory effects and prevent undesirable emergenic reactions. The nature of the interaction between midazolam and ketamine used for anesthesia induction was studied in female patients. METHODS: Quantal dose-response curves were determined in 170 female patients for the drugs, individually and in combination. Two endpoints were assessed, loss of response to verbal command (hypnosis) and loss of response to a 5-s transcutaneous tetanus (anesthesia).
Hypnosis combined with chemical sedation is uncommonly utilized by physicians, however, the combination of hypnosis and sedation can be an effective modality in the management of uncooperative pedodontic patients. In order to examine the efficacy of this combination technique, we selected 13 pedodontic patients for Ketamine sedation combined with hypnosis. The patients ranged from four to 11 years of age, and all had previous histories of violent emotional reactions before and after dental treatment.