Ketamine in the field: the use of ketamine for induction of anaesthesia before intubation in injured patients in the field.

Intubating the subconscious, struggling patient in a pre-hospital setting can be a difficult task even in experienced hands. We performed a clinical prospective study to evaluate the applicability of ketamine for induction of anaesthesia before intubation in the field. Ketamine was distributed to all air medical rescue teams--trained reserve army volunteers from various medical specialties. Lectures and literature concerning the use of ketamine for anaesthesia induction before intubation were given. The physicians were instructed to administer ketamine, in a dose of 2 mg/kg intravenously, if a single intubation attempt failed. Following the administration of ketamine, a questionnaire was filled in by the physician. Analysis of the data was performed after 24 months. During the study period, intubation was indicated in 161 injured patients evacuated by air in Israel. In 29 patients (18 per cent) the first intubation attempt had failed and they were given ketamine. The reasons for failure of the first intubation attempt were restlessness or trismus in 23 patients and traumatic distortion of the upper airway anatomical landmarks in six. Following ketamine administration, intubation was successful in 19 patients (65.5 per cent) in all of whom the indication for ketamine administration was restlessness or trismus. All patients with upper airway anatomy distortion were given a cricothyroidotomy. There were no complications attributed to ketamine. All patients reached hospital alive. This preliminary study suggests that the use of ketamine in this pre-hospital setting is safe. The drug is effective in cases where the primary reason for failure to intubate is restlessness or trismus. The drug is not effective in cases of anatomical damage to the upper airway. In these cases, cricothyroidotomy should probably be performed as early as possible.