Effects of a midazolam-ketamine admixture in human volunteers.

As the ideal sedative does not exist for all situations, we examined the effect of a midazolam-ketamine sedoanalgesic admixture in human volunteers. Ten ASA physical status I volunteers were administered loading doses of 0.07 mg/kg of midazolam followed by 0.7 mg/kg of ketamine. The same amount of midazolam and ketamine was then infused constantly over 1 hour via a 60 drops (gtts)/mL i.v. infusion set. Blood samples were analyzed for plasma catecholamine levels. Respiration rate and oxygen saturation did not alter significantly from baseline levels. Heart rate and systolic blood pressure remained stable with an increase of 15% in heart rate and 6% in systolic blood pressure only at 10 minutes following the bolus loading. Diastolic blood pressure did not alter significantly from baseline levels (P < .05). Plasma catecholamines levels remained stable except for an increase in epinephrine (38%) and norepinephrine (19%) 10 minutes following the bolus injections. Plasma dopamine levels remained unchanged. There were no cases of unpleasant dreaming, dysphoria, or emergence-type reactions. This combined nonnarcotic sedoanalgesic technique maintains spontaneous ventilation and stable cardiorespiratory parameters and may be considered as an alternative to traditional conscious sedation or general anesthesia.