Ketamine found more effective for treating highly-agitated patients during transport to hospital

These findings, publishing in the journal Clinical Toxicology, are the result of research performed over two six-month periods by clinicians based in Minneapolis. During these time periods, paramedics trained to evaluate a patient's mental status against the Altered Medical Status Scale (AMSS) recorded the findings from 146 patients, 64 who were administered ketamine and 82 who were given haloperidol. Their findings indicated that ketamine is a more effective sedative, and whilst there is a trade-off in terms of complications, it warrants further study.

Paramedics often find that patients they are about to treat can become confused, agitated or combative prior to being taken to the hospital. Often this can put both the patient and paramedic at risk, and so the patient will be sedated during their trip to the hospital in an ambulance. At present, there is some debate on the best drugs and doses for this therapy.

The AMSS rates a patient's mental status on a scale ranging from +4 (combative, very violent, or out of control), through 0 (normal response), to -4 (does not respond to mild prodding or shaking). Patients judged to be agitated were administered with either 5 mg/kg of ketamine, or 10 mg of haloperidol and timed until they returned to a state of less than +1 on the scale. Pregnant women, people under 18, and severely agitated patients (+4 on the scale) were excluded from the study.

The researchers found that the median time for a patient to be sedated using ketamine was 5 minutes, compared to 17 minutes for patients treated with haloperidol. However, the researchers also noted a marked increase in complications; 49 % for the group treated with ketamine, compared to 5 % for the group treated with haloperidol. Furthermore, 39 % of the ketamine group required intubation compared to 4 % of the group treated with haloperidol.

The paper recognizes that the study is a preliminary finding, and that there were potential confounders such as the study being neither randomized or blind. However the researchers believe that the findings warrant further study of the drugs used to sedate patients in the pre-hospital environment.