To the Editor:- Anesthetic management of uncooperative patients often is difficult, particularly when they are violent or incapable of understanding instruction. These patients may be impaired because of mental or neurologic disease. One such situation is autism. Although use of oral Ketamine as a premedication is well described in children, its use in the management of violent or uncooperative adults is not. I report these two cases because of the unique situation these autistic patients presented for an anesthetic.

A 19-yr-old, 118-kg man with a lifelong history of autism came to the outpatient surgery department for removal of an infected toenail. The patient had a history of self-abusive an violent behavior. He was taking fluoxetine and chlorpromazine nightly. The morning of surgery, he was administered 100 mg chlorpromazine orally at home. At arrival he was agitated and pacing. He began banging his head into walls and yelling. His mother was present with an electrical “stun” gun, should his behavior become uncontrollable. She had used this device in the past to protect herself from him at home. Because of his size, strength, and violent behavior, the planned procedure was cancelled and rescheduled.

One month later, the patient returned for the elective surgery. He was administered 5 mg haloperidol 600 mg ketamine in a small amount of Coca Cola. The patient became sedate during the next 20 min. He was taken to the operating room. The patient was induced with halothane and nitrous oxide. An intravenous line was placed for antibiotics and nightly medications. Local anesthesia was administered by the surgeon before removal of the toenail. After an uneventful anesthetic and surgical procedure, the patient was taken to the recovery room. He slowly returned to an alert but sedate condition. Throughout his 2-hour recovery period, he remained cooperative and quiet. He was discharged to the care of his parents. He was reportedly back to baseline condition within 6 hours of discharge and had no discernible adverse consequences of the experience.

A 35-yr-old, 60-kg male came to the outpatient surgery department for dental reconstruction and cleaning. His only medication was carbamezepam, prescribed for a history of seizures. Before arrival, he was administered 0.25 mg triazolam by his caregiver. He initially cooperated with the nurse obtaining vital signs at admission, but soon became agitated and attempted to leave. A second dosage of triazolam had no effect. He was then administered 600 mg ketamine in Coca Cola. Within 20 min, the patient was sedate and cooperative. The patient was transported to the operating room and received a general anesthetic lasting 3 hours. Recovery was uneventful and he was discharged to the care of his guardian. No complications were noted by his caregivers after discharge.

Autistic patients with symptoms necessitating operative procedures can be challenging. They frequently cannot communicate their needs or desires. Cooperating in unfamiliar environments with unfamiliar individuals can accentuate the difficulties for the patient. The two cases presented herein represent the difficulties of achieving adequate premedication to allow the patient to be safely anesthetized.

The administration of ketamine orally as a premedication for operative procedures has been reported frequently for children. [3–8]The use of oral ketamine as an analgesic also has been described in adults for postamputation stump pain, postherpetic neuralgia, phantom limb pain, neuropathic pain, and cancer pain. The use of ketamine as a sedative in adult patients has not been described.

Sedating uncooperative patients in a nonforceful manner is difficult. Attempts to either physically restrain or administer intramuscular injection in uncooperative or violent adults can be dangerous. The use of oral benzodiazepines, barbiturates, and butyrophenones is not always successful in achieving sedation and cooperation of the patient. The administration of ketamine in a drink to mask the drug may be an acceptable alternative is some autistic or uncooperative adult patients.

Kenneth L. Bachenberg, M.D.

Bellingham, Washington

(Accepted for publication April 24, 1998.)

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