MINNEAPOLIS (AP) _ A Minneapolis hospital system has halted clinical trials of
ketamine a day after suspending its study on the sedative.

The chief medical officer for Hennepin Healthcare, Dr. William Heegaard, appeared before the Hennepin County Board on Tuesday to respond to ethical concerns over the study.

The study enrolled patients without their consent. The clinical trials sought consent from patients only after treatment.

Heegaard says the system wants to suspend its research and address complaints.

Paramedics' use of the sedative on agitated people during emergency calls has been the subject of an independent investigation commissioned by Minneapolis.

An investigation by the city's Office of Police Conduct found that the number of documented ketamine injections during police calls increased from three in 2012 to 62 last year.