MINNEAPOLIS — Hennepin Healthcare is suspending a clinical trial of the sedative ketamine in emergency situations following criticism that its hospital, Hennepin County Medical Center, enrolled patients in the study without their knowledge.

Paramedics’ use of the sedative on agitated people during emergency calls is already the subject of an independent investigation commissioned by the City of Minneapolis. The number of documented ketamine injections during police calls increased from three in 2012 to 62 last year, according to an investigation by the Minneapolis Office of Police Conduct.

Hennepin County hospital researchers are trying to determine which of the drugs already in use to treat agitation — including ketamine — are the most effective.

State Sen. Jeff Hayden and Hennepin County Commissioner Peter McLaughlin Monday called the hospital’s clinical trial unethical.

“While we understand Hennepin Healthcare claims it has followed federal research procedures, we believe an urban hospital that treats a large number of people of color and low-income Minnesotans must take extra care,” Hayden and McLaughlin’s statement said. “Anything less disregards the history of maltreatment for these communities as test subjects for new drugs and medical procedures. This is unacceptable. We can — and must — do better.”