A series of newly-released calls made after the failed execution of US death row inmate Christa Pike reveal emergency services were delayed by confusion among first responders and Tennessee prison officials.

The recordings, first obtained by the Associated Press, show that minutes passed as officials and responders attempted to confirm whether the request for emergency help in the execution chamber at Riverbend Prison was legitimate.

The Nashville Department of Emergency Communications released several calls between the agency and other departments – including police and highway patrol.

“We are trying to find out if that is an actual thing that is happening and we need to send an ambulance and, or if you need police assistance or if this is someone that is just basically prank calling or, like, swatting us,” one dispatcher can be heard saying during a call.

Another recording shows Kelly Gleason, Christa Pike’s defence attorney, calling for help.

“She is still alive and breathing and needs immediate life-saving care,” she says.

Pike, 50, was sentenced to death after murdering Colleen Slemmer with her then-boyfriend in 1995. She survived two injections of the drug pentobarbital on 30 September and was taken to hospital in a critical condition.