A doctor who treats living patients and another who focuses on analysis after death both testified Thursday they don’t believe the ketamine injection Elijah McClain received killed him.

Kennon Heard, an emergency physician and toxicologist at UCHealth, said the 500 milligrams of ketamine McClain received was more than what his body weight called for based on Aurora paramedic protocols at the time. But he testified that ketamine’s sedative effect has a “ceiling,” meaning a higher dose doesn’t increase a patient’s dissociative state.

Respiratory arrest is a rare, and extreme, possible side effect of ketamine, he said.

“I would not expect life-threatening effects from this amount of ketamine,” Heard told the jury.

Aurora Fire Rescue paramedics Jeremy Cooper and Lt. Peter Cichuniec each face charges in Adams County of reckless manslaughter, criminally negligent homicide and three counts each of second-degree assault. The assault charges originally included assault causing serious bodily injury, assault with a deadly weapon and unlawfully administering the sedative without consent.

The fire medics have pleaded not guilty.

Before the jury arrived Thursday morning, Judge Mark Warner dismissed the counts of second-degree assault with a deadly weapon (ketamine), and a related sentence enhancer, against each paramedic. He determined there’s not enough evidence to show Cooper and Cichuniec intended to use the ketamine as a weapon, which is part of the analysis necessary for whether something would be considered a deadly weapon.

McClain died a few days after three Aurora police officers stopped him as he walked home from a convenience store the night of Aug. 24, 2019, after buying iced tea. During a struggle they took McClain to the ground, handcuffed him and one used a neck hold that restricts oxygen flow to the brain. The paramedics now facing trial decided to give McClain a 500-milligram dose of ketamine, a sedative used in medical care as an anesthetic and for pain management.

He went into cardiac arrest and stopped breathing within a few minutes of receiving the injection, and never regained consciousness. A doctor declared him brain dead in the hospital three days later. Prosecutors say Cooper and Cichuniec made the decision to administer ketamine from only relying on police officers’ account of McClain’s behavior, without speaking to McClain or examining him themselves.

Body-worn footage captures police saying McClain was showing extreme strength, “on something” and had tried to grab one officer’s gun. At the time, Aurora paramedics were trained to administer ketamine to patients believed to be suffering from “excited delirium” — typically described as an onset of symptoms such as extreme strength, aggression and paranoia.

However, Colorado’s licensing board for peace officers recently voted to remove the term from training documents in the state.

Ketamine is an ideal choice to treat agitation, especially in a setting without the full array of tools available in a hospital, Heard said, because it’s easy to administer and takes effect quickly.

He said the drug has a “wide safety margin,” meaning the difference between a dose that produces a desired effect in a patient and a dose that turns out to be toxic.

Notably, however, Heard would not commit to pinpointing an amount of ketamine that amounts to a fatal dose.

On cross-examination, Senior Assistant Attorney General Jason Slothouber zeroed in on Heard’s reliance on ketamine studies that focused on the drug given in correct doses to patients properly assessed to need it, in settings that involved proper monitoring and intervention tools available in case the ketamine had a negative effect.

“But people can die from the expected side effects of ketamine if they don’t get the right intervention and they’re not treated?”

“Yes,” Heard replied.

The defense attorneys’ second medical expert of the day, Michigan-based forensic pathologist Ljubisa Dragovic, shifted blame to the police officers who restrained McClain during his time on the witness stand. He testified Thursday afternoon that he determined McClain died from brain death brought on by inhaling his own vomit over the course of the struggle with police.

Dragovic is the chief medical examiner and forensic pathologist for Oakland County, Michigan.

Dragovic added he believes a depressant effect from ketamine toxicity would have shown up as fluid buildup in McClain’s lungs, which he didn’t see.

He disagreed with the characterization of McClain’s death as a homicide by a prosecution witness, Roger Mitchell. Dragovic defines a homicide as death resulting from a “purposeful act” by another person, and he saw “no demonstrative evidence of a purposeful act by anyone rendering death.”

Slothouber pressed the forensic pathologist on the implications of his definition. A death caused by a person driving 100 miles per hour, “drunk as a skunk,” is accidental as long as they didn’t mean to kill anyone, he asked?

“No matter how irresponsible someone’s actions were, as long as it wasn’t purposeful, it would be an accident?”

“Yes,” Dragovic said.

The paramedics’ defense attorneys will resume their case Friday morning by questioning Gary Ludwig, a Missouri-based veteran paramedic who has had leadership roles in St. Louis and Memphis’ fire departments. Ludwig took the stand late Thursday afternoon.