MURDER TRIAL DAY 11: Pulmonologist testifies on manner of patient deaths

TYLER, Texas (KLTV) - The trial of a former East Texas nurse accused of injecting air into patients’ arterial lines, killing at least four and injuring more. The prosecution says they will rest their case tomorrow morning. After that, William Davis’ defense will begin to call witnesses.

Today, however, the jury heard testimony from two medical experts not affiliated with the CHRISTUS health system.

“His cause of death was from the brain injury that was caused by the injection of air,” said Dr. William Yarbrough, a Dallas VA Hospital pulmonologist.

Yarbrough, going down the line of victims, telling the jury what he believes led to their unexpected decline. After examining the patients’ CT scans, he says it’s clear air was intentionally injected into their arterial lines after their surgeries, when the victims, like Pamela Henderson, were already awake and alert.

“It had to occur after that, after she was able to talk and communicate and things. That couldn’t have been this much damage before that,” Yarbrough said

Dr. Kennith Layton also reviewed the patients’ CT scans. He says it doesn’t take long for air to absorb in the brain, which is why it shows up more on some victims scans and less on others.

“It depends how much volume was there to start with so if you have a huge amount of air, it’s gonna take longer to go away. If you have a smaller amount of air it, obviously based upon the rate of resorption of the air is gonna take less time to go away,” Layton said.

Part of Dr. Yarbrough’s examination of the CT scans included coming up with other explanations for what could have caused the patients to unexpectedly crash.

“Could it be because there was a lack of saturation? Could it be because the blood pressure was low? Could it be because the heart rate was low and things like that that you have to go through to say okay can we give it another ideology another reason for this damage to be there?” Yarbrough said.

Dr. Yarbrough says his review of the scans made it clear to him: air was intentionally injected into the patients arterial lines sometime after their surgery.

“Were you able to rule out any other possibility?” prosecutor Chris Gatewood asked.

“Yes,” Yarbrough responded.

1:10 p.m. - -Defense attorney Phillip Hayes asks Dr. Yarbrough how he can be sure it’s air that was in the patients’ brains and not some other guess. “You’re guessing.” Hayes says to Yarbrough.

That concludes questioning today. The state will rest tomorrow morning and the defense will then begin calling witnesses tomorrow morning.

10:49 a.m. - Dr. William Yarbrough, a Dallas VA Hospital pulmonologist, took the stand.

Yarbrough is serving as an expert witness for the prosecution. He has an extensive medical background.

Yarbrough went over how blood travels away from the heart as air travels upwards to the highest area.

The trial of a former East Texas nurse accused of killing patients during his time working at a Tyler heart hospital continued Tuesday.

William Davis, 37, of Hallsville, is accused of injecting air into the arterial lines of patients at a Tyler heart hospital. Davis was arrested in April 2018.

The state is expected to rest their case today. There will be no trial on Friday due to scheduling conflicts.

Dr. Kennith Layton, of Baylor Scott and White Health, was back on the stand Tuesday for cross-examination.

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