MURDER TRIAL DAY 13: Closing arguments to begin Tuesday morning

TYLER, Texas (KLTV) - The defense rested its case Monday in the trial of former nurse William Davis.

Day 13′s witnesses included more doctors providing alternative explanations as to what caused the four patient deaths and injuries in others.

Doctor Vipul Kapoor, a Dallas medical doctor, who is not affiliated with the Christus Health system, says the defense asked him to review scans and medical records from Davis’ alleged victims. However, by their design, the defense teams states they did not tell Dr. Kapoor of what was suspected of causing the deaths and injuries, before he did his examination.

“So the commonality in all those patients, the six patients that I was asked to look at was the pattern of the stroke, so all these patients had strokes,” Kapoor said. “The pattern of the strokes was very similar in all these six patients and the pattern matched what is called a watershed stroke.”

That’s a stroke which affects one or more regions of the brain.

Another witness who testified for the defense, Doctor John Schnell, is an ER physician at UT Health East Texas. He formerly worked at Christus Mother Frances.

“I overheard a couple of the nurse talking about this case and it bothered me what I heard,” Schnell said.

While overhearing talk about the Davis case at a different hospital , Dr. Schnell testified that he became concerned that there may be another explanation for the deaths. In the case of Chris Greenaway, Schnell said the records show he had a high blood pressure just prior to crashing in the early morning hours of August 4, 2017.

“Right before this significant event, the medical records document a blood pressure of 235 over 222 and that’s a pretty significant blood pressure for any of us sitting here,” he said

Schnell brought up Seratonin Syndrome, which he says can cause higher blood pressure and can lead to seizures and strokes. He says, in his opinion, this could be what caused Greenaway to crash.

“Even though a patient may be on sedation to help suppress some of this, the Seratonin Syndrome can break through that and cause symptoms very similar to what we see in Greenaway’s case,” he said.

In other patients, Dr. Schnell said their declines could have been due to a history of blood clotting in the case of John Lafferty, previous high blood pressure in the case of Ronald Clark, and alcohol withdrawal syndrome in the case of Joseph Kalina. The prosecution argues these possible explanations are not what actually happened.

Several witnesses have previously testified that the intentional injection of air into arterial lines is what causes the patients to crash.

After dismissing the jury, Judge Austin Reeve Jackson asked William Davis if he’d reached a decision to whether he would testify in his own defense. The defendant told the judge he would not.

After resting the state recalled Dr. Charlie Crum to cross examine information heard from today’s defense witnesses.

Both sides rested their case today as the evidentiary examinations formally came to a close in the murder trial of William Davis, a former Christus Trinity Mother Frances nurse accused of murdering multiple hospital patients.

After the defense rested, the state recalled several witnesses, including Dr. Kenneth Layton, who specializes in diagnostic radiology and neuroradiology at Baylor Scott & White, as well as Dr. William Yarbrough, a pulmonologist from the Dallas VA hospital.

Layton said that it was his opinion that, without a doubt, it was air that was discovered in the patients’ brains and that serotonin syndrome was not the cause of their strokes, contradicting testimony earlier Monday from a doctor called by the defense who speculated that said syndrome is what could possibly have led to the strokes.

“If you inject air into the radial (arterial) line, it will go to the brain,” Layton said.

Yarbrough likewise ruled out serotonin syndrome as the cause of the patients’ downturn. Specifically in the case of Joseph Kalina, Yarbrough said it is his determination that alcohol withdrawal syndrome was not what caused his sudden downturn on Jan. 25, 2018.

Now that the evidentiary portion of the trial has concluded, closing arguments will begin when the trial resumes Tuesday morning. Following that, jury deliberations will begin.

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2:52 p.m. - William Davis’ defense rests their case.

2:31 p.m. - William Davis said he will not testify in his own defense.

2:14 p.m. - The cross-examination of Dr. Schnell begins.

Schnell said he doesn’t have much experience with patients post-surgery in the CVICU and did not consult with any of the nurses/doctors that treated the patients.

Schnell said the strokes were not a result of blood clots.

Prosecutor Lance Long asks Schnell if he was aware John Lafferty was awake and talking to his nurse after surgery.

“I would need to review the medical record,” Schnell said.

“Would’ve been great to do it ahead of time, wouldn’t it?” Long said.

11:40 a.m. - The next witness, Dr. John Schnell, is an ER physician at UT Health East Texas. He Formerly worked at CHRISTUS Mother Frances.

Schnell says he reached out of Defense attorney Phillip Hayes a few weeks ago, concerned that what was suspected happened to the patients wasn’t what ultimately caused their deaths.

Schnell says he doesn’t need to review all 10,000+ pages of medical records to come to a conclusion on what may have happened.

In the case of Chris Greenaway, Schnell says there was a “significant event” at 3:35am. He had a high blood pressure and heart rate. Schnell brings up Serotonin Syndrome, which can cause higher blood pressure and can lead to seizures and strokes. He says, in his opinion, this could be what caused Greenaway’s significant event.

In the case of John Lafferty, Schnell says he had a history of blood clotting. He says surgery increases risk of having a stroke.

In the case of Ronald Clark, Schnell says he also had a high blood pressure following surgery.

In the case of Joseph Kalina, Schnell says Kalina typically had several alcoholic drinks a day and appeared to be going through alcohol withdrawal syndrome around the time he crashed. He exhibited symptoms of alcohol withdrawal, such as a higher blood pressure.

10:48 a.m. - Kapoor said watershed strokes are not that common, but says they’re more likely to happen in or around cardiac surgery.

He said he thinks these strokes could be post-operative complications.

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

The defense continued to call witnesses at the trial of William Davis.

Dr. Vipul Kapoor was called to the stand. Kapoor says lead defense attorney Phillip Hayes asked him to review some medical records, but did not tell him how it was suspected they died/were injured. Hayes wanted an unbiased opinion.

Kapoor said in his opinion all of the patients had strokes. He said in his opinion, the patients’ brain scans show evidence of watershed strokes. He said heart problems can cause decrease in blood pressure, which could result in a watershed stroke. All of the alleged victims had just undergone heart surgery leading up to their crash.