Expert Testimony Excluded Over Causation, Reversed by Okla Supreme Court

In matters of negligence, it is not that alternative causes must be ruled out before causation is attributed, but that other causes must be adequately considered, the Oklahoma Supreme Court has ruled, overturning a trial court's exclusion of two medical expert witnesses based on a Daubert challenge.

In the case of Nelson v. Enid Medical Associates, Inc., Okla. Supreme Court, Jun 14, 2016, Ethel Nelsen died two days after going to an emergency room with severe abdominal pain. The emergency room physician, Dr. Vaughan, diagnosed her with an incarcerated hernia and possible bowel obstruction. Dr. Vaughan contacted Dr. Shepherd, Nelsen's primary care physician, who advised contacting Dr. Shreck, a surgeon, to treat the hernia.

Dr. Shreck manually reduced Nelson's hernia, but soon after she became septic, went into septic shock, had a cardiac arrest while being prepared for bowl surgery, was resuscitated, and then had the surgery. Afterwards, Dr. Shepherd switched Nelson's medication to vasopressip, allegedly causing her blood pressure and pulse to drop, resulting in her death. 

Nelson's husband and son sued the physicians involved, providing as their expert witnesses Dr. Douglas Sheena, an emergency medicine physician and hospitalist from Dallas, and Dr. James Russell, a Professor of Medicine at University of British Columbia and researcher in the pharmacogenomics of septic shock.

Two of the defendants, Dr. Shepherd and Enid Medical Associates, made a Daubert motion to exclude the proposed testimony of Drs. Sheena and Russell, arguing that their opinions were mere speculation and not based upon scientific research or proper clinical observation.

Dr. Russell had relied in part on animal studies and academic studies, including his own published articles, to form his opinion. While he noted that the use of vasopressin in septic shock is "off label", Dr. Russell did not object to the its usage, but opined  that Nelsen was given too high a dose of vasopressin, for too long a time, without tapering off the dosage, and that high dosage significantly contributed to her death. 

Dr. Sheena, in his deposition, also opined that Nelson's death was caused by "a combination of septic shock and the overdose of vasopressin."

The trial court found that neither Drs. Russell or Sheena ruled out other potential causes of Nelson's death. They offered nothing, the trial court said, to rule out other medications that were given to Nelson (eg: Dopamine, Levophed), or to rule out septic shock, or some other natural cause, as the sole cause of Nelson's death.

The Oklahoma Supreme Court found, however, that the trial court did not properly address the scope of Dr. Sheena's opinion on contributory causes of the cardiac arrest, including the vasopressin dosage. The trial court ruled Dr. Sheena's testimony inadmissible because he failed to rule out other potential causes, including septic shock, that his opinion was mere ipse dixit.

The Supreme Court found otherwise, noting that Dr. Sheena had in fact "ruled in" septic shock as a contributing cause. The Court noted as well that the defendants appeared to agree with Drs. Russell and Sheena on the proper dosage of vasopressin in patients similar to Nelson. In Dr. Shepherd's deposition, he admitted: "I think the dose I wrote was a mistake. The question, I guess, is whether or not it caused harm."

The Supreme Court found that neither Drs. Russell nor Sheena testified that the vasopressin dosage was the sole cause of Nelson's cardiac arrest, and they both considered alternative causes. They testified that the high dosage of vasopressin was the "most probable cause, or contributory cause," to Nelson's death.

The Supreme Court reversed the trial court's order excluding Drs. Russell and Sheena's testimony and the granting of summary judgment, vacated the opinion of the Court of Civil Appeals, and remanded the case back to the District Court.