On December 20, 2017, the South Dakota Supreme Court affirmed a June 2016 jury verdict in favor of a pediatric gastroenterologist, Dr. Stephen Nanton.  The case was captioned Basil O’Day and Tracy McClure, as Guardians Ad Litem for N.W.O. v. Stephen Nanton, M.D. 

According to the Supreme Court’s Opinion, the Plaintiffs sued Dr. Nanton for medical malpractice alleging that he improperly treated N.W.O., an infant at the time of treatment, with a prescription drug called Reglan.  After a week-long trial, the jury found in Dr. Nanton’s favor, concluding that he did not violate the standard of care in treating N.W.O.

Two of the trial court’s rulings were considered on the Plaintiffs’ appeal.  First was the trial court’s decision to disallow the Plaintiffs from presenting undisclosed expert opinion relating to MRI imaging of N.W.O.’s brain.  The trial court excluded the testimony because the opinions were new and undisclosed; the Plaintiffs knew that the MRI imaging would be discussed at trial, yet they still failed to disclose the opinion; and the Plaintiffs’ use of the undisclosed opinions could have unfairly prejudiced the Defendant.  On the appeal, the Plaintiffs argued they were not required to disclose the expert opinion because it was only going to be used in rebuttal.  The Supreme Court rejected the Plaintiffs’ arguments because, regardless of whether the new expert opinion was or was not allowed, it could not have changed the trial result.  This was true because the new opinion related only to causation, an issue the jury never had to address because it determined that Dr. Nanton did not breach the standard of care to begin with.

The second appeal issue was the trial court’s rejection of the Plaintiffs’ proposed aggravation of preexisting injury jury instruction.  The Supreme Court agreed with the trial court’s conclusion that the instruction was not warranted given the evidence.  Specifically, the Plaintiffs presented evidence of an all or nothing proposition – they argued N.W.O. was a healthy baby until he began taking Reglan.  Under their theory, there was no preexisting condition to aggravate.

The full version of the O’Day opinion can be found at:


Note that author, Matt Murphy, was part of the defense team at trial and he handled the defense’s briefing to the South Dakota Supreme Court.