Substantial-factor test analyzed in medical malpractice case

Emily De Young, Volume 50 Staff Member


The issue in this case was whether legally sufficient evidence supported a jury’s conclusion that the negligence of a premature infant’s treating neonatologist proximately caused her loss of vision. The Supreme Court of Texas held that legally sufficient evidence supported the jury’s finding that the neonatologist’s negligence, more likely than not, caused the plaintiff’s poor visual outcome.

In Bustamante v. Ponte, the parents of D.B. sued Dr. Ponte, her neuroneonatologist and attending physician, and Dr. Llamas, her ophthalmologist, claiming their negligence caused D.B.’s blindness resulting from her development of retinopathy of prematurity (ROP). The jury found that the defendants’ negligence caused D.B.’s injuries and rendered judgment holding Dr. Ponte and Dr. Llamas jointly and severally liable. The court of appeals reversed and rendered judgment that the Bustamantes take nothing, since they failed to adduce any non-conclusory evidence of causation. The Bustamantes filed a petition for review in the Texas Supreme Court, but Dr. Llamas settled the claims against himself, thus only Dr. Ponte remained as respondent.

The Court noted that to establish proximate cause in a medical-malpractice case, there must be evidence of a reasonable medical probability or reasonable probability that the plaintiff’s injuries were proximately caused by the negligence of one or more defendants.

Here, the Court held that the applicable test should be a substantial-factor test because the jury heard ample evidence supporting the combined negligence of Dr. Ponte and Dr. Llamas. The Court also held that because the expert witnesses’ opinions were based on more than epidemiological studies, and were informed in part by the results of the Revised Indications for Treatment of Retinopathy of Prematurity (ETROP) study, the ETROP study was evidence supporting their opinion that the untimely diagnosis and treatment of D.B.’s ROP caused her vision impairment. The Court ultimately concluded that legally sufficient evidence supported the jury’s conclusion that Dr. Ponte’s negligence more likely than not caused D.B.’s impaired vision.

Bustamante v. Ponte, No. 15-0509 (Tex. Dec. 8, 2016).