Wade Clark Mulcahy LLP

Res Ipsa Loquitur is defined in Pennsylvania as a discrete category of circumstantial evidence that may suffice to establish negligence where more specific evidence of the events surrounding the injury eludes even diligent investigation. Essentially, the doctrine permits a jury to exercise common sense and conclude that the alleged accident could not occur absent negligence. Pennsylvania has historically taken this a step further and allowed the doctrine to be applied to cases involving complex facts and theories, including in medical malpractice cases.

In Lageman by and through Lageman v. Zepp, the Pennsylvania Supreme Court analyzed the doctrine in a medical malpractice action and clarified the scope of when the doctrine can be given as a jury instruction. Lageman by & through Lageman v. Zepp, 266 A.3d 572 (Pa. 2021). In Lageman, the trial court originally returned a defense verdict and did not permit Lageman to instruct the jury on finding negligence under Res Ipsa Loquitur since Lageman also presented direct evidence of Zepp’s negligence. Lageman argued that “accepting Zepp's version of how he performed the procedure... arterial cannulation[] would not ordinarily occur in the absence of negligence”; and Pepple's further testimony that no other plausible causes were present, Lageman contended that she made out a prima facie case under Section 328D and was entitled to the instruction. The trial court disagreed and only instructed the jury on negligence since Lageman introduced direct evidence in support of her malpractice claim. Lageman by & through Lageman v. Zepp, 266 A.3d 572, 586 (Pa. 2021).

Following the defense verdict, Lageman appealed to the Pennsylvania Superior Court, and the verdict was reversed. The Superior Court found that a plaintiff has no obligation to choose one theory of liability to the exclusion of the other. If the evidence satisfies the bare minimum requirements to support a jury instruction, the instruction should be given. Therefore, presentation of Res Ipsa Loquitur theory to support a medical malpractice claim was not precluded when the plaintiff also introduced direct evidence sufficient to support a malpractice claim, so Res Ipsa Loquitur was not the only avenue to a finding of liability; the two approaches to satisfying the plaintiff's evidentiary burden were not mutually exclusive.

Zepp appealed the Pennsylvania Superior Court’s finding, but the Pennsylvania Supreme Court affirmed and found that Lageman was entitled to have the jury instructed on both theories of liability. The Pennsylvania Supreme Court affirmed that in these “gray zone” cases, where the plaintiff presents direct evidence of negligence and circumstantial evidence of negligence under the doctrine of Res Ipsa Loquitur, the jury may be instructed on both theories of liability.