Arizona Court of Appeals Division One Holds That an Expert Witness Called by the Defense to Testify About Causation in a Medical Malpractice Case May Testify About “Possible” Causes of the Plaintiff’s Injury.

In 2003, Judy Benkendorf underwent surgery to remove her cancerous left kidney.  After the surgery, she developed a blood clot that went to her lung.  Her doctor prescribed Coumadin, and, in connection therewith, Judy began regular visits to Defendant’s Coumadin Clinic to monitor her Coumadin dosage.  Approximately six months later, Judy suffered an intracranial hemorrhage while at her home and died two days later.

Judy’s husband sued Defendant, alleging that it caused Judy’s death by negligently monitoring and adjusting her Coumadin dosage.  The trial court denied the husband’s motion in limine seeking to preclude testimony from Defendant’s causation expert regarding possible causes of Judy’s death and the jury returned a general verdict in favor of the Defendant.  The husband timely appealed.

On appeal, the Court of Appeals affirmed the trial court’s denial of the husband’s motion in limine, concluding that Defendant’s expert could properly testify to the possible causes of Judy’s brain hemorrhage.  In Arizona, a plaintiff in a medical malpractice lawsuit must ordinarily prove the causal connection between an act or omission and the ultimate injury through expert medical testimony.  To establish the requisite causal connection, the plaintiff’s expert is generally required to testify as to probable cause of the plaintiff’s injury.  The rationale behind this requirement stems from the basic principle that a plaintiff has the burden of proving his or her injuries were caused by defendant’s conduct.  Because the defendant, in contrast, need only convince the trier of fact that the alleged negligence was not the legal cause of the injury, the Court of Appeals concluded that it would be inequitable to prohibit the defendant from rebutting his prima facie malpractice case by introducing evidence regarding other possible causes of the injury.  Following the majority of jurisdictions to have addressed the issue, the Court, therefore, held that an expert witness called by the defense to testify about causation in a medical malpractice case may testify about “possible” causes of the plaintiff’s injury.  The Court did note, however, that the requirements of the Arizona Rules of Evidence governing the admission of expert testimony must still be satisfied. 

Judge Brown authored the opinion; Judges Johnsen and Gemmill concurred.