Substantial factor test in Texas medical malpractice cases: Proving that the negligence of multiple parties caused patient harm

As an experienced Houston, Texas medical malpractice attorney, I always look at potential new cases from the perspective of being able to all of the elements of evidence required under Texas law.

It’s not enough that a doctor, nurse, or other healthcare provider makes a mistake. In fact, that is just one piece of the puzzle. To prove medical negligence, a Texas plaintiff must prove that there is a duty owed to the patient, that the defendant breached the duty, and that it proximately caused injury or harm to the patient.

To prove the negligence element of duty, lawyers frequently talk about the standard of care. This involves retaining a medical expert to testify about what a reasonably prudent doctor or healthcare provider would have done (or not done) under the same or similar circumstances.

The next essential element of the negligence cases breach of a duty. This is the part of negligence that captures the attention of everyone. It is when a doctor or nurse makes a mistake. This also requires testimony from a medical expert witness.

The final piece of the puzzle is connecting the negligent act or omission to harm, which we refer to as causation.

In my experience, proving proximate causation is what trips up many plaintiffs and their attorneys. Under Texas law, proximate causation requires the plaintiff to prove two separate points. First, cause in fact, or a substantial factor, and second, foreseeability.

In some cases, proximate causation is pretty easy to show. For example, I am working on a case now in Waco where a neurosurgeon operated on the wrong part of the brain. It is straightforward to link the neurosurgeon’s mistake, or negligence, to the injuries the patient now has in other parts of his brain. This type of situation is sometimes called “but for” causation, meaning that but for the neurosurgeon’s negligence, the injury would not have occurred.

In other cases, proximate causation is a bit more subtle because there are multiple negligent healthcare providers involved.

For example, I am currently investigating a case in College Station, where a patient went to a hospital emergency room and was diagnosed with appendicitis. She had to go to the operating room for an appendectomy, a surgical procedure to remove her appendix. During the surgery, the surgeon mistakenly perforated her colon, but did not recognize it in the operating room and ended up discharging her home.

Overnight, her condition got worse. The patient’s family members called the surgeon’s office and spoke to a nurse several times. Unfortunately, the nurse provided bad information that there was nothing to worry about. The family eventually returned her to the emergency room (ER) at the same hospital.

An ER doctor saw her and somehow came up with the mistaken idea that the patient had an acute kidney injury. We have no idea where that diagnosis came from. As a result, there was a delay in getting the surgeon back to see her and a further delay in returning her to the operating room to repair her dangerous, toxic perforated colon.

Who is at fault? The surgeon? The nurse at the surgeon’s office? What about the emergency room doctor?

In my view, they all bear some responsibility. In these situations, the plaintiff typically must sue all of the healthcare providers who contributed to the negligence but still must prove proximate causation as to each of them. This is where the substantial factor rule comes into play.

Substantial factor rule

The Texas Supreme Court has held that, “the ultimate standard of proof on the causation issue ‘is whether, by a preponderance of evidence, the negligent act or omission is shown to be a substantial factor in bringing about the harm and without which the harm would not have occurred.’” Park Place Hosp. v. Estate of Milo, 909 S.W.2d 508, 511 (Tex. 1995) (citation omitted).

In another decision, the court noted that “It has long been the law in the state that the defendants act or omission need not be the sole cause of injury, as long as it is a substantial factor in bringing about injury.” Bustamante v. Ponte, 529 S.W.447 (Tex. 2017). In other words, there can be more than one proximate cause of an injury.

In the Bustamante opinion, the Texas Supreme Court held that there was legally sufficient evidence to supported jury’s conclusion that a neonatologist proximally caused a premature infants loss of vision. The court’s rationale was that, despite the expert testimony that both the neonatologist and ophthalmologist treating the infant were at fault, the conduct of each physician was a substantial factor in causing harm to the infant.

We are here to help

If you or a loved one has been seriously injured by poor medical, surgical, or hospital care, then the experienced medical malpractice attorneys at Painter Law Firm, in Houston, Texas, are here to help. Click here to send us a confidential email via our “Contact Us” form or call us at 281-580-8800.

All consultations are free and, because we only represent clients on a contingency fee, you will owe us nothing unless we win your case. We handle cases in the Houston area and all over Texas. We are currently working on medical malpractice lawsuits in Houston, The Woodlands, Sugar Land, Conroe, Dallas, Austin, San Antonio, Corpus Christi, Bryan/College Station, and Waco.


Robert Painter is a medical malpractice attorney at Painter Law Firm PLLC, in Houston, Texas. He is a former hospital administrator who represents patients and family members in medical negligence and wrongful death lawsuits against hospitals, physicians, surgeons, anesthesiologists, and other healthcare providers. A member of the board of directors of the Houston Bar Association, he was honored, in 2017, by H Texas as one of Houston’s top lawyers. In May 2018, the Better Business Bureau recognized Painter Law Firm PLLC with its Award of Distinction.

Robert Painter
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Robert Painter

Robert Painter is an award-winning medical malpractice attorney at Painter Law Firm Medical Malpractice Attorneys in Houston, Texas. He is a former hospital administrator who represents patients and family members in medical negligence and wrongful death lawsuits all over Texas. Contact him for a free consultation and strategy session by calling 281-580-8800 or emailing him right now.