Kelly on Malpractice 2.0

by Clint Kelly on May. 15, 2019

Accident & Injury Medical Malpractice 

Summary: Causation

VIII.   Causation


            Causation is the centerpiece of any medical malpractice defense.  If negligence did not cause the plaintiff’s injury, then you don’t have a case.[i]  This is frequently called the “so what” defense.  For instance, the defendant might assert that even if he had discovered and treated the plaintiff’s cancer six months earlier, the plaintiff still would have died.  The defendant may contend that some other malady or preexisting condition was the “but for” cause of your client’s demise.  In most medical negligence cases, the plaintiff will face a motion for directed verdict on the issue of causation.  You must give deep thought and preparation to this issue well in advance of trial.  You should be ready to file a memorandum of law to oppose the inevitable motion for directed verdict.  Your memorandum should incorporate basic principles of causation and a solid factual framework for establishing that the negligence was the “but for” cause of the injury or death.

            Here are some rudimentary principles of causation. Causation must be determined “in light of logic and common sense.”[ii] The jury decides causation unless undisputed facts permit a reasonable person to reach only one conclusion.[iii]  When the testimony of medical experts conflict, the jury “should be left free to adopt that view which is most consistent with reason and justice.”[iv]  A negligent act or omission must have been a substantial factor in bringing about the injury in order to be a proximate cause of that injury.[v]  More than one negligent act may be the cause of an injury.[vi]  Thus, a negligent act or omission may be the proximate cause of an injury although it is not the singular cause.[vii]

            No evaluation of the medical negligence claim is complete without solid proof of causation.  You can’t wait to deal with it later in the case.  You will need an expert to establish causation.  The expert’s testimony must meet the burden of admissibility –evidence to a reasonable degree of medical certainty.[viii]  Trial lawyers know that “reasonable degree of medical certainty” and “more probably than not” are synonymous terms of art.  Yet, we also know that juries get confused when these phrases are used interchangeably.  Certainty and probability have completely different meanings to laymen. Nevertheless, we accept this contradiction as part of our ritualistic practice ordained by precedent.  

What happens when precedent and pattern jury instructions collide?  The Court of Appeals faced such a dilemma in Bara v. Clarksville Memorial Health Systems, Inc., 2002 WL 31039333 (Tenn.Ct.App.). Over objection of the plaintiff, the trial court charged the jury in accordance with the defendant’s special jury request that stated, “in order for you to find that the injuries and/or death of Ms. Bara were proximately caused by the negligence of any defendant, the plaintiffs must have proven causation to a reasonable degree of medical certainty.” This special charge came on the heels of another instruction that stated, “Plaintiffs have the burden of proving more likely true than notthat the defendant’s conduct was the legal cause of her injuries.”  This inconsistency is obvious.  The jury returned a defense verdict.  

            The Court of Appeals found “reasonable degree of medical certainty” was an oxymoron.  The phrases “reasonable degree of medical certainty” and “more probable than not” were not synonymous.  The Supreme Court used both phrases interchangeably in Kilpatrick v. Bryant, 868 S.W.2d 594, 602 (Tenn.1993) by stating, “causation in fact is a matter of probability, not possibility, and in a medical malpractice case must be shown to a reasonable degree of medical certainty.”  Kilpatrickarguably left us with two different legal standards to prove causation in medical malpractice cases.  The Court of Appeals concluded in Barathat the standard for the admission of expert testimony – reasonable certainty – was erroneously converted into a burden of proof instruction.  Therefore, the BaraCourt reversed and held that the defendant’s special charge was inconsistent with the pattern jury instruction on burden of proof.[ix]   

Keep in mind that the burden of admissibility for experts is professional medical judgment that one cause is the most likely cause of the injury; its weight is to be determined by the jury.[x]  For this reason, Tennessee law does not allow a claim for “loss of chance” unless the plaintiff’s odds of survival or avoiding the injury are 51% or greater, i.e., more likely than not.[xi]  Spend time to critically examine the nexus between negligence and injury in your case. Causation has torpedoed many malpractice cases.  

In Mitchell v. Ensor, 2002 WL 31730908 (Tenn.Ct.App.), the issue for review was whether the defense expert could testify as to alternate causes of the plaintiff’s condition. The plaintiff asserted that the physician expert’s admission that he did not know the specific cause of the plaintiff’s condition rendered his testimony speculative.  The plaintiff also contended that the expert’s “alternate cause” theories were rooted in possibility rather than probability. Thus, the plaintiff moved to exclude the defense expert’s testimony regarding causation.[xii]  The Court of Appeals concluded that defendants in medical malpractice actions may introduce expert testimony about causation couched in terms of “possibility.” The defendant does not need to prove another cause, only to convince the jury that the negligence was not the cause of injury.  In proving such a case, a defendant may produce other “possible” causes of the plaintiff’s injury.  The result of Mitchellwas that plaintiffs had to fight all kinds of phantom causes for their damages introduced by the defendant.

            Fortunately, the Supreme Court fixed this problem in Hunter v. Ura, 163 S.W.3d 686 (Tenn.2005). The trial court excluded the defendant’s expert, Dr. Hays, after finding that his causation testimony was speculative about phantom possible causes. The Court of Appeals reversed the trial court’s ruling because it was proper for Dr. Hays to present “possible alternative causes” of the decedent’s death.  The Supreme Court disagreed based on McDaniel v. CSX Transp.Inc.,955 S.W.2d 257 (Tenn.1997), which governs the admissibility of scientific evidence.  The effect of Hunteris that “possible alternative cause” will not suffice because experts must offer more than possibilities.

            An intervening / superseding cause breaks the chain of causation.  This is a neat legal fiction that divorces a negligent act from the injury.  The key to successful application of the intervening cause doctrine is a lack of foreseeability.[xiii]  If the injury is unforeseeable, then there is no proximate cause and hence no liability. The law is equally clear, however, that “[a]n intervening act, which is a normal response created by negligence, is not a superseding, intervening cause that relieves the original wrongdoer of liability, provided the intervening act could have reasonably been foreseen.  An intervening act will not exculpate the original wrongdoer unless it is shown that the intervening act could not be reasonably anticipated. McClenahan v. Cooley, 806 S.W.2d 767, 775 (Tenn.1991); Haynes v. Hamilton County, 883 S.W.2d 606 (Tenn.1994).  Whether such an act or event constitutes an intervening / superseding cause is almost always for the jury.

            A nurse is incompetent to offer an opinion about causation.  In Richberger v. The West Clinic, P.C., 2004 WL 787162 (Tenn.Ct.App.), the plaintiff filed a medical malpractice action for injuries suffered as a result of negligent chemotherapy treatment.  The key issue was whether a registered nurse was prohibited from testifying as an expert witness as to the issue of causation in a medical malpractice action for the purpose of satisfying Tenn.Code Ann. § 29-26-115(a)(3).  The trial court ruled that a nurse is not competent to give causation opinions.  A registered nurse is prohibited from making a medical diagnosis pursuant to Tenn.Code Ann. § 63-7-103(b).  Therefore, a nurse is not competent to offer opinions on medical causation in a medical malpractice action.  In Nash v. Goodlark Hosp., 1990 WL 56192 (Tenn.Ct.App.), the court held that a nurse is not permitted to make a diagnosis.  Moreover, in Bishop v. Smith Nephew Richards, Inc., 1995 WL 99222 (Tenn.Ct.App.), the court held that an opinion regarding causation is outside the expertise of a nurse.  Following this line of authority, the Court of Appeals affirmed the trial court’s exclusion of the nurse’s medical causation opinion in Richberger.

            The error in judgment jury charge has received attention in the last couple of years:


A physician is not negligent or guilty of malpractice simply because his efforts prove unsuccessful.   It is possible for a physician to err in judgment or be unsuccessful in diagnosis or treatment of care without being negligent.   An error of judgment is not necessarily evidence of a want of skill or care because mistakes and miscalculations are incident to all of the business of life.   A physician will not be liable for a mistake in judgment so long as he exercised the reasonable and ordinary care and competence that was competent to his calling and his specialty.


In Ward v. Glover, 206 S.W.3d 17 (Tenn.Ct.App.2006), the parents filed an original complaint for themselves and on behalf of baby against doctors, medical clinic, hospital and anesthesia provider, alleging that their baby suffered catastrophic and permanent injuries because the mother’s uterus ruptured, thereby causing baby to be ejected into mother’s abdomen.  The plaintiffs contended at trial that Dr. Glover did not respond quickly enough to a telephone call from an obstetrics nurse.  Plaintiffs alleged this was a deviation from the standard of care.  Dr. Glover convinced the trial court to give the error of judgment charge.  The plaintiffs objected arguing that the speed by which the defendant responds to the hospital does not involve a choice of treatment or a decision between two medically accepted courses of action.  Therefore, the jury should not be instructed on errors in judgment.

            The Court of Appeals disagreed with the plaintiffs’ position on this issue.  The Court stated: 


Without question, Dr. Glover used his medical judgment in all of the decisions he made with respect to Mrs. Ward and Faith on the morning of February 10, 2002: in advising the Wards in their initial telephone call to him; in advising Nurse Chellino on the care and treatment of Mrs. Ward following the 6:02 a.m. phone call; in determining the appropriate course of action to take after evaluating Mrs. Ward upon his arrival at the hospital; and, ultimately, in the delivery of Faith.  Dr. Glover certainly used his medical judgment when, after listening to Nurse Chellino describe Mrs. Ward's symptoms at 6:02 a.m., he relayed that he was coming in to the hospital immediately, but did not, at that time, give further instructions with respect to preparations for surgery.   Clearly, the timeliness with which Dr. Glover responded following the 6:02 a.m. telephone call involved his medical judgment, thus justifying the jury instruction.(emphasis added).


Compare the result in Ward v. Gloverwith Godbee v. Dimick, 213 S.W.3d 865 (Tenn.Ct.App.2006).  In Godbee, the doctor denied any mistake, honest or otherwise.  His defense did not envision an “honest mistake.”   Nevertheless, the trial court charged honest mistake and error of judgment.  The Court of Appeals reversed because the defendant never admitted making a mistake or error in his care of the plaintiff.  It is a little difficult to square Wardwith Godbee.  The best strategy is to get the doctor to concede that many of the rudimentary aspects of his or her conduct did not involve a judgment call but were mandated by the standard of care.  Moreover, you should ask the doctor whether he made any mistakes or errors in the case whatsoever.  Then, you can argue Godbeeto defeat the charge if the defendant refuses to admit to any mistakes.

Suppose you have a malpractice / wrongful death case based upon misdiagnosis where the defendant failed to order a CT scan, which you contend would have revealed a life-threatening condition.  The defendant argues that your experts cannot “speculate” about what the diagnostic tests or subsequent medical evaluations would have shown if the defendant had followed the standard of care.  In other words, your experts can testify that the defendant’s negligence caused the decedent’s death, but they can’t speculate why she would have survived.  The defendant cites Jennings v. Case, 10 S.W.3d 625 (Tenn.Ct.App.1999) for this argument.  What do you do?  

InJennings, two doctors in succession misdiagnosed the patient’s arm condition, which led to an amputation.  The second doctor testified that the first doctor did not provide him with the patient’s pertinent medical history.  Nevertheless, the second doctor opined that there was no causation.  He testified that even if he had been provided with the patient’s prior history, he “would not have done anything differently.”  The trial court granted summary judgment, and the plaintiff appealed.

The court of appeals reversed the trial court. In medical malpractice cases, the cause of an injury must be shown to be reasonably certain, not a mere possibility. Logic demands that speculation about a situation that never occurred is insufficient to disprove causation.  The court explained its rationale as follows:


What Dr. Stewart believes he would have done in a hypothetical situation is incapable of being disproved by anyone else.  The best Plaintiff can do, and what she has done, is present expert testimony that her prior symptoms should have made a difference under the applicable standard of care.  Thus, there is a fundamental problem with dismissing Plaintiff’s claims against Dr. Case on the basis of Dr. Stewart’s statements that he would have done nothing different in a situation which never occurred.


The point of Jenningsis that a doctor cannot defeat a patient’s claim simply because he testifies hypothetically that additional information would not have changed the outcome. Otherwise, a patient would never be able to win a case of misdiagnosis.  The doctor could simply say, “nothing more would make a difference here,” and then the patient could not prove causation.  The plaintiff had expert proof that her prior symptoms would have made a difference under the standard of care.  This is why the court reversed the summary judgment in Jennings.

Jacobs v. Nashville Ear, Nose & Throat Clinic, 338 S.W.3d 466 (Tenn.Ct.App. 2010) is another case of misdiagnosis that undercuts the defendant’s argument.  Mr. Jacobs was a patient who died of sinus cancer. Mrs. Jacobs brought a medical malpractice action against the otolaryngologist and neuroradiologist because they misdiagnosed her husband’s cancer.  The defendants moved for summary judgment.  Mrs. Jacobs opposed their motion with the testimony of her expert surgeon, Dr. Bayles.  

One of the linchpin issues was causation – whether Mr. Jacobs would have survived the cancer with earlier surgery in May of 2000. In his deposition, Dr. Bayles offered the following opinions about causation:


1.         He extends or saves lives of cancer patients;

2.         He explained the surgery that would have been used in May of 2000 and testified that he had successfully performed this type of surgery on other patients; 

3.         He testified the surgery was a “widely accepted ... standard skull base craniofacial operation;” 

4.         He testified why Mr. Jacob’s tumor was operable in 2000 as opposed to 2001; and 

5.         He testified that Mr. Jacobs probably would have survived if surgery had been performed in May of 2000.


The trial court granted summary judgment because Dr. Bayles’ causation opinion was “speculative.” The court of appeals reversed the trial court finding that Dr. Bayles’ opinion was not speculative. The court of appeals determined that Dr. Bayles opinion about whether the decedent would have survived was based on “relevant scientific methods, processes and data, and not upon [his] mere speculation.”  Since the case did not involve an untested or novel approach in treating sinus cancer, the court saw no need to work through the factors set forth in McDaniel.

Like the experts in Jennings and Jacobs, your experts need to explain in painstaking detail why the decedent would have survived if the defendant had complied with the standard of care. Their opinions should be based on relevant scientific methods, processes and data, and not mere speculation.  Your experts should also refute the defense that the decedent’s survival with timely care is “speculative” at best.  This will get your case to a jury.

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