CA Court Excludes Medical Expert Causation Testimony

Jennings filed a malpractice claim against Palomar Pomerado Hospital and the doctors who operated on him based solely on the failure to remove the retractor at the conclusion of the original surgery.

Plaintiff's sole causation expert, Dr. Howard Miller, testified that the retention of the contaminated retractor was a substantial factor in causing Jennings' infection. Dr. Miller testified that the retained retractor contributed to the infection in the upper subcutaneous tissue and fascia by remaining lodged below in the peritoneal cavity. He theorized that there was “guilt by association,” even though he admitted there was no reported evidence of an infection in the peritoneal area where the retractor was lodged. (Jennings, supra, 114 Cal.App.4th at pp. 1113-1115 [8 Cal. Rptr.3d at pp. 366-367].)

Dr. Miller summarized his causation theory as follows: “It just sort of makes sense [that the retained retractor contributed to Mr. Jennings' infection.] We have that ribbon retractor and it's contaminated, he's infected.” (Jennings, supra, 114 Cal.App.4th at pp. 1119-1120 [8 Cal. Rptr.3d at p. 371].) As Dr. Miller acknowledged, however, a retractor can be left inside a patient without any infection occurring; in other words, the mere retention of a retractor does not, ipso facto, lead to the conclusion that it more likely than not caused a subsequent infection. (Id. at pp. 1114-1115, fn. 7 [Id. at p. 367].)

The defendants moved to strike Dr. Miller's testimony, arguing that his testimony lacked foundation because it was based on factual assumptions that lacked evidentiary support and was too speculative to satisfy the “more probable than not” causation standard. The trial court granted the motion.

The Court of Appeal upheld the exclusion of the medical expert's causation testimony. In doing so, the court explained the development of the rule governing the admission of expert testimony under California Evidence Code section 801 and placed it in the context of the applicable “reasonable medical probability” causation standard. (Jennings, supra, 114 Cal.App.4th at pp. 1116-1121 [8 Cal. Rptr.3d at pp. 368-372].) The Jennings court explained that under section 801, the admissibility of an expert opinion “cannot be assessed in a vacuum, but must instead be considered through the prism of the purpose for plaintiff's proffer of [the] opinion” (Jennings, supra, 114 Cal.App.4th at p. 1117 [8 Cal. Rptr.3d at pp. 369]), and that “proffering an expert opinion that there is some theoretical possibility [a] negligent act could have been a cause-in-fact of a particular injury is insufficient to establish causation. Instead, the plaintiff must offer an expert opinion that contains a reasoned explanation illuminating why the facts have convinced the expert, and therefore should convince the jury, that it is more probable than not the negligent act was a cause-in-fact of the plaintiff's injury” (Id. at p. 1118, italics and citations omitted [Id. at p. 370]).

The Jennings opinion provides much-needed guidance to trial courts on the required nexus between the foundation for an expert opinion and the facts of the particular case for which the opinion is being offered, and the interplay between a determination of the admissibility of expert opinion testimony and substantive causation standards. (See Jennings, supra, 114 Cal.App.4th at pp. 1117 [8 Cal. Rptr.3d at pp. 369] (“Exclusion of expert opinions that rest on guess, surmise or conjecture [citation] is an inherent corollary to the foundational predicate for admission of the expert testimony: Will the testimony assist the trier of fact to evaluate the issues it must decide? … [A]n expert's conclusory opinion that something did occur, when unaccompanied by a reasoned explanation illuminating how the expert employed his or her superior knowledge and training to connect the facts with the ultimate conclusion, does not assist the jury. In this latter circumstance, the jury remains unenlightened in how or why the facts could support the conclusion urged by the expert, and therefore the jury remains unequipped with the tools to decide whether it is more probable than not that the facts do support the conclusion urged by the expert. An expert who gives only a conclusory opinion does not assist the jury to determine what occurred, but instead supplants the jury by declaring what occurred”) (Id. at p. 1118 [Id. at p. 370] (explaining why an expert opinion that there is “some theoretical possibility [a] negligent act could have been a cause-in-fact of a particular injury is insufficient to establish causation” under the “more probable than not” substantial factor causation standard).)

The Jennings opinion builds on prior California case law recognizing a trial court's duty to examine expert opinions and exclude the expert's testimony if it lacks proper foundation. (See, e.g., Pacific Gas & Electric Co. v. Zuckerman (1987) 189 Cal.App.3d 1113, 1134-1136, 234 Cal. Rptr. 630, 643; Korsak v. Atlas Hotels, Inc. (1992) 2 Cal.App.4th 1516, 1524, 3 Cal. Rptr.2d 833, 838; Smith v. ACandS, Inc. (1994) 31 Cal.App.4th 77, 93, 37 Cal. Rptr.2d 457, 465-466, overruled on another ground in Camargo v. Tjaarda Dairy (2001) 25 Cal.4th 1235, 1245, 108 Cal. Rptr.2d 617, 624; Bay Area Rapid Transit Dist. v. Superior Court (1996) 46 Cal.App.4th 476, 482 , 53 Cal. Rptr.2d 906, 909). But Jennings clarifies that, as a threshold matter, a trial court has the responsibility to carefully examine expert testimony under California Evidence Code ' 801 and exclude that testimony from the jury's consideration if the court's examination reveals that the expert's opinion lacks an adequate foundation. As the Jennings court explained, just “because an expert expresses a conclusion supported only by a statement telling the jury (in essence), 'Trust me, I'm an expert, and it makes sense to me,'” the party submitting the expert testimony “has provided no grist for the jury's decisional mill;” rather, to be able to testify at trial, an expert “must provide some articulation of how the jury, if it possessed his or her training and knowledge and employed it to examine the known facts, would reach the same conclusion as the expert.” (Jennings, supra, 114 Cal.App.4th at p. 1120, fn. 12 [8 Cal. Rptr.3d at p. 371, fn. 12].)

The Jennings decision significantly contributes to trial courts' understanding of their responsibility to carefully examine expert testimony and exclude expert testimony that lacks foundation.

Recently, the California Court of Appeal (Fourth Appellate District, Division One) issued a decision that confirms and clarifies the broad scope of trial court authority under California Evidence Code section 801 to exclude expert testimony that lacks adequate foundation. (Jennings v. Palomar Pomerado Health Systems, Inc. (2004) 114 Cal.App.4th 1108 [8 Cal. Rptr.3d 363].)

Details of the Case

Daniel Jennings underwent surgery at Palomar Pomerado Hospital to remove an atypical connection between his colon and bladder, and make necessary subsequent repairs to his bladder. One of the instruments used during the surgery, a metal retractor, was left in Jennings' abdominal cavity. During a second surgery to remove the retractor, which was lodged deep in the peritoneal cavity amid the abdominal organs, doctors discovered and treated a post-operative abdominal infection in an upper region of subcutaneous tissue and fascia.

Jennings filed a malpractice claim against Palomar Pomerado Hospital and the doctors who operated on him based solely on the failure to remove the retractor at the conclusion of the original surgery.

Plaintiff's sole causation expert, Dr. Howard Miller, testified that the retention of the contaminated retractor was a substantial factor in causing Jennings' infection. Dr. Miller testified that the retained retractor contributed to the infection in the upper subcutaneous tissue and fascia by remaining lodged below in the peritoneal cavity. He theorized that there was “guilt by association,” even though he admitted there was no reported evidence of an infection in the peritoneal area where the retractor was lodged. (Jennings, supra, 114 Cal.App.4th at pp. 1113-1115 [8 Cal. Rptr.3d at pp. 366-367].)

Dr. Miller summarized his causation theory as follows: “It just sort of makes sense [that the retained retractor contributed to Mr. Jennings' infection.] We have that ribbon retractor and it's contaminated, he's infected.” (Jennings, supra, 114 Cal.App.4th at pp. 1119-1120 [8 Cal. Rptr.3d at p. 371].) As Dr. Miller acknowledged, however, a retractor can be left inside a patient without any infection occurring; in other words, the mere retention of a retractor does not, ipso facto, lead to the conclusion that it more likely than not caused a subsequent infection. (Id. at pp. 1114-1115, fn. 7 [Id. at p. 367].)

The defendants moved to strike Dr. Miller's testimony, arguing that his testimony lacked foundation because it was based on factual assumptions that lacked evidentiary support and was too speculative to satisfy the “more probable than not” causation standard. The trial court granted the motion.

The Court of Appeal upheld the exclusion of the medical expert's causation testimony. In doing so, the court explained the development of the rule governing the admission of expert testimony under California Evidence Code section 801 and placed it in the context of the applicable “reasonable medical probability” causation standard. (Jennings, supra, 114 Cal.App.4th at pp. 1116-1121 [8 Cal. Rptr.3d at pp. 368-372].) The Jennings court explained that under section 801, the admissibility of an expert opinion “cannot be assessed in a vacuum, but must instead be considered through the prism of the purpose for plaintiff's proffer of [the] opinion” (Jennings, supra, 114 Cal.App.4th at p. 1117 [8 Cal. Rptr.3d at pp. 369]), and that “proffering an expert opinion that there is some theoretical possibility [a] negligent act could have been a cause-in-fact of a particular injury is insufficient to establish causation. Instead, the plaintiff must offer an expert opinion that contains a reasoned explanation illuminating why the facts have convinced the expert, and therefore should convince the jury, that it is more probable than not the negligent act was a cause-in-fact of the plaintiff's injury” (Id. at p. 1118, italics and citations omitted [Id. at p. 370]).

The Jennings opinion provides much-needed guidance to trial courts on the required nexus between the foundation for an expert opinion and the facts of the particular case for which the opinion is being offered, and the interplay between a determination of the admissibility of expert opinion testimony and substantive causation standards. (See Jennings, supra, 114 Cal.App.4th at pp. 1117 [8 Cal. Rptr.3d at pp. 369] (“Exclusion of expert opinions that rest on guess, surmise or conjecture [citation] is an inherent corollary to the foundational predicate for admission of the expert testimony: Will the testimony assist the trier of fact to evaluate the issues it must decide? … [A]n expert's conclusory opinion that something did occur, when unaccompanied by a reasoned explanation illuminating how the expert employed his or her superior knowledge and training to connect the facts with the ultimate conclusion, does not assist the jury. In this latter circumstance, the jury remains unenlightened in how or why the facts could support the conclusion urged by the expert, and therefore the jury remains unequipped with the tools to decide whether it is more probable than not that the facts do support the conclusion urged by the expert. An expert who gives only a conclusory opinion does not assist the jury to determine what occurred, but instead supplants the jury by declaring what occurred”) (Id. at p. 1118 [Id. at p. 370] (explaining why an expert opinion that there is “some theoretical possibility [a] negligent act could have been a cause-in-fact of a particular injury is insufficient to establish causation” under the “more probable than not” substantial factor causation standard).)

The Jennings opinion builds on prior California case law recognizing a trial court's duty to examine expert opinions and exclude the expert's testimony if it lacks proper foundation. (See, e.g., Pacific Gas & Electric Co. v. Zuckerman (1987) 189 Cal.App.3d 1113, 1134-1136, 234 Cal. Rptr. 630, 643; Korsak v. Atlas Hotels, Inc. (1992) 2 Cal.App.4th 1516, 1524, 3 Cal. Rptr.2d 833, 838; Smith v. ACandS, Inc. (1994) 31 Cal.App.4th 77, 93, 37 Cal. Rptr.2d 457, 465-466, overruled on another ground in Camargo v. Tjaarda Dairy (2001) 25 Cal.4th 1235, 1245, 108 Cal. Rptr.2d 617, 624; Bay Area Rapid Transit Dist. v. Superior Court (1996) 46 Cal.App.4th 476, 482 , 53 Cal. Rptr.2d 906, 909). But Jennings clarifies that, as a threshold matter, a trial court has the responsibility to carefully examine expert testimony under California Evidence Code ' 801 and exclude that testimony from the jury's consideration if the court's examination reveals that the expert's opinion lacks an adequate foundation. As the Jennings court explained, just “because an expert expresses a conclusion supported only by a statement telling the jury (in essence), 'Trust me, I'm an expert, and it makes sense to me,'” the party submitting the expert testimony “has provided no grist for the jury's decisional mill;” rather, to be able to testify at trial, an expert “must provide some articulation of how the jury, if it possessed his or her training and knowledge and employed it to examine the known facts, would reach the same conclusion as the expert.” (Jennings, supra, 114 Cal.App.4th at p. 1120, fn. 12 [8 Cal. Rptr.3d at p. 371, fn. 12].)

The Jennings decision significantly contributes to trial courts' understanding of their responsibility to carefully examine expert testimony and exclude expert testimony that lacks foundation.