United States District Court, D. Minnesota
In re BAIR HUGGER FORCED AIR WARMING DEVICES PRODUCTS LIABILITY LITIGATION This Document Relates to All Actions.
N. ERICKSEN UNITED STATES DISTRICT JUDGE
judicial districts across the nation, Plaintiffs have sued
Defendants 3M Company and Arizant Healthcare Inc. These
lawsuits have been transferred or consolidated into this
multidistrict litigation for pretrial. Generally, Plaintiffs
allege that Defendants' Bair Hugger Forced Air Warming
Device (“the Bair Hugger”) caused their
deep-joint infections as a sequela to orthopedic-implant
surgery. Some Plaintiffs have sued alleging other surgical
infections related to the Bair Hugger. The Bair Hugger, a
device for keeping surgical patients warm, has a central
unit, hose and blanket. The central unit draws in
operating-room air through an inlet filter. It then heats and
forces that air through the hose. The hose feeds the forced
air into passageways within the blanket. During surgery, the
blanket covers the patient's torso, with perforations
facing the patient. The forced air then exits the blanket
through these perforations, thereby transferring heat to the
allege theories about how the Bair Hugger's forced-air
warming can cause deep-joint infection. After warming the
patient, the Bair Hugger's forced air flows into the
operating room at large. Because this effluent forced air is
warmer than the air-conditioned operating-room air, it
convects. This convection stirs the operating-room air,
allegedly lifting squames (skin flakes shed from people) and
preventing them from safely settling away from the surgical
wound. The parties agree that squames can carry skin
bacteria, some of which can cause deep-joint infection.
Plaintiffs also have a theory about bacteria that reside
within the Bair Hugger's central unit or hose. These
bacteria allegedly get out riding the forced air, thereby
increasing the bacterial threat within the operating-room
parties have moved to exclude expert testimony about whether
the Bair Hugger can cause deep-joint infection. Defendants
move to exclude Plaintiffs' engineering experts Said
Elghobashi, Daniel Koenigshofer, Michael Buck and Yadin
David. Dkt. No. 794. Defendants move to exclude David's
regulatory opinions separately. Dkt. No. 758. Defendants also
move to exclude Plaintiffs' medical experts Jonathan M.
Samet, William Jarvis and Michael J. Stonnington. Dkt. No.
745. Plaintiffs move to exclude Defendants' rebuttal
experts John Abraham, Dkt. No. 821, Jonathan B. Borak, Dkt.
No. 778, Jim Ho, Dkt. No. 733, Alexander A. Hannenberg, Dkt.
No. 727, Theodore R. Holford, Dkt. No. 801, Antonia Hughes,
Dkt. No. 826, Michael Keen, Dkt. No. 738, Thomas Kuehn, Dkt.
No. 787, Samsun Lampotang, Dkt. No. 743, Michael Mont, Dkt.
No. 796, Gary Settles, Dkt. No. 832, Timothy Ulatowski, Dkt.
No. 755, and Richard Wenzel, Dkt. No. 812. The Court heard
oral argument at an October 24-26, 2017 hearing. The Court
DENIES the Motions, except for Defendants' Regulatory
Motion about David, which the Court GRANTS IN PART and DENIES
IN PART. The Court also denies Defendants' dependent
Motion for Summary Judgment, Dkt. No. 759.
Federal Rule of Evidence 702, the Court need only exclude
expert testimony that is so fundamentally unsupported that it
can offer no assistance to the jury.
testimony is governed by Rule 702. The expert-testimony
proponent must prove facts supporting admissibility as more
likely than not. Polski v. Quigley Corp., 538 F.3d
836, 841 (8th Cir. 2008). Under Rule 702:
A witness who is qualified as an expert by knowledge, skill,
experience, training, or education may testify in the form of
an opinion or otherwise if:
(a) the expert's scientific, technical, or other
specialized knowledge will help the trier of fact to
understand the evidence or to determine a fact in issue;
(b) the testimony is based on sufficient facts or data;
(c) the testimony is the product of reliable principles and
(d) the expert has reliably applied the principles and
methods to the facts of the case.
relevant and reliable, a qualified expert's testimony
need not be excluded. Children's Broad.
Corp. v. Walt Disney Co., 357 F.3d 860, 864 (8th Cir.
2004). “Only if the expert's opinion is so
fundamentally unsupported that it can offer no assistance to
the jury must such testimony be excluded.” Id.
opponent's “full opportunity to
cross-examine” and to “present expert testimony
to rebut” weighs in favor of admission. See
id.; Bonner v. ISP Techs., Inc., 259 F.3d 924,
932 (8th Cir. 2001) (“[Once the] methodology was
scientifically valid, the scientific questions were best
addressed by allowing each side to present its experts . . .
to the jury.”). Better than exclusion at the threshold,
these trial tools address issues that can go to how the jury
should weigh the testimony or whether the jury should believe
the expert. Children's Broad., 357 F.3d at
864-65 (affirming admission when trial court ruled that
opponent's objections “were better directed to the
weight of the testimony rather than admissibility”).
The Motions are disposed of below, by expert.
expert Elghobashi opines that the Bair Hugger's forced
air convects particles ten microns in diameter from just
above the operating-room floor to the surgical wound.
Elghobashi Rpt. ll. 825-27. The parties agree that, because
ten-micron particles include squames, these particles can
carry enough bacteria in a permissive package to cause a
deep-joint infection if, during surgery, they reach the
prosthetic joint. See Defs.' Mem. Excl Pls.'
Eng'g Experts (“Eng'rs Mem.”) 32
(diminishing expert's finding because “he found
few, if any, particles larger than 5µm, and even fewer
over 10µm.”). Elghobashi simulates the Bair
Hugger's forced air in a model operating room by
large-eddy simulation, the reliability of which Defendants
concede. Elghobashi Rpt. ll. 832-33; see Eng'rs
Mem. 55 (conceding “that CFD[, or, computational-fluid
dynamics, ] evidence can be admissible, if properly supported
by reliable boundary conditions.”). To simulate the
Bair Hugger's alleged operating-room convection,
Elghobashi had to learn about the device. First, by watching
Defendants' videos and reading their internal documents,
he learned how hot the forced air leaves the device's
blanket. Eng'rs Mem. 40. Then, while he observed an
active Bair Hugger, “he simply ran his hand
under” its blanket to learn where the forced air comes
challenge Elghobashi's testimony under Rules 702 and 403.
They argue that Elghobashi speculated about how hot and where
the Bair Hugger's forced air enters the operating room at
large. They also argue that his simulated images are unduly
prejudicial and likely to confuse the jury because the images
could seem to show bacteria invading the surgical wound and
because the images were simulated. See Fed. R. Evid.
testimony is admissible. Elghobashi has tested his opinion by
simulation, the physics of which Defendants concede is
reliable. As for the simulation's inputs,
Elghobashi's testimony is not so fundamentally
unsupported that it can offer no assistance to the jury.
Elghobashi may rely on Defendants' representations.
Bonner, 259 F.3d 924, 931 (affirming admission when
expert relied on opponent's “consumer
information”). And generally, the credibility of an
expert's basis goes to weight. So too here. Elghobashi
has bases for how hot and where the Bair Hugger's forced
air goes; the jury may weigh his testimony as it believes
those bases. Defendants may back away from their
representations in rebuttal. They may cross-examine
Elghobashi to test what, exactly, he felt with his hand
during his observations. They may contradict Elghobashi's
inputs by presenting their own fluids expert Abraham, see
below. The Court thus DENIES Defendants' Motion as to
Elghobashi because his testimony meets Rule 702.
testimony is not unduly prejudicial or likely to confuse the
jury. Elghobashi consistently describes his simulated
particles as squames, not bacteria, e.g., Elghobashi
Rpt. l.815, and, anyway, Defendants have conceded that
ten-micron particles can be dangerous. Defendants have also
conceded the physics of large-eddy simulation, so objections
to the simulation as simulation are without merit. The Court
thus DENIES Defendants' Motion as to Elghobashi also
because his testimony does not offend Rule 403.
expert Koenigshofer opines that the Bair Hugger detracts from
air quality in the operating room and at the surgical wound,
thus increasing infection risk. Koenigshofer Rpt. 23. Among
other qualifications, Koenigshofer wrote a chapter about
“Infection Control” in a published book about
operating-room design. Id. at 2. The American
Society of Heating, Refrigerating and Air-Conditioning
Engineers (ASHRAE) selected him to be this chapter's
author. Id. Koenigshofer relies on Elghobashi's
testimony, among other sources, and describes what this
testimony means for infection risks in the operating room.
Id. at 20. He adds that the Bair Hugger can suck in
particles from the air near the operating-room floor, citing
a 1968 study to note that some of these particles can carry
bacteria. Id. at 21-22. To say that squames can be
near the floor, he cites an ASHRAE figure, which says that a
ten-micron particle takes 8.2 minutes to settle five feet in
still air. See Id. fig.5. Defendants object that
Koenigshofer is unqualified and has insufficient factual
testimony is admissible. Defendants do not dispute
Koenigshofer's published book chapter about
operating-room infection, which appears to qualify him for
his testimony's scope. Cf. Wheeling Pittsburgh Steel
Corp. v. Beelman River Terminals, Inc., 254 F.3d 706,
715 (8th Cir. 2001) (reversing admission of warehousing
testimony because, although expert had dealt with other
facilities, he had never published about, worked for or
studied warehouses). And Koenigshofer's testimony is not
so fundamentally unsupported that it can offer no assistance
to the jury. Defendants do not dispute that the Bair
Hugger's central unit sucks in operating-room air and can
sit on the operating-room floor. They do not attack the ASRAE
figure. And they only object to the 1968 study's age. The
jury may decide whether to believe that study. Likewise,
Defendants may contradict it with their particle expert
Ho's testimony, see below. The Court thus DENIES
Defendants' Motion as to Koenigshofer because his
testimony meets Rule 702.
expert Buck opines that the Bair Hugger emits particles, some
of which are ten-micron particles. Buck Rpt. 16-17. By
measuring what comes out of a Bair Hugger's blanket when
the device is on with a commercially available particle
counter, Buck counts emitted particles by size. Id.
at 14. He adapts a plastic storage container to capture the
device's post-blanket forced air. Before counting
particles, he sets his particle counter to “a zero
point [by] zeroing the machine.” Buck Dep. 203:16-18.
Defendants object that Buck's testimony is irrelevant
because he did not sterilize the container before counting
particles and because he did not measure bacteria directly.
testimony is admissible because it is not so fundamentally
unsupported that it can offer no assistance to the jury. Buck
zeroed his particle counter, which should reduce background
from his container, sterilized or not. If he should have done
a more thorough test, that issue goes to weight, not
admissibility. Defendants may cross-examine Buck and may
submit rebuttal about whether zeroing is adequate. And
Buck's lack of bacterial testing is harmless because he
found some ten-micron particles. Defendants argue that these
particles are experimental artifacts. With the benefit of
adversarial presentation, the jury may decide whether to
credit this argument or, alternatively, accept Buck's
testimony for what he says. The Court thus DENIES
Defendants' Motion as to Buck because his testimony meets
expert Samet opines that, compared to warming devices that
warm patients through modes other than forced air, the Bair
Hugger increases the risk of deep-joint infection from
orthopedic-implant surgery. Samet Rpt. 4. He cites an
observational study that found a drop-off in these infections
over time at a hospital. Id. at 11 (citing McGovern
et al, Forced-Air Warming and Ultra-Clean Ventilation Do
Not Mix: An Investigation of Theatre Ventilation, Patient
Warming and Joint Replacement Infection in Orthopaedics,
93 J. Bone Joint (Br.) 1537 (2011) [hereinafter the
Observational Study]). At the Observational
Study's hospital, the drop-off happened when the
hospital discontinued using the Bair Hugger. To ascribe that
drop-off to this discontinuation, and not alternative
explanations, Samet draws on Elghobashi's testimony,
buttressed by scientific publications. Samet relies on
Elghobashi for a mechanistic, causal link between the
drop-off and discontinuing the Bair Hugger. E.g.,
Samet Rpt. at 15-16. Recall that, Elghobashi simulates, using
accepted physical principles, how the Bair Hugger could
convect squames to the surgical wound. To Samet, this
physics-based simulation justifies pointing to the Bair
Hugger, instead of alternative explanations, as the cause of
the observed hospital's high rate of deep-joint
infections while it was using Bair Huggers to warm patients.
Defendants argue that the Observational Study is not
scientifically convincing and that Elgobashi's testimony
about convection is too unreliable to support Samet's
testimony is admissible. First, Defendants acknowledge the
drop-off in infections; they dispute why the drop-off
occurred. See Defs.' Mem. Excl. Pls.' Med.
Experts (“Med. Experts Mem.”) 22, Dkt. No. 750.
But the Court may not exclude expert testimony for
disagreeing with a conclusion about why something happened.
See Smith v. BMW N. Am., Inc., 308 F.3d 913, 920 n.9
(8th Cir. 2002) (reversing exclusion for “attack[ing] .
. . conclusion”). Second, to support his causal
inference, Samet relies on, among other things,
Elghobashi's testimony about Bair Hugger convection.
Samet may rely on admissible expert testimony.
Elghobashi's testimony is admissible, see above. Samet
thus may rely on Elghobashi's testimony. Defendants
apparently concede that, once admitted, Elghobashi's
testimony is sufficient to support Samet's causal
inference. See Med. Experts Mem. 24. And anyway,
Samet need not rule out every alternative explanation for the
observed hospital's drop-off in infections. Johnson
v. Mead Johnson & Co., LLC, 754 F.3d 557, 563 (8th
Cir. 2014) (reversing exclusion because “we have