LIVER TRANSPLANTATION 21:89–95, 2015
Association Between Anesthesiologist Experience and Mortality After Orthotopic Liver Transplantation Ira Hofer,1 John Spivack,2 Miguel Yaport,3 Jeron Zerillo,2 David L. Reich,2 David Wax,2 and Samuel DeMaria Jr2 1 Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA; 2Department of Anesthesiology, Mount Sinai Medical Center, New York, NY; and 3Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
The anesthesiologist has been recognized as an integral member of the liver transplant team, and previous studies have demonstrated that inter-anesthesiologist variability can be a driver of outcomes for high-risk patients. We hypothesized that anesthesiologist experience, defined as the number of previous liver transplants performed at our institution, the Icahn School of Medicine at Mount Sinai, would be independently associated with outcomes for liver transplant patients. Eight hundred forty-nine liver transplants performed between January 2003 and January 2013 with a total of 22 anesthesiologists were analyzed. Each transplant was assigned an incremental case number that corresponded to the number of transplants that the attending anesthesiologist had already performed at our institution. Several perioperative covariates were controlled for in the context of a generalized linear mixed effects model to detail the influence of threshold levels of the incremental case number on the primary outcome, 30-day mortality, and a secondary outcome, 30-day graft failure. Sensitivity analyses were conducted to confirm the robustness of these findings. An incremental case number 5 was associated with a significantly greater risk of 30-day mortality (odds ratio 5 2.24, 95% confidence interval 5 1.11-4.54, P 5 0.025), and there was evidence suggestive of a greater risk of 30-day graft failure (odds ratio 5 1.93, 95% confidence interval 5 0.95-3.93, P 5 0.071). Sensitivity analyses ruled out threats to the validity of these findings, including dropout effects and time trends in the overall performance of the transplantation unit. In conclusion, this study shows that an anesthesiologist’s level of experience has a significant effect on outcomes for liver transplant recipients, with increased mortality and possibly graft failure during a provider’s first 5 cases. These findings may indicate the need for increased training and supervision for anesC 2014 AASLD. thesiologists joining the liver transplant team. Liver Transpl 21:89-95, 2015. V Received May 18, 2014; accepted September 14, 2014. Intraoperative anesthetic management has been increasingly identified as a driver of perioperative outcomes.1-4 Although anesthesiologists are recognized as integral members of the transplant team,4-7 there is a paucity of data regarding the effects of intraoperative anesthetic interventions on orthotopic liver transplantation (OLT) outcomes. Furthermore, the potential effect of anesthesia practitioner experience is often not considered; most publications concentrate on the opti-
mization of OLT recipient outcomes by appropriate risk stratification and sound surgical technique.8,9 The effects of anesthesia provider characteristics have been examined for non-OLT patients. Anesthesiologist board certification status10 and the presence of a physician versus a nurse anesthetist11 were both found to have little influence on outcomes for patients of average risk. There have been but 2 studies examining interindividual variability in outcomes among cohorts
Abbreviations: AKI, acute kidney injury; CI, confidence interval; ICU, intensive care unit; MELD, Model for End-Stage Liver Disease; NA, not available; OLT, orthotopic liver transplantation; OR, odds ratio; SD, standard deviation. Potential conflict of interest: Nothing to report. Address reprint requests to Samuel DeMaria, Jr, M.D., Department of Anesthesiology, Mount Sinai Medical Center, One Gustave Levy Place, Box 1010, New York, NY 10029. Telephone: 212-241-7475; E-mail: [email protected]
DOI 10.1002/lt.24014 View this article online at wileyonlinelibrary.com. LIVER TRANSPLANTATION.DOI 10.1002/lt. Published on behalf of the American Association for the Study of Liver Diseases
C 2014 American Association for the Study of Liver Diseases. V
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TABLE 1. Demographic Data for the Anesthesiologist Cohort (n 5 22) Median age at time of first transplant, years (range)
Figure 1. Consort diagram for the patient database. Two pediatric transplants were coded as adult transplants and were excluded.
of anesthesia providers in the context of cardiac surgery.12,13 Despite small patient samples and the age of the studies, they remain the best evidence that interindividual anesthesia provider variability is an independent predictor of outcomes for higher risk patients. Liver transplantation is similarly high-risk surgery, and Yosaitis et al.14 recommended an experience level of “approximately 15-20 cases before a junior anesthesiologist feels comfortable and is ready to work unsupervised.” Additionally, the United Network for Organ Sharing has established criteria for a director of liver transplant anesthesia that include training involving the care of at least 10 liver transplant recipients or experience managing 20 liver transplant recipients within the last 5 years (postresidency training; see http://optn.transplant.hrsa.gov/policiesandbylaws2/ bylaws/optnbylaws/pdfs/bylaw_162.pdf). Although these recommendations are reasonable and have face validity, they are not evidence-based. We hypothesized that increasing anesthesia attending experience is associated with measurably improved OLT patient outcomes.
PATIENTS AND METHODS Study Design and Data Collection The institutional review board of the Icahn School of Medicine at Mount Sinai approved the study, and a waiver of consent was obtained for this retrospective data analysis. One thousand ninety-eight consecutive primary adult OLT procedures performed from January 2003 through January 2013 were included in the review and screened for enrollment (Fig. 1). These were unscheduled operations in which the assignment of anesthesiologists had taken place independently of patient and surgical team characteristics by means of a monthly schedule of on-call days. We excluded cases
Male sex, n (%) American Board of Anesthesiology certification at time of first transplant, n (% yes) Fellowship training in liver transplantation, n (%) Years of practice as an attending anesthesiologist at time of first transplant, n (%) 0-1 2-5 >5 Number of OLT procedures performed in training setting, n (%) 20-30 31-50 >50
35 (31-39) 20 (91) 22 (100)
8 (36) 11 (50) 3 (14)
3 (14) 18 (82) 1 (4)
with multiple attending anesthesiologists; multiple organ transplantation; living related donor transplantation; and miscoded, incomplete, or indecipherable data sets. Those cases with multiple attending anesthesiologists (