Error traps in liver transplantation
Agnes Hunyady, MD, Bukola Ojo, MD, David M Polaner, MD, FAAP (all of the authors are members of the Seattle Children’s Hospital)
“A trap is only a trap if you don’t know about it. If you know about it, it’s a challenge.”
The publication of the Institute of Medicine’s (IOM) Quality Committee publication “To Err is Human: Building a Safer Health System”,1 has inspired a more systematic and objective approach to evaluating errors and improving outcomes in healthcare over the past two decades. Error traps describe the combination of circumstances and human cognitive limitations that lead to avoidable harm if unmitigated.2,3 Error traps include heuristics that result in missing subtle but important clues and findings at the stage at which intervention can be initiated before harm occurs. In their well-referenced article titled “Educational Review: Error traps in anesthesia for pediatric liver transplantation”, Ballard et al. give a succinct primer on theanesthetic care for pediatric patients for orthotopic liver transplantation (OLT) and highlight issues that can result in adverse events if overlooked.4 The complexity and clinical lability during pediatric liver transplantation lead to a high risk of these events occurring, so cognizance of these traps is a high priority.
Another in the journal’s series on error traps in various subspecialties of pediatric anesthesia, the authors summarize the main intraoperative challenges of each of the three phases of the operation: pre-anhepatic (dissection), anhepatic, and post-anhepatic or neo-hepatic. Eight error traps where failures occur are highlighted: preparation for and mitigation of massive blood loss, monitoring for and management of coagulation derangement during the pre-anhepatic (dissection) phase, preparation for and management of hemodynamic changes related to inferior vena cava clamping, mitigating metabolic disturbances related to lack of hepatic function, optimization of the homeostasis for graft reperfusion during the anhepatic phase, management of post-reperfusion syndrome, optimization of liver perfusion, and maintenance of hemostatic balance during post-anhepatic (neo-hepatic) phase. These errors fall into multiple categories: errors of commission (planning and execution), diagnostic errors, treatment errors, and preventive errors.
Ballard et al. also discussed the omission errors of preparation-in particular, the hazards of lack of a dedicated transplant team. Before the transplant itself takes place, anesthesiologist input into recipient selection is a crucial contributor to better outcomes in pediatric liver transplant, and requires thorough evaluation of the underlying disease and perioperative management planning. Deficiencies in these can cause errors of principle, omission, and commission (planning). A dedicated pediatric transplant anesthesia team brings the specialized knowledge about our role in perioperative care to this planning process. Beyond knowledge and experience, the interdisciplinary team dynamics generated by utilizing specialized pediatric transplant anesthesiologists, nurses and scrub techs are equally critical to perioperative performance and good outcomes.
Time pressure from the race against prolonged ischemia is inherent to OLT and can contribute to error. Anesthesiologists should be aware of various equipment, system, and communication failures that can occur in these long procedures. Fatigue, and failure to recognize it, is an ever-present risk. A fatigued team is prone to the bias of premature closure, attribution of slow-to-improve graft function at the time of abdominal closure to ischemic reperfusion injury, and failure to consider other etiologies such as kinking of vascular supply of a technical variant graft.
Expected blood transfusion needs (0->100 ml/kg) and rate vary widely depending on, among other things, the indication for OLT. Recent traumatic experience with massive blood loss in a fulminant liver failure case might make one, under time pressure, succumb to affect heuristics and expose a patient withan inborn error of metabolism without liver failure to complications of venous cannulation by selecting more or larger cannulae than necessary. While inadequate transfusion due to lack of recognition of the severity of blood loss and coagulopathy is discussed, an important error trap that is not explicitly mentioned is that of over-transfusion and over-correction of coagulopathy, the first of which may predispose to both volume overload and transfusion related circulatory overload (TACO). Both increase the risk of hepatic artery thrombosis, a leading cause of graft failure and dysfunction andof emergency return to the OR in the first few days after transplantation.
Because of the complexity, constantly changing state, and physiologic instability of these patients, a general error trap is fixation error, where a single or related cluster of findings or events lead the anesthesiologist to miss the bigger picture or fail to consider alternate explanations. This is a trap that is especially risky in OLT. Too many simultaneous tasks and frequent suction noises from the surgical field coupled withcommission bias (tendency toward action over inaction) might make one act on lab values resulted from sampling error instead of repeating the test, react erroneously or overreact to rapidly evolving events.
Factual knowledge, clinical experience and involvement with multidisciplinary meetings might make one less prone to certain types of cognitive errors, but don’t make one entirely immune to them. The examples are numerous, and the concepts and tips in this paper are worthwhile to review for transplant teams. The paper is both a delineation of error traps to be aware of as well as a concise review of transplant anesthesia management itself, and we have now included it in the material our fellows are expected to read in preparation for pediatric OLT.
Having a dedicated anesthesia team for pediatric liver transplant is not a panacea for cognitive or performance errors, but if we don’t succumb to overconfidence bias, are aware of these error traps and maintain a culture of psychological safety within our teams, we should be able to utilize these strategies and knowledge to prevent adverse outcomes. This is a lesson for any complex pediatric anesthetic.
1. Institute of Medicine (US) Committee on Quality of Health Care in America. To Err is Human: Building a Safer Health System. Kohn LT, Corrigan JM, Donaldson MS, editors. Washington (DC): National Academies Press (US); 2000. PMID: 25077248.
2. Highly S. An Encounter with an Error Trap https://www.hastam.co.uk/an-encounter-with-an-error-trap/
3. Stiegler MP, Neelankavil JP, Canales C and Dhillon A. Cognitive errors detected in anaesthesiology: a literature review and pilot study. British Journal of Anaesthesia 108 (2): 229–35 (2012)
4. Ballard HA, Jones E, Malavazzi Clemente MM, Damian D, Kovatsis PG. Educational Review: Error traps in anesthesia for pediatric liver transplantation. Pediatric Anesthesia. 2022;32:1285–1291.