Methods
This study was conducted under Mayo Clinic IRB 19-005899. It is a single-center, retrospective review of patients who underwent orthotopic liver transplantation between 01/01/2015 to 05/31/2018 at Mayo Clinic, Florida. We included patients who were part of the “fast track” protocol at our institution as they would receive neuromuscular blockade antagonism and be extubated in the operating room at the conclusion of the case. “Fast track” liver transplantation is defined as extubating in the operating room, bypassing the ICU, and going directly from the post-anesthesia care unit to the surgical ward.6 We collected the patient’s baseline characteristics, intraoperative variables, and postoperative variables using our institution’s medical record system (Epic, Verona, WI). Baseline characteristics included age, sex, weight, body mass index (BMI), physiologic model for end-stage liver disease (MELD) score on the day of surgery, and liver graft types, including donation after circulatory death (DCD) or donation after brain death (DBD). Both preoperative and immediate postoperative laboratory variables were collected, which included international normalized ratio (INR), aPTT, and creatinine. We also collected blood products transfused in the postoperative day (POD) 0 to day 1, POD 0-1 respiratory complication, POD 0 PONV status, POD 0-1 need for re-operation for bleeding, POD 0-7 organ rejection, and the length of stay. PONV status is defined as if the patient needed rescue antiemetics. POD 0-7 organ rejection was confirmed by biopsy in the first-week post-transplant.
Induction of anesthesia was at the anesthesiologist’s discretion and performed using 1 to 2 ug/kg fentanyl, 0.6 mg/kg rocuronium or 1 mg/kg succinylcholine, and 2 to 2.5 mg/kg propofol. Intraoperatively patient received rocuronium based on subjective evaluation with a peripheral nerve stimulator (PNS); maintenance of anesthetic with sevoflurane. All patients were kept normothermic with forced-air warming devices, warming mattresses, and a fluid warmer. Intraoperative coagulation labs included platelet count (Plts), PT/INR, aPTT, fibrinogen, and thromboelastography (TEG) were collected post-induction, 10 minutes before and after the anhepatic phase, 5 minutes before and after the reperfusion phase. Additional labs and TEG were collected at the discretion of the attending anesthesiologist. Patients received various blood products based on the lab results with a goal of the following: Hgb 9 to 10 mg/dl, INR 1.5 to 2.0, fibrinogen above 180, Plts around 100, 000.
The anesthesiologist and the transplant surgeon made the decision to “fast-track” based on their clinical judgment rather than a defined clinical protocol. At the time of emergence, all patients received either sugammadex (2-4 mg/kg) or neostigmine (0.03-0.07 mg/kg) based on values obtained from the PNS. All patients were extubated after the NMBA antagonist was administered, and the anesthesia team felt neuromuscular function had been restored based on values from a PNS.
The primary outcomes were POD 0-1 bleeding events (re-operation for bleeding, packed red blood cell (PRBC) transfusion), and POD 0 values of aPTT and INR. Secondary outcomes were POD 0-1 respiratory complication, POD 0 PONV, POD 0-7 organ rejection, and length of stay.
Continuous variables were summarized as mean (standard deviation) or median (range), while categorical variables were reported as frequency (percentage). Continuous baseline and preoperative variables were compared between the standard and sugammadex groups using the Wilcoxon rank-sum test, and categorical variables were compared using the Chi-squared test. All tests were two-sided, with an alpha level set at 0.05 for statistical significance. The difference and corresponding 95% confidence intervals (CI) in the continuous postoperative outcome variables between the two groups were estimated using linear regression models, and odds ratios and 95% CI in dichotomous outcomes were estimated using logistic regression models.