Effects of vasoactive agents on blood loss and transfusion requirements during pre-reperfusion stages of the orthotopic liver transplantation

Objective: To evaluate the effects of vasoactive drugs, specifically low-dose vasopressin and phenylephrine infusions, on blood loss / transfusion requirements during dissection and anhepatic (pre-reperfusion) stages of orthotopic liver transplantations. Methods: A retrospective analysis of 110 orthotopic liver transplantation (OLT) cases was performed. The variables studied were: blood loss before and after reperfusion of the liver graft; blood volumes returned by cell-saver and amounts of transfused blood products; amounts of infused colloids and crystalloids; hemodynamic parameters such as MABP, MPAP, CO/CI, SVR; dosage of vasoactive drugs. Short - and long-term outcome measures included length-of stay (LOS), ICU LOS, 48 -hours return to the OR rate, incidence of the primary non-function of the liver graft, amounts of fresh frozen plasma (FFP) and cryoprecipitate, administered in the ICU, and 1-year mortality. The study subjects were allocated in two groups. Study group consisted of 15 patients that received a low-dose (0.04U/min) vasopressin infusion alongside with other vasoactive agents, such as phenylephrine and epinephrine, during the dissection and anhepatic stages of the procedure. Control group consisted of 95 patients, that received the same vasoactive agents except a lowdose vasopressin infusion. Anesthetic and transfusion management in both groups were otherwise identical. Results: The estimated blood loss before reperfusion of the liver graft was in 50.2% lower (p=0.0094) and total blood loss was in 38.8% lower (p=0.0548) in the vasopressin group in comparison with control group of subjects of the same age, sex and with the same MELD score. No statistically significant differences neither in hemodynamic parameters between the two groups, nor in transfusion requirements and volumes of crystalloid and colloids infused, were detected. No differences were found also in long-term outcome parameters. Conclusions: The decrease in blood loss in the vasopressin group may be attributed to the use of a vasopressin infusion. A low-dose (0.04U/min) vasopressin infusion may be an effective technique for blood loss reduction during the pre-reperfusion stages in orthotopic liver transplantation.