Low-flow anesthesia in adult orthotopic liver transplantation: a preliminary clinical experience

Abstract

Background: Anesthesia in orthotopic liver transplantation (OLT) may carry with complex hemodynamic, body temperature, and metabolic alterations. Although OLT cases increased in recent years in Taiwan, experiences remained limited. Notable advantage of low flow anesthesia may include reduced consumption of anesthetic gases and vapors, reduced environmental pollution and cost-saving. This study investigated patient profiles and the feasibility of low-flow rebreathing technique for adult orthotopic liver transplantation.

Methods: Since June 1996, there were six OLT patients who received low flow anesthesia with isoflurane. All patients received hepatic veno-venal anastmosis (so-called piggy back procedure). Two patients were excluded from this study because of different surgical procedure (total occlusion of inferior vena cava and inferior vena cava veno-venal anastmosis). During maintenance of anesthesia, isoflurane was carried by a mixture of oxygen and air at a total fresh gas flow of 0.6 L/min. Alongside with the standard anesthesia machine and physiologic monitors, a newly designed Swan-Ganz catheter was introduced to measure and record cardiac output, systemic vascular resistance, pulmonary artery pressure, central venous pressure, and core temperature in a real-time manner. Blood samples were collected at 6 predetermined time-points in each patient for analysis of arterial blood gases, electrolytes, lactate and glucose concentrations.

Results: The anesthetic time was 916 +/- 26 min (900 to 930 min). All patients regained their consciousness within 30 min after completion of surgery. The hemodynamics were relatively stable except after reperfusion of the liver. There was a significant decrease in mean arterial blood pressure, which occurred with accompaniment of a reduction of systemic vascular resistance and increased cardiac output. Arterial blood gas, electrolyte, and glucose were, however, maintained within acceptable limits. Blood lactate was progressively increased and reached its peak after reperfusion of the liver until the end of surgery. The core temperature was well maintained above 34 degrees C. No patient developed hypoxia or hypercapnia.

Conclusions: Low-flow rebreathing anesthetic technique maintained acceptable patient profiles and good body temperature preservation in orthotopic liver transplantation. These characteristics make it a promising method in maintenance of anesthesia for OLT.