MIDDLE CEREBRAL-ARTERY TRANSCRANIAL DOPPLER VELOCITY MONITORING DURING ORTHOTOPIC LIVER-TRANSPLANTATION - CHANGES AT REPERFUSION - A REPORTOF 6 CASES

Study Objective: To determine the effect of reperfusion of the grafted liver on transcranial Doppler blood flow velocity in the middle cereb ral artery in humans during orthotopic liver transplantation. Design: Clinical study. Setting: University hospital. Patients: 6 patients sch eduled for orthotopic liver transplantation. Interventions: Middle cer ebral artery blood flow velocity (MCAVm) was monitored continuously us ing a transcranial Doppler (TCD) probe. The TCD measurements were noni nvasive. Measurements and Main Results: The EME TC2000S TCD probe (Nic olet, Inc., Memphis, TN) was secured to the head using a strap providi ng continuous measurement of MCAVm. All other data were recorded by a patient monitoring system and a respiratory gas analyzer. Averaged MCA Vm increased significantly in 5 of 6 patients (p < 0.001) when pre-rep erfusion and post-reperfusion values were compared. Maximum Post reper fusion values for MCAVm, pulsatility index (PI), and systolic Doppler velocity (Vs) were greater than the corresponding immediate pre-reperf usion values (p < 0.05, p < 0.05, and p < 0.001, respectively). The in creases in MCAVm cannot be explained on the basis of hypercarbia alone and were observed in the presence of systemic arterial hypotension an d abrupt increases in central venous pressure, particularly at the tim e of graft reperfusion. Conclusions: MCAVm increased with reperfusion of the grafted liver. These data suggest that multiple factors-includi ng hypercarbia, lactic acidosis, or multiple vasoactive substances rel eased by the grafted liver-may contribute to the observed increases in MCAVm, Vs, and PI.