PERIOPERATIVE MUCOSAL PH AND SPLANCHNIC ENDOTOXIN CONCENTRATION IN ORTHOTOPIC LIVER-TRANSPLANTATION

Although impairment of splanchnic perfusion may induce mucosal hypoxia and endotoxaemia during orthotopic liver transplantation (OLT), littl e is known about the changes in mucosal oxygenation during and after t he procedure. To study the effects of liver surgery itself on mucosal pH (pH(i)) and the response of pH(i) to acute changes in portal flow, we measured gastric pH(i) during six liver resections using tonometry: in two patients, after clamping of the hepatoduodenal ligament, pH(i) decreased within 30 min and recovered promptly after reperfusion. We then investigated gastric and sigmoid pH(i) (pH(ig), pH(is)) during th e perioperative phase in 18 OLT. Median pH(i) values were low before s urgery (pH(ig) 7.28 (first/third quartiles 7.22/7.34); pH(is) 7.27 (7. 12/7.36)). Although global oxygen delivery and haemodynamic variables remained constant and veno-venous bypass (VVB) was used to maintain po rtal flow, pH(i) declined during the anhepatic phase (pH(ig) 7.19 (7.1 3/7.23), P < 0.01; pH(is) 7.13 (7.06/7.24), P < 0.05). After reperfusi on of the graft, pH(i) recovered and did not differ from baseline valu es by the end of OLT. After operation pH(ig) increased further, reachi ng the highest values 30 h after ICU admission (7.34 (7.26/7.38)). In the intraoperative period, no significant endotoxaemia was observed ei ther in portal or systemic blood. The maximum reduction in pH(i) was r elated neither to the duration of VVB and OLT nor to the number of red cell units transfused. pH(i) after reperfusion did not correlate with graft viability or dysfunction of the lung or kidney. We conclude tha t pH(i) indicates mucosal ischaemia during OLT which is not necessaril y associated with endotoxaemia, and intraoperative pH(i) monitoring do es not appear to be a valuable predictor of postoperative graft failur e and organ dysfunction.