title: Urinary ammonia excretion increases acutely during living donor liver transplantation.
abstract: BACKGROUND
  Arterial ammonia concentrations increase acutely during the anhepatic phase of a liver transplantation (LTx) and return to baseline within 1 h after reperfusion of a functioning liver graft. So far, this return to baseline has solely been attributed to hepatic ammonia clearance. No data exist on the potential contribution of altered renal ammonia handling to peritransplantation ammonia homoeostasis.
  
  
  OBJECTIVE
  The present study investigated the consequences of a hepatectomy and subsequent implantation of a partial liver graft on arterial ammonia concentrations and urinary ammonia excretion during a living donor liver transplantation (LDLTx).
  
  
  METHODS
  Patients with end-stage liver disease undergoing LDLTx were selected. Samples of arterial blood and urine were taken before, during and 2 h after the anhepatic phase. Differences were tested using Wilcoxon's test. Results are given as median and range.
  
  
  RESULTS
  Eleven adult patients undergoing an LDLTx were included. Before hepatectomy, arterial ammonia concentrations were 89 μM (40-156 μM), increasing to 146 μM (102-229 μM) (P<0.001) during the anhepatic phase and returning to 79 μM (46-111 μM) (P<0.01) after reperfusion. Urinary ammonia excretion was initially 1.06 mmol/h (0.02-6.00 mmol/h), increasing to 3.81 mmol/h (0.32-12.55 mmol/h) (P=0.004) during the anhepatic phase and further increasing to 4.00 mmol/h (0.79-9.51 mmol/h) (P=0.013) after reperfusion.
  
  
  CONCLUSIONS
  The kidney significantly increased urinary ammonia excretion during the anhepatic phase, which was sustained after reperfusion, contributing to the rapid decrease of ammonia concentrations. Accordingly, the plasma ammonia concentrations measured directly after LTx cannot simply be used as a read-out of initial liver graft function.
authors: Department of Surgery, Maastricht University, Maastricht, the Netherlands.
authors: Liliane
authors: L
authors: Mpabanzi
authors: Maartje A J
authors: MA
authors: van den Broek
authors: Ruben G J
authors: RG
authors: Visschers
authors: Marcel C G
authors: MC
authors: van de Poll
authors: Silvio
authors: S
authors: Nadalin
authors: Fuat H
authors: FH
authors: Saner
authors: Cornelis H C
authors: CH
authors: Dejong
authors: Massimo
authors: M
authors: Malago
authors: Steven W M
authors: SW
authors: Olde Damink
mesh_terms: D000328:Adult; D000368:Aged; D000641:Ammonia / Q000097:blood / Q000652:urine*; D015415:Biomarkers / Q000097:blood / Q000652:urine; D005260:Female; D005858:Germany; D006498:Hepatectomy / Q000009:adverse effects; D006501:Hepatic Encephalopathy / Q000209:etiology / Q000517:prevention & control; D006706:Homeostasis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D022124:Hyperammonemia / Q000209:etiology / Q000517:prevention & control; D007432:Intraoperative Period; D007668:Kidney / Q000378:metabolism*; D016031:Liver Transplantation / Q000009:adverse effects; D019520:Living Donors; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D013997:Time Factors; D016896:Treatment Outcome; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D000641:Ammonia