Research
Standardized intensive care unit management in an anhepatic pig model: new standards for analyzing liver support systems
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* Corresponding author: Martin Schenk martin.schenk@med.uni-tuebingen.de
1 Department of General, Visceral and Transplant Surgery, Tübingen University Hospital, Hoppe-Seyler-Str. 3, Tübingen, D-72076, Germany
2 Department of Anaesthesiology, Tübingen University Hospital, Hoppe-Seyler-Str. 3, Tübingen, D-72076, Germany
3 Department of Neurosurgery, Tübingen University Hospital, Hoppe-Seyler-Str. 3, Tübingen, D-72076, Germany
Critical Care 2010, 14:R138 doi:10.1186/cc9196
Published: 22 July 2010Abstract
Introduction
Several anhepatic pig models were developed in the past. Most models suffer from short anhepatic survival times due to insufficient postoperative intensive care unit (ICU) management. The aim of this study was to analyze anhepatic survival time under standardized intensive care therapy in a pig model.
Methods
Eight pigs underwent total hepatectomy after Y-graft interposition between the infrahepatic vena cava and the portal vein to the suprahepatic vena cava. An intracranial probe was inserted for intracranial pressure (ICP) monitoring. Animals received pressure-controlled ventilation under deep narcosis. Vital parameters were continuously recorded. Urinary output, blood gas analysis, haemoglobin, hematocrit, serum electrolytes, lactate, and glucose were monitored hourly, and creatinine, prothrombin time, international normalised ratio, and serum albumin were monitored every 8 hours. Sodium chloride solution 0.9%, hydroxyethyl starch 6%, fresh frozen plasma, and erythrocyte units were used for volume substitution, and norepinephrine was used to prevent severe hypotension. Serum electrolytes and acid-base balance were corrected as required. Antibiotic prophylaxis with ceftriaxon was given daily, as well as furosemide, to maintain diuresis.
Results
Postoperative survival was 100% after 24 hours, with a maximum survival of 73 (mean, 58 ± 4) hours. Haemodynamic parameters such as heart rate, mean arterial pressure, and pulse oximetry remained stable during surgical procedures and following anhepatic status due to ICU therapy until escalating at time of death. Deteriorating pulmonary function could be stabilized by increasing oxygen concentration, positive end-expiratory pressure, and maximal airway pressure. Furosemide was used to maintain diuresis until renal failure occurred. ICP started at 15-17 mmHg and increased continuously up to levels of 41-43 mmHg at time of death. All animals died as a result of multiple-organ failure.
Conclusions
Using standardized intensive care management after total hepatectomy, we were able to prolong anhepatic survival over 58 hours without the use of liver support systems. The survival benefit of liver support systems in previous animal studies should be reevaluated against our model.