Experimental pericardial tamponade-translation of a clinical problem to its large animal model.

Objectives: Pericardial tamponade is a life-threatening medical emergency, when the hemodynamic consequences of low cardiac output severely disturb the perfusion of the peripheral tissues. Our aim was to design a reliable large animal model to reproduce the clinical scenario with the relevant pathophysiological consequences of pericardial tamponade -induced cardiogenic shock.

Material and Methods: Anesthetized Vietnamese mini pigs were used (n=12). Following laparotomy, a cannula was fixed into the pericardium through the diaphragm without thoracotomy. A sham-operated group (n=6) served as control, while in the second group (n=6) pericardial tamponade was induced by intra-pericardial injection of heparinized own blood. Throughout the 60-min pericardial tamponade and the 180-min reperfusion, macro hemodynamics, renal circulation and the mesenteric macro- and micro-circulatory parameters were monitored. Myeloperoxidase activity was measured to detect neutrophil leukocyte accumulation and in vivo histology was performed by confocal laser scanning endomicroscopy to observe the structural changes of the intestinal mucosa.

Results: PT increased the central venous pressure, heart rate, and decreased mean arterial pressure. The mesenteric artery flow (from 355.5±112.4 vs 182.0±59.1 mL/min) and renal arterial flow (from 159.63±50.7 vs 35.902±27.9 mL//min) and the micro-circulation of the ileum was reduced. The myeloperoxidase activity was elevated (from 3.66±1.6 to 7.01±1.44 mU/mg protein) and manifest injury of the ileal mucosa was present.

Conclusion: This experimental model suitably mimics the hemodynamics and the pathology of clinical pericardial tamponade situations, and on this basis, it provides an opportunity to study the adverse macro- and micro-circulatory effects and biochemical consequences of human cardiogenic shock.