Thorac Cardiovasc Surg 2011; 59 - V79
DOI: 10.1055/s-0030-1269016

Miniaturized cardiopulmonary bypass versus conventional extracorporeal circulation: Behaviour of the organspecific pO2 and pCO2 metabolism

P Curcic 1, I Ovcina 1, E Beran 1, D Dacar 1, J Krumnikl 2, W Marte 2, K Tscheliessnigg 1, I Knez 1
  • 1Universitätsklinik für Chirurgie, Klinische Abteilung für Herzchirurgie, Graz, Austria
  • 2Universitätsklinik für Anästhesiologie, Klinische Abteilung für Herz-, Gefäß- und Thoraxanästhesie, Graz, Austria

Aims: In a multidisciplinary experimental animal model, organ specific parenchymal pO2/pCO2 changes were simultaneously evaluated and metabolic variables measured from parieto-temporal lobe of the pigs' brain, left ventricular myocardium and right hepatic lobe.

Methods: PCO2 and pO2was measured using fibre-optical sensors based on phase modulation fluorometry, adapted for continuous monitoring. Haemodynamic and respiratory variables were recorded and adjusted to a predefined cardio-surgical perfusion model. Samples of arterial, central-venous and intracranial venous metabolic variables were recorded at the time points defined by the study protocol. 14 pigs (30.7±2.5kg) were randomized either to the mini-CPB group or controls conv-ECC (conventional extracorporeal circulation). The perfusion systems were minimized and adjusted to basic variables comparable to extracorporeal perfusion settings as used in congenital cardiac surgery. After baseline measurements (T1) cardiopulmonary bypass was established (T2) and the aorta cross-clamped for 60min (T3–T6). The test animals were reperfused for 30min (T7–T8) and observed for another 30min. off-bypass (T9–T10).

Results: There were no differences in pre- and intra-operative variables, except for the significantly higher volume of blood transfusion (1000±823mls vs. 50±36mls, p≤0.00001*) and higher lactate levels in the conv-ECC group (p≤0.00001*). ANOVA for repeated measurements at T1–T10 revealed significantly higher cerebral pO2 levels (p=0.007*) in the mini-CPB group, while pCO2 levels appeared similar. In contrast, both hepatic and myocardial pCO2 levels were significantly higher in conv-ECC group (p=0.004*), while pO2 levels reacted homogenously.

Conclusion: Under standardized conditions, mini-CPB produced less lactate and showed significantly favourable changes concerning O2/CO2 metabolism.