Right atrial bypass model in the dog

Peter H. Breen From the Department of Anesthesia and Critical Care, The University of Chicago, Chicago, IL 60637.

Search for other papers by Peter H. Breen in
Current site
Google Scholar
PubMed
Close
 MD
and
Schlomo A. Isserles From the Department of Anesthesia and Critical Care, The University of Chicago, Chicago, IL 60637.

Search for other papers by Schlomo A. Isserles in
Current site
Google Scholar
PubMed
Close
 MD

Click on author name to view affiliation information

SUMMARY

In gas exchange studies addressing the storage and transport of CO2 in dogs, a model in which cardiac output (Q˙t) can be precisely controlled and measured would be beneficial. We identified problems with described extracorporeal circuits and implemented right atrial bypass (rab) in dogs. In 6 anesthetized (chloralose and urethane), heparinized dogs (mean ± sd, 24 ± 4 kg) with open thorax, cannulas were inserted in both vena cavas to drain venous blood return to a reservoir (anaerobic bag or bubble oxygenator). A roller pump then drove blood through a heat exchanger back to the right atrial appendage. After 1.8 ± 1.4 hour of rab, physiologic variables remained within reference limits for dogs (Q˙t, 1.5 ± 0.3 L/min; blood pressure, 92 ± 25 mm of Hg; arterial PCO2, 35 ± 4 mm of Hg; PCO2, 513 ± 39 mm of Hg; pH, 7.39 ± 0.08; and tissue CO2 production, 126 ± 56 ml/min). To permit study of gas exchange, venous return (and thus, Q˙t) and venous PCO2 and PCO2 could be accurately regulated and measured over a wide range. Maintenance of native pulsatile lung perfusion and cardiogenic oscillations minimizes mismatching of pulmonary ventilation and perfusion and facilitates studies addressing pulmonary gas exchange. This rab model is designed so that investigators can establish the preparation in a few hours.

SUMMARY

In gas exchange studies addressing the storage and transport of CO2 in dogs, a model in which cardiac output (Q˙t) can be precisely controlled and measured would be beneficial. We identified problems with described extracorporeal circuits and implemented right atrial bypass (rab) in dogs. In 6 anesthetized (chloralose and urethane), heparinized dogs (mean ± sd, 24 ± 4 kg) with open thorax, cannulas were inserted in both vena cavas to drain venous blood return to a reservoir (anaerobic bag or bubble oxygenator). A roller pump then drove blood through a heat exchanger back to the right atrial appendage. After 1.8 ± 1.4 hour of rab, physiologic variables remained within reference limits for dogs (Q˙t, 1.5 ± 0.3 L/min; blood pressure, 92 ± 25 mm of Hg; arterial PCO2, 35 ± 4 mm of Hg; PCO2, 513 ± 39 mm of Hg; pH, 7.39 ± 0.08; and tissue CO2 production, 126 ± 56 ml/min). To permit study of gas exchange, venous return (and thus, Q˙t) and venous PCO2 and PCO2 could be accurately regulated and measured over a wide range. Maintenance of native pulsatile lung perfusion and cardiogenic oscillations minimizes mismatching of pulmonary ventilation and perfusion and facilitates studies addressing pulmonary gas exchange. This rab model is designed so that investigators can establish the preparation in a few hours.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 39 39 3
PDF Downloads 23 23 1
Advertisement