Pulmonary circulatory support. A quantitative comparison of four methods.

Area of Science:

• Cardiovascular Surgery
• Biomedical Engineering
• Critical Care Medicine

Background:

• Severe right ventricular failure poses significant challenges in circulatory support.
• Effective pulmonary blood flow is crucial for maintaining systemic circulation during cardiac failure.

Purpose of the Study:

• To quantitatively compare four distinct methods for providing pulmonary blood flow in a model of profound right ventricular failure.
• To identify the most effective method for pulmonary circulatory support in this critical condition.

Main Methods:

• Profound right ventricular failure was induced in 16 goats using ventricular fibrillation, with systemic circulation supported by a left atrial-aortic bypass pump.
• Four pulmonary blood flow methods were evaluated: passive flow, intra-aortic balloon pulsation, sac-type pulsatile assist device, and right atrial-pulmonary arterial bypass pump.
• Cardiac index was measured as the primary outcome for each method.

Main Results:

• Passive pulmonary artery flow alone was insufficient for adequate circulatory support.
• Pulmonary artery pulsation via an intra-aortic balloon improved cardiac index but remained inadequate.
• A 65 ml sac-type pulsatile assist device provided marginally adequate cardiac index.
• The valved right atrial-pulmonary arterial bypass pump significantly increased cardiac index to a satisfactory level (102.0 +/- 20.7 ml/min/kg).

Conclusions:

• Passive pulmonary blood flow is inadequate in profound right ventricular failure.
• Pulsatile assist devices offer incremental improvements but may not reach satisfactory levels.
• Valved right atrial-pulmonary arterial bypass is the recommended method for pulmonary circulatory support in profound right ventricular failure due to its superior efficacy.