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Overcoming right ventricular failure with left ventricular assist devices
W P Santamore1, E H Austin, L Gray
1Jewish Hospital Cardiothoracic Surgical Research Institute, Division of Thoracic and Cardiovascular Surgery, University of Louisville, Ky., USA.
Summary
Shunting blood can increase cardiac output in patients with left ventricular assist devices but may decrease oxygen saturation. Monitoring systemic venous oxygen saturation can indicate if cardiac output has adequately increased, ensuring patient safety.
Area of Science:
- Cardiovascular physiology
- Medical device engineering
Background:
- Right ventricular failure is a critical complication during left ventricular assist device (LVAD) support, potentially leading to circulatory collapse.
- Shunting blood from the femoral vein to the LVAD can augment cardiac output but may compromise arterial oxygen saturation.
Purpose of the Study:
- To develop a predictive model for oxygen (O2) delivery during LVAD support with femoral vein shunting.
- To evaluate the relationship between cardiac output, shunt flow, and systemic O2 delivery and saturation.
Main Methods:
- A mathematical model was constructed based on pulmonary O2 uptake and whole-body O2 consumption.
- An equation was derived to relate cardiac output, shunt-to-systemic blood flow ratio, and systemic O2 delivery.
Main Results:
- Increased cardiac output with shunting enhances systemic O2 delivery but reduces arterial O2 saturation, leaving systemic venous O2 saturation unchanged.
- If cardiac output does not increase, shunting decreases systemic O2 delivery, arterial O2 saturation, and systemic venous O2 saturation.
Conclusions:
- Systemic venous oxygen saturation monitoring is proposed as a safety indicator during LVAD shunting procedures.
- A drop in systemic venous O2 saturation suggests an insufficient increase in cardiac output, signaling potential patient risk.