Pulse wave analysis to assess systemic blood flow during mechanical biventricular support

Area of Science:

• Cardiology
• Biomedical Engineering
• Critical Care Medicine

Background:

• Systemic blood flow measurement is critical for patients requiring mechanical circulatory support (MCS).
• Severe cardiogenic shock necessitates advanced hemodynamic monitoring.
• Ventricular assist devices (VADs) are crucial for supporting failing hearts.

Observation:

• A case study involving a 65-year-old female patient with severe cardiogenic shock receiving both left and right ventricular assist devices (LVAD and RVAD).
• Blood flow was assessed using ultrasonic flowmetry, continuous thermodilution, and the pressure recording analytical method (PRAM).
• PRAM, a pulse contour system, analyzes radial artery pressure waveforms for beat-by-beat systemic blood flow assessment.

Findings:

• At Jarvik pump speeds ≤10000 rpm, PRAM and thermodilution provided comparable blood flow values.
• At Jarvik pump speeds ≥11000 rpm, the aortic valve remained closed, resulting in nonpulsatile flow, rendering PRAM unable to provide blood flow data.
• This study represents the initial use of PRAM in a patient with combined VAD support.

Implications:

• PRAM's utility in monitoring systemic blood flow in MCS patients is limited, particularly with high-speed axial flow pumps causing nonpulsatile flow.
• Further research is needed to validate PRAM as a supplementary monitoring tool in VAD patients.
• Understanding the limitations of hemodynamic monitoring devices is essential for optimizing patient care in advanced heart failure.