Clinical Scorecard: Discrepancies in Cardiac Output Measurements: A Comparison of Pressure Recording Analytical Method and Pulmonary Artery Thermodilution in Low Cardiac Output Patients - Initial Findings from a Prospective Observational Pilot Study

At a Glance

Key Highlights

• PRAM demonstrated high feasibility for data acquisition (98.8%) in patients with LVEF < 35%.
• PRAM significantly underestimated cardiac output compared to PAC with a bias of −2.02 L/min and wide limits of agreement.
• Trending ability of PRAM was poor with low concordance rates (four-quadrant 36.6%, polar plot 10.1%) indicating unreliable monitoring in this population.

Guideline-Based Recommendations

Diagnosis

• Use pulmonary artery catheter thermodilution as the reference standard for cardiac output measurement in patients with severely impaired LVEF.
• Consider limitations of pulse contour methods like PRAM in low cardiac output states and complex hemodynamics.

Management

• Employ continuous hemodynamic monitoring to guide goal-directed vasopressor and inotropic therapy in high-risk cardiac surgery patients.
• Exercise caution when interpreting PRAM-derived cardiac output values in patients with severely reduced ventricular function.

Monitoring & Follow-up

• Prefer PAC-derived continuous cardiac output measurements over PRAM in patients with LVEF < 35% due to better accuracy and trending ability.
• Monitor for potential discrepancies and validate pulse contour method readings against reference methods when possible.

Risks

• Inaccurate cardiac output estimation by PRAM may lead to inappropriate hemodynamic management decisions in patients with severe low ejection fraction.
• Invasive PAC use carries procedural risks but remains the gold standard for accurate hemodynamic assessment in this population.

Patient & Prescribing Data

High-risk cardiac surgery patients with severely impaired left ventricular function (LVEF < 35%)

PRAM is feasible for data collection but shows poor agreement and trending reliability compared to PAC; thus, reliance on PRAM alone for hemodynamic management in this group is not recommended.

Clinical Best Practices

• Use pulmonary artery catheter thermodilution as the preferred method for cardiac output monitoring in patients with severely reduced LVEF undergoing cardiac surgery.
• Recognize the limitations of uncalibrated pulse contour analysis methods like PRAM in complex hemodynamic states.
• Validate new cardiac output monitoring technologies against established reference standards before clinical implementation in high-risk populations.
• Consider patient-specific pathophysiology, such as severe low ejection fraction, when selecting hemodynamic monitoring modalities.
• Further research is needed to refine PRAM algorithms and assess their accuracy in diverse clinical scenarios.

Related Resources & Content

• Clinical Trial Registration