Cardiac index validation using the pressure recording analytic method in unstable patients

Area of Science:

• Cardiovascular Physiology
• Critical Care Medicine
• Hemodynamic Monitoring

Background:

• Accurate cardiac index (CI) measurement is crucial for managing unstable patients.
• Minimally invasive monitoring devices often face challenges in critically ill populations.
• Thermodilution is a standard method for CI assessment, but it is invasive.

Purpose of the Study:

• To evaluate the accuracy and precision of the pressure recording analytic method (PRAM) for cardiac index measurement.
• To compare PRAM with thermodilution in unstable patients, including those requiring intra-aortic balloon pump or high-dose inotropic support.
• To determine the clinical utility of PRAM in a challenging patient cohort.

Main Methods:

• A prospective study involving 32 post-cardiac surgery patients with low cardiac output syndrome.
• Comparison of cardiac index measurements obtained via PRAM and pulmonary artery thermodilution.
• Exclusion of patients with artifacts in arterial pressure monitoring and atrial fibrillation.
• Analysis of data using correlation coefficients, bias, limits of confidence, and Bland-Altman plots.

Main Results:

• A significant correlation (r = 0.72, p < 0.001) was observed between PRAM and thermodilution for cardiac index.
• The mean bias was 0.072 ± 0.41 L/min/m², with 95% confidence limits of -0.089 to 0.233 L/min/m².
• The percentage error between the two methods was 30%, indicating sufficient agreement as visualized by Bland-Altman plots.

Conclusions:

• The pressure recording analytic method (PRAM) demonstrates clinical usefulness for cardiac index assessment in unstable patients.
• PRAM provides accurate and precise measurements comparable to thermodilution, even in patients on mechanical circulatory support or high-dose inotropes.
• This minimally invasive technique offers a viable option for hemodynamic monitoring in complex critical care scenarios.