New algorithm to quantify cardiopulmonary interaction in patients with atrial fibrillation: a proof-of-concept study

Area of Science:

• Critical care medicine
• Anesthesiology
• Cardiovascular physiology

Background:

• Traditional pulse pressure variation (PPV) calculations are unreliable in patients with atrial fibrillation (AF) due to arrhythmia-induced variations.
• A novel algorithm has been developed to specifically address and quantify ventilation-induced pulse pressure variation (VPPV) in the presence of AF.

Purpose of the Study:

• To develop and validate a new algorithm for calculating VPPV in patients with AF.
• To assess the algorithm's robustness under altered hemodynamic loading conditions.
• To investigate the relationship between VPPV and changes induced by passive leg raising (PLR).

Main Methods:

• A generalized additive model was employed, incorporating the influence of AF on preceding RR intervals and ventilation on pulse pressure.
• Invasive pressure data and ECG were collected from patients with AF undergoing general anesthesia and mechanical ventilation.
• Loading conditions were manipulated using passive leg raising (PLR) to assess VPPV changes.

Main Results:

• The developed algorithm demonstrated high predictive ability, with a median r² of 0.92.
• Ventilation-induced pulse pressure variation (VPPV) significantly decreased after passive leg raising (PLR) (P<0.014).
• A statistically significant relationship was found between pre-PLR VPPV values and the magnitude of change induced by PLR (P<0.001).

Conclusions:

• The novel algorithm successfully quantifies VPPV in patients with AF.
• This method allows for the detection of dynamic changes in loading conditions.
• The findings support the utility of this algorithm for hemodynamic monitoring in AF patients.