A novel method for assessment of airway opening pressure without the need for low-flow insufflation

Background: Airway opening pressure (AOP) detection and measurement are essential for assessing respiratory mechanics and adapting ventilation. We propose a novel approach for AOP assessment during volume assist control ventilation at a usual constant-flow rate of 60 L/min.

Objectives: To validate the conductive pressure (P_cond) method, which compare the P_cond-defined on the airway pressure waveform as the difference between the airway pressure level at which an abrupt change in slope occurs at the beginning of insufflation and PEEP-to resistive pressure for AOP detection and measurement, and to compare its respiratory and hemodynamic tolerance to the standard low-flow insufflation method.

Methods: The proof-of-concept of the P_cond method was assessed on mechanical (lung simulator) and physiological (cadavers) bench models. Its diagnostic performance was evaluated in 213 patients, using the standard low-flow insufflation method as a reference. In 45 patients, the respiratory and hemodynamic tolerance of the P_cond method was compared with the standard low-flow method.

Measurements and main results: Bench assessments validated the P_cond method proof-of-concept. Sensitivity and specificity of the P_cond method for AOP detection were 93% and 91%, respectively. AOP obtained by P_cond and standard low-flow methods strongly correlated (r = 0.84, p < 0.001). Changes in SpO₂ were significantly lower during P_cond than during standard method (p < 0.001).

Conclusion: Determination of P_cond during constant-flow assist control ventilation may permit to easily and safely detect and measure AOP.