Detecting Intrathoracic Airway Closure during Prehospital Cardiopulmonary Resuscitation Using Quasi-Static...

Area of Science:

• Emergency Medicine
• Cardiopulmonary Physiology
• Respiratory Mechanics

Background:

• Intrathoracic airway closure is a frequent complication during cardiac arrest, potentially hindering effective ventilation.
• Previous detection methods relied on capnogram analysis; quasi-static pressure-volume curves are standard in other patient groups.
• This research pioneers the use of quasi-static pressure-volume curves for detecting airway closure during prehospital cardiopulmonary resuscitation.

Purpose of the Study:

• To assess the feasibility and utility of quasi-static pressure-volume curves for detecting intrathoracic airway closure during prehospital cardiopulmonary resuscitation.
• To quantify the degree of airway closure in cardiac arrest patients using this novel method.

Main Methods:

• A pressure and flow sensor was attached to the endotracheal tube during prehospital cardiopulmonary resuscitation.
• Low-flow inflations were performed using a manual resuscitator during interruptions in chest compressions (e.g., rhythm analysis).
• The lower inflection point on the resulting pressure-volume curves was identified to detect and quantify intrathoracic airway closure.

Main Results:

• The method was successfully applied to ten prehospital cardiac arrest patients.
• Intrathoracic airway closure, indicated by a lower inflection point, was detected in all participants.
• The median pressure at the lower inflection point was 5.56 cmH2O (IQR 4.80-8.23), with variations observed between patients.
• Lower inflection point pressures were noted in patients who achieved return of spontaneous circulation.

Conclusions:

• Quasi-static pressure-volume curves can be effectively obtained during prehospital cardiopulmonary resuscitation.
• Intrathoracic airway closure is consistently present in cardiac arrest patients treated prehospitalily.
• Further investigation is warranted to explore ventilation strategies targeting airway closure and its prognostic value.