Diagnostic and therapeutic challenges in managing persistent air leaks

Sound-guided assessment and localization of pulmonary air leak

Pulmonary air leak is the most common complication of lung surgery, with air leaks that persist longer than 5 days representing a major source of post-surgery morbidity. Clinical management of air leaks is challenging due to limited methods to precisely locate and assess leaks. Here, we present a sound-guided methodology that enables rapid quantitative assessment and precise localization of air leaks by analyzing the distinct sounds generated as the air escapes through defective lung tissue. Air leaks often present after lung surgery due to loss of tissue integrity at or near a staple line. Accordingly, we investigated air leak sounds from a focal pleural defect in a rat model and from a staple line failure in a clinically relevant swine model to demonstrate the high sensitivity and translational potential of this approach. In rat and swine models of free-flowing air leak under positive pressure ventilation with intrapleural microphone 1 cm from the lung surface, we identified that: (a) pulmonary air leaks generate sounds that contain distinct harmonic series, (b) acoustic characteristics of air leak sounds can be used to classify leak severity, and (c) precise location of the air leak can be determined with high resolution (within 1 cm) by mapping the sound loudness level across the lung surface. Our findings suggest that sound-guided assessment and localization of pulmonary air leaks could serve as a diagnostic tool to inform air leak detection and treatment strategies during video-assisted thoracoscopic surgery (VATS) or thoracotomy procedures.

Persistent air leak management in critically ill patients

Persistent air leak (PAL) is a challenging clinical entity, particularly in the setting of critical illness. It is a significant cause of morbidity, health care expenditure, and resource utilization. Data on its prevalence in the critically ill patient population are limited. Unique patient factors often necessitate an individualized approach. Guidelines on this subject are antiquated and do not specially address patients on mechanical ventilation. Critically ill patients may not be able to tolerate surgical intervention. Treatment in this population relies upon lung protective ventilation, various anecdotal modalities, chemical pleurodesis, autologous blood patching, and bronchoscopic insertion of endobronchial valves. Ventilation strategies center on rapid weaning and reduction of airway pressures. Anecdotal methods include implantable devices and chemical agents. Data on these modalities are limited to case reports. None have United States Food and Drug Administration (FDA) approval. The Spiration Valve System is FDA approved as a Humanitarian Device Exemption. Data on endobronchial valves are based on large case series, and only one small case series has focused exclusively on critically ill patients. The majority of valves in critically ill mechanically ventilated patients are used for non-FDA approved indications. Updated guidelines are desperately needed to ensure a standardized approach to this common clinical situation.