PEEP Mask for Tracheobronchomalacia-Induced Cough

PROSPECTIVE:

Twenty subjects with chronic cough and TBM diagnosed by bronchoscopy or computed tomography (CT) scan will be recruited to enroll 12 participants. Comorbid conditions that can cause chronic cough, such as asthma, COPD, and GERD, must be treated if present, for subjects to qualify. At the pre-baseline visit (V0), after obtaining verbal informed consent, each subject will complete validated cough questionnaires to quantify their cough severity and cough-related QOL at baseline. The baseline visit (V1) will occur in-person approximately two weeks later, after a run-in period to minimize observation bias related to the cough questionnaires. Written consent will be performed at this visit. At V1, the cough questionnaires will be repeated and subjects' airway resistance and reactance will be measured with impulse oscillometry (IOS). A study physician will perform a physical exam and determine eligibility. Eligible subjects will then be given the nPEP device by the study team and instructed on its use. Approximately four to six weeks after device delivery, at the follow-up visit (V3), cough questionnaires and IOS will be repeated and they will be asked for feedback regarding device design and user experience. Subjects may then be entered into a cohort for up to six additional months, during which there will be no study visits or procedures, but subjects may be contacted by investigators for additional narrative feedback on the device and its use.

Study subjects will be given an nPEP device to use for four to six weeks. During this time participants will be asked to remain on their current medical regimen and not to make any dose changes or add new drugs, unless indicated by their primary care provider. Impulse oscillometry will be measured at V1 and 4-6 weeks later at V3 to assess effect of the nPEP device on airway physiology. A lung CT scan will be performed at V2.

RETROSPECTIVE:

This device was tried on two individuals and it was initiative and was beneficial. Many patients are not candidates for tracheobronchoplasty itself due to medical comorbidities, prefer to avoid the associated risks, or are not candidates for the required tracheal stenting due to trachea size or anatomy. These patients are left without a viable therapeutic option for their severe cough.

Continuous positive airway pressure (CPAP) devices have been reported to stop or prevent cough in TBM, presumably through pneumatic stenting the large airways to maintain their patency during exhalation. CPAP devices, however, are not labeled for this indication and their functional utility is very limited given size of the device, need for a power source, and multiple steps to don the equipment that are not easily completed while actively and uncontrollably coughing.

The physicians aimed to provide positive airway pressure at a low cost and through readily accessible means, in order to abort coughing paroxysms in patients who were not candidates for tracheal stenting and did not have access to commercial CPAP devices. Patients at Duke University Hospital referred to the Interventional Pulmonary service for evaluation of severe, debilitating TBM-related cough and possible tracheal stenting, but who were not candidates for tracheal stenting given their airway anatomy, were given positive end expiratory pressure (PEEP) masks assembled using existing hospital supplies. Specifically, a standard, adjustable (5-20 cm H2O) positive end expiratory pressure (PEEP) valve manufactured for attachment to a manual resuscitation (commonly known as bag-valve-mask) device was attached directly to a flexible face mask, also from a manual resuscitation device. Patients were instructed by their physicians how to use the PEEP masks. The patients used the PEEP mask immediately during their clinical encounter and were given a mask to take home. (The device was created by fellow, Lindsay Boole.)

This was a limited intervention for a very small number of patients (two), specifically identified as being referred to Duke Interventional Pulmonary service with severe cough related to TBM, but with anatomy that ruled them out as candidates for tracheal stenting. There were no formal data collected and no separate follow-up for the purpose of this project (though patients had ongoing clinical follow-up per standard of care). The patients' subjective improvement with the masks was submitted as a case report abstract and poster at the American College of Chest Physician meeting in 2017.

Other physicians asked Dr. Boole about the mask and if it could be used for their patients. Therefore, the investigators would like to request a retrospective review of all patients that used the PEEP mask between January 1, 2009 and August 20, 2019 to be included in this pilot study. Approximately 15 records will be reviewed.