Sleep medicine network: Home-based mechanical ventilation and neuromuscular section
Role of airway clearance therapies in neuromuscular disease
Individuals with neuromuscular weakness have an impaired ability to cough and clear secretions from the airway, which can result in atelectasis and pneumonia. Proximal airway clearance therapies (ACT), including manual lung volume recruitment (LVR) and mechanical in-exsufflation (MI-E), mobilize secretions, improve cough efficacy, maintain chest wall compliance, and slow progression of restrictive lung impairment (Chatwin et al. Respir Med. 2018;136:98-110; Sheers et al. Respirology. 2019;24:512-520).
ACT are recommended in international care guidelines for respiratory management of individuals with neuromuscular disease. At a recent Home-based Mechanical Ventilation and Neuromuscular Disease Section “PEEPS Talking PAP” rounds, participants discussed their approach to ACT. Practices varied by country and between adult/pediatric care providers. MI-E is most often used in the United States, but elsewhere in the world, LVR with a self-inflating bag and one-way valve is first-line therapy. Clinical care guidelines suggest initiation of regular ACT when cough peak flow is < 270 L/minute, forced vital capacity < 40%-60% predicted, or with subjectively weak cough (Hull et al. Thorax. 2012;67(7):654-655; Amin et al. Can J Resp Crit Care Sleep Med. 2017;1(1):7-36; McKim et al. Can Resp J. 2011;18(4):197-215; Birnkrant et al. Lancet Neurol. 2018;17(4):347-361; Sheehan et al. Pediatrics. 2018;142(Suppl 2):S62-s71).
Optimal timing for initiation of routine ACT, however, is not clear. A newly published randomized controlled trial of twice daily LVR in boys with Duchenne muscular dystrophy with relatively normal baseline lung function did not demonstrate a significant slowing of decline in forced vital capacity over 2 years. In individuals with preserved lung function, the burden of regular therapy may outweigh benefit (Katz et al. Thorax. 2022; doi: 10.1136/thoraxjnl-2021-218196). (While we are still learning about how best to apply this therapy in less advanced neuromuscular disease, ACT has demonstrated benefits during respiratory exacerbations, and routine use plays a role in preservation of lung function in more advanced disease (Katz et al. Ann Am Thorac Soc. 2016;13(2):217-222; McKim et al. Arch Phys Med Rehab. 2012;93(7):1117-1122; O’Sullivan et al. Arch Phys Med Rehabil. 2021;102(5):976-983; Bach et al. Am J Phys Med Rehab. 2008;87(9):720-725).
Sherri Katz, MD, FCCP
Section Steering Committee Chair
Critical care network: Mechanical ventilation and airways management section
NIV following extubation: Which devices and which patients?
For those of us interested in studying mechanical ventilation, an interesting paradox exists: despite our interest and enthusiasm in studying it, our patients benefit from avoiding it! Patients who require re-intubation are at high risk of in-hospital mortality (Frutos-Vivar et al. J Crit Care. 2011;26:502-9).
Dr. Daniel Ouellette
Studies in high-risk patients receiving mechanical ventilation have demonstrated that patients treated with immediate noninvasive ventilation (NIV) following extubation had reduced risk of re-intubation. CHEST guidelines focused on ventilator liberation considered these studies in a metanalysis which led to recommendations to employ NIV immediately after extubation in high-risk patients to reduce re-intubation rates (Ouellette D et al. Chest. 2017;151:166-80).
In the years since the publication of the CHEST guidelines, more information has been forthcoming. Evidence has emerged that treatment with high-flow nasal cannula devices following extubation may mitigate against re-intubation. An interesting strategy from the High-Wean Study Group suggested that postextubation combination therapy with both a high-flow cannula and NIV leads to improved outcomes compared with high-flow alone (Thille AW et al. JAMA. 2019;322:1465-75).
Thille and coworkers recently broadened our concept of patients who may benefit from NIV post extubation. They examined a cohort of obese patients requiring mechanical ventilation, finding that when patients were treated with NIV and high-flow nasal cannula post extubation, that they had a reduced risk of re-intubation compared with a group receiving high flow alone (Thille AW, et al. Am J Respir Crit Care Med. 2022;205:440-9).
As the incoming chair of the Mechanical Ventilation and Airways Management Section of the CHEST Critical Care Network, I look forward during the next 2 years to having interesting conversations about topics like this one and working with section members to develop exciting new projects concerning mechanical ventilation.
Daniel Ouellette, MD, MS, FCCP
Section Steering Committee Chair