• Neeraj M Shah, Chloe Apps, Georgios Kaltsakas, Sophie Madden-Scott, Eui-Sik Suh, Rebecca F D'Cruz, Gill Arbane, Maxime Patout, Elodie Lhuillier, Nicholas Hart, and Patrick B Murphy.
• Lane Fox Respiratory Service, St Thomas' Hospital, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; Lane Fox Clinical Respiratory Physiology Centre, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom; Centre for Human and Applied Physiological Sciences (CHAPS), King's College London, London, United Kingdom. Electronic address: Neeraj.shah@gstt.nhs.uk.
• Chest. 2024 Apr 1; 165 (4): 929941929-941.

BackgroundRespiratory muscle weakness can impair cough function, leading to lower respiratory tract infections. These infections are an important contributor to morbidity and mortality in patients with neuromuscular disease. Mechanical insufflation-exsufflation (MIE) is used to augment cough function in these patients. Although MIE is widely used, there are few data to advise on the optimal technique. Since the introduction of MIE, the recommended pressures to be delivered have increased. There are concerns regarding the use of higher pressures and their potential to cause lung derecruitment and upper airway closure.Research QuestionWhat is the impact of high-pressure MIE (HP-MIE) on lung recruitment, respiratory drive, upper airway flow, and patient comfort, compared with low-pressure MIE (LP-MIE), in patients with respiratory muscle weakness?Study Design And MethodsClinically stable patients using domiciliary MIE with respiratory muscle weakness secondary to Duchenne muscle dystrophy, spinal cord injury, or long-term tracheostomy ventilation received LP-MIE (30/-30 cm H2O) and HP-MIE (60/-60 cm H2O) in a random sequence. Lung recruitment, neural respiratory drive, and cough peak expiratory flow were measured throughout, and patients reported comfort and breathlessness following each intervention.ResultsA total of 29 patients (10 with Duchenne muscle dystrophy, eight with spinal cord injury, and 11 with long-term tracheostomy ventilation) were included in this study. HP-MIE augmented cough peak expiratory flow compared with LP-MIE (mean cough peak expiratory flow HP-MIE 228 ± 81 L/min vs LP-MIE 179 ± 67 L/min; P = .0001) without any significant change in lung recruitment, neural respiratory drive, or patient-reported breathlessness. However, in patients with more pronounced respiratory muscle weakness, HP-MIE resulted in an increased rate of upper airway closure and patient discomfort that may have an impact on clinical efficacy.InterpretationHP-MIE did not lead to lung derecruitment or breathlessness compared with LP-MIE. However, it was poorly tolerated in individuals with advanced respiratory muscle weakness. HP-MIE generates more upper airway closure than LP-MIE, which may be missed if cough peak expiratory flow is used as the sole titration target.Clinical Trial RegistrationClinicalTrials.gov; No.: NCT02753959; URL: www.Clinicaltrialsgov.Copyright © 2023 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

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