Individuals with neuromuscular and chest wall disorders experience respiratory muscle weakness, reduced lung volume and increases in respiratory elastance and resistance which lead to increase in work of breathing, impaired gas exchange and respiratory pump failure. Recently developed methods to assess respiratory muscle weakness, mechanics and movement supplement traditionally employed spirometry and methods to evaluate gas exchange. These include recording postural change in vital capacity, respiratory pressures (mouth and sniff), electromyography and ultrasound evaluation of diaphragmatic thickness and excursions. In this review, we highlight key aspects of the pathophysiology of these conditions as they impact the patient and describe measures to evaluate respiratory dysfunction. We discuss potential areas of physiologic investigation in the evaluation of respiratory aspects of these disorders.

Asthma prevalence, morbidity, and mortality disproportionately impact African American/Black (AA/B) and Hispanic/Latinx (H/L) communities. Adherence to daily inhaled corticosteroid (ICS), recommended by asthma guidelines in all but the mildest cases of asthma, is generally poor. As-needed ICS has shown promise as a patient-empowering asthma management strategy, but it has not been rigorously studied in AA/B or H/L patients or in a real-world setting. Design and Aim The PeRson EmPowered Asthma RElief (PREPARE) Study is a randomized, open-label, pragmatic study which aims to assess whether a patient-guided, reliever-triggered ICS strategy called PARTICS (Patient-Activated Reliever-Triggered Inhaled CorticoSteroid) can improve asthma outcomes in AA/B and H/L adult patient populations. In designing and implementing the study, the PREPARE research team has relied heavily on advice from AA/B and H/L Patient Partners and other stakeholders. Methods PREPARE is enrolling 1200 adult participants (600 AA/Bs, 600H/Ls) with asthma. Participants are randomized to PARTICS + Usual Care (intervention) versus Usual Care (control). Following a single in-person enrollment visit, participants complete monthly questionnaires for 15 months. The primary endpoint is annualized asthma exacerbation rate. Secondary endpoints include asthma control; preference-based quality of life; and days lost from work, school, or usual activities. Discussion The PREPARE study features a pragmatic design allowing for the real-world assessment of a patient-centered, reliever-triggered ICS strategy in AA/B and H/L patients. Outcomes of this study have the potential to offer powerful evidence supporting PARTICS as an effective asthma management strategy in patient populations that suffer disproportionately from asthma morbidity and mortality.

This review emphasizes key findings in physiologic research of sarcoidosis reported over the past year. Sarcoidosis, a multiorgan disease involving the formation of epithelioid-cell granulomas, is characterized by reduced lung volumes, compliance, and diffusion capacity (D(L)CO), and, in a small number of cases, by airflow limitation. Recent studies do not show a close relationship between changes in lung volume and radiographic stage. Fatigue and exercise limitation are characteristic of this condition, and can be assessed by health-related quality of life (HRQOL) instruments. Recent investigations have focused on the evaluation of the extent of parenchymal and nodal inflammatory activity by PET using 18F-fluorodeoxyglucose (FDG-PET imaging). Pulmonary hypertension in advanced cases of sarcoidosis contributes to increased physical impairment, and decreased HRQOL and survival. It is best associated with ambulatory desaturation, reduced D(L)CO, and abnormal cardiopulmonary exercise testing findings indicative of pulmonary vascular disease. If pulmonary hypertension is suspected, it should be screened for by echocardiography and confirmed by right heart catheterization. Selected patients with progressive disease unresponsive to medical therapy or with severe pulmonary hypertension should be considered for lung transplantation. Current criteria for lung transplantation include New York Heart Association functional class III-IV, pulmonary hypertension, and/or right atrial pressure at least 15 mmHg. Periodic assessment of HRQOL measures, exercise-induced hypoxemia, and right-sided cardiac pressures for pulmonary hypertension provides, to date, the best insight into the magnitude of physiologic impairment, serving as guideposts for management (including lung transplantation) and prognosis.

Background: Expiratory flow limitation (EFL), determined by the negative expiratory pressure (NEP) technique, can exhibit overlapping patterns in COPD, obstructive sleep apnea (OSA) and non-OSA obesity. We assessed the ability of a quantitative method to assess EFL to discriminate COPD from obese and OSA patients during NEP (-2 to -3 cm H ₂ O) testing. Methods: EFL was quantified by measuring the area under the preceding control tidal breath (Vt) subtended by the NEP curve (%AUC). To quantify mean lost flow, the ratio of %AUC to percentage of control Vt over which EFL occurred (%EFL) (= %AUC/%EFL) was computed. Percent EFL, %AUC, and %AUC/%EFL was compared in 42 patients with COPD, 28 obese subjects without OSA, 50 with OSA (26 mild-moderate, 24 severe) and 19 control subjects, in seated and supine postures. Results: All patients exhibited %EFL values significantly higher than control subjects, corrected for age and gender (ANOVA). All but the COPD group exhibited higher %EFL while supine, but not %AUC or %AUC/%EFL. Amongst seated subjects, %EFL was highest in COPD, and amongst supine groups, it was greatest in OSA and COPD. %AUC/%EFL was significantly higher in mild-moderate OSA than in COPD only while seated. %AUC or %AUC/%EFL did not discriminate amongst other cohorts in either posture. Conclusions: Computation of %EFL helps distinguish EFL in COPD, obese and OSA patients from those of control subjects. Computation of %AUC and %AUC/%EFL is useful in determining the magnitude of extrathoracic FL in individuals with obesity and OSA, but does not distinguish between cohorts.