Diaphragmatic dysfunction at the first visit to a chest diseases outpatient clinic in 500 patients with amyotrophic lateral sclerosis

Abstract

Introduction In this study, we aimed to evaluate diaphragmatic dysfunction (DD) by using a practical approach in patients with amyotrophic lateral sclerosis (ALS) at the first visit to a chest diseases outpatient clinic. Methods Patients with ALS seen in our outpatient clinic for the past 5 y and followed up for at least 1 y, were retrospectively evaluated. Having at least one of the following three criteria was accepted as DD: (a) paradoxical abdominal movement (PAM), (b) sitting‐supine forced vital capacity (FVC) difference ≥ 20%, (c) sitting‐supine arterial oxygen saturation measured by pulse oximetry (SpO2) difference ≥ 4%. Respiratory symptoms, arterial blood gas analysis, sleep studies, noninvasive mechanical ventilation use, and mortality were recorded. Results Five‐hundred patients with ALS were included (female/male: 220/280, age: 58.9 ± 11.3 y). Of the patients, 22.8% had daytime hypercapnia. DD was observed in 55% of the patients (PAM in 112, sitting‐supine FVC difference ≥ 20% in 50, and sitting‐supine SpO2 difference ≥ 4% in 113 patients). Of the patients with DD, 31.6% (n = 87) had no respiratory symptoms, 46.4% had FVC > 70% and 33.5% had FVC <50%. Nocturnal hypoxemia (sleep time spent with SpO2 < 90% ≥30%) was present in 59.7%, and all patients with nocturnal hypoxemia had DD. Obstructive sleep apnea (8 severe, 14 moderate, 39 mild) was detected in 55% of the patients with polysomnography (n = 61) or polygraphy (n = 50). During follow‐up, 52.2% of the patients died. Mean survival time was shorter in patients with DD (P < .001). Conclusion Paradoxical abdomimal movement (PAM), sitting‐supine SpO2 difference ≥ 4% and sitting‐supine FVC difference ≥ 20% are indicators of DD, which should be routinely evaluated at every outpatient visit.

Pilot Feasibility of Web-Based Implementation of Respiratory Therapist Supervised At-Home Telespirometry in Amyotrophic Lateral Sclerosis

“…Seated eFVC using both conventional and portable spirometers during the same-day [Figure 2A] and within 7-day encounter [Figure 2C] showed no significant difference in FVC supporting reproducibility of measurements obtained with portable spirometry. Supine FVC may reveal early diaphragmatic weakness with or without orthopnea [Lechtzin 2002, Pihtili 2021]. Performance of testing in supine position, with enhanced ability to detect respiratory insufficiency, may be less burdensome when conducted from home with caregiver assistance as more subjects performed sFVC in the home setting.…”