Beschreibung:
<jats:p><jats:bold>Introduction:</jats:bold> In slowly progressive myopathies, diaphragm weakness early manifests through sleep-related hypoventilation as reflected by nocturnal hypercapnia. This study investigated whether daytime tests of respiratory muscle function and diaphragm ultrasound predict hypercapnia during sleep.</jats:p><jats:p><jats:bold>Methods:</jats:bold> Twenty-seven patients with genetic myopathies (myotonic dystrophy type 1 and 2, late-onset Pompe disease, facioscapulohumeral dystrophy; 48 ± 11 years) underwent overnight transcutaneous capnometry, spirometry, measurement of mouth occlusion pressures, and diaphragm ultrasound.</jats:p><jats:p><jats:bold>Results:</jats:bold> Sixteen out of 27 patients showed nocturnal hypercapnia (peak p<jats:sub>tc</jats:sub>CO<jats:sub>2</jats:sub> ≥ 50 mmHg for ≥ 30 min or increase in p<jats:sub>tc</jats:sub>CO<jats:sub>2</jats:sub> by 10 mmHg or more from the baseline value). In these patients, forced vital capacity (FVC; % predicted) and maximum inspiratory pressure (MIP; % of lower limit or normal or LLN) were significantly reduced compared to normocapnic individuals. Nocturnal hypercapnia was predicted by reduction in FVC of &lt;60% [sensitivity, 1.0; area under the curve (AUC), 0.82] and MIP (%LLN) &lt;120% (sensitivity, 0.83; AUC, 0.84), the latter reflecting that in patients with neuromuscular disease, pretest likelihood of abnormality is <jats:italic>per se</jats:italic> higher than in healthy subjects. Diaphragm excursion velocity during a sniff maneuver excluded nocturnal hypercapnia with high sensitivity (0.90) using a cutoff of 8.0 cm/s.</jats:p><jats:p><jats:bold>Conclusion:</jats:bold> In slowly progressive myopathies, nocturnal hypercapnia is predicted by FVC &lt;60% or MIP &lt;120% (LLN). As a novelty, nocturnal hypercapnia can be excluded with acceptable sensitivity by diaphragm excursion velocity &gt;8.0 cm/s on diaphragm ultrasound.</jats:p>