Background: Forced vital capacity (FVC) and maximal inspiratory pressure correlate with nocturnal hypoventilation in adults with neuromuscular disease, but children may not be able to perform these volitional tests.
Objective: To identify volitional and non-volitional parameters reflecting lung and respiratory muscle function which differ in children treated or not with nocturnal noninvasive positive pressure ventilation (NPPV).
Methods: Parameters reflecting lung function and respiratory muscle performance were measured in 27 children not treated with NPPV (Unventilated group) and 8 children treated with NPPV (Ventilated group).
Results: Concerning noninvasive tests, the Ventilated group had a rapid shallow breathing and a lower ventilatory response to carbon dioxide compared to the Unventilated group. FVC (performed by 69% of the patients) and sniff nasal inspiratory pressure were lower in the Ventilated group. Concerning invasive tests, the non-volitional measurement of diaphragmatic strength by magnetic stimulation of the phrenic nerves showed lower results in the Ventilated group as compared to the Unventilated group. Volitional tests evaluating inspiratory and expiratory muscle strength and endurance by means of the sniff and cough manoeuvres and the tension time indexes, revealed lower values in the Ventilated group as compared to the Unventilated group.
Conclusions: Several lung function and respiratory muscle function tests are lower in children treated with NPPV as compared to children not treated with NPPV. A prospective hierarchical evaluation of these tests, according to their feasibility and invasiveness, may be helpful to identify children with neuromuscular disease at risk for nocturnal hypoventilation.