Patients with Chronic Paralytic/Restrictive Ventilatory Dysfunction (2)
Bach et al reported the cases of 41 patients with paralytic/ restrictive ventilatory insufficiency who switched from BVs (including the iron lung, chest shell, wrap ventilators, and rocking bed) to noninvasive ventilatory assistance by intermittent positive airway pressure (NV-PAP) because of the decreasing effectiveness of BV assistance with time. Many of the 41 patients had developed symptoms of OS AS, which may have been caused by chronic underventilation or by BV-associ-ated upper airway obstruction. flovent inhaler
For patients using BVs, the presence of nocturnal dSa02 can be explained by the concurrent presence of paroxysmal nocturnal dyspnea, daytime hypoxemia with ventilation perfusion mismatching, nocturnal bronchospasm, gastroesophageal reflux with recurrent aspiration and bronchospasm, airway obstruction, or chronic underventilation due to suboptimal BV assistance. In the latter three conditions, switching to NV-PAP might be expected to correct dSa02. Even without switching to NV-PAP, left ventricular failure with paroxysmal nocturnal dyspnea or chronic daytime hypoxia, severe intrinsic lung disease, and recurrent aspiration can usually be readily excluded, leaving suboptimal BV assistance or secondary obstructive phenomena as the differential diagnosis of dSa02.