A preliminary evaluation of a prospective study of pulmonary function studies and symptoms of hypoventilation in ALS/MND patients

There is still no consensus as to which physiologic marker should be used a s a trigger for the initiation of non-invasive positive pressure ventilatio n (NPPV) in patients with amyotrophic lateral sclerosis (ALS). Current prac tice parameters recommend that the decision to begin treatment be based upo n forced vital capacity (FVC) measurements. A prospective, randomized study was performed in 20 ALS patients who had an FVC of 70-100%. Patients recei ved baseline assessments including: ALS functional rating scale-respiratory version (ALSFRS-R), pulmonary symptom scale, Short form 36 (SF-36), FVC%, maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and nocturnal oximetry. Patients were randomized to receive NPPV based upon noc turnal oximetry studies suggesting oxygen desaturation < 90% for one cumula tive minute ("early intervention") or a FVC < 50% ("standard of care"). At enrollment there was no significant correlation between FVC% and the ALSFRS -R, symptom score, MEP, MIP, or duration of nocturnal desaturation < 90%. A n increase in the vitality subscale of the SF-36 was demonstrated in 5/6 pa tients randomized to "early intervention" with NPPV. Our data indicate that FVC% correlates poorly with respiratory symptoms and suggests that MIP and nocturnal oximetry may be more sensitive measures of early respiratory ins ufficiency. In addition, intervention with NPPV earlier than our current st andard of care may result in improved quality of life. (C) 2001 Published b y Elsevier Science B.V.