Lung insufflation capacity in neuromuscular disease.
Bach JR, Mahajan K, Lipa B, Saporito L, Goncalves M, Komaroff E.
Department of Physical Medicine and Rehabilitation, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey, USA.
OBJECTIVE: To compare maximal passive lung insufflation capacity (LIC) with lung inflation by air stacking (to maximum insufflation capacity [MIC]) and with vital capacity (VC); to explore relationships between these variables that correlate with glottic function and cough peak flows (CPF); to demonstrate the effect of routine inflation therapy on LIC and MIC; and to determine the relative importance of lung inflation therapy as a function of disease severity. DESIGN: Case series of 282 consecutive neuromuscular disease (NMD) clinic patients 7 yrs and older with VC <70% of the predicted normal value. All cooperative patients meeting these criteria were prescribed thrice-daily air stacking and/or maximal passive lung insufflation to pressures of 40-80 cm H2O, and they underwent measurements of VC, MIC, LIC, and unassisted and assisted CPF on every visit. RESULTS: Means +/- standard deviations for VC, MIC, and LIC were 1131 +/- 744, 1712 +/- 926, and 2069 +/- 867 ml, respectively, and, for unassisted and assisted CPF, they were 2.5 +/- 2.0 and 4.3 +/- 2.2 liters/sec, respectively, with all differences statistically significant (P < 0.001). MIC minus VC correlated inversely with LIC minus MIC (P = 0.01) and, therefore, with glottic function. Both MIC and LIC increased with practice (P < 0.001). Increases in LIC but not MIC over VC were greatest for patients with the lowest VC (P < 0.05). There were no complications of lung mobilization therapy. CONCLUSIONS: Passive lung insufflation can distend the lungs of patients with NMD significantly greater than air stacking, particularly when glottic and bulbar-innervated muscle dysfunction is severe. LIC, MIC, and VC measurements permit quantifiable assessment of glottic integrity and, therefore, bulbar-innervated muscle function for patients with NMD. The patients who benefit the most from insufflation therapy are those who have the lowest VC.
PMID: 18716483 [PubMed - indexed for MEDLINE]