ArticlesSupine fall in lung volumes in the assessment of diaphragmatic weakness in neuromuscular disorders☆,☆☆
Section snippets
Methods
Between 1990 and 1998, 24 patients with generalized neuromuscular disease from various causes, but who did not have chronic obstructive pulmonary disease, were referred to our laboratory for pulmonary function testing and transdiaphragmatic pressure measurement. All patients had experienced a recent increase in breathlessness and/or a clinical suspicion of diaphragmatic dysfunction and/or unexplained hypercapnia.
The tests were performed after a 2-week period of stability for all subjects. Blood
Statistics
Data were expressed as mean ± standard deviation. Comparison of groups with and without paradoxical diaphragmatic motion (ΔPga/ΔPdi < 0) was performed by using the nonparametric Mann-Whitney test. In addition, we looked for correlations between noninvasive and invasive variables, by using least-square linear regression techniques. Univariate analysis was used to evaluate the independent contribution of each variable. A full model, stepwise, multiple, linear regression analysis was then
Results
A total of 18 men and 6 women were studied. Individual data are summarized in table 1.Paradoxical diaphragmatic motion (ΔPga/ΔPdi < 0) was noted in 14 patients, of whom 7 were on nocturnal mechanical ventilation, versus none of the 10 patients without paradoxical diaphragmatic motion. No variation in expiratory abdominal activity, as judged by analysis of the shape of the Pga curve, was found in any of the patients. Age and height were similar in the 2 groups (table 1). Pdi sniff and Pdi max
Discussion
Almost all neuromuscular disorders causing limb weakness can affect the respiratory muscles, including the diaphragm. In some patients, the diaphragm is selectively or disproportionately affected.1 Assessment of diaphragmatic function is important because several studies have found that the prognosis in neuromuscular disease was worse when diaphragmatic function was disproportionately impaired than when it was relatively spared.2, 3
There is a need for a simple test that can identify patients in
Conclusion
Our data indicate clearly a need to perform lung volume measurements in both the sitting and the supine positions when respiratory function impairment caused by neuromuscular disorders is being evaluated. Patients with neuromuscular disorders are supine much of the time and detecting a supine fall in VC will help diagnose predominant diaphragmatic weakness and, therefore, predict the occurrence of hypercapnic respiratory failure.
References (21)
- et al.
Relationship of rib cage and abdomen motion to diaphragm function during quiet breathing
Chest
(1981) - et al.
Clinical relevant diaphragmatic dysfunction after open-heart surgery
J Thorac Cardiovasc Surg
(1994) - et al.
Fall in vital capacity with posture
Br J Dis Chest
(1985) - et al.
Mechanical ventilation beyond the intensive care unit: report of a consensus conference of the American College of Chest Physicians
Chest
(1998) Diaphragmatic paresis: pathophysiology, clinical features and investigation
Thorax
(1989)The respiratory system in muscular dystrophy
Br Med Bull
(1980)- et al.
Diaphragmatic paralysis in motor neuron disease
Neurology
(1978) - et al.
Diaphragm function and alveolar hypoventilation
Q J Med
(1976) - et al.
Assessment of diaphragm weakness
Am Rev Respir Dis
(1988) - et al.
Diaphragm dysfunction induced by upper abdominal surgery
Am Rev Respir Dis
(1983)
Cited by (0)
- ☆
No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated.
- ☆☆
Reprint requests to Dr. Frédéric Lofaso, Service de Physiologie-Explorations Fonctionnelles, Hôpital Raymond Poincaré, 92380 Garches, France, e-mail: [email protected].
- NO LABEL
a. ABL 330; Radiometer Medical A/S, DK 2700 Brønshøj, Denmark.
- NO LABEL
b. Model DP45 Low Pressure Transducer; Validyne Engineering Corp, 8626 Wilbur Ave, Northridge, CA 91324.
- NO LABEL
c. Marquat Gbm, BP11, 94471 Boissy-St. Leger Cedex, France.