Am. J. Respir. Crit. Care Med., Vol 155, No. 3, 03 1997, 1080-1084.
Respiratory muscle dysfunction associated with human immunodeficiency virus infection
L Schulz, HN Nagaraja, N Rague, J Drake and PT Diaz
Department of Internal Medicine, College of Medicine, Ohio State University, Columbus, USA.
Although skeletal muscle abnormalities have been described in association
with human immunodeficiency virus (HIV), the effects of HIV infection on
respiratory muscle function have not been well characterized. We
hypothesized that HIV+ individuals may develop respiratory muscle weakness
and that respiratory muscle dysfunction may contribute to the unexplained
dyspnea that occurs in the setting of HIV. To test this hypothesis we
studied maximal inspiratory pressure (MIP), maximal expiratory pressure
(MEP), inspiratory muscle endurance, and respiratory symptoms in 23 HIV+
male outpatients who had no history of acquired immune deficiency syndrome
(AIDS)-related pulmonary complications, with a CD4+ T-lymphocyte count of
331.6 +/- 62.1 (mean +/- SEM). Respiratory muscle endurance was measured
with an incremental threshold loading (ITL) protocol. We compared these
results to those for 14 HIV- males matched for age and weight. Compared
with the controls, HIV+ subjects had a significantly lower mean MIP (98.7
+/- 7.4 versus 121.4 +/- 9.3 cm H2O, p < 0.05) and MEP (115.0 +/- 9.3
versus 152.1 +/- 14.8 cm H2O, p < 0.05). Furthermore, during ITL, the
mean load at task failure in the HIV+ group was 295.7 +/- 36.2 g, versus
405.8 +/- 52.2 g in the control group (p < 0.05). In the HIV+ subjects
there was no relationship between muscle performance and CD4+ count or
azidothymidine (AZT) use. There was, however, a highly significant
relationship between respiratory muscle dysfunction and symptoms of
dyspnea. We conclude that HIV seropositivity is associated with a decline
in respiratory muscle performance. This impairment in respiratory muscle
function may contribute to the feeling of breathlessness that has been well
described in this patient population.
