Am. J. Respir. Crit. Care Med., Vol 151, No. 3, Mar 1995, 743-750.
Inspiratory fall in systolic pressure in normal and asthmatic subjects
MD Goldman, M Mathieu, JM Montely, R Goldberg, JM Fry, JL Bernard and R Sartene
Medical College of Pennsylvania, Philadelphia.
We used a noninvasive monitor of arterial pressure to determine whether
respiratory changes in arterial pressure were closely correlated with
airflow obstruction in asthmatic patients during bronchial challenge with
methacholine. To validate the noninvasive measurement of respiratory
changes in arterial pressure, a preliminary study in 6 subjects with normal
cardiovascular and respiratory systems was done during cardiac
catheterization for suspected coronary artery disease. There were no
significant differences between inspiratory falls in systolic pressure
measured noninvasively and those measured from intraaortic pressure. In 11
otherwise healthy asthmatic patients we measured finger arterial pressure,
end-expiratory lung volume (FRC), and forced expired volume (FEV1) during
baseline and bronchial challenge in the supine posture. Finger arterial
pressure was also measured in 11 normal control subjects seated and supine.
Normal subjects had an inspiratory fall in systolic pressure (IFSP) of 3.2
mm Hg supine and 5.1 mm Hg seated (p < 0.01). Asthmatic patients when
bronchodilated (seated FEV1 = 83 +/- 7% of predicted) had an IFSP of 5.9 mm
Hg supine (p < 0.01 compared with supine normal subjects). During
bronchial challenge (average fall in FEV1 = 22%), IFSP increased to 16.1 mm
Hg (p < 0.001 compared with baseline). In asthmatic subjects, there was
a significant correlation between IFSP and FEV1 (mean r = -0.92 +/- 0.05, p
< 0.01), and the average change in IFSP/change in FEV1 was -0.38 mm Hg
per percentage change in FEV1. During subsequent bronchodilation, IFSP
decreased with a similar time course as relaxation of airway smooth muscle,
assessed by the breath-to- breath fall in FRC.(ABSTRACT TRUNCATED AT 250
WORDS)
