Chest wall hyperinflation during acute bronchoconstriction in asthma

• Published in: American journal of respiratory and critical care medicine Vol. 160; no. 3; pp. 808 - 816
• Main Authors: GORINI, M, IANDELLI, I, MISURI, G, BERTOLI, F, FILIPPELLI, M, MANCINI, M, DURANTI, R, GIGLIOTTI, F, SCANO, G
• Format: Journal Article
• Language: English
• Published: New York, NY American Lung Association 01-09-1999
• Subjects: Abdominal Muscles - physiopathology; Adult; Airway Resistance; Asthma - physiopathology; Biological and medical sciences; Bronchoconstriction; Chronic obstructive pulmonary disease, asthma; Forced Expiratory Volume; Histamine - administration & dosage; Humans; Lung Volume Measurements; Male; Medical sciences; Middle Aged; Oxygen - blood; Pneumology; Regression Analysis; Respiratory Mechanics; Signal Processing, Computer-Assisted; Thorax - physiopathology; Human; Bronchoconstriction; Hyperinflation; Pathophysiology; Respiratory disease; Bronchus disease; Obstructive pulmonary disease; Chest wall; Asthma
• ISSN: 1073-449X; 1535-4970
• DOI: 10.1164/ajrccm.160.3.9712088

The mechanics of the chest wall was studied in seven asthmatic patients before and during histamine-induced bronchoconstriction (B). The volume of the chest wall (VCW) was calculated by three-dimensional tracking of 89 chest wall markers. Pleural (Ppl) and gastric (Pga) pressures were simultaneously recorded. VCW was modeled as the sum of the volumes of the pulmonary-apposed rib cage (VRC,p), diaphragm-apposed rib cage (VRC,a), and abdomen (VAB). During B, hyperinflation was due to the increase in end-expiratory volume of the rib cage (0.63 +/- 0.09 L, p < 0.01), whereas change in VAB was inconsistent (0.09 +/- 0.07 L, NS) because of phasic recruitment of abdominal muscles during expiration. Changes in end-expiratory VRC,p and VRC,a were along the rib cage relaxation configuration, indicating that both compartments shared proportionally the hyperinflation. VRC,p-Ppl plot during B was displaced leftward of the relaxation curve, suggesting persistent activity of rib cage inspiratory muscles throughout expiration. Changes in end-expiratory VCW during B did not relate to changes in FEV(1) or time and volume components of the breathing cycle. We concluded that during B in asthmatic patients: (1) rib cage accounts largely for the volume of hyperinflation, whereas abdominal muscle recruitment during expiration limits the increase in VAB; (2) hyperinflation is influenced by sustained postinspiratory activity of the inspiratory muscles; (3) this pattern of respiratory muscle recruitment seems to minimize volume distortion of the rib cage at end-expiration and to preserve diaphragm length despite hyperinflation.