Abstract
Increased end-expiratory lung volume (EELV) and airway resistance are both characteristic features of obstructive lung disease. Increased EELV alone loads the respiratory muscles and may cause respiratory failure, changes that could be reversed by continuous positive airway pressure (CPAP). To study the effects of elevated EELV on respiration without increased airway resistance, we used a mechanical analogue of airway closure to increase EELV in six spontaneously breathing anesthetized dogs. Hyperinflation of 0.84 ± 0.11 liter for 30 min decreased minute ventilation from 4.8 ± 0.37 to 3.5 ± 0.21 l/min and increased arterial PCO2 from 40.3 ± 1.5 to 73.2 ± 8.1 Torr (both P <0.01). Inspiratory work per breath increased 3-fold, work per liter increased 3.7-fold, and work per minute increased 2.8-fold (all P <0.01). CPAP at 15 cmH2O restored minute ventilation to 4.3 ± 0.3 l/min and reduced arterial PCO2 to 54 ± 6.6 Torr (NS vs. baseline). All measurements of inspiratory work were also restored to baseline, but cardiac output was reduced (baseline 3.09 ± 0.36, hyperinflation 2.71 ± 0.36, hyperinflation + CPAP 1.94 ± 0.29 l/min; P <0.05, baseline vs. hyperinflation + CPAP). We conclude that increases in EELV mimic important features of airway obstruction, increase inspiratory work, and can cause respiratory failure independent of increased airway resistance. This respiratory failure is reversed by CPAP at the potential expense of hemodynamic compromise.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 819-827 |
| Number of pages | 9 |
| Journal | Journal of Applied Physiology |
| Volume | 77 |
| Issue number | 2 |
| State | Published - 1994 |
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Keywords
- continuous positive airway pressure
- hypercapnia
- pleural pressure
- ventilation
ASJC Scopus subject areas
- Endocrinology
- Physiology
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation
Cite this
Effects of hyperinflation and CPAP on work of breathing and respiratory failure in dogs. / Shade, E.; Kawagoe, Y.; Brower, Roy G; Permutt, S.; Fessler, Henry Eric.
In: Journal of Applied Physiology, Vol. 77, No. 2, 1994, p. 819-827.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effects of hyperinflation and CPAP on work of breathing and respiratory failure in dogs
AU - Shade, E.
AU - Kawagoe, Y.
AU - Brower, Roy G
AU - Permutt, S.
AU - Fessler, Henry Eric
PY - 1994
Y1 - 1994
N2 - Increased end-expiratory lung volume (EELV) and airway resistance are both characteristic features of obstructive lung disease. Increased EELV alone loads the respiratory muscles and may cause respiratory failure, changes that could be reversed by continuous positive airway pressure (CPAP). To study the effects of elevated EELV on respiration without increased airway resistance, we used a mechanical analogue of airway closure to increase EELV in six spontaneously breathing anesthetized dogs. Hyperinflation of 0.84 ± 0.11 liter for 30 min decreased minute ventilation from 4.8 ± 0.37 to 3.5 ± 0.21 l/min and increased arterial PCO2 from 40.3 ± 1.5 to 73.2 ± 8.1 Torr (both P <0.01). Inspiratory work per breath increased 3-fold, work per liter increased 3.7-fold, and work per minute increased 2.8-fold (all P <0.01). CPAP at 15 cmH2O restored minute ventilation to 4.3 ± 0.3 l/min and reduced arterial PCO2 to 54 ± 6.6 Torr (NS vs. baseline). All measurements of inspiratory work were also restored to baseline, but cardiac output was reduced (baseline 3.09 ± 0.36, hyperinflation 2.71 ± 0.36, hyperinflation + CPAP 1.94 ± 0.29 l/min; P <0.05, baseline vs. hyperinflation + CPAP). We conclude that increases in EELV mimic important features of airway obstruction, increase inspiratory work, and can cause respiratory failure independent of increased airway resistance. This respiratory failure is reversed by CPAP at the potential expense of hemodynamic compromise.
AB - Increased end-expiratory lung volume (EELV) and airway resistance are both characteristic features of obstructive lung disease. Increased EELV alone loads the respiratory muscles and may cause respiratory failure, changes that could be reversed by continuous positive airway pressure (CPAP). To study the effects of elevated EELV on respiration without increased airway resistance, we used a mechanical analogue of airway closure to increase EELV in six spontaneously breathing anesthetized dogs. Hyperinflation of 0.84 ± 0.11 liter for 30 min decreased minute ventilation from 4.8 ± 0.37 to 3.5 ± 0.21 l/min and increased arterial PCO2 from 40.3 ± 1.5 to 73.2 ± 8.1 Torr (both P <0.01). Inspiratory work per breath increased 3-fold, work per liter increased 3.7-fold, and work per minute increased 2.8-fold (all P <0.01). CPAP at 15 cmH2O restored minute ventilation to 4.3 ± 0.3 l/min and reduced arterial PCO2 to 54 ± 6.6 Torr (NS vs. baseline). All measurements of inspiratory work were also restored to baseline, but cardiac output was reduced (baseline 3.09 ± 0.36, hyperinflation 2.71 ± 0.36, hyperinflation + CPAP 1.94 ± 0.29 l/min; P <0.05, baseline vs. hyperinflation + CPAP). We conclude that increases in EELV mimic important features of airway obstruction, increase inspiratory work, and can cause respiratory failure independent of increased airway resistance. This respiratory failure is reversed by CPAP at the potential expense of hemodynamic compromise.
KW - continuous positive airway pressure
KW - hypercapnia
KW - pleural pressure
KW - ventilation
UR - http://www.scopus.com/inward/record.url?scp=0027941102&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027941102&partnerID=8YFLogxK
M3 - Article
C2 - 8002534
AN - SCOPUS:0027941102
VL - 77
SP - 819
EP - 827
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
SN - 0161-7567
IS - 2
ER -