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The effect of lung mechanics on gas transport during high‐frequency oscillation
Author(s) -
Schindler Margrid,
Seear Michael
Publication year - 1991
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.1950110410
Subject(s) - saline , lung , medicine , respiratory physiology , oxygenation , tidal volume , respiratory system , anesthesia , mean airway pressure , lung volumes , oxygen tension , oxygen , cardiology , chemistry , organic chemistry
With the general aim of obtaining clinically relevant information on the use of high‐frequency oscillation (HFO), we examined the effects of altering oscillatory frequency (f), tidal volume (V T ), and mean airway pressure (P aw ) on gas exchange in rabbits, both before and after altering the animal's pulmonary mechanics by saline induced lung injury. Twenty‐seven combinations of f (5,8,12 Hz), V T (0.5, 1,2 mL/kg), and P aw (5, 10, 13 cm H 2 O) were used. Acute pulmonary injury was induced by instilling 10 mL/kg of warm saline into the lung. Gas exchange was assessed by steady‐state levels of arterial oxygen tension (Pa O 2) and carbon dioxide tension (Pa CO 2). Arterial Pa O 2was independent of f or V T before or after lung injury; it was independent of P aw before injury but highly dependent on P aw after lavage. The difference was presumably related to lung volume recruitment. Arterial Pa CO 2was dependent on f and V T but independent of P aw at any time. The relationship was modeled by the equation Pa CO 2∝ f a · V T b where the exponents a = −0.4 and b = −0.6. Our technique of a standardized saline instillation gave a reproducible and stable model of lung injury. In damaged rabbit lungs the principles of HFO appear to be similar to conventional mechanical ventilation: oxygenation depends on P aw and inspired oxygen concentration, while CO 2 removal is determined by f and V T .