title: Relationship between PaO2 and lung volume during high frequency oscillatory ventilation.
abstract: The relationship between oxygenation and lung volume during high frequency oscillatory ventilation (HFOV) was studied. We ventilated anesthetized, tracheostomized adult rabbits that were rendered surfactant-deficient by lung lavage. Lung volume was measured by the 'disconnection technique'. In the first experiment, HFOV was commenced after conventional mechanical ventilation (CMV) for 1 hr. In the absence of sustained inflation (SI), oxygenation improved with time during HFOV. In the second experiment, HFOV was instituted after CMV for 4 hr. In the absence of SI, all animals expired during the experimental period. In the third experiment we ventilated rabbits for 4 hr and then switched to HFOV. We applied SI first and increased mean airway pressure (MAP) by increments of 2 cmH2O every 15 min. However, there was little improvement in PaO2 despite the use of repeated SI and the increase in MAP. We conclude that oxygenation has a linear relationship to lung volume during HFOV, and that secondary lung injury due to long-term CMV impairs the response to HFOV. Therefore, it is important to minimize the risk of such secondary injuries before instituting HFOV.
authors.affiliation: Department of Pediatrics, Saitama Medical School, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Papazoglou
authors.forename: A C
authors.initials: AC
authors.lastname: Bryan
mesh_terms: D000403:Airway Resistance; D000818:Animals; D001784:Blood Gas Analysis; D004195:Disease Models, Animal; D005069:Evaluation Studies as Topic; D006612:High-Frequency Ventilation / Q000592:standards*; D006801:Humans; D007231:Infant, Newborn; D008176:Lung Volume Measurements; D008297:Male; D011817:Rabbits; D012127:Respiratory Distress Syndrome, Newborn / Q000097:blood / Q000503:physiopathology / Q000628:therapy*