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Exhalation time effects on arterial and venous blood oxygen content and arterial P CO 2 during high frequency jet ventilation of surfactant‐depleted cats
Author(s) -
Johnston Jerrilyn,
Carlstrom Jeffrey R.,
Gonzalez Felipe,
Richardson Peter
Publication year - 1987
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.1950030107
Subject(s) - arterial blood , medicine , ventilation (architecture) , anesthesia , exhalation , arterial ph , venous blood , oxygen , blood flow , chemistry , mechanical engineering , engineering , organic chemistry
Since high frequency jet ventilation (HFJV) relies on lung mechanics for the passive removal of expiratory gas, one would predict that the time allowed for exhalation would have serious effects on cardiopulmonary function. To document these effects we lavaged the lungs of ten cats with 30 ml/kg of saline six times, then sampled arterial and venous blood while the animals were ventilated conventionally at 30 BPM and then with HFJV at 600 BPM, varying inspiratory/expiratory ratios (I/E) from 1:1 to 1:5. The animals breathed 100% O 2 throughout the study, and the mean airway pressure was held constant for each animal when the I/E was varied during HFJV. Decreasing the I/E from 1:1 to 1:5 during HFJV resulted in an increase of arterial oxygen content (Ca O 2) from 11.3 ± 1.2S E to 13.6 ± 1.2 ml O 2 /100 ml blood (P < 0.01), a decrease of Pa CO 2from 43 ± 6 to 27 ± 4 mm Hg, and an increase of alveolar to arterial oxygen gradient from 351 ± 49 to 377 ± 49 mm Hg. The ratio of systemic blood flow to oxygen consumption (Q̇/V̇ O 2) was similar during conventional ventilation and with HFJV at I/E of 1:1 (18.9 ± 3.7 vs 18.0 ± 2.9) but decreased when I/E was reduced to 1:5 during HFJV (13.9 ± 2.1). The ratio of the product of Ca O 2and Q̇ (systemic oxygen availability) to V̇ O 2(S O 2T/V̇ O 2) remained unchanged during all modes of ventilation (1.75 ± 0.15). The increase in Ca O 2observed when I/E was reduced from 1:1 to 1:5 during HFJV was counterbalanced by a decrease in Q̇/V̇ O 2such that S O 2T/V̇ O 2remained relatively constant. Pediatr Pulmonol 1987; 3:19–23 .