| Autor: |
OSHER, ALAN B., GOTHE, BARBARA, SIMMONS, D. H., WAYMOST, B., GREEN, H. |
| Zdroj: |
Pediatric Research (Ovid); September 1978, Vol. 12 Issue: 9 p923-926, 4p |
| Abstrakt: |
The physiologic effects of continuous positive airway pressure (CPAP) of 5,10,15, and 20 cm H2O during spontaneous ventilation were studied in six anesthetized dogs with simulated respiratory distress syndrome (RDS) induced by iv infusion of oleic acid and in three normal controls. After oleic acid, mean PaO2dropped to 63.6 ± 3.1 mm Hg while breathing 100 oxygen and mean shunt fraction was 48.3 ± 3.0. PaO2and shunt fraction improved significantly at the two highest levels of CPAP (e.g., PaO2271.3 ± 41.3 mm Hg and shunt fraction 17.8 ± 2.2 at 20 cm H2O CPAP). Mean mixed venous PO2rose from 37.4 ± 1.5 mm Hg with no CPAP to 60.8 ± 3.1 mm Hg at 20 cm H2O CPAP. Tissue oxygenation appeared to improve during CPAP, since cardiac output, oxygen delivery, and serum lactate were not significantly affected and mixed venous PO2rose significantly. However, significant hypoventilation occurred at all but the lowest level of CPAP, mean PaCO2rising from 44.1 ± 1.8 mm Hg with no CPAP to 77.6 ± 6.8 mm Hg at 20 cm H2O CPAP. The hypoventilation during CPAP is consistent with increased work of breathing due to a combination of decreased lung compliance and increased dead space ventilation due to rapid, shallow breathing. |
| Databáze: |
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