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Surfactant dysfunction makes lungs vulnerable to repetitive collapse and reexpansion
1Department of Clinical Physiology, University Hospital of Lund, Sweden.
American Journal of Respiratory and Critical Care Medicine
|January 1, 1997
Summary
Negative end-expiratory pressure (NEEP) causes lung injury when surfactant is perturbed. This study shows that surfactant-damaged lungs are vulnerable to damage from repeated lung collapse and reexpansion (RECOREX) via NEEP.
Area of Science:
- Pulmonary physiology
- Respiratory medicine
- Critical care
Background:
- Lung reexpansion generates intrapulmonary shear forces.
- Negative end-expiratory pressure (NEEP) can induce lung collapse and reexpansion (RECOREX).
- Surfactant dysfunction is implicated in acute lung injury.
Purpose of the Study:
- To investigate the effects of NEEP-induced RECOREX on lungs with surfactant perturbation.
- To compare NEEP-induced RECOREX with positive-end expiratory pressure (PEEP) ventilation in a surfactant-perturbed lung model.
Main Methods:
- Rabbit lungs were exposed to dioctyl sodium sulfosuccinate (DOSS) to model surfactant perturbation.
- Animals underwent either NEEP-induced RECOREX or PEEP ventilation for 3 hours.
- Lung mechanics, gas exchange, and histology were assessed.
Main Results:
- PEEP ventilation maintained normal lung function and morphology, even with DOSS pretreatment.
- NEEP-induced RECOREX caused lung injury, disturbed mechanics, and impaired gas exchange in DOSS-treated rabbits.
- Histologic damage was dose-related to DOSS and persistent.
- NEEP alone without DOSS did not cause significant lung damage.
Conclusions:
- Surfactant system perturbation renders lungs vulnerable to injury from NEEP-induced RECOREX.
- The combination of surfactant inactivation and increased shear forces may cause lung damage.
- These findings suggest mechanisms relevant to lung injury in respiratory distress syndrome.