Hyperoxia exacerbates microvascular lung injury following acid aspiration
| Autor: | Paul R. Knight, Bruce A. Davidson, N. Nader-Djalal, Kent J. Johnson |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Pulmonary and Respiratory Medicine
Male ARDS Time Factors medicine.medical_treatment Pulmonary compliance Lung injury Hyperoxia Critical Care and Intensive Care Medicine Pneumonia Aspiration Gastric Acid medicine Animals Prospective Studies Saline Lung Lung Compliance Respiratory Distress Syndrome Blood-Air Barrier business.industry Rats Inbred Strains Hydrogen-Ion Concentration medicine.disease Capillaries Rats Specific Pathogen-Free Organisms medicine.anatomical_structure Anesthesia Arterial blood Gastric acid medicine.symptom Cardiology and Cardiovascular Medicine business |
| Zdroj: | Chest. 112(6) |
| ISSN: | 0012-3692 |
| Popis: | To examine the effects of an increase in ambient oxygen (O2) concentrations on the extent of inflammatory pulmonary damage following acid aspiration.Prospective, controlled laboratory study.University-affiliated animal research facility.Male, Long Evans rats weighing 250 to 300 g.Rats were injured by instillation of 1.2 mL/kg normal saline solution/HCl, pH= 1.25 (acid), into the lungs via a tracheotomy. Animals were allowed to awaken and were exposed to 21%, 50%, or 98% O2 for 0 to 5 h (n/groupor = 10). In a separate set of experiments, injured rats exposed to 98% O2 were treated with different doses of deferoxamine, just prior to injury. Uninjured rats and rats injured with normal saline solution, pH = 5.3, were used as the control group.Injury was determined by assessing lung function (lung compliance and arterial blood gases) and alveolar-capillary wall integrity (wet/dry weight, lung albumin permeability index [PI], and intrapulmonary hemorrhage [HI]).Intrapulmonary instillation of acid increased PI, HI, and decreased static lung compliance compared to uninjured control animals. Increased ambient oxygen following acid aspiration decreased lung compliance, 1.06+/-0.03 mL/kg/cm H2O, in oxygen-exposed lungs when compared to the lungs exposed to air, 1.26+/-0.04, following a low pH aspirate (p0.05). An increase in protein leakage into the lung tissue was noted in oxygen-exposed animals, PI=1.33+/-0.10, vs air-exposed rats, 0.89+/-0.07 (p0.05). The hyperoxia-induced increase in lung injury was prevented by 30 mg/kg or higher deferoxamine treatment, 0.78+/-0.05 (p0.05). Exposure of animals to 98% O2 for 2 h was sufficient to produce the same increase in microvascular protein leakage as 5-h exposure to O2 following low pH aspirate.Hyperoxia increases acid aspiration-induced inflammatory microvascular lung injury. This appears to be mediated by production of reactive species of O2. |
| Databáze: | OpenAIRE |
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