Respiratory Care

After the FIO2 of mechanically ventilated patients is decreased, 30 minutes or more is often allowed to elapse before follow-up arterial blood gas (ABG) values are obtained. However, waiting this long to assess the PaO2 after an FIO2 reduction may subject the patient to unnecessary hypoxemia. Method: We compared the PaO2 at 10 minutes with that at 30 minutes after we lowered the FIO2 by 0.10 in 17 patients receiving mechanical ventilation. All the patients in our study required mechanical ventilation due to head injury associated with multiple trauma; none had chronic obstructive pulmonary disease (COPD). Results: There was no statistical difference between PaO2 at 10 minutes and that at 30 minutes after the FIO2 reduction (P = 0.39 by Student's paired t test). Conclusion: We conclude that in mechanically ventilated patients who do not have chronic underlying pulmonary disease, ABG values obtained 10 minutes after an FIO2 reduction of 0.10 are valid for the assessment of arterial oxygenation on the new FIO2. (Respir Care 1985;30:1037-1041.)

We investigated whether vital capacity (VC) and forced expiratory volumes in 1 and 3 seconds (FEV1, FEV3) were lower and whether respiratory symptoms were more common in chicken farmers exposed to occupational dusts than in community control subjects and whether smoking had a synergistic influence on the effects of the inhalation of occupational dusts by chicken farmers. Methods: Data were obtained retrospectively from spirometry and questionnaire records of 200 subjects randomly selected from approximately 10,000 persons' records. The 200 subjects were 50 smoking farmers, 50 nonsmoking farmers, 50 smoking controls, and 50 nonsmoking controls. For one part of the study we divided the subjects into two groups of 100 on the basis of occupation only, in order to study the effect of chicken farming independent of the effect of smoking. In another aspect of the study, we made comparisons among the four groups of 50. Results: The 100 farmers as a group had significantly lower FEV than did the 100 controls, but VC and FEV3 were not significantly different. The farmers had a significantly higher incidence of cough, shortness of breath, and chronic bronchitis, but the incidence of wheezing was not significantly different. The 100 smokers as a group had significntly lower VC, FEV1, and FEV3 and a significantly higher incidence of all symptoms. When the four groups of 50 were compared, their pulmonary function values ranked, from best to worst, in the following order: (1) nonsmoking controls, (2) nonsmoking farmers, (3) smoking controls, (4) smoking farmers. Comparison of symptoms among the four groups showed that the incidence of all symptoms was significantly higher in nonsmoking farmers than in nonsmoking controls, significantly higher in smoking controls than in nonsmoking farmers, significantly higher in smoking farmers than in nonsmoking controls, and significantly higher in smoking controls than in nonsmoking controls. The incidence of cough, shortness of breath, and chronic bronchitis (but not wheezing) was significantly higher in smoking farmers than in nonsmoking farmers. There was no significant difference in the incidence of symptoms or in VC, FEV1, or FEV3 between smoking farmers and smoking controls. Conclusions: Our study indicated that when compared to nonsmoking controls, nonsmoking chicken farmers had a higher incidence of respiratory symptoms but not significantly lower pulmonary function; that, in general, smoking farmers and smoking controls had a higher incidence of symptoms and lower pulmonary function values than did nonsmoking farmers and nonsmoking controls; but that in terms of incidence of symptoms and pulmonary function values, smoking farmers were not significantly worse off than smoking controls. However, a synergistic effect of cigarette smoke and the inhalation of farm dusts may take place in the small airways and thus remain undetected by "standard" pulmonary function tests. (Respir Care 1985;30:1042-1048.)

Pulmonary eosinophilic granuloma (EG) is a rare disease of unknown etiology typically presenting with mild symptoms of cough or dyspnea, which usually resolve spontaneously. However, occasional cases have a more fulminant course resulting in extensive lung destruction and respiratory failure. Chest radiographs characteristically demonstrate reticulonodular or cystic changes, and pneumothoraces complicate pulmonary EG in 10% to 20% of cases. No therapy has been shown to be effective. We report a previously healthy 19-year-old male who developed rapidly progressive respiratory failure and bilateral pneumothoraces due to pulmonary EG. Persistent alveolar leaks and recurrent pneumothoraces posed major management problems despite an aggressive surgical approach. During a 7-week hospitalization period, the patient required 21 thoracostomy tubes and underwent thoracotomy and surgical pleurodesis three times. The patient was discharged with full expansion of the left lung and a small right pneumothorax. In the months following discharge, despite two brief periods of rehospitalization due to enlargement of the right pneumothorax, his dyspnea lessened and his exercise tolerance gradually improved. One year after the onset of symptoms, he reported continued improvement and a chest radiograph showed fewer infiltrates and no evidence of pneumothorax or residual bullae. We suggest that an aggressive surgical approach is required for patients with pneumothorax complicating EG. We recommend a standard posterolateral thoracotomy to expose the entire pleural surface, the stapling and excision of all blebs and bullae, and the vigorous abrasion of the entire pleural surface. (Respir Care 1985;30:1049-1056.)

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