Chest
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The mechanical work on the lung required during spontaneous breathing with positive end-expiratory pressure (PEEP) was compared with different methods of continuous positive airway pressure (CPAP) in nine young healthy athletes (surfers) at levels of 5, 10, 15, and 20 cm H2O. At the level of 20 cm H2O, PEEP increased the mean total work per minute by 116 percent and the total work per liter by 121 percent. The percent increase rose linearly with the level of PEEP. ⋯ Use of PEEP did not increase the functional residual capacity (FRC) in these spontaneously breathing subjects. In contrast, CPAP resulted in a rise in FRC proportional to the level of CPAP. This suggests that CPAP must be applied in a manner that maintains Paw constant to provide optimal assistance to ventilation.
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Results of preoperative pulmonary function tests were evaluated in 106 patients who had major thoracic or upper abdominal cardiovascular surgery. These results were related to the occurrence of postoperative complications by comparison of pulmonary function data in patients with an ICU stay of less than 5 days versus patients with an ICU stay of greater than 5 days. However, quantitative analysis of several specific parameters of pulmonary function tests failed to reveal any difference in the incidence of postoperative complications between patients with modest versus severe preoperative dysfunction. ⋯ Abnormalities on pulmonary function tests were not the major determinants of use of preoperative respiratory therapy, and its use was unrelated to the length of stay postoperatively in the ICU. We conclude that prior to cardiovascular surgery, routine quantitation of clinically apparent pulmonary dysfunction may be of little value in predicting postoperative morbidity and much less important than careful clinical evaluation. When pulmonary function tests are performed in such patients, simple spirometric tests and arterial blood gas levels are adequate.
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A group of 157 patients with chronic obstructive pulmonary disease who were treated before surgery using a standardized pulmonary preparation underwent physiologic assessment both before and after the prophylactic program. The postoperative course of each patient also was evaluated to assess the incidence of respiratory morbidity and mortality. Although many physiologic values were statistically improved after the pulmonary preparation, most of the changes are of doubtful functional significance. ⋯ The single most reliable test for this purpose was the mean forced expiratory flow during the middle half of the forced vital capacity. The frequency of postoperative respiratory complications was related to the type of operation, with the highest incidence occurring in the group that had extensive upper-abdominal surgery. While the occurrence of these complications was significantly reduced in patients undergoing a standard preoperative pulmonary preparation, the explanation for the beneficial effect of this procedure is not apparent.
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Tuberculosis in Oriental immigrants is likely to be resistant to therapy with certain drugs. In 73 military dependents with positive cultures for tuberculosis who immigrated from six Asian countries, the tuberculosis was found to be resistant to isoniazid in 58 percent (42 patients), to streptomycin in 36 percent (26 patients), to p-amino-salicylic acid in 14 percent (ten patients), to rifampin in 7 percent (five patients), and to ethambutol in 7 percent (five patients). ⋯ Consideration of the high incidence of drug-resistant tuberculosis should be made in planning a program of treatment for these patients. Recognition of cultural differences may also be of value in the successful treatment of this difficult group of patients.