The American review of respiratory disease
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Am. Rev. Respir. Dis. · Apr 1990
Lung structure and gas exchange in mild chronic obstructive pulmonary disease.
To investigate the influence of pulmonary emphysema and small airways abnormalities on ventilation-perfusion (VA/Q) mismatching in mild chronic obstructive pulmonary disease (COPD), we studied 23 patients (mean predicted FEV1, 76 +/- 15%) before lung resection because of a localized neoplasm. Respiratory gas exchange and VA/Q distributions were measured while the patients breathed room air and 100% O2. Breathing room air, the AaPO2 was moderately increased (25 +/- 12 mm Hg) as was VA/Q mismatching, indicated by the dispersion (log SD) of both blood flow (Q) and ventilation (V) distributions (log SD Q, 0.78 +/- 0.3; and log SD V, 0.66 +/- 0.28, respectively) (normal range, 0.3-0.6). ⋯ During 100% O2 breathing there was an increase in VA/Q mismatching (log SD Q rose to 1.12 +/- 0.08, p less than 0.001), suggesting release of hypoxic pulmonary vasoconstriction. This increase in VA/Q inequality was not significantly related to the severity of lung pathologic findings. We conclude that, in mild COPD, both pulmonary emphysema and small airways abnormalities contribute to VA/Q mismatch, the severity of emphysema being the major morphologic correlate of the increase in AaPO2.
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Am. Rev. Respir. Dis. · Apr 1990
Long-term effects of treatment with nasal continuous positive airway pressure on daytime lung function and pulmonary hemodynamics in patients with obstructive sleep apnea.
Fifty-four patients with obstructive sleep apnea (OSA) syndrome received long-term treatment with nasal continuous positive airway pressure (CPAP). The effects on daytime lung function and pulmonary hemodynamics were prospectively evaluated by repeating pulmonary function tests, including right heart catheterization after a follow-up period of at least 1 yr (554 +/- 28 days, mean +/- SEM). PaO2 increased in the patient group as a whole from 69.9 +/- 1.4 to 72.8 +/- 1.4 mm Hg (p less than 0.02). ⋯ Both the red blood cell count and the hematocrit decreased significantly, from 5,347 +/- 90 to 5,024 +/- 61 10(3)/mm3 and from 49.4 +/- 0.9 to 47.1 +/- 0.6%, p less than 0.001 and p less than 0.02, respectively. No change was observed in the resting pulmonary arterial pressure. We conclude that nasal CPAP is effective in improving daytime blood gases in patients with OSA.
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Am. Rev. Respir. Dis. · Mar 1990
Randomized Controlled Trial Comparative Study Clinical TrialExercise tolerance during nasal cannula and transtracheal oxygen delivery.
Previous studies have reported that exercise tolerance improves with transtracheal oxygen delivery. However, patients were not blinded to the delivery technique used, introducing a potential source of bias. The purpose of this study was to compare exercise tolerance during nasal cannula and transtracheal delivery using a randomized double-blinded technique. ⋯ We conclude that exercise tolerance improves when oxygen is delivered by transtracheal catheter. This improvement is unrelated to an increase in SaO2. We speculate that the increase in exercise tolerance may be related to other physiologic effects of flow through the catheter.
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Am. Rev. Respir. Dis. · Mar 1990
Clinical Trial Controlled Clinical TrialAcute and long-term amiloride inhalation in cystic fibrosis lung disease. A rational approach to cystic fibrosis therapy.
Cystic fibrosis (CF) is the most common inherited fatal disorder among Caucasians. Bronchial mucus in CF contains more potassium and less sodium, which may be due to increased sodium absorption, resulting in a reduced airway water content. We studied 23 patients with CF after inhalation of normal saline or amiloride (10(-3) M), a sodium transport blocker. ⋯ Sputum filance values also decreased significantly after amiloride inhalation. There were no adverse effects of the amiloride inhalation compared with saline. We conclude that amiloride inhalation administered as a single dose or as long-term therapy is able to increase MC and CC in CF airways and that the effect of 10(-3) M amiloride inhalation on MC lasts at least 40 min. (ABSTRACT TRUNCATED AT 250 WORDS)
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Am. Rev. Respir. Dis. · Mar 1990
Comparative StudyOxygen delivery and consumption and ventricular preload are greater in survivors than in nonsurvivors of the adult respiratory distress syndrome.
In patients with adult respiratory distress syndrome (ARDS), oxygen consumption (VO2) is pathologically dependent on oxygen delivery (DO2). Because of alterations in ventricular function, DO2 may be inadequate to satisfy oxygen demand and may contribute to multiple-system organ failure (MSOF). To determine whether there are differences in DO2, VO2, ventricular function, and MSOF, between survivors and nonsurvivors of ARDS, we studied 29 patients without cardiac disease early in the course of ARDS (hypoxemia, diffuse bilateral pulmonary infiltrates, and pulmonary artery occlusion pressure less than 18 mm Hg). ⋯ There were no differences between survivors and nonsurvivors in biventricular ejection fractions. We conclude that survivors of ARDS have greater DO2 and VO2 than do nonsurvivors. Survival may be explained by the strong inverse relation between DO2 and development of MSOF.(ABSTRACT TRUNCATED AT 250 WORDS)