The American review of respiratory disease
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Am. Rev. Respir. Dis. · May 1986
Risk factors for pneumonia and fatality in patients receiving continuous mechanical ventilation.
We studied risk factors for nosocomial pneumonia and fatality in 233 intensive care unit patients requiring continuous mechanical ventilation. Ventilator-associated pneumonia was diagnosed in 49 (21%) of the 233 patients. ⋯ Ventilator-associated pneumonia was 1 of 18 variables univariately associated with overall patient fatality, but it was not among the 7 variables present after multivariate analysis. The data delineate risk factors associated with the development of nosocomial pneumonia and fatality in patients receiving continuous mechanical ventilation.
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Am. Rev. Respir. Dis. · Apr 1986
Effect of flow rate on blood gases during constant flow ventilation in dogs.
We studied the effect of flow rate (V) on arterial blood gases during constant flow ventilation (CFV) in 9 anesthetized, paralyzed dogs weighing 9.5 to 26.5 kg. The constant flow was administered through catheters placed in each mainstem bronchus. Alveolar ventilation increased linearly with increasing V over the range of 0.18 to 1.0 L/s but was relatively constant at flows above 1.0 L/s. ⋯ However, we did not find any significant relationship between body weight and the V required for normocapnia. At all flow rates we found a relatively large alveolar to arterial oxygen difference (48.9 +/- 8.8 mmHg, mean +/- SD), suggesting significant inhomogeneities in ventilation-perfusion. Our data are consistent with a 2-zone model of gas exchange where gas exchange is dominated by bidirectional convective streaming in the airways closest to the jets, cardiogenic induced flows in the most peripheral airways, and jet-induced turbulence in those airways between these 2 regions.
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Am. Rev. Respir. Dis. · Apr 1986
The dead space to tidal volume ratio in the diagnosis of pulmonary embolism.
In order to assess the value of the measurement of the physiologic dead space (VD) to tidal volume (VT) ratio in pulmonary embolism (PE), a prospective study was performed in hospital inpatients suspected to have PE (n = 110; mean age +/- SD, 52.2 +/- 15.5 yr). In 16 of 29 patients in whom the diagnosis of PE was excluded on the basis of a normal radioisotope perfusion scan and/or normal pulmonary angiogram, VD/VT was less than 40%; in the other 13 patients, a VD/VT greater than 40% was associated with an abnormal spirogram. In all patients in whom PE was angiographically diagnosed (n = 16), VD/VT was greater than 40%. ⋯ These data indicate that a VD/VT value of less than 40% makes the diagnosis of PE extremely unlikely, whereas VD/VT value greater than 40% in the presence of a normal spirogram is highly suggestive of PE. The diagnostic sensitivity of a VD/VT greater than 0.4 with a normal spirogram as a positive test of PE, and a VD/VT less than 0.4 excluding the diagnosis of PE was 100%, whereas the specificity was 94%; applying Bayesian analysis, the probability of a correct diagnosis of PE using these criteria in a similar population would be 90.5%, and of excluding PE, 96.7%. Thus, as a diagnostic test in PE, VD/VT measurement is comparable, in terms of sensitivity and specificity, to radioisotope lung scanning.
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Am. Rev. Respir. Dis. · Apr 1986
The relationship between pleural pressures and changes in pulmonary function after therapeutic thoracentesis.
The purpose of this study was to determine whether changes in pulmonary function after therapeutic thoracentesis are related to the pleural pressure or to changes in pleural pressure during thoracentesis. Spirometry was obtained before and 24 h after thoracentesis in 26 patients. Pleural pressures were measured with a U-shaped manometer initially and after each 400-ml aliquot of pleural fluid was removed. ⋯ The ratio of the improvement in the VC to the amount of fluid removed most closely correlated with the pressure change after 800 ml fluid had been removed (r = -0.43, p less than 0.05). From this study we conclude that the improvement in the FVC after therapeutic thoracentesis is small relative to the amount of fluid withdrawn. Patients with higher pleural pressures after the removal of 800 ml pleural fluid and patients with smaller decreases in the pleural pressure after removal of 800 ml pleural fluid have greater improvements in their pulmonary functions after thoracentesis.
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Numerous pharmacologic agents used in the treatment of cancer have been linked to pulmonary toxic side effects. Mechanisms of damage by these drugs include direct pulmonary toxicity and indirect effects through enhancement of inflammatory reactions. ⋯ Treatment and outcome vary with each particular agent. In Part 1 of this review, clinical aspects and pathogenic mechanisms of cytotoxic drug-induced pulmonary disease are discussed.