Chest
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Comparative Study
Differences in plethysmographic lung volumes. Effects of linked vs unlinked spirometry.
Determination of absolute lung volumes in patients is most reliable when measured with body plethysmography. Many laboratories use data obtained with a spirometer not directly linked to the plethysmograph to calculate total lung capacity (TLC) and residual volume (RV) from thoracic gas volume (Vtg) measured at functional residual capacity (FRC) in the plethysmograph. The reliability of these calculations depends on the stability of FRC between these separate devices. ⋯ The large-volume differences in TLC were often associated with differences in expiratory reserve volume (ERV) in the opposite direction, suggesting a shift in FRC. However, clinical diagnoses were infrequently (4/220) altered by these differences, and recognition of the shift in FRC should further reduce this error. Therefore, the unlinked method appears acceptable.
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The usefulness of telescoping plugged catheter (TPC) together with bronchoalveolar lavage (BAL) in the same bronchoscopic act in the diagnosis of pulmonary infiltrates was studied in 113 fiberoptic bronchoscopic examinations performed on 96 immunocompromised patients. The TPC cultures detected pulmonary bacterial infections in 25 (22 percent) cases but showed a high frequency of false positive results (12 microorganisms, 27 percent). Bronchoalveolar lavage had an overall diagnostic yield of 49 percent (53 of 113 cases). ⋯ The results obtained by both techniques allowed us to modify the treatment in 35 (31 percent) cases. Combined, TPC and BAL show a good diagnostic yield in immunocompromised patients with pulmonary infiltrates. Both techniques should be performed as the first approach in the evaluation of these patients, and be done in the same bronchoscopic procedure.
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We report our prospective experience with sensitivity, specificity, predictive values and efficiency of echocardiography in diagnosing AD involving the ascending aorta (type A). We studied two groups of patients with both echocardiography and aortography. Group 1 was made up by 46 consecutive patients with clinical suspicion of AD. ⋯ We conclude that the diagnostic usefulness of echocardiography in patients with suspected type A AD is limited by its moderate sensitivity and predictive positive value. Aortography remains the major step in diagnosis. Within these limitations, echocardiography is useful in confirmation of clinical suspicion if all three main echocardiographic signs are present (predictive positive value: 100 percent).
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A report of pulmonary edema following acute upper airway obstruction in an adult is presented, and the literature involving 25 additional cases is reviewed. This form of pulmonary edema appears to be related to markedly negative intrathoracic pressure due to forced inspiration against a closed upper airway resulting in transudation of fluid from pulmonary capillaries to the interstitium. ⋯ Aggressive diagnostic and therapeutic interventions may be avoided if the syndrome is recognized. Maintenance of oxygenation and a patent airway are the mainstays of treatment.
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A patient with right ventricular infarction and severe hypoxemia secondary to right-to-left shunting through a patent foramen ovale is presented. A balloon tip catheter was positioned in the left atrium and retracted against the atrial septum and the hypoxemia resolved.