Chest
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Neutrophils are delayed in transit in the pulmonary circulation during smoking which could reflect smoke-induced changes in local hemodynamics. The purpose of this study was to measure the changes in pulmonary hemodynamics during cigarette smoking in both healthy smokers and patients with COPD with and without pulmonary hypertension. ⋯ However, pulmonary vascular resistance fell. These changes in pulmonary hemodynamics during cigarette smoking could not account for the increased neutrophil sequestration that has been observed previously in the lungs during smoking.
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Comparative Study
Performance of a reservoir nasal cannula (Oxymizer) during sleep in hypoxemic patients with COPD.
To determine whether a reservoir nasal cannula (RNC) (Oxymizer) provides an arterial hemoglobin oxygen saturation as measured by pulse oximetry (SpO2) equivalent to that provided by the standard nasal cannula (SNC) during sleep in hypoxemic patients with COPD while reducing oxygen flow requirement and cost. ⋯ The difference of 2 percent in mean SpO2 is within the range of SpO2 measurement error. Therefore, the two devices are equally effective when the sample is considered as a whole. Nighttime oximetry is necessary prior to prescription, since nighttime efficacy of the RNC cannot be predicted on the basis of daytime pulse oximetry.
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Randomized Controlled Trial Clinical Trial
A computer-controlled ventilator weaning system. A clinical trial.
The purpose of this study was to determine if a computer-directed weaning system could wean patients with complex medical problems from mechanical ventilation and appropriately respond to signs of respiratory failure more effectively than traditional physician-directed weaning methods. In a prospective, randomized, controlled study, we tested the system in 15 patients who had required prolonged mechanical ventilation and met predetermined weaning tests. Patients were randomly assigned to one of two groups: (1) automatic, computer-directed weaning or (2) physician-controlled weaning. ⋯ The number of arterial blood gas samples drawn during the study was 1.4 +/- 0.7 for the computer group, 7.2 +/- 4.3 for the control group. The number of minutes per hour outside acceptable limits of RR > 30, RR < 8, or TV < 5 ml/kg was 3.2 +/- 2.8 min for the computer group and 6.6 +/- 4.1 min for the control group. The study suggests that use of the computer-directed weaning system results in fewer arterial blood gas samples, shorter weaning times, and less time spent outside acceptable RR and TV parameters.