Chest
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Case Reports
Upper airway obstruction due to inhalation of a tracheal T-tube resulting in pulmonary edema.
Acute upper airway obstruction may present with pulmonary edema. Following is a report of pulmonary edema secondary to acute upper airway obstruction due to inhalation of a Montgomery tracheal T-tube. The principal factor causing pulmonary edema is the generation of large negative transpulmonary pressures. This may be enhanced by changes in the cardiovascular function due to the Müller maneuver.
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Comparative Study
Evaluation of cardiac output by thoracic electrical bioimpedance during exercise in normal subjects.
We compared cardiac output determined simultaneously by two methods, the CO2 rebreathing technique and the thoracic electrical bioimpedance method (Bomed NCCOM-3 equipment). The studies were performed in duplicate in 11 healthy male subjects at rest and during three levels of steady-state exercise on a cycle ergometer at 60, 120, and 180 W. Cardiac output at 60 and 120 W was slightly lower (p less than 0.01) by the thoracic impedance method (12.2 +/- SE 2.2 and 15.7 +/- SE 3.5 L/min, respectively) than by the CO2 rebreathing method (14.0 +/- SE 2.1 and 17.9 +/- SE 3.0 L/min, respectively), suggesting a systematic bias between the two methods of measurement. ⋯ Although the results were not significantly different between the two methods at rest and at 180 W, there was no acceptable agreement between the two methods probably because the CO2 rebreathing method at rest was more liable to show error due to the small arteriovenous CO2 difference, while the impedance method was less reliable at 180 W. Cardiac output by both methods correlated with O2 consumption, with the correlation being higher for cardiac output by the rebreathing method (r = 0.94) than for thoracic impedance (r = 0.88). The results suggest that the thoracic electrical bioimpedance method can be used for determination of cardiac output during mild or moderate levels of exercise in normal subjects.
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Review Case Reports
Relapsing fever associated with ARDS in a parturient woman. A case report and review of the literature.
We report a patient who survived acute respiratory failure associated with tick-borne relapsing fever in the third trimester of pregnancy. The fetus was delivered by cesarian section and did not have spirochetemia. The severity of the patient's illness may be related to the immunosuppressive effects of pregnancy.
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Low-flow continuous oxygen can lead to significant improvement in exercise capacity in selected patients with stable hypoxemic pulmonary disease. Although the mechanisms of improvement are incompletely understood, two tenable hypotheses are (1) the relief of hypoxic pulmonary vasoconstriction and (2) improved peripheral oxygen delivery. This prospective study was performed to examine these two hypotheses. ⋯ Increased exercise capacity in response to long-term O2 therapy is associated with increased O2 delivery not relief of hypoxic vasoconstriction (in terms of pressure or resistance or arterial elastance). Increased O2 delivery can accrue from both increased cardiac output and increased arterial O2 content. Increase in arterial O2 content is unique to O2 relative to all vasodilator drugs.