Chest
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In patients with blunt chest trauma, early diagnosis of mediastinal hematoma is important, because it could be associated with thoracic vessel injury. Mediastinal hematoma is generally evoked because of a widened mediastinum on chest radiograph, but radiologic diagnosis may lead to excessive angiography being performed. Transesophageal echocardiography (TEE) provides accurate views of the mediastinum and can be rapidly performed at the bedside. ⋯ We described three different TEE signs of mediastinal hematoma: (1) an increased distance between the probe and the aortic wall; (2) a double contour of the aortic wall; and (3) visualization of the ultrasound signal between the aortic wall and the visceral pleura. The distance between the esophageal probe and the aortic wall was the most accurate sign because it could be easily obtained; the threshold value for this distance was 3 mm. TEE appears to be an accurate method to diagnose traumatic mediastinal hematoma.
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Although nasal continuous positive airway pressure (CPAP) is effective in the treatment of most patients with obstructive sleep apnea (OSA), there is a small group of such patients in whom rapid eye movement (REM) hypoventilation and CO2 retention persist despite the use of CPAP and supplemental oxygen. In this report we describe our experience with nocturnal nasal ventilation (nocturnal nasal positive pressure ventilation [NIPPV] in such patients and its effectiveness in reversing daytime hypercapnia. Thirteen patients, aged 28 to 69 years, with severe OSA confirmed on polysomnography, failed to respond to initial CPAP therapy. ⋯ We believe this improvement is the result of improved central ventilatory drive. Short-term NIPPV provides lasting benefits allowing the majority of such patients to resume CPAP therapy. Short-term intervention with this therapy should be considered as an interim measure in patients with severe hypercapnic OSA who fail to respond to initial CPAP therapy.
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We successfully implemented the delivery of noninvasive mechanical ventilation for patients with acute respiratory failure, a previously controversial use of this technique, using a simplified ventilator (BiPAP) with nasal mask. Pilot work showed this mode of support to be effective when administered by the members of a research team, and in the current study we were able to transfer this responsibility to usual care providers. ⋯ Withdrawal of ventilatory support for greater than 48 h (successful outcome) was about the same during usual care (phase 3, 80 percent) as it was during special care (phase 1, 76 percent).
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Comparative Study
Respiratory muscle strength and hemodynamics in chronic heart failure.
To examine whether respiratory muscle weakness is associated with cardiac function and/or exercise capacity in chronic heart failure (CHF), 23 patients with CHF were evaluated with respiratory muscle strength, pulmonary function tests, cardiac catheterization, and exercise test. The subjects were divided into three groups on their New York Heart Association (NYHA) functional class. Group A consisted of 13 patients with NYHA functional classification class 3 or 4, group B consisted of 10 patients with NYHA classification class 2, and group C consisted of 15 age-matched normal controls. ⋯ PImax in group A was significantly less than that in group B or C, although PImax in group B was not significantly different from that in group C. In the patients with CHF, PImax correlated positively with cardiac index and maximal oxygen consumption (r = 0.460 and r = 0.503, p < 0.05, respectively). These findings suggest that inspiratory muscle strength, which was impaired in patients with severe CHF, may be dependent on cardiac function and may be one of the limiting factors on impaired exercise capacity in the patients with CHF.