Chest
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Randomized Controlled Trial Comparative Study Clinical Trial
Cardiorespiratory effects of pressure-controlled ventilation with and without inverse ratio in the adult respiratory distress syndrome.
To assess the cardiorespiratory effects of pressure-controlled ventilation (PCV) and pressure-controlled inverse ratio ventilation (PC-IRV), we compared pressure-controlled ventilation with an inspiratory-to-expiratory time ratio (I/E) of 1/2 (PCV) and of 2/1 (PC-IRV) to volume-controlled ventilation (VCV) with an I/E of 1/2 in 10 patients suffering from the adult respiratory distress syndrome. In all modes, the inspiratory oxygen fraction, tidal volume, respiratory rate, and total positive end-expiratory pressure (PEEPt = applied PEEP + intrinsic PEEP) were kept constant. Each ventilatory mode was applied for 1 h in a randomized order. ⋯ As a consequence of this increased mPaw, PC-IRV induced a decrease in cardiac index (CI) (3.3 +/- 0.2 vs 3.7 +/- 0.2 L/min/m2 in VCV; p < 0.05) and hence in oxygen delivery (DO2) (424 +/- 28 vs 469 +/- 38 ml/min/m2 in VCV; p < 0.05). Our results suggest that neither PCV nor PC-IRV bring any benefit over VCV in terms of arterial oxygenation. Moreover, the increase in mPaw induced by PC-IRV may be deleterious to the CI and DO2.
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To evaluate the usefulness of transesophageal echocardiography (TEE) in the treatment of critically ill patients, 80 patients (51 male and 29 female; mean age, 53 years) undergoing both transthoracic echocardiography (TTE) and TEE were studied in a 2-year period. Of these, 48 patients were studied in the ICU, while the other 32 patients were directly referred from the emergency departments. Indications for the study included suspected aortic dissection (34 patients), hemodynamic instability (22 patients), suspected cardiac source of embolism (11 patients), evaluation of the severity of mitral regurgitation (7 patients), and suspected infective endocarditis (6 patients). ⋯ Transesophageal echocardiography provided critical information that was not obtained by TTE in 39 of 78 studies (50 percent, p < 0.005). Cardiac surgery was prompted by TEE findings in 14 patients (18 percent) and these findings were all confirmed at operation. Transesophageal echocardiography was a safe, well-tolerated, and valuable diagnostic approach for the rapid detection of specific cardiac abnormalities in patients with critical illness; TEE should be considered in the treatment of critically ill patients especially when TTE provided inadequate information.
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Mortality of the adult respiratory distress syndrome (ARDS) remains high and could be increased by pulmonary barotrauma induced by positive-pressure mechanical ventilation. Extracorporeal CO2 removal combined with low-frequency positive-pressure ventilation (ECCO2R-LFPPV) has been proposed to reduce lung injury while supporting respiratory failure. ⋯ Bleeding was the only complication related to the technique and was the cause of death in four patients. This method allowed improvement in gas exchange along with reduction of the risk of barotrauma caused by the ventilator.
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Recent studies have used preoperative cardiopulmonary exercise testing to improve risk assessment of pulmonary resection for lung cancer. These studies have demonstrated inconsistent correlation between peak oxygen uptake (VO2) and postoperative complications but have not systematically examined other methods of risk stratification. We analyzed the findings in 42 patients who had cardiopulmonary exercise testing prior to lung cancer resection. ⋯ We conclude that both the peak VO2 during cardiopulmonary exercise testing and a multifactorial CPRI are highly predictive of complications after lung resection. Adding the peak VO2 did not enhance the risk estimation generated by the CPRI. The association between postoperative complications and peak VO2 may be explained by the correlation between identifiable cardiopulmonary disease (CPRI) and reduced oxygen uptake with exercise.
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The purpose of this study was to determine if sigh breaths delivered during pressure support ventilation (PSV) were beneficial in maintaining arterial oxygenation (PaO2) and pulmonary mechanics. Ten patients being weaned from mechanical ventilation in the PSV mode were studied. All patients were ventilated for 4 h without sighs, 4 h with sighs, and again for 4 h without sighs. ⋯ At the end of each 4-h period, an arterial blood gas determination was obtained. There were no statistically significant differences in any of the measured variables during the different periods of ventilation. We conclude that the sigh breath is of no benefit during PSV.