Chest
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With the aim of testing a method that allows increasing concentrations of oxygen to be administered to patients with severe hypoxemia and hypercapnia while avoiding the risk of increasing respiratory acidosis, we studied 17 male patients with advanced chronic obstructive pulmonary disease (COPD) and severe hypercapnic respiratory failure. During 6 h and on one day only, all patients were given intermittent negative pressure ventilation (INPV) together with oxygenation starting at a concentration of 24 percent and increasing to 30 percent. ⋯ One hour after INPV ended, the mean values of PaO2, PaCO2, oxygen saturation, and pH were also significantly better than prestudy values. We conclude that INPV and oxygen therapy with increasing oxygen flow could constitute an alternative option to intubation and mechanical ventilation in cases of severe hypercapnic respiratory failure due to advanced COPD.
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The velocity pattern of the blood flow in the pulmonary artery was investigated in an animal model of acute pulmonary hypertension. Nine anesthetized, open-chest dogs were embolized with polystyrene microspheres, and the velocity pattern of the blood flow in the pulmonary artery was studied with use of an invasive pulsed Doppler technique. Phasic intraluminal velocity was recorded with use of a miniature piezoelectric crystal activated by 20-MHz Doppler pulses and mounted on the tip of a needle probe introduced into the pulmonary artery. ⋯ A significant shortening in the time to peak velocity (acceleration time) was found (p less than 0.005). Second-order regression analyses demonstrated an inverse correlation between the ratio of positive velocity time to negative velocity time and the mean pulmonary artery pressure in all animals (r = 0.71). These findings should be compared with the velocity patterns of the blood flow in the pulmonary artery obtained under pulmonary hypertensive conditions due to various causes to facilitate interpretation and understanding of clinical investigations.
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Cardiopulmonary resuscitation (CPR) is often performed in modern critical care units, but its efficacy has not been evaluated in this setting. It is important to evaluate CPR in critical care units because these patients often have multisystem disorders and suffer from diseases reported to carry a poor outcome after CPR. Inappropriate resuscitation of patients in this setting results in increased cost of care (both financial and emotional), with little tangible benefit. ⋯ The only arrest condition found to be independently associated with outcome following CPR was the duration of resuscitative effort (p less than 0.01). The patients who were successfully resuscitated but died before discharge were not different from the patients who were not successfully resuscitated in any parameter that we evaluated. These results demonstrate that CPR can be successful in the MICU and that there are prearrest and arrest parameters which are useful in identifying those patients most likely to benefit from CPR in the critical care setting.