Chest
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Oxygen consumption (VO2) has been shown to be decreased after acute myocardial infarction (AMI) complicated by cardiogenic shock. ⋯ VO2 is increased in UAMI and represents increased metabolic demands of peripheral tissues and not cardiac oxygen uptake. A reduction in VO2 (< 100 ml/min.m2) after AMI may be an early predictor of subsequent development of cardiogenic shock. Measurement of VO2 in UAMI by indirect calorimetry in the emergency department may be of value to identify patients at high risk and could influence their management.
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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.
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Major surgery in the elderly continues to have a high mortality rate. Preoperative myocardial ischemia is a known risk factor. Cardiac failure is also a risk factor, but is difficult to quantify objectively. ⋯ A low AT associated with preoperative ischemia resulted in the death of 8 of 19 patients, a mortality rate of 42 percent. When the ischemia was associated with the higher AT, then 1 patient out of 25 died, a mortality rate of 4 percent (p < 0.01). Both preoperative ischemia and preoperative cardiac failure are independent risk factors for perioperative mortality in the elderly.
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The incidence, degree, and duration of acute hypoxemia were evaluated with continuous arterial hemoglobin oxygen saturation monitoring by pulse oximetry in 100 postoperative patients during 40 percent oxygen administration by aerosol face tent from postanesthetic recovery room admission to discharge. Saturations were recorded by pulse oximeters (Nellcor-N 200) with desaturations of < or = 92 percent for > or = 30 s considered significant. On recovery room admission, 15 percent of patients were experiencing episodes of desaturation. ⋯ Later desaturations to 86.7 +/- 4.6 percent (72 to 91 percent) at 32 +/- 54 min after admission for 5.2 +/- 12.6 min occurred in 25 percent of patients and correlated positively with peripheral surgical procedures, low oxygen saturation on admission, duration of anesthesia, and volume of intraoperative intravenous fluids. Desaturation durations were longer for female subjects and correlated positively with body weight and intravenous fluid volume. Significant arterial hemoglobin oxygen desaturations occurred despite prophylactic oxygen administration by aerosol face tent during short-term postoperative recovery room care.