Chest
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Comparative Study
Three mixed venous saturation catheters in patients with circulatory shock and respiratory failure.
Thirty-one critically ill patients with acute respiratory failure and circulatory shock were divided into three groups. Group 1 included 11 patients with an inserted mixed venous saturation (SvO2) catheter using three-reference wavelengths and characterized by one transmitting and one detecting fiberoptic filament (Oximetrix opticath catheter); group 2 included eight patients with an inserted SvO2 catheter using two-reference wavelengths and characterized by one transmitting and one detecting fiberoptic filament; (Edwards sat-one catheter); group 3 included 12 patients with an inserted SvO2 catheter using two-reference wavelengths and characterized by one transmitting and two detecting fiberoptic filaments. Once calibration procedures were performed, SvO2 measured by the catheter and by an hemoximeter OSM 3 (reference value) were compared following each therapeutic intervention. ⋯ After 24 hours, the spontaneous drifts in the two-reference wavelength systems, using either one or two detecting fiber optic filaments (expressed as the SvO2 value measured by the catheter minus the reference SvO2 value) were significantly higher than the spontaneous drift in the three-reference wavelength system (9.3 +/- 7 percent for the Edwards catheter and +/- 6 +/- 4.1 percent for the Spectramed catheter vs 3.3 +/- 3.1 percent for the Oximetrix catheter, p less than 0.05). This study shows that a three-wavelength system is more accurate than a two-wavelength system for measuring acute changes in SvO2. The addition of a second detecting fiber optic filament does not seem to improve the accuracy of the system when SvO2 changes occur in conditions of stable hematocrit.
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We report the terms used by 223 pulmonary physicians and 54 physicians in other specialties to describe eight recorded examples of lung sounds. The participants listened to the lung sounds at the 1988 American College of Chest Physicians annual convention and wrote "free form" answers. Pulmonary physicians used the terms "crackles" and "rales" with equal frequency to describe discontinuous adventitious lung sounds (ALS) and not at all to describe continuous ALS. ⋯ The majority of participants recognized the normal breath sounds but not the pleural friction rub. Most did not use a qualifying adjective to describe ALS, and there was little agreement among those who did. The lung sound terminology used by physicians is not well standardized and the recommendations of the ATS/ACCP nomenclature subcommittee are not widely accepted.
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Comparative Study
The effects of methoxamine and epinephrine on survival and regional distribution of cardiac output in dogs with prolonged ventricular fibrillation.
This study compares the effects of methoxamine, a pure alpha 1-agonist, and epinephrine on cerebral and myocardial blood flow, central hemodynamics, and survival in a randomized placebo-controlled fashion during prolonged ventricular fibrillation (VF) in a canine model. Twenty-four anesthetized and ventilated adult mongrel dogs were instrumented for regional blood flow determinations using radio-labeled microspheres. The dogs were randomized to receive either 20 mg of methoxamine as a single intravenous bolus or repeated boluses of 0.02 mg/kg of epinephrine, 0.2 mg/kg of epinephrine, or normal saline solution placebo beginning at three minutes following induction of VF and initiation of closed chest cardiac massage (CCCM). ⋯ In contrast, organ flows measured in the animals receiving the lowest dose of epinephrine were not significantly higher than those associated with placebo. Cardiac output after 20 minutes of CPR was significantly lower with high-dose epinephrine than with methoxamine or placebo (p less than .05). Our results suggest that methoxamine significantly improves regional cerebral blood flow and survival during CPR and although high-dose epinephrine is associated with comparable improvements in regional cerebral blood flow, this treatment is associated with deterioration in central hemodynamics during prolonged VF and does not enhance survival.
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The objective of the study was to compare the serum-effusion albumin gradient (serum albumin level minus pleural effusion albumin level) to Light's traditional criteria (pleural fluid/serum total protein ratio greater than 0.5, pleural fluid/serum LDH ratio greater than 0.6, and pleural fluid LDH greater than 200 U/L) for identifying exudative pleural effusions. The design included prospective measurement of the serum-effusion albumin gradient and Light's criteria in patients with pleural effusions in an inpatient ward in a military teaching hospital. Fifty-nine consecutive patients with pleural effusions who were undergoing diagnostic or therapeutic thoracentesis in whom the etiology of the effusion could be determined were studied. ⋯ Although Light's criteria correctly identified all of the exudates, five patients with congestive heart failure were misclassified as exudates. Four of these patients had had previous diuretic therapy, and all had a clinical response to further diuretic therapy. We conclude that although Light's criteria for exudates are very sensitive, an albumin gradient of 1.2 g/dl or less tends to be more specific, especially in cases of chronic congestive heart failure.