Chest
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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 left pericardiacophrenic vein was accidentally cannulated during an attempt to establish central venous catheterization through the left internal jugular vein. Chest roentgenograms and intravenous contrast material confirmed the position of the catheter. Although our patient developed no problems during a five-day cannulation, based on published information, it is advisable to reposition the catheter to avoid perforation of the pericardiacophrenic vein and possible cardiac tamponade.
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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.
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The ventilation of 25 ventilator-dependent traumatic quadriplegic patients was supported by noninvasive means of ventilatory assistance. Twenty-four of the 25 were initially managed by endotracheal intubation, and 23 of these went on to tracheostomy intermittent positive pressure ventilation before being converted to NVA. Seventeen of the 23 patients had their tracheostomies closed. ⋯ Mouth IPPV was the most common form of NVA used both during the daytime and overnight. The wrap ventilators, intermittent abdominal pressure ventilator, and GPB were also employed for long-term respiratory support. It was concluded that, in general, because of their youth, intact mental status and bulbar musculature, and absence of obstructive lung disease, patients with traumatic high level spinal cord injury are candidates to benefit from these techniques.