The American journal of emergency medicine
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The objective of this study was to determine if hemoconcentration occurs during cardiac arrest and cardiopulmonary resuscitation (CPR). The design was an animal model of cardiac arrest and CPR performed at a research institute using six mongrel dogs. After the induction of cardiac arrest, animals were subjected to 4 minutes of ventricular fibrillation followed by 20 minutes of CPR. ⋯ Hemoglobin concentrations were obtained before arrest and every 5 minutes during CPR. An average peak increase in hemoglobin concentration of 21% was observed during CPR. Hemoconcentration occurs during cardiac arrest and CPR, and this may be a result of a shift in volume from the intravascular to the extravascular space.
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The objective of this study was to develop a decision rule for ordering x-rays in knee injuries. Phase I was a retrospective chart review of 201 consecutive patients receiving knee radiographs in the emergency department in a 10-month period. Logistic regression was performed on 11 clinical indicators to develop a clinical decision rule. ⋯ The misclassification rate was 20%. Using this decision rule, the number of x-rays taken could have been reduced by 78%. A larger multicenter validation study of this knee radiograph decision rule is needed before widespread clinical usage.