Annals of emergency medicine
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The anion gap (AG) is a helpful, yet underused, clinical tool. Not only does the presence of a high AG suggest a certain differential, but knowledge of the relationship between the rise in AG (delta AG) and the fall in bicarbonate (delta HCO3) is important in understanding mixed acid-based disorders. Simple arithmetic converts this relationship into a numerical value, the delta gap (delta gap). ⋯ If the delta gap is significantly positive (greater than +6), a metabolic alkalosis is usually present because the rise in AG is more than the fall in HCO3. Conversely, if the delta gap is significantly negative (less than -6), then a hyperchloremic acidosis is usually present because the rise in AG is less than the fall in HCO3. Familarity with the relationship between the changes in AG and HCO3 can be useful in unmasking occult metabolic disorders.
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To assess the hemodynamic determinates of peripheral subdiaphragmatic venous-to-right-heart return during closed-chest CPR. ⋯ Venous return from the subdiaphragmatic venous bed during CPR is dependent on venous pressure, not on the peripheral venous-to-right-heart pressure gradient. Abdominal binding during CPR does not affect venous return. Venous return during CPR diastole is highly dependent on central venous capacitance (left heart outflow during CPR systole).