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Acidosis = decrease in arterial pH
Alkalosis = increase in arterial pH
Anion gap: helps differentiate between acid gain and loss.
Anion gap acidosis: gap >12 mEq/L
Caused by decrease in balanced by an increase in unmeasured acid ions, not by an increase in chloride.
Causes include salicylates, methanol, paraldehyde, ethylene glycol, lactic acidosis, ketoacidosis (from diabetes or starvation), and uremia.
Non–anion gap acidosis: gap 8 to 12 mEq/L
Caused by a decrease in balanced by an increase in chloride.
Causes include renal tubular acidosis, carbonic anhydrase inhibitor, and diarrhea.
Table 22-1 gives normal values for infants and children.
Fencl-Stewart approach to understanding acid-base balance: looks for unmeasured anions, which could contribute to a pH disturbance.
H2O contribution = 0.3 (Na− + 140)
Cl− contribution = 102 − (Cl− × 140/Na)
Albumin contribution = 3.4 (4.5-albumin)
BE: base excess
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*Get BEmeasured from blood gas
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CLINICAL APPROACH TO BLOOD GAS INTERPRETATION
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Blood gases provide measurements of pH, PCO2, PO2, total hemoglobin, ...