PAH clearance, sodium excretion, and PAH extraction ratio in acidotic near-term lambs treated with hypertonic sodium bicarbonate.
The electrolyte changes and renal hemodynamic adjustment to hypertonic sodium bicarbonate (NaHCO3) correction of a metabolic acidosis were studied in 4 neonatal lambs and in 2 controls. PAH clearance increased from 0.92 to 1.65 ml/min/kg (p less than 0.05),  urine flow from 0.37 to 0.61 ml/min/kg (p less than 0.05), and Na excretion from 8.4 to 23.7 muEq/min/kg (p less than 0.05) during the NaHCO3 infusion. These increases were transient and returned to pre-infusion levels following NaHCO3 infusion. Calculation of Na intake and output revealed a net retention of 5.1 mEq/kg in the study lambs which was reflected in a rise of serum Na and osmolarity (Osm) during the post-NaHCO3 -infusion period. The extraction ratio of sodium p-aminohippurate (EPAH) and its relationship to arterial pH were studied in 4 additional lambs. The EPAH did not change with metabolic acidosis but for unknown reasons, the infusion of NaHCO3 resulted in a temporary depression of EPAH (p less than 0.001).
D000138:Acidosis / Q000188:drug therapy* / Q000378:metabolism; D000618:Aminohippuric Acids / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001639:Bicarbonates / Q000008:administration & dosage / Q000627:therapeutic use*; D001769:Blood; D001794:Blood Pressure / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D012756:Sheep; D012964:Sodium / Q000378:metabolism*
D000618:Aminohippuric Acids; D001639:Bicarbonates; D012964:Sodium