Pediatric Respiratory Acidosis Medication
- Author: Mithilesh K Lal, MD, MBBS, MRCP, FRCPCH, MRCPCH(UK); Chief Editor: Timothy E Corden, MD more...
Mechanical ventilation is the mainstay of therapy for respiratory failure associated with hypercapnia until the precipitating disease state can be reversed. Tromethamine (THAM) has been used to prevent and correct systemic or respiratory acidosis. Sodium bicarbonate (NaHCO3–) is sometimes employed but should be administered with caution if used.
Treatment of a concurrent metabolic acidosis or buffering the acidemia with a respiratory acidosis can be considered. In certain cases, THAM may be helpful.
THAM, also known as tris[hydroxymethyl]-aminomethane, is used to prevent and correct systemic or respiratory acidosis. It is a biologically inert weak base that can buffer excess carbon dioxide. It combines with hydrogen ions to form bicarbonate (HCO3–) buffer, as follows:
R-NH2 + CO2 + H2O = R-NH3 + HCO3
At 37°C, pKa is 7.8; therefore, THAM is a more effective buffer than NaHCO3– in the physiologic blood pH range. It is not protein bound and is distributed primarily in extracellular space. When protonated, THAM is excreted by the kidneys and acts as an osmotic diuretic. It is most appropriately administered as a short-term infusion during the therapeutic window to correct acute respiratory acidosis.
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