Monday, February 10, 2020

physiologic effects of severe metabolic acidosis

Q: What are the three physiologic hemodynamic effects of severe metabolic acidosis?



Answer: Infusion of bicarbonate is usually not recommended in metabolic acidosis unless PH goes below 7.1. Clinicians often used bicarbonate once PH is even below 7.3. This is not an evidence-based practice.  Said that bicarbonate may become a stabilizing agent as acidemia progressively gets worse. Once human PH falls below 7.1, it produces three physiologic effects
  • reduced left ventricular contractility 
  • arterial vasodilation, and 
  • impaired responsiveness to catecholamines
#hemodynamic
#acid-base



References:

1. Kraut JA, Madias NE. Treatment of acute metabolic acidosis: a pathophysiologic approach. Nat Rev Nephrol 2012; 8:589. 


2. Marsh JD, Margolis TI, Kim D. Mechanism of diminished contractile response to catecholamines during acidosis. Am J Physiol 1988; 254:H20. 


3.  Orchard CH, Kentish JC. Effects of changes of pH on the contractile function of cardiac muscle. Am J Physiol 1990; 258:C967. 


4. Mathieu D, Neviere R, Billard V, et al. Effects of bicarbonate therapy on hemodynamics and tissue oxygenation in patients with lactic acidosis: a prospective, controlled clinical study. Crit Care Med 1991; 19:1352.



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