This topic has never come up in the CICM fellowship exam. Likely, it is reserved for the primaries.

Consequences of Metabolic Acidosis

Respiratory consequences:

  • Increased respiratory stimulus
  • Increased work of breathing
  • Right shift of the oxyhaemoglobin dissociation curve (i.e. a decreased affinity of haemoglobin for oxygen)

Cardiovascular consequences:

  • Decreased cardiac output
  • Increased propensity to arrhythmias
  • Decreased systemic vascular tone and arterial vasodilation
  • Decreased responsiveness to catecholamines
  • Pulmonary vasoconstricition

Neurological consequences:

  • Cerebral vasodilation, thus increased intracranial pressure

Electrolyte changes

  • Hyperkalemia
  • Hypercalcemia

Effects on renal function and fluid balance

  • Increased renal ammonia production
  • Increased renal tubular ammonia secretion
  • Thus, increased renal oxygen demand
  • Diuresis (eg. due to osmotic effect of "gap" anions)

Gastrointestinal consequences

  • Decreased stomach emptying
  • Nausea and vomiting
  • Decreased splanchnic perfusion

Haematological consequences

References

Kraut, Jeffrey A., and Nicolaos E. Madias. "Metabolic acidosis: pathophysiology, diagnosis and management." Nature Reviews Nephrology 6.5 (2010): 274-285.

 

Fencl, Vladimir, et al. "Diagnosis of metabolic acid–base disturbances in critically ill patients." American journal of respiratory and critical care medicine162.6 (2000): 2246-2251.

 

Moviat, M. A. M., F. M. P. Van Haren, and J. G. Van Der Hoeven. "Conventional or physicochemical approach in intensive care unit patients with metabolic acidosis." Critical Care 7.3 (2003): R41.

 

Park, M., et al. "Clinical utility of standard base excess in the diagnosis and interpretation of metabolic acidosis in critically ill patients." Brazilian Journal of Medical and Biological Research 41.3 (2008): 241-249.

Handy, J. M., and N. Soni. "Physiological effects of hyperchloraemia and acidosis." British journal of anaesthesia 101.2 (2008): 141-150.