lotus

previous page: 06 CHLORIDE
  
page up: Interpretation Of Lab Test Profiles
  
next page: 08 ANION GAP

07 CO2 CONTENT




Description

This article is from the Interpretation Of Lab Test Profiles, by Ed Uthman uthman@neosoft.com with numerous contributions by others.

07 CO2 CONTENT

Increase in serum CO2 content for the most part reflects
increase in serum bicarbonate (HCO3-) concentration rather than
dissolved CO2 gas, or PCO2 (which accounts for only a small
fraction of the total). Increased serum bicarbonate is seen in
compensated respiratory acidosis and in metabolic alkalosis.
Diuretics (thiazides, ethacrynic acid, furosemide, mercurials),
corticosteroids (in long term use), and laxatives (when abused)
may cause increased bicarbonate.

Decrease in blood CO2 is seen in metabolic acidosis and
compensated respiratory alkalosis. Substances causing metabolic
acidosis include ammonium chloride, acetazolamide, ethylene
glycol, methanol, paraldehyde, and phenformin. Salicylate
poisoning is characterized by early respiratory alkalosis
followed by metabolic acidosis with attendant decreased
bicarbonate.

Critical studies on bicarbonate are best done on anaerobically
collected heparinized whole blood (as for blood gas
determination) because of interaction of blood and atmosphere in
routinely collected serum specimens. Routine electrolyte panels
are usually not collected in this manner.

The tests "total CO2" and "CO2 content" measure essentially the
same thing. The "PCO2" component of blood gas analysis is a test
of the ventilatory component of pulmonary function only.

 

Continue to:













TOP
previous page: 06 CHLORIDE
  
page up: Interpretation Of Lab Test Profiles
  
next page: 08 ANION GAP