Respiratory acidosis: Difference between revisions
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*determine if another primary acid/base disturbance is occurring | *determine if another primary acid/base disturbance is occurring | ||
**calculate AG | **calculate AG | ||
**if HCO3 < 24 + (pCO2-40)/10 x | **if HCO3 < 24 + (pCO2-40)/10 x 3(+/-1) then there is a superimposed primary metabolic acidosis | ||
***for every 10mm increase in pCO2 >40, HCO3expected increases by 2-4mEq (2 if acute/limited time for metabolic compensation, 4 if chronic i.e. COPD) | ***for every 10mm increase in pCO2 >40, HCO3expected increases by 2-4mEq (2 if acute/limited time for metabolic compensation, 4 if chronic i.e. COPD) | ||
**if HCO3 > 24 + (pCO2-40)/10 x | **if HCO3 > 24 + (pCO2-40)/10 x 3(+/-1) then suspect primary metabolic alkalosis | ||
Revision as of 20:32, 2 August 2011
Background
- acidemia = pH < 7.38
- respiratory acidosis = pCO2 > 42
- determine if another primary acid/base disturbance is occurring
- calculate AG
- if HCO3 < 24 + (pCO2-40)/10 x 3(+/-1) then there is a superimposed primary metabolic acidosis
- for every 10mm increase in pCO2 >40, HCO3expected increases by 2-4mEq (2 if acute/limited time for metabolic compensation, 4 if chronic i.e. COPD)
- if HCO3 > 24 + (pCO2-40)/10 x 3(+/-1) then suspect primary metabolic alkalosis
Etiology
Hypoventilation - acute vs chronic
DDX
- COPD
- Drugs (opioids)
- Chest wall dz
- Pleural dz
- Trauma
Treatment
- Improve alveolar ventilation
- Bronchodilators
- CPAP
- Intubation (esp of pH < 7.25)
- Do not reduce pH too quickly (>5Hg/h)
- Can lead to abrupt hypocalcemia/hypokalemia
- Do not reduce pH too quickly (>5Hg/h)
Source
Tintinalli