Respiratory acidosis: Difference between revisions
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==Background== | ==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 4 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 4 then suspect primary metabolic alkalosis | |||
==Etiology== | |||
Hypoventilation - acute vs chronic | |||
==DDX== | ==DDX== | ||
#COPD | #COPD | ||
#Drugs ( | #Drugs (opioids) | ||
#Chest wall dz | #Chest wall dz | ||
#Pleural dz | #Pleural dz | ||
Revision as of 19:39, 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 4 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 4 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