Respiratory acidosis
Revision as of 16:23, 22 March 2016 by Ostermayer (talk | contribs) (Text replacement - "Category:Tox" to "Category:Toxicology")
Background
- acidemia = pH < 7.38
- respiratory acidosis = pCO2 > 42
- Acute respiratory acidosis: Change in pH = 0.008 X (40 - PaCO2)
vs. Chronic respiratory acidosis: Change in pH = 0.003 X (40 - PaCO2)
- 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
Differential Diagnosis
- COPD
- Drugs (Opioid Overdose)
- Chest wall dz
- Pleural dz
- Trauma
Diagnosis
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)