Respiratory acidosis: Difference between revisions
(Created page with "==DDX== (Hypoventilation) 1) COPD 2) Drugs (opiods) 3) Chest wall dz 4) Pleural dz 5) Trauma ==Source == 2/21/06 DONALDSON (adapted from Tintinalli) [[Category:...") |
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== | ''see also [[hypercapnia]] | ||
==Background== | |||
*[[Acidosis|acidemia]] = pH < 7.38 | |||
*Respiratory acidosis = pCO2 > 42 | |||
*Acute respiratory acidosis: Change in pH = 0.008 X (40 - PaCO2) | |||
*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 (e.g. [[opioid overdose]]) | |||
*Chest wall disease | |||
*Pleural disease | |||
*[[Trauma]] | |||
==Evaluation== | |||
==Management== | |||
''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]] | |||
==See Also== | |||
*[[Acid-base disorders]] | |||
==References== | |||
<references/> | |||
[[Category:FEN]] | [[Category:FEN]] | ||
[[Category:Pulmonary]] | |||
[[Category:Toxicology]] | |||
Revision as of 15:26, 12 January 2022
see also hypercapnia
Background
- acidemia = pH < 7.38
- Respiratory acidosis = pCO2 > 42
- Acute respiratory acidosis: Change in pH = 0.008 X (40 - PaCO2)
- 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 (e.g. opioid overdose)
- Chest wall disease
- Pleural disease
- Trauma
Evaluation
Management
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)