Hypercarbia Flashcards
1
Q
What is hypercarbia?
A
The presence of abnormally high levels of carbon dioxide in the blood, usually defined as PaCO2 > 45mmHg on ABG.
2
Q
What are the clinical features of hypercarbia?
A
- flushed skin, sweating, muscle tremor, headache, MS changes
- sympathetic stimulation (tachycardia, hypertension, extrasystoles and other dysrhythmias)
- if spontaneously breathing (dyspnea/tachypnea)
- if mechanically ventilated (patient may attempt to overbreathing the ventilator)
3
Q
What is the differential diagnosis of hypercarbia?
A
- increased production of CO2
- decreased elimination of CO2
- exogenous addition of CO2 (CO2 pneumoperitoneum during laparoscopy)
4
Q
What can increase production of CO2 resulting in hypercarbia?
A
- fever, sepsis
- MH
- thyrotoxicosis
- TPN with high carbohydrate content
5
Q
What can decrease elimination of CO2 resulting in hypercarbia?
A
- decreased cardiac output (shock, hypotension)
- CNS depression (hypoventilation)
- ventilator malfunction
- neuromuscular disease
- decreased lung/chest wall compliance
splinting from pain of upper abdominal incision
6
Q
What is the management of hypercarbia?
A
- establish/maintain a patent airway
- ensure adequate oxygenation (titrate FiO2 as needed)
- Ensure adequate ventilation
- Confirm diagnosis with ABG
- Confirm and treat cause of hypercarbia
- evaluate for drug effects
- check inspired CO2 level
- evaluate for MH
- review chart to look for presence of thyroid disease and TPN regimen
- check for syringe swap (accidental opioid or NMB administration)
7
Q
What might cause increased inspired CO2 levels?
A
- stuck valve in breathing circuit
- exhausted soda lime
- administration of exogenous CO2
8
Q
What are early symptoms of hypercarbia (especially in the awake patient)?
A
- flushed skin, sweating
- muscle tremor
- headache
- confusion, lethargy CO2 narcosis
