CCP 215 - Respiratory Emergencies Flashcards
What is expected of a patient’s HCO3 on ABG if they are chronically hypercapniec?
Use the “10-4” rule to determine appropriate HCO3 compensation. For example: A chronic PaCO2 of 60 (20 above normal) should have an expected bicarbonate of 32 (8 above normal).
What is the gold standard in assessing for PE?
CT-PE.
What are the three highest yield factors for differentiating shock?
- Skin temperature (distributive vs all)
- JVP (cardiogenic/obstructive vs distributive/hypovolemic)
- U/S (cardiogenic vs obstructive)
pH below ‘x’ requires resuscitation.
7.2
PaO2 and PaCO2 general limits:
PaO2 = No less than 60. PaCO2 = No greater than 60.
PE CXR presents with:
No abnormalities. Though may later present with small areas of infarcted lung.
What is another scan that can be performed to assess for PE, other than CT-PA?
VQ scan.
Performed by sensing the gradient of diffusion of a test gas across the alveolar membrane.
List three populations that are at higher risk of PE (consider Virchow’s triad).
- Coagulopathy (ie. hormone replacement therapy).
- Endothelial dysfunction (ie. obesity).
- Stasis.
Why are trauma patients at a higher risk of PE?
Trauma patients have an impaired coagulation cascade.
What is Virchow’s triad?
Virchow’s triad describes the factors that lead to an increased risk of thrombosis.
What type of DVT indicates a high risk of PE?
Popliteal and upwards (ie. above the knee).
How can the presence of DVT be assessed?
An incompressible femoral vein may indicate the presence of a DVT.
What labs are expected to be elevated in PE?
- D-dimer, as a non-specific marker of clot degredation.
2. Troponin, from dilation of the RV and stretching of the myocardium.
Explain the treatment options of massive PE:
- Systemic thrombolysis for acute PE in any centre.
- Catheter directed thrombolysis (CDT) for patients who have had a cardiac arrest.
- Thrombectomy for pregnant patients or those in large centres.
- Anticoagulation to support the clot breakdown and no-further growth over a period of days.
Explain the treatment of sub-massive PE:
Anticoagulation.
Where do the lungs receive blood from?
The RV (though deoxygenated), as well as from the aorta.
Explain the RV spiral of death:
- Bulging of the interventricular septum into the LV.
- Impaired LV function from LV compression.
- Impaired right heart filling from high RV pressure.
- LVOT obstruction from the interventricular septum.
When should a pneumothorax be drained?
When there is hemodynamic compromise, or when deterioration is expected.
Explain obstructive atelectasis:
Obstructive atelectasis is the closure of alveoli from obstruction of the bronchiole (ie. from mucous plug). This is the cause of atelectatic lung in ARDS.
How does obstructive atelectasis cause mediastinal shift?
The mediastinum may be “pulled” towards the atelectatic lung from reduction in space-occupying lung in that particular region the thorax. There is a negative pressure exerted in the pleura during inspiration, which “pulls” the mediastinum towards the lowest area of pressure.
Explain the pathogenesis of negative pressure pulmonary edema:
Occurs in patients who are extubated and experience laryngospasm. Also occurs in chokings. Negative pleural pressure during inspiration “pulls” on the alveoli, but is unable to expand them with air due to obstruction. Instead, fluid is pulled from the adjacent capillaries.