Partial Airway Obstruction Flashcards
Identify the types of flow in A and B
A) laminar flow
B) turburlent flow produced by orificial lesion
Identify this equation
Hagen-Poiseulle equation for Laminar flow
note: the r4 is important in laminar flow
What happens to the radius in turbulent flow
what role does density play in turbulent flow?
True or False:
when assessing partial airway obstruction, on auscultation you may hear both Inspiratory and expiratory stridor.
True
For Partial Airway Obstruction assessment,
on physical examination what type of Breathing pattern might you see?
slow and deep respirations
What are flow volume loops used for ?
- Determine if partial airway obstruction (a.k.a. a lesion) is present
- Differentiate a fixed lesion from a variable lesion
- Determine intrathoracic versus extrathoracic location of variable lesions
what lung capacity is utilized when obtaining a flow-volume loop?
Mid - VC (vital capacity)
Normal flow volume loop
Things to look at:
- note the clockwise flow
- note the shapes of the I and E phases
- the Mid-VC: I:E ration is 50:50 (remember this is looking at the capacity, not
what type of obstruction (or lesion) is this?
Extrathoracic variable obstruction
Mid-VC: I < E
_________________________________
Notice: lesion is outside the box (extrathoracic)
Notice: Expiratory loop looks normal
Notice: Inspiratory flow is augmented.
When the patient breaths in, the (-) pressure force essentially makes the lesion more narrow (closes it), thus decreasing the inspiratory portion of Vital Capacity
What type of obstruction is this?
Intrathoracic variable obstruction
Mid-VC: I > E
_________________________________
Notice: lesion is inside the box (intrathoracic)
Notice: Inspiratory loop looks normal
Notice: Expiratory flow is augmented.
When the patient breaths in, the (-) pressure inside the lungs pulls the lesion open thus a normal Inspiratory loop. However, when the patient breaths out (+) pressure from the exhale causes the lesion to narrow (or close) causing expiratory portion of the Mid-VC to decrease.
what type of obstruction is this?
Fixed obstruction
________________________________
Notice: both I and E are affected
Note: Mid-VC will be normal (50:50)
Note: the lesion could be extrathoracic or intrathoracic (we don’t know with out further evaluation)
Identify the numbered loop
- intrathoracic variable obstruction
- extrathoracic variable obstruction
- fixed obstruction
what is the main goal for treating (bridge therapy) the partial airway obstruction until the problem can be treated.
OXYGENATION
(this is why heliox is used - it improves the delivery of oxygen when there is turbulent flow)
(final trx would be intubation, tracheostomy, or cricothyrotomy)
Why is the HR of 128 bpm at the SPo2 of 77% good in the following scenario:
A 37-year-old woman is admitted to the ER in respiratory distress. She is markedly dyspneic, sitting bolt upright on the stretcher, gripping both side rails. Inspiratory and expiratory stridor are evident from the doorway of the exam room. Vital signs: BP 148/92 mmHg, HR 128/min, RR 11/min, SPo2 77%. History includes subglottic stenosis x 7 years for which she has undergone 16 prior dilations of the stenotic lesion.
an increase HR indicates that she still has cardiovascular response. If she becomes bradycardic
Molecular weights (MW) of the gases we use
I would know all of them but pay especially close attention to the Heliox (He:O2) ratios and MW
Gas Densities
Identify the labeled structures and describe thoracic location
- trachea (severley deviated)
- goiter
- right lung
- left lung
this is intrathoracic variable obstruction (be able to match this image to the correct flow loop) because the apex of the lungs are noted in the xray.
