OLV Flashcards
Ventilation is sum of all inhaled or exhaled gasses in one min?
exhaled
Type of dead space that is nonresp airways?
anatomic dead space
Type of dead space that is alveoli that are not perfused?
alveolar dead space
What is the sum of anatomic and alveolar dead space?
physiologic
What is the typical dead space in most adults in upright patient? And it is mostly what type of dead space?
150 mL; 2mL/kg; anatomic
How can you grossly estimate anatomic dead space?
weight of individual in pounds is roughly equivalent to dead space in mL
Right and left lung receive what % each of ventilation?
right lung- 53%; left lung- 47%
Are the upper or lower areas better ventilated?
lower
Why are the lower areas of lungs better ventilated?
gravitationally induced gradient in intrapleural pressure and therefore transpul pressure
What does a higher transpulmonary pressure in the upper part of the lungs mean for inspiration?
the alveoli in the upper lungs are near maximally inflated and relatively non compliant so they undergo little expansion during inspiration
What happens to the smaller alveoli in dependent areas during inspiration?
they have a lower transpulmonary pressure, are more compliant, and undergo greater expansion
Laminar flow resistance is proportional to? And which law is this?
viscosity x length of conduit divided by radius to 4th power; Poiseulle’s
Flow is proportional to?
change in pressure x radius 4th power divided by viscosity times length
Halving the radius does what to flow?
flow is 1/16 what it was
Is pulmonary blood flow uniform?
no
One example where zone 1 would be present?
pulmonary hypotension
What are the characteristics of the pressures in Zone 1?
pulmonary alveolar > pulmonary artery > pulmonary vein
How are the capillaries in zone 1?
capillaries are depressed, blood flow is impeded
Why is vascular resistance increased in zone 1?
apical alveoli are inflated
What is the net result as far as ventilation and perfusion in zone 1?
ventilation without perfusion
What do the capillaries do in zone 2?
flutter open and closed in inspiration and expiration
What are the pressures in zone 2?
pulmonary artery > alveolar > venous
How is blood flow determined in zone 2?
pressure gradient between arterial and alveolar pressures
How are the pressures related in zone 3?
pulmonary artery > pulmonary vein > alveolar pressure
How is flow determined in zone 3?
arterial venous pressure differences
Where should the tip of the swan be?
zone 3
2 examples where zone 4 is present?
ARDS, pulmonary edema
What are the pressure relationships in zone 4?
interstitial pressure > venous and alveolar pressure
How do you determine blood flow in zone 4?
pulmonary artery minus pulmonary interstitial fluid gradient
Where is pleural pressure least negative?
base of lung
3 other characteristics of base of lung besides pleural pressure being least negative?
alveoli most compressed, most compliant, smallest volume
Where is pleural pressure most negative in upright person?
apex
3 other characteristics of apex of lung other than pleural pressure being the most negative?
alveoli not compressed, alveoli have greatest volume, alveoli least compliant
Ventilation preferentially goes to the base of the lung why?
pleural pressure least - in base and alveoli most compliant
Pleural pressure increases by what cm H2O per cm of lung dependency (down the lung)?
0.25
At a normal tidal volume range, which part of the lung receives the majority of ventilation?
dependent/base bc apex alveoli already overdistended they’re poorly compliant
The dependent/base of the lung is (ventilation and perfusion wise)?
ventilated and preferentially perfused
In an awake lateral position, the apex and base are equal in which part of the lung?
dependent
Distribution of ventilation is changed in an anesthetized paralyzed patient how?
changed from the dependent lung to the nondependent lung
In an anesthetized paralyzed patient how are ventilation and perfusion distributed in the lateral position?
dependent lung is poorly ventilated and well perfused, shunting; nondepedent lung is well ventilated and not well perfused, deadspace
Why are FRC and compliance of dependent lung in an anesthetized pt in lateral position decreased?
abdominal contents pushing on dependent lung, weight of the mediastinum compresses that lung, axillary rolls compresses that lung
Decreased FRC and compliance in the dependent lung favor ventilation in?
non dependent lung
Once the chest wall is opened, compliance greatly increases where?
non dependent lung
What is the sequence of cephalaud displacement of lungs?
supine, induction, paralysis, surgical position, displacement by retractors and packs
In OLV, which lung is ventilated and which collapsed? What type of mismatch do you get?
dependent ventilated, nondependent collapsed; shunt flow
How do the lungs function to decrease shunt flow in OLV?
arteriolar smooth muscle contract in areas of lung which have decreased PAO2. this directs blood flow away from the hypoxic regions
Normal perfusion w 2 lung ventilation, dependent lung gets what % of blood flow and nondependent lung which %?
dependent gets 60%, nondependent 40%
OLV with HPV, dependent and nondependent lungs get what % of blood flow?
nondep gets 20%, dep gets 80%
HPV is more effective when what % of the lungs are hypoxic?
30-70
What type of shunt happens w OLV and HPV?
right to left
Conditions that worsen right to left shunt w OLV and HPV?
very high or low PAPs, hypocapnia, high or low mixed venous PO2, vasodilators, inotropes, beta agonists, Ca channel blockers, pulmonary infection
Conditions that reduce HPV indirectly?
vasopressors, high airway pressures (PEEP, high inspiratory pressure), low FiO2
Is CO2 affected by OLV if MV is not changed?
usually not
Surgeries that may need OLV?
pneumonectomy, lobe resection, segmental resection, thoracic aneurysm repair. esophageal surgeries, thoracoscopy, single lung transplant, anterior approach to thoracic spine, bronchioalveolar lavage,
Pt related indications for OLV?
confine infection or bleeding to one lung, separate ventilation to one lung (bronchopleural fistula, tracheobronchial disruption, large lung cyst or bulla), severe hypoxemia d/t unilateral disease
3 techniques for providing OLV?
double lumen bronchial tube, single lumen tracheal tube in conjunction w bronchial blocker, single lumen bronchial tube
For a DLT, opening the port on appropriate side allows which lung to collapse?
ipsilateral
Most commonly used DLT?
Robertshaw type
DLT size range for men? for women?
39-41; 35-37
DLT size is based on pt’s?
height
DLT Carlens, which bronchus is intubated and is there a carinal hook?
left, yes
DLT White, which bronchus is intubated and is there a carinal hook?
right yes
DLT Robertshaw, which bronchus is intubated and is there a carinal hook?
right or left; no
Which sided DLT has big murphy’s eye? and bc of that which sided DLT is usually used?
right; left
One negative ab the carinal hook?
may irritate the carina and cause cough
Where is the Murphy Eye on the White tube?
right past the tracheal cuff and above bronchial cuff
How do you pass a DLT?
distal curve concave up/anteriorly and rotated 90 degrees towards side of bronchus to be intubated after tip/bronchial balloon enters larynx rotate it 90 degrees then take out stylet and advance until resistance felt
Tracheal cuff requires how many mL for inflation?
5-10
Unilateral breath sounds indicate that?
tube too far down (tracheal opening is bronchial)
How much air do you put in bronchial cuff?
1-2 mL
Which cuff do you inflate first on a DLT?
tracheal
Malposition of a DLT is usually indicated by what 2 things?
low exhaled TV and poor lung compliance
If unilateral breath sounds are heard after inflating the tracheal cuff on a DLT, where is the tube?
tube is too far down; tracheal opening is bronchial
When checking for placement of a DLT, after you inflate the bronchial tube, what step is next?
clamp the tracheal lumen and check for unilateral breath sounds
Which lumen do you place the fiberoptic bronchoscope down to check for left DLT placement?
right
When looking through a fiberoptic bronchoscope, where should the endobronchial cuff be?
just below tracheal carina
Review slide 45
yes review it
What is one complication from overinflation of the bronchial cuff?
tracheobronchial rupture. this is associated w high morbidity and mortality
What’s a disadvantage of a bronchial blocker, besides that it is hard to place?
blocked lung collapses slowly and sometimes incompletely bc of the small size of the channel w/in the blocker
What’s a Gordon Green tube?
right sided single lumen tube used for left thoracotomies
What are 2 advantages and disadvantages ab the Gordon Green tube?
had bronchial and tracheal cuff, carinal hook, hazard of carinal hook, inability to suction the left lung
How can you prevent brachial plexus injury w positioning in lateral position?
rolled towel or small pillow under axillary
