Thoracic Anesthesia Pt. 1 (Exam III) Flashcards
How many total lung segments are there?
42
How many segments make up the right lung?
22
How many segments make up the left lung?
20
What is FEV₁?
Forced expiratory volume in 1 second after a full inspiration
What is a normal Predicted FEV₁?
80 - 120%
High percentage = healthier lungs
What are good predicted FEV₁ values associated with?
Good post-op outcomes
What is the formula for postoperative FEV₁?
Postop FEV₁% = Preop FEV₁% x (1 - % of lung tissue removed/100)
Given the following:
Preop FEV₁ = 70%
25% of lung tissue removed.
What is the expected Post FEV₁?
Post FEV₁ = 70 x [(1 - (25/100)]
Post FEV₁ = 52.5%
Given the following:
Preop FEV₁ = 110%
33% of lung tissue removed.
What is the expected Post FEV₁?
Post FEV₁ = 110 x [1 - (33/100)]
73.7%
Postoperative FEV₁ of ____ or less have an increased risk of pulmonary complications.
Postoperative FEV₁ of ____ or less have a very high risk.
40%
30%
V/Q:
V = ?
Q = ?
V = Ventilation
Q = Perfusion
What PaO₂ and PCO₂ preoperative values are associated with poor postoperative outcomes?
PaO₂ < 60 mmHg
PCO₂ > 45 mmHg
What is the most useful test for determing gas exchange capacity?
DLCO (Diffusing Lung Capacity for Carbon Monoxide)
How is a DLCO test performed?
- Small amount of CO is inhaled with tracer gas (helium or methane)
- CO high affinity for Hgb
- Exhaled gas analyzed
A DLCO test will correlate with what?
Total functioning surface area of alveolar/capillary interface.
Is DLCO or FEV₁ affected by chemotherapy?
DLCO is affected by chemotherapeutics
What would a high amount of exhaled CO from a DLCO test indicate?
Poor gas exchange
Due to CO not being picked up by the bloodstream at the alveoli.
What is the absolute minimum DLCO and FEV₁ needed for thoracic surgery?
20%
What is the ideal V/Q ratio?
What is more typical?
Ideal = 1.0
Typical = 0.8
Review West Zones
Pulmonary arterial pressure ( Pa) is always greater than pulmonary ____ pressure.
venous ( Pv)
The absolute pressure of Pa and Pv is greater in the ________ portion of the lung due to hydrostatic gradients.
dependent
Blood flow is most dependent on what?
gravity
The base of the lung receives how much more blood pressure relative to the apex of the lung? (in an upright person)
20 mmHg increase
What lung zone is depicted by 1 in the figure below?
What pressures would be exhibited by this lung?
- Zone 1
- PA > Pa > Pv
How much blood flow is seen in a Zone 1 lung? Who has Zone 1 lungs?
- Very little to no blood flow. Zone 1 lungs are a pathologic condition.
What lung zone is depicted by 2 in the figure below?
What pressures would be exhibited by this lung?
- Zone 2
- Pa > PA > Pv
What lung zone is depicted by 3 in the figure below?
What pressures would be exhibited by this lung?
- Zone 3
- Pa > Pv > PA
What lung zone exhibits pulsatile blood flow?
What lung zone exhibits non-pulsatile continuous blood flow?
What is the reasoning for the difference?
- Pulsatile = Zone 2
- Continuous = Zone 3
- Gravity: ↑ pressure = ↑ perfusion
What lung zone is depicted by 1 in the figure below?
Zone 4
Which lung zone is defined by the following:
- Alveoli maximally distended
- Complete compression of capillaries
- Ventilation but no blood flow (dead space)
Zone 1 ( PA > Pa > Pv )
Which lung zone is defined by the following:
- Restricted venous flow
- Arterial flow exceeds PA
- Ventilation but no blood flow (dead space)
Zone 2
( Pa > PA > Pv )
Where is lung zone 2 located in relation to the heart?
3cm above the heart
Which lung zone is defined by the following:
- Unrestricted blood flow
- More compliant alveoli & greater ventilation.
- Vasculature more distended
Zone 3
( Pa > Pv > PA )
In which lung zone will blood flow vary with the cardiac cycle and respirations?
Lung Zone 2
Which lung zone’s blood flow is unaffected by the cardiac cycle and respirations?
Zone 3
Zone 1 is _____ in healthy patients.
absent
In a normal healthy lung Pa will be ______ than PA.
greater → Pa > PA
What two common things will produce zone 1 ventilation?
- Positive Pressure Ventilation = ↑ alveolar pressure.
- Hemorrhage/shock/hypovolemia = drop in arterial pressure.
Why does blood flow in pulses in Zone 2 of the lungs?
Systole = Pa > PA
Diastole = PA > Pa
For accurate measurement of PCWP, the PA catheter must be place in which pulmonary zone?
Zone 3
Which zone has the greatest perfusion and highest hydrostatic pressures?
Zone 3
Which pulmonary function test is used to determine if lung disease is obstructive, restrictive, or normal?
FEV₁/FVC Ratio
What is a normal FEV₁/FVC ratio in healthy adults?
70 - 85%
What are the most common disease processes exhibiting obstructive patterns?
- COPD (Bronchitis & Emphysema)
- Asthma
- Cystic Fibrosis
What is the most common comorbidity in the thoracic surgical population?
COPD
What condition is characterized by the following:
- Decreased area for gas exchange
- Air-trapping
- Hyperinflation of lung tissue
COPD
What environmental factors other than smoking have been implicated in lung cancer?
- Asbestos
- Radon
- Diesel gas
- Heavy metals
Do the below factors describe SCLC or Non-SCLC?
- Less aggressive
- Affects smokers & non-smokers
- More common
- Better prognosis
Non-Small Cell Lung Cancer
Do the below factors describe SCLC or Non-SCLC?
- Fast-growing
- Aggessive
- Associated with smoking
- Starts in bronchi
- Metastasizes
Small Cell Lung Cancer
What lung cancer is most sensitive (susceptible) to radiation therapy?
SCLC
What are the sub-categories of Lung resection? (partial lobe removal)
- Sleeve
- Wedge
- Segment
What is pleurodesis?
Obliteration of pleural space to prevent recurrence of fluid, pus, or blood build up.
What is the most common thoracotomy approach?
Anterolateral
Differentiate lung separation vs lung isolation?
Separation = Adequate lung deflation
Isolation = Complete lung deflation
What is DLT sizing for women?
What is DLT sizing for men?
What direction should a left-sided DLT be turned once at the vocal cords?
To the left
What should tidal volume be set to on an isolated lung?
4 - 6 mL/kg
(increase rate to maintain normocapnia)
100% O₂ must be avoided in chemo patients who have received _______.
bleomycin
What are the cons of hyperoxemia from excessive FiO₂?
- Absorption atelectasis
- Coronary vasoconstriction
What type of shunt occurs from one lung ventilation?
Right to Left Shunt
Venous blood returning to heart has not been oxygenated. Causes relative hypoxemia.
How is One-Lung ventilation shunt lessened during thoracic surgery?
- Surgical manipulation (obstructs blood flow to non-ventilated lung).
- Lateral Positioning (increased perfusion to dependent, ventilated lung)
- HPV reduces blood flow in operative lung
Describe Hypoxic Pulmonary Vasoconstriction.
Alveolar hypoxia results in vasconstriction of pulmonary vasculature (↑PVR).
Due to HPV, blood preferentially moves to ______ ventilated areas.
more
What happens if atelectasis occurs in the dependent (non-operative) lung?
Atelectasis → HPV → Dependent lung vasoconstriction → blood shunted to non-ventilated, operative lung.
HPV is desired in the ________ lung.
operative
Not wanted in the non-operative, dependent lung.
Which drug class attenuates HPV? How so?
All VAA’s via vasodilation
What VAA dosage will start to attenuate HPV?
1 MAC
HPV being decreased will cause an ______ shunt and ________ oxygenation.
Decreased shunt and worsening oxygenation
What factors will attenuate/decrease the effects of HPV?
- VAA > 1 MAC
- Alkalosis
- Hypocapnia
- Hypothermia
- Hemodilution
- Vasodilators
What are the most common complications associated with One-Lung Ventilation?
- DLT Malposition
- Airway ETT Trauma
- Bronchospasm
- Hypoventilation
- Hypoxemia
What can occur if 100 FiO₂ is administered to a patient receiving bleomycin?
Free Radical oxidative damage & pulmonary toxicity
How is persistent hypoxemia associated with OLV treated?
- Resume two lung ventilation
- Surgeon ligation of pulmonary artery
What is the best predictor of difficult DLT placement?
CXR
What is the gold standard for cardiopulmonary fitness?
V̇O₂ Max
What is the average healthy male V̇O₂ max?
30 - 40 mL/kg/min
What is the average healthy female V̇O₂ max?
27 - 32 mL/kg/min
There is an increased risk for thoracic surgery if a patient’s V̇O₂ max is less than ________.
15 mL/kg/min
There is much less risk during thoracic surgery if a patient’s V̇O₂ max is greater than _______.
20 mL/kg/min
Complications associated with smoking are reduced as soon as __ weeks after quitting smoking.
4 weeks
________ concentrations decrease just 12 hours after quitting smoking.
Carboxyhemoglobin
What endocrine disorder can result from SCLC? Why?
Cushing’s due to SCLC causing increased cortisol production
Other than Cushing’s disease, what disorder is associated with SCLC?
Lambert Eaton Myasthenic Syndrome
How long must thoracic surgery be delayed after bare metal coronary stenting?
4 - 6 weeks
How long must thoracic surgery be delayed after drug-eluting coronary stent placement?
6 months
What is the most common concurrent disease associated with thoracic surgery?
COPD
What cardiac disease is common in COPD patients?
RV failure
What is the most common EKG complication associated with thoracic surgery?
Atrial Fibrillation
(Due to ↑ PVR & SNS stimulation)
Where should a CVL be placed on a thoracotomy patient?
Ipsilateral Non-operative side
What VAA should be avoided in thoracic surgery?
N₂O
What type of nerve injury is common with thoracic surgeries?
Brachial Plexus injuries
How is Acute Lung Injury best avoided?
- Avoid fluid overload
- Avoid hyperinflation
What typically causes acute lung injury?
- Hypervolemia
- Excessively high ventilatory pressures
