Module 10 Flashcards
Module 10: Anesthesia for Thoracic Surgery
Preoperative Evaluation
- Should focus on the extent and severity of pulmonary disease and cardiovascular involvement
- Try to determine whether the patient will be able to tolerate the planned lung resection
- Thoracic surgery is known to be associated with high risk, especially if the patient has factors such as _______(1) and poor general health or _______(2).
Patient History
- _______(3)
- _______(4)
- Exercise _______(5)
- _______(6)
- Risk Factors for _______(7)
- Hx of ETOH abuse
- Excessive perioperative fluids
- High vent pressures
- Pneumonectomy
- Pack years = _______(8) X # of years
Answers:
1. advanced age
2. pulmonary disorders
3. Dyspnea
4. Cough
5. Tolerance
6. Cigarette Smoking
7. ALI
8. packs smoked per day
Physical Exam
- Respiratory pattern – presence of cyanosis, clubbing, respiratory pattern and rate, breath sounds
- Evaluation of the cardiovascular system – important factor is the presence of an inc. pulmonary vascular resistance secondary to a fixed reduction in the cross-sectional area of the pulmonary vascular _______(1).
Pulmonary Hypertension
- The pulmonary circulation is normally a low pressure high-compliance system capable of handling an blood flow by recruitment of normally under perfused vessels.
- This acts as a compensatory mechanism that normally prevents an increase in pulmonary arterial _______(2).
- In COPD, there is a distention on the pulmonary capillary bed with decreased ability to tolerate blood flow (decreased _______(3)).
- These patients demonstrate an ______(a) PVR (pulmonary vascular resistance) when CO (can’t compensate for the increased blood flow) resulting in pulmonary _______(4).
Answers:
1. bed
2. pressure
3. compliance
a. increased
4. hypertension
Sign of Pulmonary HTN
- Narrowly split _______(1) heart sound
- Increased intensity of the pulmonary component of the _______(2) heart sound
- Right ventricular and atrial hypertrophy ↑ _______(3)
- Factors such as acidosis, sepsis, hypoxia and application of _______(4) all further increase the pulmonary vascular resistance and increase the likelihood of right ventricular failure.
- Left-sided heart function is a concern for patients with ischemic or valvular heart disease.
EKG
- COPD patients – show _______(5) atrial and right ventricular hypertrophy and strain
- Low voltage _______(6) complex due to hyperinflation and poor R wave progression across the precordial leads
- An enlarged P wave in lead II is diagnostic of _______(7)
- Right ventricular hypertrophy – R wave voltage _______(8) S wave voltage
CXR
- Hyperinflation and vascular markings
- Hyperinflation with an increased AP chest diameter and enlarged retrosternal air space
- Location of the lung lesion
- Tracheal shift? Mediastinal mass? Deviation of mainstem bronchus?
- Collapsed lobes owing to bronchial obstruction
- Review CT of the chest is useful – more information of the tumor size
Answers:
1. second
2. second
3. PVR
4. PEEP
5. right
6. QRS
7. right atrial hypertrophy
8. exceeds
ABG Analysis
- COPD – hypoventilation and CO2 retention
- The _______(1) are cyanotic, hypercarbic, hypoxemic and usually overweight.
- Chronic state of resp. _______(2) and decreased ventilatory response to CO2
- Often, patients have _______(3).
- These patients – high PaCO2 increases _______(4) fluid bicarbonate concentration
- Medullary chemoreceptors become reset to a higher level of CO2 and sensitivity to CO2 is decreased
- Need _______(5) levels of CO2 to respond
- High _______(6) causes hypoventilation due to decreased hypoxic drive
- Patients with _______(7) (pink puffers) are typically thin, dyspneic and pink and essentially normal _______(8)
- Show increased _______(9) ventilation to maintain normal PaCO2
- This explains the increase in work of breathing and dyspnea
Evaluation for Lung Resectability
There are 3 goals in performing PFTs in a patient scheduled for lung resection:
1. To identify the patient at risk for inc. post-op morbidity & mortality: How much will be safely removed without making the patient a pulmonary cripple?
2. Identify the patient who will need short term or long post op ventilatory support
3. To evaluate the beneficial effect and reversibility of airway obstruction with the use of bronchodilators
a. Is it going to _______(10) obstruction or disease?
Answers:
1. blue bloaters
2. tolerance
3. chronic bronchitis
4. CSF
5. higher
6. FiO2
7. emphysema
8. ABGs
9. minute
10. REVERSE
Procedures- Surgeries requiring one lung ventilation:
- _______(1)
- _______(2)
- _______(3)
- Great vessels
- _______(4)
- Mediastinal structures
Indications for OLV
Absolute
- Prevent contamination of healthy lung
- _______(5)
- Massive hemorrhage
- Control distribution of ventilation
- _______(6)
- Bullae
- Major bronchial trauma
- Unilateral lung lavage
- _______(7)
- Video assisted thoracic surgery
Relative
- Surgical exposure (high priority)
- Thoracic AA
- _______(8)
- Lung volume reduction
- Minimally invasive cardiac surgery
- Upper lobectomy
- Surgical exposure (low priority)
- Esophageal surgery
- Middle and lower lobectomy
- Mediastinal mass
Study Table 25-1
Indications for one-lung ventilation
Answers:
1. Lungs
2. Pleura
3. Esophagus
4. Vertebra
5. Infection
6. Fistula
7. VATS
8. Pneumonectomy
Physiological Considerations
- Mixing of unoxygenated blood from the collapse lung with oxygenated blood from the still-ventilated dependent lung widens the alveolar-arterial (A-a) O2 gradient
- _______(1)
- _______(2)
Positioning
- Table is _______(3)
- _______(4)
- Brachial plexus _______(5)
Lateral Decubitus Position
- Alters the normal pulmonary _______(6) relationships and derangements are further accentuated by _______(7) of anesthesia
- Initiation of mechanical ventilation; neuromuscular blockage; surgical retraction
- Although perfusion continues to favor the dependent (lower) lung, ventilation progressively favors the less perfused upper lung. The resulting mismatch increases the risk of _______(8).
- Schematic representation of the effects of gravity on the distribution of pulmonary blood flow in the lateral decubitus position.
- Vertical gradients in the lateral decubitus position are similar to those in the upright position and cause the creation of West zone 1,2 & 3.
“1 and 2, 2 and 3” Up/down
- Consequently, pulmonary blood flow ______(a).
Please study the following diagram:
- Distribution of pulmonary blood flow in the upright position
- Effects of gravity on the distribution of pulmonary blood flow (lateral decubitus)
Answers:
1. Hypoxemia
2. Right to left shunt
3. flexed
4. Bean Bag
5. roll
6. ventilation/perfusion
7. induction
8. hypoxemia
a. increases
Awake State
- Supine position → lateral decubitus
- V/Q is preserved during spontaneous ventilation as the _______(1) receives more perfusion than does the upper lung due to _______(2) influences on blood flow distribution in the pulmonary circulation.
- The dependent lung receives _______(3) ventilation due to:
- _______(4) of the dependent hemi-diaphragm is more ______(a).
- The dependent lung is on a more favorable part of the _______(5) curve.
The effect of the lateral decubitus position on lung compliance
Answers:
1. dependent lung (lower lung)
2. gravitational
3. MORE
4. Contraction
5. compliance
Study The effect of the lateral decubitus position on lung compliance
Answers:
1. dependent lung (lower lung)
2. gravitational
3. MORE
4. Contraction
a. efficient
5. compliance
Induction of anesthesia in the lateral decubitus position
- Decrease in FRC with induction of anesthesia moves the upper lung to a more ______(a) part of the compliance curve and the lower lung moves to a less favorable position.
- Upper lung is more ventilated than the dependent lung.
- V/Q mismatching occurs because the _______(1) continues to have greater perfusion.
- *Note: This is PRIOR to one-lung, prior to incision etc.
One Lung Ventilation, paralyzed chest open
- During two-lung ventilation in the _______(2) position, mean blood flow to the nondependent lung is assumed to be _______(3) of cardiac output (CO), whereas _______(4) of CO goes to the dependent lung
- Definitely - could see this as a T/F
- Normally, venous admixture (shunt) in the lateral position is _______(5) of CO and is equally divided as 5% in each lung.
- Therefore, the average % of CO participating in gas exchange is _______(6) in the nondependent lung and _______(7) in the dependent lung.
- Or this one
OLV creates an obligatory right to left transpulmonary shunt through the non-ventilated, nondependent lung because the V/Q ratio of that lung is ______(b).
- However, assuming active HPV, blood flow to the nondependent hypoxic lung will be decreased by 50% and therefore 35% divided by 2 = _______(8).
- To this add, 5% of the obligatory shunt thru the non dependent lung and you get _______(9).
- (This shiznit won’t be on the test)
Please study the Fractional Blood Flow Diagram
Nonventilated lung has some blood flow (obligatory shunt not present during two lung ventilation (2LV)).
The increase in shunt from 2LV to OLV is assumed to be due solely to the % blood flow through the non-ventilated, nondependent lung during OLV.
Answers:
a. favorable
1. dependent lung
2. lateral
3. 40%
4. 60%
5. 10%
6. 35%
7. 55%
b. zero
8. 17.5%
9. 22.5%
One-lung Ventilation (OLV)
- Other considerations that impair optimal ventilation to the dependent lung and combine to create a low V/Q ratio and a large P(A-a) O2 gradient include:
- Absorption atelectasis (as seen in _______(1))
- Accumulation of _______(2)
- Formation of a transudate in the _______(3) lung
The effect of anesthesia on lung compliance in the lateral decubitus position. The upper lung assumes a more favorable position, and the lower lung becomes less compliant.
Answers:
- high FiO2
- secretions
- dependent
Positive Pressure Ventilation
- Favors the _______(1) in the lateral position because it is more compliant
- Neuromuscular blockade enhances this effect
- Rigid bean bag – _______(2) of the dependent hemi-diaphragm
- [Surgically] opening the nondependent side of the chest _______(3) the differences in compliance between the 2 sides
- Resulting in _______(4) V/Q mismatching and increased risk of hypoxemia.
- Paradoxical breathing – during inspiration, the relatively negative pressure in the intact hemi-thorax can cause movement of air from non-dependent lung into the dependent lung.
- Opposite occurs during expiration.
- _______(5) ventilation or adequate sealing of the open chest eliminates paradoxical breathing
Open Pneumothorax
- Lung expansion is maintained by a negative pleural pressure
- Net result of the tendency of the lung to _______(6) and the chest wall to ______(a).
- When the side of the chest wall is opened – negative pressure is _______(7).
- Elastic recoil of the lung on that side tends to collapse
- Spontaneous ventilation with an open pneumothorax in the lateral position results in:
- _______(8)
- _______(9)
Answers:
- upper lung
- restricts movement
- accentuates
- increased
- Positive pressure
- collapse
a. expand - lost
- paradoxical respirations
- mediastinal shift
Mediastinal shift
- During spontaneous ventilation (SV) in the lateral position:
- Inspiration causes pleural pressure to become more negative on the _______(1) side, but not on the side of the open pneumothorax.
- _______(2) of the mediastinum during inspiration
- _______(3) during expiration.
- Major effect of the mediastinal shift is to decrease the contribution of the _______(4) lung to the tidal volume.
- Can cause circulatory and reflex changes that are similar to shock and respiratory distress
- You HAVE to reduce your _______(5)
Mediastinal shift in a spontaneously breathing patient in the lateral decubitus position.
Answers:
1. dependent
2. Downward shift
3. Upward shift
4. dependent
5. Tidal Volumes
Intraoperative Monitoring
- Mediastinoscopy:
- Arterial line placement (down arm)
- Want to identify if artery compression occurs
- Pulse Oximetry (_________(1))
- _________(2) of the innominate artery
- Bleeding
- What is the purpose: Node biopsy vs. mass resection?
- Large bore IV
- Head of bed turned to surgeon
- _________(3)
Answers:
- opposite side of arterial line
- Compression
- Airway compromise
Intraoperative Monitoring
- Thoracotomy:
- One lung ventilation (OLV)
- Arterial line (down arm)
- 2 large bore IV’s
- Central line +/-
- T & C PRBC (at least T & S- She would not recommend)
- Foley
- Keep the patient dry (IVF)- _______(1) and other volume expanders
- Pain control
- Positioning: _______(2)
- Thoracoscopy (aka VATS)
- OLV
- 1 or 2 large bore IVs
- For diagnosis (wedge bx or lung resection?)
- Pleurodesis
- Arterial line +/-
- _______(3) position
- T & C or T & S, depending on extent of case
- Pain control
Answers:
1. Albumin
2. lateral decubitus
3. Lateral
Double Lumen Endobronchial Tubes
- A longer bronchial lumen enters the right or left main bronchus and shorter tracheal lumen
- Performed curve that when properly aimed allows entry into a _______(1)
- A _______(2) cuff
- A _______(3) cuff
- Sizes 35, 37, 39 and 41 _______(4)
Please study the Anatomy of the tracheobronchial tree. Note bronchopulmonary segments (1–10) as numbered.
Answers:
- bronchus
- bronchial
- tracheal
- Fr
Anatomic Considerations
- Trachea is ~11-13 cm long and begins at the level of the _______(1) C-6
- Bifurcates at the level of the carina behind the _______(2) joint
- Major differences between Right and Left Bronchi:
- Right bronchus _______(3) diameter and diverges away from the trachea at a less _______(4) angle
- Left bronchus diverges away at a more horizontal angle.
Major Differences
- Right bronchus has 3 lobes, left bronchus has 2 lobes
- Orifice of the right bronchus 1-2.5 cm
- Makes doing the right sided _______(5) more difficult due to short distance before branching into right upper bronchi
- Orifice of the left bronchus 5 cm
- Occasionally the right upper lobe bronchus will arise from the trachea itself.
Correct position of a left and right _______(6)
Methods of Lung Separation
- Double lumen endobronchial tube (DLT)
- Bronchial Blocker
Answers:
- cricoid cartilage
- sternomanubrial
- larger
- acute
- DLT (Double Lumen Tube)
- DLT
Double Lumen Endobronchial Tube
- Essentially, 2 ETTs bonded together
- 2 lumens
- Tracheal lumen
- Bronchial lumen (mainstem bronchus)
- 2 lumens
- 2 cuffs
- Proximal tracheal cuff
- Distal bronchial cuff
- Right and left-sided
- Right-sided → opening to permit ventilation of _______(1)
- Minimize risk of occluding _______(2)
- _______(3) DLTs is recommended for both left and right-sided procedures
- Select largest DLT that will safely fit the bronchus
- Width of left main bronchus is directly proportional to tracheal width
- (tracheal width x _______(4))
- Women 35-37 _______(5)
- Men 37, _______(6)
- 35 Fr has been used safely
- Width of left main bronchus is directly proportional to tracheal width
- Depth correlates with height
- 170 to 180 cm ~ _______(7) deep for left-sided DLT
- For every 10 cm ↑ or ↓ in height, advance or withdraw _______(8) cm
- Essentially, _______(9) is standard, if short 28, if tall 30
- 170 to 180 cm ~ _______(7) deep for left-sided DLT
Left-sided DLTs
- Used for most surgical procedures irrespective of the operative site. However, there are certain clinical situations in which the use of a _______(10) DLT is recommended
- Distorted anatomy of the left main bronchus by an intrabronchial or extra bronchial mass
- Compression of the left main bronchus due to descending thoracic aortic _______(11)
- Left sided _______(12)
- Left sided single lung _______(13)
- Left sided _______(14) resection.
Answers:
- RUL (Right Upper Lobe)
- RUL
- left sided
- 0.68
- Fr
- 39-41 Fr
- 29 cm
- 1.0
- 29
- right-sided
- aneurysm
- pneumonectomy
- transplantation
- sleeve
Double Lumen Endobronchial Tube
- Prepare and check DLT
- _______(1) using 10 ml syringe
- _______(2) using 3 ml syringe
- Coat liberally with H2O soluble lubricant
- Withdraw and lubricate stylet and replace without changing _______(3)
- MAC blade preferred
- Pass tube with distal curve facing anteriorly
- Once tip passes through cords,
- remove stylet and
- _______(4) 90 degrees to the left (right angle)
- Advance DLT until moderate resistance encountered
- Gently and under direct _______(5)
Placement of a left-sided double-lumen tube. Note that the tube is turned 90° as soon as it enters the larynx. A: Initial position. B: Rotated 90°. C: Final position.
Answers:
- Tracheal cuff
- Bronchial cuff
- curvature
- rotate tube
- laryngoscopy
Double Lumen Endobronchial Tube
- Inflate tracheal cuff & auscultate bilateral breath sounds
- If breath sounds unequal, DLT likely down too far; tracheal lumen in mainstem or at carina; _______(1)
- Clamp tracheal lumen of DLT and open cap (use “rubber-shod clamp”)
- Slowly inflate bronchial cuff to eliminate leak (usually not > 2 ml air)
- Remove clamp and make sure that _______(2)
- Clamp each side selectively
- Watch for absence of movement and breath sounds on ipsilateral side
- Ventilated side should have clear breath sounds
- Chest movement should feel compliant
- Gas moisture seen with each TV
- No gas leak
- PAWP
- _______(3) = 20 cm H2O,
- THEN during OLV should not _______(4) for same TV
Answers:
- withdraw 2 to 3 cm
- bilateral breath sounds can be auscultated
- during 2LV
- exceed 40 cm H2O
Double Lumen Endobronchial Tube cont.
- Check the placement with Fiberoptic Bronchoscopy (FOB)
- First introduce the FOB through the tracheal lumen
- Visualize _______(1)
- No bronchial cuff _______(2) should be seen (above the carina)
- Upper surface of blue endobronchial cuff should be just below the tracheal carina.
- It will look like a sliver of the moon.
- Visualize _______(1)
- Then introduce FOB through bronchial lumen
- _______(3) bronchial orifice should be identified
- Right-sided DLT must visualize the orifice of the _______(4) bronchus
- First introduce the FOB through the tracheal lumen
The view of the carina looking down the tracheal lumen
Answers:
- carina
- herniation
- LUL (Left Upper Lobe)
- RUL (Right Upper Lobe)
TABLE 25–2
Protocol for checking placement of a left-sided double-lumen tube.
- Inflate the tracheal cuff (_______(1)).
- Check for _______(2) breath sounds. Unilateral breath sounds indicate that the tube is too far down (tracheal opening is _______(3)).
- Inflate the _______(4) cuff (1–2 mL).
- Clamp the tracheal _______(5).
- Check for unilateral left-sided breath sounds.
a. Persistence of _______(6) breath sounds indicates that the bronchial opening is still in the trachea (tube should be advanced).
b. Unilateral right-sided breath sounds indicate incorrect entry of the tube in the _______(7) bronchus.
c. Absence of breath sounds over the entire right lung and the left upper lobe indicates that the tube is too far down the left _______(8). - Unclamp the tracheal lumen and clamp the bronchial _______(9).
- Check for unilateral right-sided breath sounds. Absence or diminution of breath sounds indicates that the tube is not far enough down and that the bronchial cuff is occluding the _______(10) trachea.
Answers:
1. 5–10 mL of air
2. bilateral
3. bronchial
4. bronchial
5. lumen
6. right-sided
7. right
8. bronchus
9. lumen
10. distal
Answers:
1. 5–10 mL of air
2. bilateral
3. bronchial
4. bronchial
5. lumen
6. right-sided
7. right
8. bronchus
9. lumen
10. distal
DLT troubleshoot
- Malpositioned: accidentally directed to wrong _______(1)
- Inadequate _______(2)
- Increased airway _______(3)
- Instability of the _______(4)
- Lung opposite of the lumen will _______(5)
- Tracheal or bronchial lacerations due to _______(6)
- Obstruction of _______(7)
- Inserted too far _______(8)
- Diminished or inaudible breath sounds over _______(9) side
- Withdraw tube so that tracheal lumen is above _______(10)
- Not inserted far _______(11)
- Bronchial lumen above carina (bronchial cuff occludes flow from tracheal lumen)
- Good breath sounds heard bilaterally when ventilating through _______(12) lumen
- No breath sounds audible when ventilating through _______(13) lumen
- Deflate bronchial cuff, rotate, and _______(14)
- Bronchial lumen above carina (bronchial cuff occludes flow from tracheal lumen)
- RUL or LUL orifice may be _______(15)
- Possible if using right or left-sided DLT, respectively
- Bronchial cuff _______(16)
- Completely obstructs the _______(17) bronchus
- Can herniate over the carina and obstruct the right _______(18) bronchus
- Tracheal or bronchial _______(19)
- Overinflation of the bronchial _______(20)
- Inappropriate positioning
- Trauma due to intraoperative dislocation
- Bronchial Cuff
- Cuff should be deflated during positioning unless separation absolutely required
- Keep cuff deflated and inflate slowly when needed
- Assess pressure in cuff and deflate as needed
- Postoperative hoarseness
Answers:
1. mainstem
2. separation
3. pressures
4. DLT
5. collapse
6. curvature
7. RUL
8. down
9. contralateral
10. carina
11. enough
12. bronchial
13. tracheal
14. advance
15. obstructed
16. herniation
17. mainstem
18. mainstem
19. rupture
20. cuff
Bronchial Blocker
1. Use with single-lumen ETT
a. Inflation of cuff at distal end of blocker blocks ventilation to that lung
i. High distending pressure
ii. Can slip out of bronchus easily (change in position, surgical manipulation)
b. Lumen of blocker permits suctioning distal to catheter tip
2. Do not have to change ETT at end of case
3. Can apply CPAP through blocker lumen
4. Univent tube
a. Single-lumen ETT with a movable endobronchial blocker
b. Blocker contains a high-volume, low pressure balloon
c. Angled to permit external direction into desired bronchus using fiberoptic bronchoscope
5. Drawbacks
a. May be difficult to maintain position of blocker
b. Satisfactory seal sometimes difficult to achieve
c. External diameter is large
Snare-guided bronchial blocker
1. Wire-guided catheter with a loop snare
2. Requires at least an 8.0 single-lumen ETT
3. Scope passed through loop and guided into desired bronchus
4. Blocker then slid distally over the scope and into the bronchus
5. Placement and bronchial occlusion confirmed under visualization
6. Wire removed
7. Hollow lumen for suction to facilitate collapse and insufflation of O2
8. “Flexi-Tip” independent bronchial blocker
a. Made so that user can deflect the tip into the desired bronchus
b. Can be placed ahead of the fiberoptic bronchoscope
c. Can be used with a smaller ETT (7.0)
Answers:
1. ETT
2. high-volume, low pressure
3. fiberoptic bronchoscope
4. Wire-guided
5. 8.0 single-lumen
6. O2
7. Flexi-Tip
8. 7.0
Lung Separation
- Tracheostomy
o _______(1)
- Difficult airway
o _______(2) using flexible fiberoptic bronchoscope
o _______(3)
o Single lumen tube
o _______(4)
o Exchange for _______(5)
- Tube Exchanger
o 11 Fr exchanger will pass through a 35 to 41 Fr _______(6)
o 14 Fr will not pass through 35 Fr _______(6)
o Passage of tube over guide past supraglottic tissues should be facilitated using _______(7)
Please study the diagram of Lung Separation
Answers:
1. Bronchial blocker
2. Awake intubation
3. DLT
4. Bronchial blocker
5. DLT
6. DLT
7. Laryngoscopy
When OLV is initiated:
- FiO2 1.0
- Ventilate dependent lung
o TV 6 to 8 ml/Kg (avoid increased risk for acute lung injury (ALI) due to over distention and stretching of lung parenchyma)
o _______(1) < 25 cm H2O
o _______(2) 35 +/- 3 mmHg
- Hypercapnia
- increases vascular resistance in the _______(3)
- Inhibits HPV in the nondependent lung
- Increases shunt and decreases PaO2
- Apply _______(4) 5 - 10 cm H2O to dependent lung
- Frequent lung recruitment maneuvers
o Reverse alveolar collapse, hypoxemia, and decreased compliance
OLV Management
- _______(4) 5 - 10 cm H2O to Dependent Lung
o Increases lung volume at end-expiration (FRC)
o Improves the V/Q relationship in the _______(5)
o Prevents airway and alveolar _______(6)
- PaO2 < 80 mmHg and diseased dependent lung (low lung volume and low V/Q ratio)
o May increase FRC to normal values
o May lower PVR
o May improved V/Q and PaO2
- Higher PaO2 (≥ 80 mm Hg) and adequate FRC
o May cause increased PVR
o May divert blood flow to nondependent lung
o May increase shunt and decrease PaO2
CPAP to Nondependent Lung
- CPAP 5 to 10 cm H2O
o “Single most effective maneuver to increase PaO2 during OLV”
o Maintains patency of _______(7)
o Allowing some O2 uptake
o Diverts blood flow away from non-ventilated lung
- Often not acceptable for optimal surgical exposure
- _______(8) will also significantly improve PaO2
Answers:
1. Plateau airway pressure
2. Respiratory rate to maintain PaCO2
3. dependent lung
4. PEEP
5. dependent lung
6. closure at end-expiration
7. nondependent lung alveoli
8. Intermittent re-inflation of collapsed lung with O2
Management of OLV
- If the _______(1) > 40 cm H2O
o Check for _______(2)/TB malposition
- Hypoxemia
o CPAP 10 cm H2O to nondependent lung (not during VATS)
o _______(3) 5 to 10 cm H2O to ventilated lung if additional correction needed
o If necessary, intermittently inflate and deflate the operated lung
- Resume 2LV until problem resolved
o Unstable
o Hypotensive
o Dusky
o Tachycardic
- Expect dysrhythmias and periods of hypotension due to surgical manipulation
o Have vasopressors readily available
One Lung Ventilation
At the conclusion of the surgery:
- Excessive secretions or edema may contraindicate extubation
- Bronchial blocker may be withdrawn
- _______(2) is generally NOT left in place
o Difficult to suction distal to the endobronchial lumen
o Can be easily dislodged
o Inexperienced caretakers
- Use Cook Tube Exchanger & place single-lumen ETT
HPV During OLV (Hypoxic pulmonary vasoconstriction)
- Factor governing redistribution of blood flow during OLV
o Thought to be able to decrease blood flow to non-ventilated lung by 50%
o _______(4) is primarily alveolar O2 tension (PAO2)
o _______(5) precapillary vasoconstriction
- Redistribution of blood flow away from hypoxemic lung regions
- Collapse of non-ventilated, nondependent lung
o Activation of the HPV reflex in the lung
o Causes local increases in PVR (pulmonary)
o Diverts blood flow to better oxygenated parts of pulmonary vasculature (dependent oxygenated and ventilated lung)
Answers:
1. PAWP (Pulmonary Artery Wedge Pressure)
2. DLT (Double Lumen Tube)
3. PEEP (Positive End-Expiratory Pressure)
4. Stimulus
5. Stimulates
Effects of GA on HPV
- Inhibit or antagonize HPV → Increased blood flow to hypoxic region
- Volatile Anesthetics
- Inhibit HPV in a dose-dependent manner
- In doses less than or equal to 1 MAC, modern volatile anesthetics are weak, _______(1) of HPV (keep it low)
- Isoflurane, sevoflurane, desflurane
_______(2) does not readily improve oxygenation when compared with 1 MAC of modern volatile anesthetics
- Vasodilator drugs
o NTG, SNP
- _______(3)
- Metabolic alkalosis/acidosis
- Surgical trauma
o Causes local release of vasoactive metabolites
o Autonomic effects due to trauma to the perihilar plexus
- Cardiac Output
o ______(a) CO→ increased PAP passive dilatation of pulmonary vascular bed
- Opposes HPV and increases shunt
- Increases mixed venous O2 saturation
o Increasing CO to supranormal levels (inotropes) has negative impact on PaO2
o Allowing CO to fall will lead net effect of decreased PaO2
o Very important to maintain CO during OLV!
Answers:
1. equipotent inhibitors
2. TIVA (Total Intravenous Anesthesia)
3. Hypocarbia
a. Increased
Fluid Management for OLV
- Hydrostatic effects of excessive fluids can cause increased shunting or pulmonary edema of dependent lung
- Replace volume deficits and maintenance only
- _______(1)
OLV Management
- ______(a) should be avoided in Thoracic Anesthesia
- N2O/O2 mixtures are more prone to cause atelectasis in poorly ventilated lung than O2 alone or air/O2 mixtures
- N2O tends to increase PAP in patients with pulmonary HTN
- N2O inhibits HPV
- N2O is contraindicated in patients with blebs or bullae
Temperature
- Heat loss due to surgery (open hemithorax)
- _______(2)
- Maintain body temperature
o Increase ambient room temperature
o Use fluid warmers
o Use forced-air warmers or other warming devices
Postoperative Pain Control
- Adequate pain control is essential to ensure good respiratory effort and pulmonary toilet
- Regional anesthesia is ideal (next slide)
- IV opioids may cause
o Sedation
o Respiratory depression
- PCA
o Decreases pain, drug use, sedation, pulmonary complications
- _______(3)
o _______(4) as adjunct to epidural analgesia
Answers:
1. No volume replacement for “third spacing”
a. Nitrous Oxide
2. Hypothermia inhibits HPV
3. Ketamine
4. Infusion 0.05 mg/kg/hr
Postoperative Pain Control- Regional
- _______(1)
o Easiest for surgeon to perform under direct vision while chest is open
o 0.5% bupivacaine at incision and around chest tube sites
- Intrapleural analgesia
o Local anesthetic placed by surgeon via catheter with chest open
- Thoracic epidural or subarachnoid LA opioids
o If opioids are included, then must monitor for delayed respiratory depression
Postoperative Complications
- _______(2) → most significant cause of postoperative morbidity
o More commonly in basal lobes
o Reduction of normal effort due to splinting
o Obesity (Sit upright, remove pressure from diaphragm)
o Intrathoracic blood/fluid accumulation
o Poor cough with limited airway clearance of secretions
o Mucous plug
o Suction those airways bros
- Results in:
o Decreased compliance
o Rapid, shallow breathing
o Small airway closure
o Obstruction with secretions
o Alveolar air reabsorption and terminal airway collapse
- _______(2)
o CXR
o Clinical findings
o ABGs
- Resolve:
o Increase FRC (Incentive spirometry, CPAP)
o Increase transpulmonary pressure
o Increase compliance
- Bronchodilator therapy
- Coughing and clearance of secretions
- Chest PT
- Mobilizing patients
- Adequate analgesia
Answers:
1. Intercostal nerve blocks
2. Atelectasis
Cardiovascular Complications
- “Low cardiac output syndrome” (next slide)
- Must rule out:
o Pericardial effusion/tamponade
o Hypovolemia
o Pulmonary emboli
o Effects of PPV/PEEP
o Fluid overload/pulmonary edema
- “Low cardiac output syndrome” due to reduction of pulmonary vascular bed leading to right-sided heart failure
- Treat with _______(1) + _______(2)
- Watch for cardiac dysrhythmias and rule out underlying cause
o _______(3)
Hemorrhage or Pneumothorax
- Slow or rapid development of hypovolemic shock or tension pneumothorax
- _______(4) requires surgical re-exploration to rule out hemorrhage
- Chest tubes
o Bottles/systems must be kept below the level of the chest
o Chest tubes must not be clamped during transport
- Dehiscence of surgical stump
o Avoid increased airway pressures!
Postoperative complications
More serious complications:
- ______(a) present from sudden large air leak with an increasing pneumothorax and partial lung collapse
- Severe bleeding
- ______(b) of the lobe causing venous obstruction
- Acute ______(c) of the heart through pericardial defect from ______(d)
- Injuries to the phrenic, vagus, or left recurrent laryngeal nerves
Answers:
1. vasodilator
2. inotropes
3. Hypoxemia
4. Drainage of > 200 ml/hr of blood
a. Bronchopleural fistulae
b. Torsion
c. herniation
d. pneumonectomy
Myasthenia Gravis
- Autoimmune disorder; a disorder of the neuromuscular junction
- Diagnosis is suspected by patient’s history, confirmed by clinical, pharmacologic, electrophysiologic or immunologic testing
- Associated with relapses and remissions
- People of any age may be affected, but peaks of incidence occur in the third decade for women and fifth decade for men
- Chronic disorder characterized by clinical course of fluctuating painless weakness and fatigability of voluntary muscles with improvement following rest.
- Most common onset is _______(1); onset is slow and _______(2)
- Any skeletal muscle or group of muscles are affected
- If disease remains localized to the eyes for 2 years then the likelihood of progression is low
- Some cases involve breathing and swallowing
- A _______(3) in the # of postsynaptic acetylcholine receptors at the endplates of affected muscles
- _______(4) to non-depolarizing muscle relaxants (NDMR)- Don’t mix this up with the quiz question that was false
- Anticholinesterases are used to prolong the action of acetylcholine at the postsynaptic membrane
- Muscarinic side effects are treated with _______(5)
- Long term treatment of the disease is _______(6)
- Clinical outcome for thymectomy is equivalent whether performed via a _______(7) or video assisted thoracoscopic approach
Answers:
1. ocular
2. insidious
3. decrease
4. Sensitive
5. atropine
6. surgical thymectomy
7. transsternal
Management of GA with Myasthenia Gravis
- Patients with MG should ideally be scheduled as the ______(a) case of the day
- Discuss the _______(1) with the surgeon and the patient
- Anticholinesterase therapy generally _______(2) (avoids interactions)
- Opioids usually avoided due to risk of respiratory depression
- Induction with Propofol and intubation with deep inhalation agent preferred
- Sensitivity to NDMR
- _______(3) (ED95 is 2.6 times normal)
Other surgeries requiring OLV
- Esophagectomy – used to treat cancers and perforations of the esophagus
- Thoracic aneurysm repair
- Video assisted thoracoscopies (VATS) for various diagnosis
Answers:
a. first
1. possibility of post-op ventilation
2. withheld on the morning of surgery
3. Resistant to succinylcholine
Single Lung Transplantation
- Often attempted without CPB
- Performed through a posterior thoracotomy
- _______(1) (SPO2 < 88%) or a sudden _______(2) in the PAP = conversion to CPB
- Goals are to reduce pulmonary HTN and prevent right ventricular heart failure
- Inotropic support may be necessary
- After recipient lung is removed, the pulmonary artery, left atrial cuff (pulmonary veins) and bronchus of the donor lung are anastomosed
- _______(3) is utilized to examine the bronchial suture line
Double Lung Transplantation
- Sternotomy for double lung and heart-lung transplantation
- _______(4) or sequential thoracotomies for double lung transplantation
Answers:
1. Persistent arterial hypoxemia
2. increase
3. Flexible bronchoscopy
4. Cardiopulmonary Bypass (CPB)
Post Transplantation Management
- After transplantation, ventilation to both lungs is resumed.
- Peak pressures maintained at minimum pressure compatible with good lung expansion.
- Inspired FiO2 should be maintained as close to room air as possible while maintaining a PaO2 > 60 mmHg.
- _______(1) and _______(2) are often administered
- ______(a) may occur due to washout of the donor organ
- If CPB is employed then weaning from CPB is necessary.
- Pulmonary vasodilators, inhaled nitric oxide and inotropes may be needed
- TEE
- _______(3) (Can’t expel lower secretions)
- Bronchial hyperreactivity in some patients
- Predisposition to pulmonary edema
Answers:
1. Methylprednisolone
2. mannitol
3. Cough reflex is abolished below the carina
a. Hyperkalemia
