Thoracic Surgery Flashcards
Leading cause of cancer deaths in the US
Bronchogenic tumors
Is it better for prognosis to resect or radiate/chemo bronchogenic tumors?
resect
Advantages of VATS vs. open surgery
Decrease in post-op complications:
- Dysrhythmias
- MI
- PE
- Pneumonia
- Empyema
COPD patients are how many times more at risk of getting lung cancer
4x
Risk factors for bronchogenic tumors
Smoking, air pollution, industrial chemicals
If lung cancer patient also needs coronary bypass, which procedure should be done first?
- Coronary bypass
- 6 week delay if this is needed
What electrolyte abnormality occurs in up to 25% of lung cancer patients? What are the signs and symptoms?
Hypercalcemia
S/S: polyuria, polydipsia, confusion, vomiting, abdominal cramping, bradycardia
Smokers should be evaluated for what conditions prior to thoracic surgery?
HTN or ischemic heart disease
Patients with history of COPD need what type of testing prior to thoracic surgery?
Stress testing
Why do patients requiring thoracic surgery for lung cancer require endocrine evaluation?
To rule out para-neoplastic syndromes caused by some lung tumors
- Can cause carcinoid syndrome
Airway evaluation required for mediastinal masses
Radiographic
To determine if there is airway infringement
Symptoms of COPD
- Paradoxical breathing
- Tympanic chest percussion
- Rhonchi
- Wheezing
Symptoms of Cor pulmonale
- JVD
- Peripheral edema
- Split S2
- Rales
What are we looking for on chest x-ray of patient with lung cancer?
Evaluating for:
- airway infringement
- CHF
- pneumothorax
- tracheal shift
- PA enlargement
What does PA enlargement indicate on CXR?
Sign of increased pulmonary vascular resistance
EKG abnormality seen in RVH
Tall R in V1
EKG abnormality seen in R atrial hypertrophy
Biphasic P in V1
EKG abnormality combo indicative of increased risk of ischemia/infarction
Pathologic Q waves + LVH
Other EKG abnormalities we are looking for pre-op
S-T depression, BBB, T wave inversion
Best initial tool to evaluate pulmonary HTN?
Caveat?
Echo is best initial tool
BUT, higher level studies may need to follow
What room air ABG value indicates poor function in a COPD pt?
CO2 >45
Lab values indicative of increased risk of post-op complications
- SpO2 <90
- Albumin <3.6 g/dL–> increases risk 2.5 times
- BUN >22 mg/dL
- Renal function labs elevated esp. in chemo
- Electrolytes (Na, K, Ca especially)
Why does low albumin place patient at higher postop risk of complications?
Makes them prone to third-spacing and pulmonary edema
Which test is best predictor of pulmonary function?
No one test is good predictor
- Multi-modal testing is best
One pulmonary function test evaluates responsiveness to bronchodilators. How much of an improvement should be seen?
12% increase
What are general cut-offs in pulmonary function for increased risk?
- Predicted Post-op FEV1 and DLCO <40%
- PPO VO2 max <15 ml/kg/min
VO2 max of pt with inability to climb 1 flight of stairs
< 10
VO2 max of >20
Ability to climb 5 flights of stairs
Risk of complications in non-cardiac surgery for smokers?
Previous smokers?
Non-smokers?
- Smokers= 22%
- Past smokers = 13%
- Non-smokers - 5%
What percent of lung cancer patients are smokers?
87%
Mortality for smokers vs non-smokers in lung cancer
- 5% in smokers
0. 4% in non-smokers
Calculate pack year index for patient who smoked
0.5 pack/day for 14 years
7 pack year
What pack year has increased incidence of complications over “moderate smokers”?
> 20 pack year
How long before surgery must patient quit smoking to see risk reduction?
Best time to quit smoking before surgery?
- > 4 weeks
- At least 8 weeks before has more improvement
why might smoking cessation 4 days before surgery actually increase risk?
Increased mucus production
How does smoking cessation 1-2 weeks before surgery affect lung function?
Does this improve outcomes?
- Carboxyhemoglobin drops and mucociliary clearance improves
- no difference in outcomes
Best 2 leads to monitor during surgery
- Lead II for dysrhythmias
- V5 for ischemia
Which arm should art line be placed in for thoracotomy?
Dependent arm
Does PA catheter improve outcomes in thoracic surgery?
No
Frequent inaccurate measurements
Caution in vessels that could be clamped or ligated
Problem with EJs in thoracic surgery
Easily kinked in the lateral position
You are going to place a subclavian CVL to monitor CVP on your patient with lung cancer in the OR prior to excision of the mass. Which side should you place the CVL?
On the operative side so that if you do cause a pneumo its not in your one decent lung, its in the one they are about to operate on anyways
Tell me about the trachea
- Where does it begin?
- How long is it?
- Where does it bifurcate?
- Begins at C6
- 11-12 cm long
- Bifurcates at T5 (sternomanubrial joint)
Tell me about the Right Mainstem Bronchus
- Is it narrower or wider than the left?
- Degree of angle from the trachea
- What does it divide into?
- Where is the orifice from the carina?
- Wider than left
- angles away from trachea at 20 degrees
- Divides into 3 lobar branches
- Orifice of right upper lobe 1-2 cm from carina
Tell me about the Left Mainstem Bronchus
- Is it narrower or wider than the right?
- Degree of angle from the trachea
- What does it divide into?
- Where is the orifice from the carina?
- Narrower than right
- Angles away fro trachea at 45 degree
- Divides into 2 lobar branches (upper, and lower)
- Orifice of left upper lobe 5 cm from carina
Pressures in lung zone 1
PA > Pa > Pv
Pressures in lung zone 2
Pa > PA > Pv
Pressures in lung zone 3
Pa > Pv > PA
If a patient is laying supine, where is each lung zone?
Zone 1 is anterior
Zone 2 is the axilla
Zone 3 is posterior
In awake, spontaneous ventilation where is perfusion and ventilation best?
bases of lungs
Why is ventilation better in the bases?
- More negative pressure in the apices keep alveoli distended
- Alveoli in bases are less distended and more compliant, so most tidal breathing distributed to bases
Effects of awake patient laying lateral on V/Q
- Better ventilation of dependent lung
- Perfusion higher in dependent lung (gravity)
- No significant change in V/Q
Effect of laying lateral on diaphragm
Cephalad diaphragm displacement and reduced FRC
Effect of anesthetized patient with spontaneous ventilation laying lateral with chest closed on V/Q
- Nondependent lung is more compliant- so increased ventilation
- Dependent lung is more perfused because of gravity
- Result is V/Q mismatch
V/Q in mechanically ventilated paralyzed patient lying lateral with chest closed
What intervention can change this?
- diaphragm no longer helping maintain FRC
- Further decrease in ventilation in Dependent lung
- Increased ventilation in non-dependent lung
- More V/Q mismatch
Add PEEP to improve FRC and lessen V/Q mismatch
How does PEEP lessen V/Q mismatch?
Improves FRC
Effect of anesthetized patient with an open chest laying lateral on V/Q
- Huge reduction in resistance in non-dependent lung
- Increased ventilation to non-dependent lung
- Further decreased ventilation in dependent lung
- Mediastinum shifts downward d/t loss of negative intrathoracic pressure
- Vessels can be compressed and decrease CO
What would happen if we theoretically had a patient with an open chest spontaneously ventilating?
Would this ever be a good idea?
Paradoxical inefficient exchange
- On inspiration, air moves from the open-chest non-dependent lung into the dependent lung
- On expiration, air moves from the dependent lung to the non-dependent lung
- Net result: tidal volume moves back and forth between the lungs
- not good, use mechanical ventilation
- Mechanical ventilation helps but non-dependent lung is still much better ventilated while dependent lung is much better perfused
- Still have shunt in dependent lung
What is a shunt?
Perfusion without ventilation
What is dead-space ventilation?
Ventilation without perfusion
Effect of mechanical positive pressure ventilation on V/Q in a mechanically ventilated, lateral, paralyzed open-chest pt
Paradoxical respiration and mediastinal shift are reduced
High compliance of the non-dependent lung in the open chest still results in huge V/Q mismatch
What patient has the worst V/Q mismatch?
Lateral, anesthetized, paralyzed, open chest patient
How does one lung ventilation decrease V/Q mismatching?
- Ventilation stops in non-dependent lung and is diverted to dependent lung
- Perfusion to non-dependent lung now creates shunt
- Hypoxic pulmonary vasoconstriction in non-dependent lung diverts perfusion to dependent lung to decrease effect of shunt
What exactly is “hypoxic” in HPV? the arterial blood or alveolar?
Hypoxic ALVEOLI in lung that is not receiving ventilation causes vasoconstriction to that lung
Patient related reasons for one-lung ventilation
- Lung abscess
- Copious bleeding on one side
- Bronchopulmonary fistula
- Bronchial rupture
- Large lung cyst
- Bronchopleural lavage
Surgical reasons for one-lung ventilation
- Thoracic aortic aneurysm
- Pneumenectomy
- Upper lobectomy
- Lower/middle lobectomies
- Sub- segmental resections
- Esophageal surgery
Which sided DLT is most commonly used?
Why?
Left sided tube
Because it is easy to miss the Right upper lobe when using right sided DLT is not positioned perfectly
Contraindications for using L DLT
- Distorted L main bronchus due to mass
- Compression of L main bronchus due to aortic aneurysm
- Left-sided pneumonectomy
- Left sided single lung transplantation
- Left sided sleeve resection
Most common compliction of DLT
Malposition
DLT complications other than malpositioning
- Thoracic aneurysm rupture
- Vocal cord damage from carinal hook, or hook breaking off
- Bronchial cuff rupture due to overinflation
- Barotrauma if DLT inserted too deeply
- Inadvertent suturing of DLT to bronchus
You go to remove your DLT at the end of surgery on left lobe and you deflate your cuff but it feels stuck.. should you just yank on it really hard???
NO
- surgeon may have accidentally sutured your tube to the L bronchus
Blue tube is the tracheal or bronchial lumen?
Bronchial
Stylet should be in which lumen of DLT?
Bronchial
How to insert DLT
- Insert with anterior curve, over and under shotgun with bronchial lumen on top, through the vocal cords
- Then turn 90 degrees towards the bronchus (usually L) and advance until resistance
How to auscultate for DLT placement
- Inflate the tracheal cuff (5-10 ml)
- Check for BBS (unilateral BS = too deep)
- Inflate bronchial cuff (1-2 ml)
- Clamp tracheal lumen
- Check for unilateral L BS (L side DLT)
(I ended up splitting the rest of the steps up to make it easier)
Is auscultating sufficient for checking placement of DLT?
If not, what should you use?
No, up to 80% of DLTs are malpositioned when verified by auscultation only
Use a fiberoptic scope down the tracheal side to confirm
You should recheck placement of DLT with fiberoptic after what?
After you reposition patient into lateral position
What is a bronchial blocker and what is the purpose?
Catheter with inflatable balloon
To block operative lung bronchus
Advantages of bronchial blocker
- May be better with difficult airway than DLT
- When ETT change is risky
- Can be used in children
Disadvantages of bronchial blocker
- Higher incidence of malposition than DLT
- Lung deflation less effective than DLT
- No ability to suction below balloon
- Must caution with removal in dirty lung cases
- Also same problem as DLT with missing RUL, so only use for L sided surgery
Without HPV, what percent shunt would result?
40%
How quickly does HPV occur?
How long until max effect?
How long can it be maintained?
Occurs with seconds of hypoxia
Max effect in a few mins
Can be maintained for long periods
How much of lung must be hypoxic for HPV to occur and improve sat?
20-80%
Usual condition with one-lung ventilation
Things to avoid that prevent effective HPV
- Alkalosis/hypocapnea
- Excessive PIP, TV, or PEEP
- Hemodilution/hypervolemia (L atrial pressure >25 mmHg)
- Prostacyclins
- Hypothermia
- Vasodilators, PDE inhibitors, Calcium channel blockers
- > 1.5 MAC of volatiles
Which is better- TIVA or volatiles for one lung ventilation?
No difference in outcomes
- TIVA does not inhibit HPV
- Volatiles <1.5 MAC do not inhibit HPV
- Volatiles are a good choice due to bronchodilation, allow for high FiO2, and rapidly eliminated for emergence
Anesthetic considerations for use of NMB in one lung ventilation
- Use intermediate relaxants
- Monitor
- Avoid residual blockade
What is required for open-lung case?
GA
Advantages of regional for one lung ventilation
- Good choice for post-op pain control
- Vasodilation from epidural does not seem to affect local HPV
Respiratory effects of pain on pt with one lung ventilation
- Same response as heavy opioids
- Decreased respiratory effort
- Hypoxemia
- Acidosis
Pain control options for thoracic surgery patient
- IV PCA
- Thoracic epidural (T6-T8)
- Paravertebral nerve block
- Ketamine
- NSAIDs
Protective ventilation strategies for thoracic surgery: Tidal volumes? PEEP? PiP? CO2 goal? etc
- Physiologic tidal volumes: 6-8 ml/kg (less needed on left)
- PEEP (as low as possible) to dependent lung
- Limit peak inspiratory pressure to 20-25 cm H20
- Permissive hypercapnia (<60 mmHg) to support HPV
- Air/O2 mix at lowest level that maintains PaO2 (100% O2 frequently needed tho)
- Pressure limiting ventilation modes
Which lung is larger?
Significance?
- R is larger than L
- So, worse hypoxemia in R sided procedures
What can predict chance of hypoxia in one lung ventilation?
Greater Initial drop in EtCO when shifting to OLV, greater chance of hypoxia
Causes of hypoxia in one lung ventilation
Which is the most common/one you should consider first?
- Tube malposition (most common- consider first)
- Bronchospasm
- Drop in cardiac output
- Hypoventilation
- Low FiO2
- PTX of dependent lung
If the patient is still hypoxic after checking tube position, what else can you do?
- CPAP to non-dependent lung (start at 2 cmH20 and use lowest pressure possible)
- Low flow O2 via catheter insufflated through non-dependent lung
- Hand ventilate non-dependent lung with very small tidal volume
if still hypoxic……
- PEEP to dependent lung
- Intermittent reinflation of non-dependent lung (communicate with surgeon)
- HFJV to non-dependent lung
- Selective oxygenation of non-operative lobes of non-dependent lung with bronchial blocker/bronchoscope
- Early ligation of pulmonary artery for pneumenectomies
What can happen if you use too much CPAP on non-dependent lung?
Can interfere with surgery and make surgeon angry 😡
Good and bad things about using PEEP when hypoxic
Good:
- Produces alveolar recruitment
- Increases lung compliance and FRC
Bad:
- High PEEP can decrease CO
- PEEP + fast rate can cause auto-PEEP with CO2 retention and lung trauma
Steps to take when surgery is finished and OLV no longer needed
- Unclamp operative side
- Use PiP of 30-40 cm H20 to re-inflate operative lung
- Deflate bronchial cuff
- Inhaled selective pulmonary vasodilators such as NO and prostacyclin can help with perfusion (if necessary)
New research regarding use of almitrine and iNO
- Almitrine to non-dependent lung
- iNO to dependent lung
Symptoms of most mediastinal masses
They are usually asymptomatic
If they are symptomatic, usually means they are malignant and larger with more extensive involvement
Mediastinal tumors are frequently associated with systemic syndromes such as (6)
- Myasthenia gravis (thymoma)
- Cushing’s (thymoma, carcinoid)
- Hypercalcemia (parathyroid adenoma)
- Hypertension (pheochromocytoma)
- Myasthenic syndrome (lung cancer)
- Cough, dyspnea, stridor, JVD, exaggerated postural changes in BP
What causes serious problems with mediastinal masses
- Supine position
- Induction/anesthesia
- Loss of spontaneous ventilation
Pre-op goals for mediastinal mass patients
- Radiate to shrink mass prior to surgery
- CXR, CT, MRI, TEE, PFTs to determine size, location, compression effects
MAJOR goal of anesthetic mgmt of mediastinal mass
- Maintain spontaneous ventilation
- Can use BiPAP to support airway during spontaneous ventilation with sedation
Good choice for intubation of patient with mediastinal mass
- Awake fiberoptic
- Avoid muscle relaxants until ability to ventilate confirmed
What should you be prepared for if mediastinal mass is encroaching on heart, aorta, or vena cava?
Potential for CV arrest so be prepared crash onto CP bypass
What is superior vena cava syndrome?
Who can have this?
Where should you place peripheral IVs?
- Venous distension of thorax and neck, redness/edema of face, neck, torso, airway, conjunctiva, SOB, headache, confusion
- Patients with mediastinal masses can develop
- Place peripheral IVs in lower extremities
Must haves for mediastinoscopy
- Good IV access
- Cross- matched blood
Complications of mediastinoscopy
SERIOUS THINGS because you are close to every major artery, nerve, and major structure possible
- Hemorrhage
- Pneumothorax
- bronchospasm
- laryngeal nerve damage
- tracheal or esophageal rupture
- chylothorax
- air embolus
- DEATH, yes she said death
Which arm should you monitor BP in for mediastinoscopy?
R arm due to pressure on inominate artery
What position is mediastinoscopy done in?
Do you need one lung ventilation?
Supine
No to OLV
Say your patient needs to be ventilated post-op after thoracic surgery, can you leave your DLT in and send them to the unit?
Nope, switch it out for regular single lumen ETT
How is anesthesia for VATS most commonly done?
GA with DLT
but can be done with epidural, sedation, spontaneous ventilation for patients with poor pulmonary function
What is a bullectomy and how is surgery approached and anesthesia done?
For COPD patients with bullae prone to rupture and cause PTX
- VATS approach
- Spontaneous ventilation until chest is open to decrease risk of rupture
Vent settings for bullectomy (after chest is open)
Low tidal volume
High RR
100% O2
PIP <20 cm H20
Which gas should you avoid in bullectomy?
Nitrous
Who is at highest risk of complications post-thoracotomy?
- > 80 yrs old
- PPO FEV1 or DLCO <40%
- ASA status >/= 3
- > 80 mins surgery time
- hemorrhage
Most common complications post-thoracotomy
- Respiratory failure
- Dysrhythmia
- Cardiac failure
- ALI
Highest risk factors for ALI
- R pneumonectomy
- Overhydration
- High PiPs during OLV
- Pre-op ETOH abuse
How much chest tube drainage is too much?
- Should not exceed 500 ml/day
- 200 ml/hr requires surgical exploration
How does lung resection put you at risk for RV failure?
- Increased pulmonary vascular resistance
- Even more increased risk with pneumonia, hypercarbia, and acidosis
What dysrhythmia is common postop complication of thoracotomy?
Significance?
Treatment?
- Supraventricular dysrhythmias
- Morbidity high: 25% death in 1st 30 days post-op
- Treat aggressively with beta-blockers
Respiratory complications post-thoracotomy (6)
- Atelectasis
- Pneumonia
- Respiratory failure
- Fistulas
- Pneumothorax
- Pulmonary edema
Which nerves/structures are sometimes injured in thoracic surgery?
IDK how to word this
- Phrenic or laryngeal nerve
- Spinal cord injury if radicular artery is damaged, epidural hamtoma is formed, or positioning injury from lateral decubitus
Cause of carcinoid syndrome
Kinins and histamine from carcinoid tumors in GI tract and lungs
Symptoms of carcinoid syndrome
- Hemodynamic instability
- Bronchoconstriction
- Flushing
- Dysrhythmias
How to cure carcinoid syndrome
Excise tumor
Anesthesia method for carcinoid syndrome pt
GA better than regional because it avoids undesired sympathectomy
Usual insertion depth of DLT on female and male
Female: 27 cm
Male: 29 cm
What is almitrine? What does it cause?
Carotid body chemoreceptor agonist
- Promotes HPV
What does it indicate if you have a L DLT, the tracheal lumen is clamped, but you hear L and R BS?
Bronchial lumen is in the trachea
Advance DLT into L side
What does it indicate if you have a L DLT, the tracheal lumen is clamped, but you hear unilateral right-sided breath sounds?
DLT is in the R bronchus
What does it indicate if you have a L DLT, the tracheal lumen is clamped, but no R BS, and no LUL BS?
DLT is too deep in the L side
You have a L DLT, with bronchial lumen clamped and tracheal lumen unclamped. What should you hear?
Unilateral R BS
You have a L DLT, with bronchial lumen clamped and tracheal lumen unclamped. What does it mean if you have weak or absent R BS?
DLT too shallow, occluding distal trachea
What percent of thoracotomy patients still have pain 1 year out?
50 percent
1/3 of thoracotomy patients still have pain how much later?
4 years
