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N934 Advanced Principles of Anesthesia II > Thoracic Anesthesia > Flashcards

Thoracic Anesthesia Flashcards

1
Q

Challenges in thoracic anesthesia

A
  • physical derangements caused by lateral decubitus
  • open pneumo for surgery
  • surgical manipulation interfering with heart and lung function
  • risk of rapid, massive bleeding
  • necessity for one-lung ventilation
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2
Q

lateral decubitus position

A
  • optimal surgical access for many thoracic procedures
  • potential for significant alteration in normal respiratory physiology
  • disrupts vent/perf relationships
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3
Q

complications with lateral decubitus

A
  • coughing, tachy, HTN during turn to lateral decub
  • hypotension from blood pooling in dependent portions
  • V/Q mismatching = hypoxemia
  • interstitial pulm edema of dependent lung
  • brachial plexus and peroneal nerve injury
  • mononuclear blindness (pressure on dependent eye)
  • outer ear ischemia
  • axillary artery compression
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4
Q

awake patient, upright position, spontaneous respirations, closed chest

A
  • apex of the lungs are maximally dilated (zone 1)
  • most ventilation occurs at base of lungs
  • perfusion also favors base of lungs
  • V/Q matching is preserved during spontaneous respirations
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5
Q

awake patient, lateral decubitus position, spontaneous respirations, closed chest

A
  • V/Q matching preserved

- dependent lung receives more ventilation and perfusion than the upper lung (non-dependent lung)

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6
Q

things that cause progressive cephalad displacement of diaphragm during surgery

A
  • supine position
  • induction of anesthesia
  • paralysis
  • surgical position and displacement
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7
Q

anesthetized patient, lateral decubitus position, paralyzed, closed chest

A
  • positive pressure ventilation
  • decrease in FRC
  • V/Q mismatching
  • dependent lung = greater perfusion; not as much ventilation in this situation because abdominal contents are not pressing up and diaphragm is not pulling down more (so not as much ventilation compliance)
  • non-dependent lung = greater ventilation
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8
Q

anesthetized patient, lateral decubitus position, paralyzed, open chest

A
  • V/Q mismatching
  • perfusion remains greater in dependent lung
  • upper lung collapse leads to progressive hypoxemia
  • upper lung collapse also leads to –> mediastinal shift and paradoxical respirations
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9
Q

anesthetized patient, lateral decubitus position, paralyzed, open chest, 2 lung ventilation

A
  • positive pressure ventilation
  • may worsen V/Q mismatching
  • ventilation greater in non-dependent lung
  • perfusion greater in dependent lung
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10
Q

Summary of lateral decubitus + open chest on ventilation and perfusion

A
  • V/Q mismatch
  • non-depdendent V > Q
  • dependent V < Q
  • effects of positioning, open chest (mediastinal shift), anesthesia with paralysis
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11
Q

hypoxic pulmonary vasoconstriction (HPV)

A
  • diverts blood away from the hypoxic regions of the lungs
  • decreased blood flow to the non-ventilated lung
  • helps improve arterial oxygen content, improving hypoxemia
  • decreases shunt
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12
Q

Left lung non-dependent blood flow distribution

A
  • non-dependent lung (L) 35%

- dependent lung (R) 65%

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13
Q

Right lung non-dependent blood flow distribution

A
  • non-dependent lung (R) 45%

- dependent lung (L) 55%

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14
Q

average blood flow distribution with both lungs being non-dependent

A
  • non-dependent 40%

- dependent 60%

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15
Q

factors that inhibit HPV

A
  • high pulmonary vascular resistance (increased PAP, volume overload, mitral stenosis)
  • hypocapnia
  • high or very low mixed venous PO2
  • vasodilators - NTG, SNP, beta agonists (dobutamine), calcium channel blockers
  • pulmonary infection
  • inhalation anesthetics (1 MAC = 4% increase in shunt)
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16
Q

which inhalation agents increase shunt

A
  • isoflurane

- halothane

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17
Q

HPV & OLV

A
  • OLV causes a 50% HPV response
  • decreases the blood flow in the non-dependent lung to 20%
  • increases the blood flow in the dependent lung to 80%
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18
Q

HPV & Isoflurane

A
  • 1 MAC isoflurane inhibits HPV by 21%
  • blood flow 24:76
  • therefore the intrapulmonary shunt is increased by 4%
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19
Q

why is OLV beneficial in thoracic procedures

A
  • better operating conditions with collapse of diseases lung
  • facilitates access to the aorta and esophagus
  • prevents cross-contamination with abscess, secretions, blood
  • prevents loss of anesthetic gases with bronchopleural fistula
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20
Q

relative contraindications for OLV

A
  • difficult airway with poor visualization of the larynx

- lesion in bronchial airway precluding bronchial intubation

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21
Q

ABSOLUTE indications for OLV

A
  • pulmonary infection
  • copious bleeding on one side
  • bronchopulmonary fistula
  • bronchial rupture
  • large lung cyst
  • bronchopleural lavage
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22
Q

RELATIVE indications for OLV

A
  • thoracic aortic aneurysm
  • pneumonectomy
  • lobectomy
  • thoracotomy; thoracoscopy
  • subsegmental resections
  • esophageal surgery
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23
Q

what three techniques can be used to achieve OLV?

A
  • double lumen ETT
  • bronchial blocker (used with standard ETT)
  • single lumen ETT
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24
Q

characteristics of double lumen endotracheal tubes (DLT)

A
  • longer bronchial lumen which enters either the R or L mainstem bronchus
  • shorter tracheal lumen remaining in the distal trachea
  • preformed curve that allows preferential entry into the L or R side
  • separate bronchial and tracheal cuffs
  • tubes specifically designed for L or R side due to differences in anatomy
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25
Q

anatomy of adult trachea

A
  • 11-12 cm long
  • begins at C6 (cricoid cartilage)
  • bifurcates at the sternomanubrial joint (T5)
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26
Q

anatomy R bronchus

A
  • wider
  • diverges away from trachea at 20-25 degree angle
  • orifice of RUL sits only 1-2 cm to carina
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27
Q

anatomy L bronchus

A
  • narrower
  • diverges away from trachea at 40-45 degree angle
  • orifice of LUL sits about 5 cm distal to carina
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28
Q

sizing the DLT

A
  • small = 4’6” - 5’3” –> 35-37 Fr
  • medium = 5’3” - 5’7” –> 37-39 Fr (most commonly used size)
  • tall = >5’7” –> 41 Fr
  • proper size allows for 1-2 mm smaller than patient’s L bronchus to allow for space of bronchial cuff
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29
Q

best predictor of DLT size

A

height of patient

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30
Q

DLT insertion technique

A
  • laryngoscopy with curved blade provides optimal space to place DLT
  • DLT is passed with the distal curvature concave anteriorly, then rotated 90 degrees toward the side that is to be intubated after the tip enters the larynx
  • advance DLT until resistance felt (avg insertion dept is 28-29 cm at teeth)
  • confirm correct placement (FOB)
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31
Q

protocol for checking DLT placement

A
  • inflate tracheal cuff (5-10 mL of air)
  • check for bilateral breath sounds (unilateral breath sounds indicate tube too far down and tracheal opening is endobronchial)
  • inflate bronchial cuff (1-2 mL air)
  • clamp tracheal lumen
  • check for unilateral L breath sounds
  • persistence of R sided breath sounds indicate bronchial opening still in trachea and tube should be advanced
  • unilateral R sided breath sounds indicate incorrect entry of the tube into the R bronchus
  • unclamp tracheal lumen and clamp bronchial lumen
  • check for unilateral R breath sounds
  • fiberoptic confirmation (check both supine and after LDP positioning)
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32
Q

problems with DLT placement

A
  • in too far
  • not far enough
  • wrong side
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33
Q

most common problem with L endobronchial tube placement

A

-inserting too deeply excluding R lung from ventilation

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34
Q

most common problem with R endobronchial tube placement

A

-exclusion of R upper lobe from ventilation

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35
Q

indications for L endobronchial tubes

A
  • used for R sided thoracotomy –> tracheal lumen is clamped and L lung ventilated through bronchial lumen
  • used for L sided thoracotomy –> bronchial lumen clamped and R lung ventilated through tracheal lumen; if surgeon needs to clamp L mainstem for pneumonectomy, move bronchial lumen into the trachea and use as standard ETT
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36
Q

indications for R DLT

A
  • resection of thoracic aortic aneurysm
  • tumor in L mainstem bronchus
  • L lung transplantation or L pneumonectomy
  • L sided tracheo-bronchial disruption
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37
Q

bronchial blockers

A
  • inflatable devices passed alongside or through single lumen ETT to selectively occlude a bronchial orifice
  • regular ETT used with inflatable catheter (Fogarty cath), guide wire used for placement
  • blocker must be advanced, positioned, and inflated under direct visualization via flexible bronchoscope
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38
Q

univent tube

A
  • single lumen ETT with built-in side channel for retractable bronchial blocker
  • ETT placed with blocker fully retracted
  • ETT is then turned 90 degrees toward operative side
  • bronchial blocker pushed into mainstem bronchus under direct visualization with fiberoptic scope
  • cuff of blocker is high pressure, low volume cuff, so use minimum volume to prevent leak
  • channel within blocker allows lung to slowly deflate
  • channel can also be used for oxygenation and suctioning
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39
Q

major advantage of bronchial blockers

A

patient who requires intubation post op do not have to redo their laryngoscopy and change out ETT

40
Q

major disadvantage of bronchial blockers

A

blocked lung collapses slowly and sometimes incompletely due to small size of channel within the blocker

41
Q

Fogarty Catheter

A
  • used with standard ETT
  • guide wire in catheter is used to facilitate placement through ETT
  • does not allow suctioning or ventilation of the isolated lung
42
Q

indications for lung resection

A
  • diagnosis and treatment of pulmonary tumors
  • necrotizing pulmonary infections
  • bronchiectasis
43
Q

preoperative testing for lung resection

A
  • CXR/Chest CT
  • EKG
  • ABG
  • PFTs –> FEV 1 > 2L or 80% predicted is low risk; FEV1 < 2L or 40% predicted is high risk
  • ventilation perfusion tests
44
Q

ABG high risk patient

A

PaCO2 > 45 mmHg (on room air)

PaO2 < 50 mmHg

45
Q

FEV1 high risk patient

A
  • most commonly used and most important

- <2L or < 50% predicted

46
Q

FEV1/FVC high risk patient

A

-< 50% predicted

47
Q

maximum O2 uptake VO2 high risk patient

A

< 10 mL/kg/min

48
Q

max voluntary ventilation high risk

A

< 50% predicted

49
Q

split lung function test

A
  • uses radio-labeled albumin to calculate the predicted pulmonary function, postop outcome, and survival after pneumonectomy
  • predicts FEV1 of isolated lung if other lung is removed
  • minimal predicted postop FEV1 necessary for long-term survival is 800-1000 mL
50
Q

chemo that causes cardiomyopathy

A
  • doxorubicin
  • cyclophosphamide
  • check preop ECHO
51
Q

chemo that causes pulmonary toxicity

A
  • bleomycin (pulmonary tox with high FiO2)
  • mitomycin-C
  • cyclophosphamide
52
Q

chemo side effects

A
  • bone marrow suppression

- check platelets, RBCs, WBCs

53
Q

small cell lung carcinoma

A
  • paraneoplastic syndrome
  • SIADH - oat cell carcinoma of lung may cause low UOP, hypervolemia, hyponatremia, CHF, pulmonary edema
  • LEMs - associated with small lung CA; increased muscle weakness due to decreased calcium levels at neuromuscular junction
  • carcinoid syndrome
54
Q

non-small cell lung carcinoma

A
  • paraneoplastic syndrome

- ectopic parathyroid hormone

55
Q

assessment of patients with lung cancer pneumonic

A
  • Mass effects
  • Metabolic effects
  • Metastases
  • Medications
56
Q

Mass Effects of patients with lung cancer

A
  • obstructive pneumonia
  • SVC syndrome
  • tracheo-bronchial distortion
  • RLN or phrenic nerve paresis
57
Q

Metabolic Effects of patients with lung cancer

A
  • LEMs
  • hypercalcemia
  • hyponatremia
  • Cushing syndrome
58
Q

Metastases of patients with lung cancer

A
  • brain
  • liver
  • bone
  • adrenals
59
Q

Medications Effects of patients with lung cancer

A

-chemo induced lung/cardiac changes

60
Q

premedication of patient for pneumonectomy

A
  • bronchodilators
  • anticholinergics - like glyco; decrease secretions; increase HR to counteract interference with vagus nerve stimulation when the pleura is opened
61
Q

patient equipment/monitoring for pneumonectomy

A
  • airway equipment = multiple ETT (DLT and standard); difficult airway cart
  • A line = standard of care for OLV to do ABGs; placed on dependent limb to monitor perfusion to extremity
  • CVP = not necessary, but desirable to guide fluid management
  • PA Cath = LV dysfunction or severe pulm HTN; not used a lot anymore
62
Q

pain management for pneumonectomy

A

-consider thoracic epidural for postop pain management

63
Q

positioning for pneumonectomy

A

lateral decubitus; properly placed ax roll to protect brachial plexus

64
Q

pneumonectomy fluids

A
  • 2 large bore IVs
  • avoid over hydration bc do NOT want pulmonary edema
  • have blood warmer and rapid infusion device available
  • T & C
  • PRBCs
65
Q

OLV management

A
  • ALWAYS get baseline ABG prior to institution of OLV (reference point)
  • maintain two lung ventilation until pleura is opened
  • need max depth of anesthesia with chest opening and rib splitting
  • one lung ventilation –> operative lung deflated
  • 100% O2 to dependent lung
  • obtain ABG 15 min after OLV is initiated; guide therapy to maintain near baseline
  • major adjustments in ventilation usually not necessary
66
Q

greatest risk for OLV

A

hypoxemia

67
Q

what to do if you have high peak inspiratory pressures with OLV

A
  • check ETT position (with FOB)

- reduce Vt and increase RR to maintain minute ventilation

68
Q

ventilation settings for the dependent lung

A
  • FiO2 100%; can decrease after ABG obtained
  • Vt 5-6 mL per kg (OK with OLV)
  • RR 12-15 to keep PaCO2 35-45 mmHg or close to preop value
  • PEEP 0-5
  • PCV most ideal especially for those at risk of lung injury
69
Q

what to do if hypoxemia occurs during OLV?

A
  • confirm tube placement and increase FiO2 to 100%
  • check hemodynamic status
  • adjust Vt and/or RR
  • add 2-10 cmH2O CPAP to collapsed lung
  • periodically inflate collapsed lung with 100% O2 (inform surgical team)
  • add 5-10 cmH2O PEEP to dependent lung
  • continuous insufflation to collapsed lung with 100% O2
  • early ligation/clamping of ipsilateral pulmonary artery
70
Q

OLV alternatives

A
  • stop ventilation for short periods and employing use of 100% O2 insufflated at a rate greater than O2 consumption
  • HFJV - low volume, high pressure
71
Q

emergence for OLV

A
  • inflate lung to 30 cmH2O pressure/may need valsalva
  • if stapling bronchus check for leaks
  • to re-inflate collapsed lung, check for microbleed
  • thoracostomy tubes may be placed
  • standard extubation criteria for patients you anticipate extubating at end of procedure
  • if patient to remain intubated, must change out to single-lumen ETT prior to transporting to unit
72
Q

complications from thoracic anesthesia

A
  • hypoxemia/respiratory acidosis (#1 complication)
  • postop hemorrhage
  • arrhytmias
  • bronchial rupture
  • acute RV failure
  • positioning injury
73
Q

VATS (video assisted thoracoscopic surgery)

A
  • use of video camera and surgical instruments inserted through ports in the thoracic wall
  • usually 3-5 ports
  • staplers also used to resect lung tissue and divide large blood vessels
74
Q

indications for VATS

A
  • lung biopsy
  • wedge resection
  • biopsy of hilar and mediastinal masses
  • esophageal and pleural biopsy
  • pericardiectomy
75
Q

advantages of thoracoscopic over thoracotomy

A
  • smaller incision
  • no intraoperative rib spreading
  • less post op pain
  • less risk of postop hypoxemia
  • faster recovery and discharge from hospital
76
Q

thoracoscopic surgery types of anesthesia

A
  • local
  • regional
  • GA
  • two lung ventilation
  • OLV
77
Q

preop planning for thoracoscopic procedures

A
  • discuss pain management options with patient
  • PCA for chest tube pain
  • NSAIDs usually sufficient
  • consult with surgeon about likelihood of proceeding to thoractomy
  • otherwise preop considerations are same as thoracotomy
78
Q

intraoperative anesthetic considerations for thoracoscopic procedures

A
  • GA/OLV with DLT or bronchial blocker (deflate ASAP because with robot and insufflation much more limited space)
  • infiltration with LA by surgeon prior to placement of ports
  • lateral decub
  • routine monitors
  • minimum of one large bore PIV (better to have two)
  • a line usually placed
  • end of proceudre lung is suctioned and gently re-inflated; change DLT to standard ETT if patient cannot be extubated
  • chest tube placed prior to closing
79
Q

intraoperative complications during VATS

A
  • CO2 insufflation used to improve surgical visualization (gas embolism, hemodynamic compromise)
  • tension pneumo
  • hemorrhage
  • perforation of diaphragm or other organs
  • complications related to positioning and DLT
80
Q

mediastinoscopy

A
  • procedure is usually performed with lymph node or tissue biopsy to either establish a diagnosis or determine the resectability of an intrathoracic tumor
  • performed through small transverse incision just above suprasternal notch
  • blunt dissection along pre-tracheal fascia permits biospy of paratracheal lymph nodes to the level of the carina
81
Q

mediastinoscopy anesthetic considerations

A
  • compression to innominate artery can cause poor flow to the right carotid –> poor cerebral perfusion
  • central airway obstruction due to compression of the trachea may occur during induction of anesthesia or during the manipulation of the mediastinoscope near the trachea
  • technique –> GA with ETT and CV
  • moniotr a line/pulse ox on R arm to monitor innominate artery (if absent waveform ask surgeon to reposition scope)
  • BP on left
82
Q

what does the innominate artery supply?

A
  • R common carotid

- R arm

83
Q

S/S associated with mediastinal masses

A
  • most are asymptomatic and discovered incidentally CXR
  • symptomatic masses are usually malignant are large with extensive involvement –> airway obstruction, impaired cerebral circulation, distortion of anatomy
  • frequently associated with systemic syndromes
  • other s/s = cough, dyspnea, stridor, jugular distention, exaggerated changes in BP associated with postural changes
84
Q

syndromes associated with mediastinal tumors

A
  • Myasthenia gravis (thymoma)
  • cushing’s (thymoma, carcinoid)
  • hypercalcemia (parathyroid adenoma)
  • hypertension (pheochromocytoma)
  • myasthenic syndrome (lung cancer)
85
Q

SVC syndrome

A
  • progressive mediastinal tumor growth may result in compression of the SVC
  • obstructs venous drainage in the upper thorax
86
Q

SVC Syndrome clinical manifestations

A
  • caval obstructions –> venous distention in neck, thorax, upper extremities
  • edema of face, conjunctiva, neck and upper chest
  • external edema may be accompanied by edema of the mouth, larynx, and associated with severe airway obstruction
  • cyanosis - mucosal edema and direct compression can severely compromise airflow in trachea
  • CO may be severely depressed due to impeded venous return from upper body or by direct mechanical compression on the heart from tumor
  • venous backflow into upper extremity IV lines
  • evidence of increased ICP
87
Q

relative contraindications to mediastinoscopy

A
  • SVC syndrome
  • previous mediastinoscopy
  • obstruction and distortion of airway
  • impaired cerebral circulation
  • myasthenic syndrome
88
Q

absolute contraindications to mediastinoscopy

A
  • inoperability
  • coagulopathy
  • thoracic aortic aneurysm
89
Q

preop considerations for mediastinoscopy

A
  • assess for evidence of airway compromise –> dyspnea, tachypnea, tracheal compression or deviation
  • preop CXR and CT scan are essential to assess size and location of tumor and to evaluate tracheal distortion or compression
  • if airway compression is present, obtain PFTs in upright and supine positions (flow-volume loops detect airway obstruction)
  • may patients will favor the upright position
  • assess for evidence of SVC obstruction
  • worsening of symptoms may be precipitated by muscle relaxants, coughing and breath holding, position changes
90
Q

mediastinoscopy monitoring

A
  • large bore PIV x 2 may need to place in lower extremities if S/S of SVC
  • monitor R radial pulse; doppler arterial pressure line, pulse oximeter on R hand finger
  • BP cuff monitoring in L arm
  • PNS
91
Q

mediastinoscopy complications

A
  • acute airway obstruction (use reinforced tube)
  • anticipate difficulties with intubation and ventilation (have many ETTs available, establish ability to ventilate before muscle relaxation, muscle relaxation intraop or to prevent coughing or straining)
  • venous air embolism (HOB often 30 degrees elevation)
  • mediastinal hemorrhage
92
Q

anesthetic management of mediastinoscopy

A
  • deep anesthesia to blunt autonomic reflexes
  • monitor for pneumo, avoid N2O
  • monitor for instrument pressure against innominate, T subclavian or R carotid arteries (loss of distal pulse, postop neuro deficits)
  • observe postop respiratory status closely
  • vagally-mediated reflex bradycardia from compression of trachea or great vessels
93
Q

what to do if airway obstruction or SVC obstruction occur

A
  • place patient in lateral, reverse T, prone or high fowlers position
  • may cause mass to shift away from the trachea or SVC and relieve the obstruction
94
Q

emergence for mediastinoscopy

A
  • prior to extubation have full TOF, full return of airway reflexes, patients with SVC syndrome must be fully awake as they can easily obstruction
  • postop CXR on all patients to rule out pneumo
95
Q

major complications of mediastinoscopy

A
  • hemorrhage
  • pneumothorax
  • RLN injury
  • phrenic nerve injury/Left hemiparesis
  • esophageal injury
  • air embolism
  • dysrhythmias

N934 Advanced Principles of Anesthesia II (17 decks)

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