Anesthesia for Thoracic Surgery 1

Question 1

Challenges associated with thoracic surgery include:

Answer 1

physiologic derangements caused by lateral decubitus position
problem of an open pneumothorax
surgical manipulations interfering with pulmonary and heart function
risk of rapid, massive bleeding
necessity for one-lung ventilation

Question 2

The lateral decubitus positioning provides

Answer 2

optimal surgical access for many thoracic procedures

Question 3

The lateral decubitus positioning has the potential for

Answer 3

significant alteration in normal respiratory physiology

disrupts ventilation/perfusion relationships

Question 4

Complications with lateral decubitus positioning includes:

Answer 4

brachial plexus & peroneal nerve injury
monocular blindness–> minimize pressure on dependent eye
outer ear ischemia–> flat or in donut
axillary artery compression

Question 5

Pulmonary & CV complications with lateral decubitus positioning includes:

Answer 5

coughing, tachycardia, hypertension during turn to lateral decubitus position
hypotension from blood pooling in dependent portions
V/Q mismatching= hypoxemia
interstitial pulmonary edema of dependent lung

Question 6

When the table is flexed,

Answer 6

ensure position of tube hasn’t moved because if it is tight, it can be pulled out

Question 7

Describe ventilation and perfusion in the awake patient who is upright, has spontaneous respirations & a closed chest:

Answer 7

apex of lungs are maximally dilated
most ventilation occurs at the base of the lungs
perfusion also favors the base of the lungs
V/Q matching is preserved during spontaneous respirations
V/Q matching is best preserved in zone 3

Question 8

Describe ventilation & perfusion in the lateral decubitus position in the spontaneously breathing, closed chest patient.

Answer 8

V/Q matching is preserved
dependent lung receives more ventilation and perfusion than the upper lung (non-dependent lung)
non-dependent lung is now zone 1

Question 9

Factors that cause diaphragm displacement include:

Answer 9

surgical position
paralysis
supine position
induction of anesthesia

Question 10

Describe the V/Q matching in the anesthetize patient who is in the lateral decubitus position, paralyzed and has a closed chest.

Answer 10

Positive pressure ventilation
decrease in FRC
V/Q mismatching
dependent lung= greater perfusion
non-dependent lung= greater ventilation

Question 11

Describe the V/Q matching for the anesthetized patient in the lateral decubitus position with an open chest

Answer 11

V/Q mismatching
perfusion remains greater in dependent lung
upper lung collapse leads to progressive hypoxemia–> mediastinal shift impedes ventilation to lower lung, paradoxical respirations

Question 12

Describe V/Q matching of the anesthetized patient in the lateral decubitus position, paralyzed with open chest (2 lung ventilation).

Answer 12

Positive pressure ventilation
may worse V/Q mismatching
ventilation greater in non-dependent lung
perfusion greater in dependent lung

Question 13

The following have an effect on V/Q matching:

Answer 13

positioning
open chest- mediastinal shift
anesthesia with paralysis

Question 14

Describe the V/Q match in the lateral position.

Answer 14

non-dependent V> Q

Dependent V

Question 15

Hypoxic pulmonary vasoconstriction works by

Answer 15

diverting blood away from the hypoxic regions of the lung

decrease blood flow to the non-ventilated lung

Question 16

Hypoxic pulmonary vasoconstriction ________ shunt

Answer 16

decreases

Question 17

Hypoxic pulmonary vasoconstriction helps improve

Answer 17

arterial oxygen content improving hypoxemia

Question 18

Describe blood flow distribution of the nondependent & dependent lungs in the lateral decubitus position.

Answer 18

Nondependent: 40%
Dependent: 60%

Question 19

Factors that inhibit HPV include:

Answer 19

high pulmonary vascular resistance (increased PAP, volume overload, mitral stenosis)
hypocapnia
high or very low mixed venous PO2
vasodilators
pulmonary infection
inhalation anesthetics

Question 20

Vasodilators that inhibit HPV include

Answer 20

nitroglycerin
nitroprusside
beta agonists (dobutamine)
calcium channel blockers

Question 21

1 Mac of anesthetic causes a ________ in shunting

Answer 21

5% increase

Question 22

One lung ventilation blood flow with hypoxic pulmonary vasoconstriction is

Answer 22

20% in nondependent

80% in dependent

Question 23

1 MAC of isoflurane ______ hypoxic pulmonary vasoconstriction by ____

Answer 23

inhibits by 21%

Question 24

One lung anesthesia is beneficial for

Answer 24

better operating conditions with collapse of the disease lung
facilitates access to the aorta & esophagus
prevents cross-contamination with abscess, secretions, bblood
prevents loss of anesthetic gases with bronchopleural fistula

Question 25

Relative contraindications for one-lung anesthesia include

Answer 25

difficult airway with poor visualization of the larynx | lesion in bronchial airway precluding bronchial intubation

Question 26

Absolute indications for one-lung ventilation include:

Answer 26

``` pulmonary infection copious bleeding on one side bronchopulmonary fistula bronchial rupture large lung cyst bronchopleural lavage ```

Question 27

Relative indications for one-lung ventilation include

Answer 27

``` thoracic aortic aneurysm pneumonectomy lobectomy thoracotomy; thoracoscopy subsegmental resections esophageal surgery ```

Question 28

Techniques for achieving one lung ventilation include

Answer 28

``` double-lumen endotracheal tubes bronchial blocker (used with standard single-lumen endotracheal tube) single-lumen endotracheal tube ```

Question 29

Shared characteristics of double-lumen endotracheal tubes include

Answer 29

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

Question 30

Describe the anatomic considerations of the adult trachea for DLT

Answer 30

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

Question 31

Describe anatomic considerations for the right bronchus when using the double lumen tube.

Answer 31

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

Question 32

Describe anatomic considerations for DLT for the left bronchus.

Answer 32

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

Question 33

The stylet goes through the ________ of the double lumen tube

Answer 33

bronchial side

Question 34

The ______ is more difficult to place for the double lumen tube.

Answer 34

the right

Question 35

The best predictor of DLT size is

Answer 35

patient height

Question 36

For someone who is 4'6" to 5'3" the size of the DLT is

Answer 36

35-37 french

Question 37

For someone who is 5'3" to 5'7", the DLT size is

Answer 37

37 or 39 FR- most commonly used size

Question 38

For someone who is taller than 5'7", the DLT used is a

Answer 38

41 FR

Question 39

Proper size of the DLT allows for

Answer 39

1-2 mm smaller than patients left bronchus to allow for space of bronchial cuff

Question 40

Describe the insertion technique of the double lumen tube.

Answer 40

laryngoscopy with curved blade provides optimal space to place DLT DLT is passed with the distal curvature concave anteriorly, then rotated 90 degree towards the size that is to be intubated after the tip enters the larynx advance DLT until resistances felt confirm correct placement

Question 41

The average insertion depth of the DLT is

Answer 41

28-29 cm at teeth

Question 42

Correct position of the double lumen tube when one tube is clamped includes:

Answer 42

ipsilateral breath sounds disappear ipsilateral hemothorax does not move no change in moisture contralateral breath sounds remain contralateral hemothorax rises & falls contralateral respiratory gas moisture disappears on inhalation and reappears on exhalation breathing bag has the expected compliance for one-lung ventilation

Question 43

The protocol for checking placement includes:

Answer 43

``` inflate tracheal cuff check for bilateral breath sounds inflate bronchial cuff clamp tracheal lumen check for unilateral LEFT breath sounds unclamp tracheal lumen & clamp bronchial lumen check for unilateral RIGHT breath sounds fiberoptic confirmation (check both supine & after LDP) ```

Question 44

The tracheal cuff should be inflated to

Answer 44

5-10 mL of air

Question 45

The bronchial cuff should be inflated with

Answer 45

1-2 mL of air

Question 46

When checking for bilateral breath sounds, if unilateral breath sounds are heard, this indicates

Answer 46

tube too far down & tracheal opening is endobronchial

Question 47

When checking for unilateral LEFT breath sounds, persistence of right-sided breath sounds indicate

Answer 47

bronchial opening still in trachea & tube should be advanced

Question 48

When checking for unilateral LEFT breath sounds, if unilateral right sided breath sounds are heard instead, this indicates

Answer 48

incorrect entry of the tube into right bronchus