Week 13 - One Lung Ventilation and Hypoxia Management

Question 1

What are the different techniques to achieve lung isolation?

Answer 1

Double Lumen Tube (L or R):

• surgical exposure
• prevention of contamination
• differential lung ventilation

Bronchial Blocker:

• video thoracoscopic surgery
• difficult airways
• unique situations (tracheostomy pts)
• selective lobar blockade
• acute chest trauma

Question 2

What are the typical sizes of double lumen tubes for females and males?

Answer 2

Females = 35 or 37 Fr
Males = 39 or 41 Fr

• can use tracheal ultrasound examination to predict DLT size using height and tracheal diameter
• Tracheal Diameter: female (14-16mm); male (18-22mm)

Question 3

How much air is needed to seal the bronchial balloon on a DLT?

Answer 3

3cc of air

• if it requires 5-6cc the tube is too small
• cuff should be 1-2 cm below the carina

Question 4

What is the technique for placing a DLT?

Answer 4

Once cuff passes the vocal cords, turn the tube 90 degrees

In a 170cm pt the depth will be no deeper than 29cm (for every 10cm taller advance tube 1 cm, vice versa for shorter)

Question 5

What will you see during a fiberoptic exam of a DLT placement?

Answer 5

A) Tracheal carina
B) Take off of Right upper lobe and middle lobe
C) Apical, Anterior, Posterior branches of RUL
D) Left Upper and Left Lower Lobes

Question 6

What ultrasound sign shows lung movement? Which sign means no lung movement?

Answer 6

Pleura Sliding Sign = lung movement

Bar Code Image = no lung movement

Question 7

What is viva sight for DLT?

Answer 7

Continuous monitoring of DLT position

-if connected for 2 hours you must disconnect for at least 10min to prevent over heating

Question 8

When are bronchial blockers useful to use?

Answer 8

• Useful in pts with airway abnormalities or nasal intubations or tracheostomies
• Useful in the already intubated pt
• Selective lobar blockade in pts with previous lobectomy or pneumonectomy
• OLV during acute trauma to the chest

Question 9

What are the characteristics of the Arndt Blocker?

Answer 9

• Has nylon loop on the end that hooks the fiberoptic scope
• Need 8.0 ETT to be placed
• Needs 2 people to place

To place turn the patient to lateral position then inflate the balloon with 4-5cc air

Question 10

What are the characteristics of the Cohen Blocker?

Answer 10

Has turn dial on the top to move the tip

Need 8.0 ETT

Question 11

What are the characteristics of the Fuji UniBlocker?

Answer 11

Has natural bend in the end making it go to the left

Can be placed alone

Requires 8.0 ETT

Question 12

What are the characteristics of the EZ-Blocker?

Answer 12

Has a “Y” at the end that sits across the carina with balloons on each side that can be inflated

Question 13

What steps should you take at the beginning of lung isolation with a bronchial blocker?

Answer 13

• Administer 100% FiO2
• Prior to balloon inflation stop ventilation
• Under direct FOB insufflate balloon
• Start intermittent suction
• Reassume ventilation in dependent lung

Question 14

How do DLTs and Bronchial Blocker compare?

Answer 14

• No difference in quality of lung collapse between the two

- Bronchial blockers become mispositioned more frequently

Question 15

What is the division of pulmonary blood flow between the non-dependent lung and dependent lung?

Answer 15

Non-Dependent Lung (operating lung) = 40% PBF

Dependent Lung (ventilated lung) = 60% PBF

Question 16

What is the division of pulmonary blood flow between the non-dependent lung and dependent lung during one lung ventilation?

Answer 16

Non-Dependent Lung (operating lung) = 20% PBF

Dependent Lung (ventilated lung) = 80% PBF

• hypoperfused lung
• contraction of smooth vascular muscle
• activation of inflammation

Question 17

What comorbidities increase the risk for circulatory compromise caused by hypoxia?

Answer 17

Cardiovascular disease

Cerebrovascular disease

Severe pulmonary disease

Question 18

What is the incidence of hypoxia during one lung ventilation?

Answer 18

Less than 4% (SpO2 <90% or PaO2 <60)

• better understanding of the pathophysiology of OLV
• use of flexible fiberoptic bronchoscopy during placement of lung isolation devices
• new volatile anesthetics with less inhibition of hypoxic pulmonary vasoconstriction

Question 19

What factors can predict risk of hypoxia during OLV?

Answer 19

• Right sided surgery
• Preoperative FEV1%
• Intraop PaO2
• BMI >30
• > intraop hypoxemia
• Increased alveolar arterial O2 concentration

Question 20

How do you manage intraoperative hypoxia during OLV?

Answer 20

• Observe surgical field
• Increase FiO2 100%
• Restore 2 lung ventilation
• Check hemodynamics
• Check position of lung isolation device w/ FOB
• Clear secretions and inspect bronchial segments

Question 21

What are the effects of large and low tidal volumes during OLV?

Answer 21

Large TV (10mL/kg):

• increase pro-inflammatory response
• injury to the alveoli
• increased rate of post pulmonary complications

Low TV (4-6mL/kg):

• associated with lower PaO2
• lower airway pressures
• higher PaCO2

Question 22

What are the settings for protective ventilation during OLV?

Answer 22

• Alveolar recruitment maneuvers (5 up to 20 cmH2O)
• TV 6mL/kg during OLV
• PEEP 5-10 cmH2O to the dependent lung – CPAP to non-dependent lung

Question 23

What are the steps for preventing hypoxia prior to or during OLV?

Answer 23

1. Consider Alveolar Recruitment Maneuvers
2. Hypoxia (SpO2 <90 or PaO2 <60) –> FiO2 100%
3. Convert 2 lung ventilation w/ FiO2 100%
4. Improvement in SpO2 –> return to OLV