Airway Management II: Lecture 4 - One Lung Ventilation

Question 1

What is One Lung Ventilation (OLV)?

Answer 1

• Intentional collapse of a lung on the operative side of the patient which facilitates most thoracic procedures.
• Requires skill of the anesthesia team
  Difficult to place lung isolation equipment
  Tends to dislodge when positioning patient

Question 2

Define hypoxic pulmonary vasoconstriction (HPV).

Answer 2

A physiological response where blood vessels constrict in areas of the lung that are not receiving enough oxygen.

Hypoxia is a powerful stimulus for pulmonary
vascular constriction

Body’s mechanism to divert blood flow away from areas of no ventilation to areas of ventilation

Vasoconstriction that decreases blood flow from alveoli that are not ventilated to alveoli that are ventilated

Body’s way to decrease the shunt that was
created by change
Position
V/Q mismatch

Clinical Notes:
Direct acting vasodilators inhibit HPV response
Volatile agents at higher concentrations inhibit HPV
response

No HPV =
Increases shunt
Decreases PaO2

Question 3

Management of Hypoxia during One Lung Ventilation

Answer 3

100% FIO2

10 mL/kg tidal volume
Do not change the tidal volume from 2 lung ventilation (NEED TO ASK SURGEON IF HE THINKS PHYSIOLOGICALLY ANY OPTION AT THIS)

Maintain normocapnia

Maintain correct tube position (If you see a sudden dip in EtCO2, could shift down and less Bronchi are now getting O2)

Suction both lungs

Apply PEEP to dependent lung

Apply CPAP to non-dependent lung

Re-inflate collapsed lung at various intervals

Extreme cases
Clamp the pulmonary artery to collapsed lung

PEEP = extra pressure added during expiration on the ventilator to keep alveoli open.

CPAP = constant pressure delivered all the time while the patient breathes on their own

Question 4

What is a thoracotomy?

Answer 4

A surgical procedure involving an incision into the chest wall to access the thoracic organs.

Question 5

What does VATS stand for?

Answer 5

Video-Assisted Thoracoscopic Surgery.

Less invasive.

Question 6

Positioning for Thoracic Anesthesia

Answer 6

Question 7

Double Lumen Tube

Answer 7

Question 8

Tracheal vs Bronchial

Answer 8

Question 9

What is the dependent lung?

Answer 9

The lung that is ventilated.

The downside lung

Question 10

What is the non-dependent lung?

Answer 10

The lung that is collapsed to facilitate the surgery.

The upside long

Question 11

What is a significant physiological impact of OLV?

Answer 11

Creation of a significant intrapulmonary shunt resulting in hypoxia.

Question 12

What is the physiological goal during One Lung Ventilation?

Answer 12

Promote blood flow to the nonsurgical, dependent lung, contribute to improved V/Q matching, reduce PVR of dependent lung.

Question 13

List factors that increase PVR of the dependent lung. (Pulmonary Vascular Resistance)

Answer 13

• Excessive PEEP
• Airway pressures
• Hypoxia
• Hypercapnia
• Hypovolemia

Question 14

What does increased PVR of the dependent lung lead to?

Answer 14

Increase in shunt fraction.

Question 15

What are the absolute indications for One-Lung Ventilation?

Answer 15

• Isolation of one lung from an other to prevent spillage or contamination (infection, massive hemorrhage)
• Control of distribution of ventilation
  Bronchopleural fistula
  Surgical opening of major conducting airway
• Unilateral bronchopulmonary lavage
  Pulmonary alveolar proteinosis

Question 16

What are the relative indications for One-Lung Ventilation?

Answer 16

• Surgical exposure - high priority (thoracic aortic aneurysm, pneumonectomy, upper lobectomy)
• Surgical exposure - lower priority (middle lobe lobectomies, esophageal resection, thoracoscopy, thoracic spine procedures)
• Post-removal of totally-occluding chronic unilateral pulmonary emboli

Question 17

Name methods of lung separation.

Answer 17

• Bronchial blockers
  Single-lumen tracheal tubes with a bronchial blocker
  Stand alone endobronchial blockers
  Arterial embolectomy catheter
• Single-lumen endobronchial tubes
  Gordon-Green tube (carinal hook)
• Double-lumen endobronchial tubes
  Robert-Shaw (R or L), Carlens (L), White (R)
  Carlens and White both have carinal hooks
  From 35Fr to 41Fr (35, 37, 39, 41)
  28Fr and 32Fr used for pediatric patients 10 and older

Most common used is Robert-Shaw (L)

Question 18

What are single-lumen endobronchial tubes?

Answer 18

Gordon-Green tube (carinal hook).

Question 19

List types of double-lumen endobronchial tubes.

Answer 19

• Robert-Shaw (R or L)
• Carlens (L)
• White (R)

Bronchial balloon only gets 3ccs of air (only hook up 3cc syringe to blue bulb)

Question 20

What are advantages of double lumen tubes?

Answer 20

• Relatively easy to place
• Allow conversion back and forth from OLV to two-lung ventilation
• Allow suctioning of both lungs individually
• Allow CPAP to be applied to the non-dependent lung
• Allow PEEP to be applied to the dependent lung
• Ability to ventilate around scope in the tube

Question 21

What are disadvantages of double lumen tubes?

Answer 21

• Cannot take patient to PACU or the Unit
• Must be changed out for a regular ETT if post-op ventilation
• Correct positioning is dependent on appropriate size for height of patient
  Length of trachea

Question 22

DLT Placement Process

Answer 22

Prepare and check tube
Ensure cuff inflates and deflates

Lubricate tube (Big difference between regular tube)

Insert tube with distal concave curvature facing anteriorly

Remove stylet once through the vocal cords

Rotate tube 90 degrees (in direction of desired lung)

Advancement of tube ceases when resistance is encountered. Average lip line is 29 ± 2 cm.

*If a carinal hook is present, must watch hook go through cords to avoid trauma to them.

Question 23

What is the average lip line measurement for DLT placement?

Answer 23

29 ± 2 cm.

Question 24

DLT Placement Process POST Placement

Answer 24

Check for placement by auscultation

Inflate tracheal cuff- expect equal lung ventilation

Clamp the white side (marked “tracheal” for left-sided tube) and remove cap from the connector
Expect some left sided ventilation through bronchial lumen, and some air leak past bronchial cuff, which is not yet inflated

Slowly inflate bronchial cuff until minimal or no leak
is heard at uncapped right connector
Go slow- it only requires 1-3 cc of gas and bronchial rupture is a risk

Remove the clamp and replace the cap on the tracheal side

Check that both lungs are ventilated

Selectively clamp each side, and expect visible chest movement and audible breath sounds only on the right when left is clamped, and vice versa

Question 25

What should be done to check for DLT placement?

Answer 25

Check for placement by auscultation.

Question 26

Checking DLT Placement with Fiberoptic

Answer 26

Checking tube placement with the fiberoptic bronchoscope Several situations exist where auscultation maneuvers are impossible (patient is prepped and draped), or when they do not provide reliable information (preexisting lung disease so that breath sounds are not very audible, or if the tube is only slightly mispositioned) The double-lumen tube's precise position can be most reliably determined with the fiberoptic bronchoscope In patients with double-lumen tubes whose position seemed appropriate to auscultations, 48% had some degree of malposition. So always check position with fiberoptic After advancing the fiberoptic scope thru the “tracheal” tube you should see the “bronchial blue balloon” in a semi lunar shape, just peeking out of the bronchus

Question 27

What is the gas requirement for bronchial cuff inflation?

Answer 27

It only requires 1-3 cc of gas.

Question 28

What is the risk associated with the balloon of an endobronchial blocker?

Answer 28

The balloon may become dislodged during surgery and enter the trachea proper, causing a complete airway obstruction.

Question 29

Arndt Endobronchial Blocker

Answer 29

Snare guided endobronchial blocker Wire guided catheter w/ loop snare Guided into mainstem bronchus via FFOB Available sizes 9 or 7-F for adults 5-F for pediatrics

Question 30

Advantages of Endobronchial Blocker

Answer 30

Quickly and precisely navigate the airway The pediatric bronchoscope acts as a guide, allowing the endobronchial blocker to be advanced over it into the correct position Allows one-lung ventilation with a single-lumen endotracheal tube Allows one-lung ventilation in: critically ill patient in whom reintubation may be difficult or impossible patients with a known difficult airway requiring fiberoptic intubation with a conventional endotracheal tube Unnecessary to convert from a conventional double-lumen endotracheal tube to a single-lumen tube at the end of surgery Hollow lumen allows suction to facilitate lung collapse and insufflation of oxygen Multiport adaptor allows uninterrupted ventilation during blocker positioning

Question 31

Disadvantages of Endobronchial Tube

Answer 31

Satisfactory bronchial seal and lung separation are sometimes difficult to achieve The “blocked” lung collapses slowly (and sometimes incompletely) The balloon may become dislodged during surgery and enter the trachea proper, causing a complete airway obstruction – It is important that the balloon be fully deflated when not in use and only be re-inflated with the same volume used during positioning and bronchoscopy.

Question 32

Indications for Wire-Guided Endobronchial Blockers vs DLT

Answer 32

Critically ill patients Rapid sequence induction Known and unknown difficult airway Postoperative intubation Small adult and pediatric patients Obese adults

Question 33

Endobronchial Blocker Adaptor

Answer 33

Question 34

Univent Tubes

Answer 34

Endotracheal intubation can be performed in the conventional manner, just like a single lumen endotracheal tube One-lung ventilation achieved by placement of the blocker to either the left or right lung, or to lung segments Insufflation and CPAP can be achieved through the lumen of the blocker shaft Blocked lung can be collapsed by aspirating air through the lumen of the blocker shaft The blocker can be retracted into its pocket to facilitate post- operative ventilation Improved "torque control" bronchial blocker: Easier to direct by twisting than previous nylon catheter High torque control malleable shaft for smooth intubation Flexible blocker shaft with softer open lumen tip Latex-free

Question 35

Univent Pieces

Answer 35

Question 36

What is the purpose of rapid sequence induction?

Answer 36

A technique used to quickly induce anesthesia and secure the airway in emergency situations.

Question 37

What does V/Q mismatch refer to?

Answer 37

A condition where ventilation and perfusion in the lungs are not matched, leading to decreased oxygenation.

Question 38

What is the role of the pediatric bronchoscope in airway management?

Answer 38

Acts as a guide, allowing the endobronchial blocker to be advanced over it into the correct position.

Question 39

What are complications associated with one-lung ventilation?

Answer 39

All difficult airway complications Injury to lips, mouth, teeth Injury to airway mucosa from stylet Hoarseness Sore Throat Bronchial Rupture Decreased saturation – HPV Inability to isolate lung

Question 40

Fogarty Embolectomy Catheters

Answer 40

Single-lumen balloon tipped catheter with a removable stylet In the parallel fashion, the Fogarty catheter is inserted prior to intubation In the co-axial fashion, the Fogarty catheter is placed through the endotracheal tube Both techniques require fiberoptic bronchoscopy to direct the Fogarty catheter into the correct pulmonary segment (BIG TAKE AWAY) Once the catheter is in place, the balloon is inflated, sealing the airway Clinical limitations to the Fogarty technique Difficult to direct and cannot be coupled to a fiberoptic bronchoscope No accessory lumen for either removal of gas from the blocked segment or insufflation of oxygen to reverse hypoxemia Ventilate w/ 100% O2 prior to balloon inflation to aid in gas removal

Question 41

True or False: The Fogarty technique is always effective for lung separation.

Answer 41

False.

Question 42

What are direct acting vasodilators?

Answer 42

Medications that can inhibit the hypoxic pulmonary vasoconstriction response.

Question 43

Fill in the blank: The balloon must be fully _______ when not in use.

Answer 43

deflated

Question 44

What is the purpose of applying PEEP to the dependent lung?

Answer 44

To maintain alveolar recruitment.

Question 45

What is the function of applying CPAP to the non-dependent lung?

Answer 45

To prevent collapse.

Question 46

What technique is used as a last resort to manage hypoxia during one-lung ventilation?

Answer 46

Clamp the pulmonary artery to the collapsed lung.

Question 47

Case Setup for DLT & OLV

Answer 47

Airway – Have standard supplies & assortment of sizes for DLT or other OLV choice equipment Fiberoptic cart Hemostat or clamp to occlude lumen of the tube

Question 48

Chest Tube

Answer 48

Always added at end of a thoracic surgery