One Lung Ventilation

Question 1

Which position is most often associated with thoracic surgery?

Answer 1

Lateral decubitus position

Question 2

The dependent lung while in the lateral position is the upper or lower lung?

Answer 2

Lower lung.

D=down=dependent

Question 3

The nondependent lung while in the lateral position is the upper or lower lung?

Answer 3

Upper lung

Question 4

While AWAKE and lateral position, which lung is better perfused and ventilated?

Answer 4

The dependent lung

Question 5

With induction of anesthesia, what happens to the lung ventilation/perfusion?

Answer 5

the nondependent lung is preferred lung for ventilation.

Question 6

Which lung is the surgeon working on?

Answer 6

The Non-dependent lung.

Question 7

Does positive pressure ventilation favor the dependent or nondependent lung in the lateral position?

Answer 7

The non-dependent lung.

Question 8

How does an open pneumothorax cause a right to left intrapulmonary shunt?

Answer 8

Nondependent/Upper lung is not ventilated but is still perfusing (although less than dependent lung).

Question 9

What interventions should be done to minimize V/Q mismatch and hypoxemia.?

Answer 9

Give 100% FiO2 whole case.
Add PEEP.
Place long suction down nondependent lung’s lumen to bleed in 2L/min O2.

Question 10

What decreases blood flow to nondependent lung?

Answer 10

Hypoxic pulmonary vasoconstriction (HPV).
Or.
Surgical compression of upper lung can decrease blood flow and improve shunt.

Question 11

What are factors that inhibit the natural hypoxic pulmonary vasoconstriction?

Answer 11

Hypocapnia, Inhalation agents, Vasodilators, very low or high PAP, high or very low mixed venous PO2, Pulmonary infections.

Question 12

What are some factors that decrease blood flow to dependent lung?

Answer 12

Low FiO2 causes HPV in ventilated lung,
High MAWP from PEEP/increased PIP,
Vasoconstrictors, Intrinsic PEEP from inadequate expiratory times.

Question 13

CO2 elimination typically isnt affected by one lung ventilation provided two things:

Answer 13

1. Minute ventilation is unchanged.

2. Preexisting CO2 rentention was not present pre-op (COPD).

Question 14

During apnea, how much is PCO2 increased?

Answer 14

PCO2 increases 5mmHg for the first minute and then 3mmHg for each additional minute of apnea

Question 15

What can be done if hypoxia is experienced during one lung ventilation?

Answer 15

1. FiO2 of 100%.
2. Check TV-want 10cc/kg
3. Fiberoptic scope to ensure proper placement.
4. Adjust RR to keep PaCO2 at 40mmHg.
5. Add 5cm CPAP for nondependent lung.
6. Add 5cm H20 PEEP to dependent lung.
7. Ask surgeon to clamp or ligate nondependent PA.
8. Return to two lung ventilation is always an option.

Question 16

What are criteria for if one lung resection is survivable?

Answer 16

PFTs:
-Predicted post-op FEV1 >800ccs.
Preop FEV1>2L.

Question 17

Left or right tube typically used for one lung ventilation? and Why?

Answer 17

Left; Right main stem bronchus is shorter.

Question 18

What complications can occur with Right double lumen tube?

Answer 18

Can inadvertently block off the upper lobes of the lung.

Question 19

What is the only true indication of using a right double lumen tube?

Answer 19

Left mainstem bronchus surgery.

Question 20

What is the average depth for a Left double lumen tube in proper placement?

Answer 20

29cm.