Lung Isolation

Question 1

Indications

Question 2

Contraindications

Question 3

Options

Answer 3

Question 4

Double lumen tube

Question 5

Anatomy of bronchus

Question 6

Sizing of DLT

Question 7

Confirming position of DLT

Question 8

Bronchial blockers

Question 9

Songkran lumen ETT for OLV

Question 10

Difficult airway for OLV

Question 11

Tracheostomy requiring OLV

Question 12

Postoperative ventilation

Question 13

Risk factors for hypoxia during OLV

Question 14

Management of hypoxia during OLV

Answer 14

If a patient desaturates during OLV, the following steps should be done:
(1) Confirm the position of the DLT – both lumen might migrate down one bronchus
(2) Increase FiO2 to 1.0
(3) Suction down the tracheal port to relieve obstruction
(4) Ensure adequate muscle relaxation
(5) Recruitement of the dependent lung might improve shunting by alleviating atelectasis
(6) Optomise PEEP to the dependent lung
(7) Ensure adequate CO and O2 carrying capacity
(8) CPAP 2-5cm H2O to the nondependent lung
(9) Revert back to two-lung ventilation in severe hypoxia (after consulting the surgeon)
(10)Clamping and subsequent ligation of the nondependent lung pulmonary artery
(11) Consider a pneumothorax of the dependent lung

Question 15

Acute lung injury during OLV

Question 16

5. Alternatives to OLV

Answer 16

Apneic oxygenation: High flow FiO2 (low pressure) without ventilation to the dependent lung can keep the patient oxygenated for extended periods of time.
The biggest concerns are of worsening atelectasis and hypercarbia with subsequent worsening of respiratory acidosis. Arterial PCO2 rises by 6mmHg during the first minute followed by a rise of 3-4mmHg during each subsequent minute (normothermic patient). Therefore this technique should be limited to 10-20min intervals only, followed by careful recruitment of the dependent lung.

○ High frequency PPV (Oscillation ventilation) and high frequency jet ventilation: There are some case reports of successful use during thoracic procedures. A standard single lumen ETT can be used with small tidal volumes (<2ml/kg). This will lead to adequate oxygenation and ventilation with minimal lung excursion. The biggest drawback is mediastinal bounce that can interfere with surgery.

Question 17

Risk factors for ALI

Answer 17

Risk factors for ALI after thoracic surgery: Medical:
1) Severe pulmonary dysfunction
2) Neoadjuvant chemotherapy
3) Chronic alcoholism
4) Infection/sepsis

Surgical:
1) Right pneumonectomy
2) Extended lung resection
3) Impaired/disrupted lymphatic drainage

Anaesthetic:
1) Fluid overload and blood transfusions
2) Ventilatory trauma
3) Aspiration
4) Oxidative stress (lungs predominant)
5) Ischemia-reperfusion 2° OLV

Answer 18