Thoracics

Question 1

What are the three essential components of a pre-operative assessments for a thoracics case?

Answer 1

Assessment of cardiorespiratory reserve
Climb > 2 flights of stairs and normal spirometry – accept for surgery
Major medical problems and grossly impaired exercise tolerance – high risk and consider other options

Optimise lung function
Non-pharm: smoking, incentive spirometry, physiotherapy
Pharm: bronchodilators, oral steroids

Investigations
Pulmonary function tests
ABG - baseline oxygenation and CO2 retention
CXR/CT scans: airway obstruction, carinal distortion/compression (DL tube placement), complexity of surgery

Question 2

Difference between spirometry and diffusion capacity

Answer 2

Spirometry – quantifies severity of ventilator dysfunction and reflects bellows function of the respiratory system.

Minimum pre-operative values
Reference values vary with age and sex but generally normal FEV1/FVC = 70%.
No evidence that spirometry alone should preclude surgery.
FEV1 < 1000ml suggests impaired post-op coughing and secretion clearance and need for respiratory support.

Diffusion capacity – reflects ability of lungs to transfer oxygen into blood. Single breath of 0.3% CO and 10% He held for 20s. Reduced in interstitial lung disease. Normal 17-25 mL/min/mmHg.

Diffuse alveolar lung disease can have normal spirometry but grossly impaired DLCO.