5.8 Lung Resection and Investigation Flashcards
Q8 — Lung resection and investigations
A 67-year-old male attends the clinic for a preoperative assessment before
a right lower lobe lung resection for a localised non-small cell cancer.
a) Name any three bedside pulmonary function tests that could be done in this patient.
● Ventilatory frequency.
● Cough strength and effectiveness.
● Pulse oximetry.
● Arterial blood gas.
● Lung volume measurements.
b) What are the diagnostic criteria for COPD based on spirometry?
Global initiative for chronic Obstructive Lung Disease (GOLD):
● Post-bronchodilator FEV1/FVC <70% is a key criterion for diagnosis.
● May be overdiagnosed in the elderly;
the ratio is important if it is less
than the lower limit of normal (LLN)
for that patient.
c) What does lung carbon monoxide transfer factor (TLCO) indicate and what is its significance?
● TLCO indicates parenchymal lung function.
● It is severely impaired in
interstitial lung disease and fibrosis.
● TLCO is also reduced in emphysema
(reduced surface area for gas exchange).
d) What suggestive values of FVC (forced vital capacity) might need mechanical ventilation in neuromuscular diseases?
● FVC of <20ml/kg.
● 30% decrease in FVC or
maximal inspiratory or expiratory pressures.
e) What is the NICE guidance on preoperative testing with regards to spirometry in the normal general population?
NICE does NOT recommend routine preoperative spirometry for any groups of patients.
f) In the above question with regards to the patient’s lung resection, what is the role of pulmonary function tests (PFTs) and how would you interpret them?
● The aim of PFTs is to identify patients with a high risk of cardiorespiratory morbidity and mortality.
● To assess the magnitude of risk.
● Tests for respiratory mechanics:
- FEV1 is a good indicator of pulmonary reserve;
- FEV1 <60% can have significant postoperative complications;
- FEV1 <30% can increase risks by 60%.
● Tests for lung parenchymal function:
- TLCO and % predicted postoperative TLCO;
- both are prognostic of long-term survival after surgery.
● Test for cardiopulmonary reserve:
- stair climbing test;
- shuttle walk test;
- CPET studies;
- VO2 max less than 15ml/kg/min —
increased morbidity; - VO2 max less than 10ml/kg/min —
increased mortality.
g) Name a few techniques of calculating the ppo (predicted postoperative) pulmonary function.
● Anatomical calculation.
● Ventilation/perfusion scintigraphy.
● Quantitative CT scanning.
● Dynamic perfusion MRI.
h) What are the selection criteria for the suitability of lung volume reduction surgery (LVRS)?
● FEV1 and TLCO both more than 20% predicted.
● PaCO2 less than 7.3kPa.
● Upper lobe predominant emphysema
on high-resolution CT.
