spirometry

Question 1

contraindications for spirometry (8)

Answer 1

can’t do it

• can’t cooperate with spirometry
• can’t sit upright

lung

• pneumothorax in past 6 weeks
• hemoptysis in past 48 hours
• suspected communicable infectious disease

vascular

• Acute coronary syndrome in past 4 weeks
• thoracic, aortic or cerebral aneurysm

viscera
* abdominal, thoracic or eye surgery in past 6 weeks

Question 2

spirometry - medications to withhold beforehand, and for how long

Answer 2

SABA - 4-6 hours
twice daily LABA - 12 hours
once daily LABA, LAMA, SAMA, theophylline - 24 hours

Question 3

what is the acceptability criteria for spirometry

Answer 3

single continuous breath without stopping for inhalation or coughing, with flattening of volume - time curve at the end of trial

Question 4

what is the repeatability criteria for spirometry

Answer 4

difference in FVC of top 2 measures is < 0.15L

difference in FEV1 of top 2 measures is < 0.15L

Question 5

what is the minimum and maximum attempts at a spirometry

Answer 5

at least 3 attempts, at most 8 attempts

Question 6

basic spirometry interpretation pathway

Answer 6

1. look at FEV1 / FVC (raw value)
   if ratio is < 80%, there’s obstructive ventilatory defect (or its below LLN if supplied)
2. look at FVC (% predicted)
   if its < 80% of predicted, there’s restrictive vent defect
3. look at the FEV1 difference between best pre, best post ventolin to check for positive bronchodilator response

Question 7

define a positive bronchodilator response

Answer 7

Look at FEV1 pre and post bronchodilator.
adults - if its >=200mL, and >=12% improvement then its a positive bronchodilator response
children, if its >= 12% improvement in FEV1 its a positive bronchodilator response