Flashcards in Pulmonary Function Tests (referencing M&M) Deck (14)
Post-surgical morbidity and mortality rates are higher in patients with restrictive and/or obstructive ventilatory defects. What disease in these groups is MOST amenable to treatment? Most difficult to reverse with treatment?
2) restrictive disorders are generally difficult to reverse with therapy
_______ helps distinguish restrictive ventilatory defects from obstructive ventilatory defects.
What are 2 advantages of flow volume loops over spirometry?
1) FVL studies are a sensitive means of detecting early COPD
2) FVL studies differentiate the anatomic location of flow obstruction
What 3 parameters CANNOT be measured directly with spirometry?
*can obtain--> TV, VC, insp capacity, insp reserve vol, exp reserve volume
What are 3 ways to measure FRC?
1) helium dilution
2) nitrogen washout
3) body plethysmography (uses Boyle's law)
What is the definition of FEV1?
forced expiratory volume in one second; this is the volume of gas that can be exhaled within one second of beginning a forced expiration
What is the definition of FVC?
forced vital capacity; this is the volume of gas that can be exhaled during a forced expiratory maneuver
What is FEV1/FVC?
a ratio that is useful in distinguishing between restrictive and obstructive diseases
What are the main diseases categorized as obstructive?
--> chronic bronchitis (blue bloater)
--> emphysema (pink puffer)
*airways are obstructed
What are the main diseases categorized as restrictive?
1) pulmonary fibrosis
3) chest wall disease (scoliosis)
4) neuromuscular diseases (amyotrophic lateral sclerosis, myasthenia gravis)
*expansion of lungs and/or chest wall is restricted
What is considered a normal FEV1/FVC ratio?
normally is >0.7
How can you determine if FEV1 and FVC results indicate an obstructive disease? restrictive disease?
*if BOTH FEV1 and FVC are low AND FEV1/FVC is OBSTRUCTIVE
*if BOTH FEV1 and FVC are low and FEV1/FVC ratio is > or equal to 0.7---> RESTRICTIVE
What is a normal FEV1?
>2L or 80% of predicted; normal patients can expire 80% of their predicted normal value