Respiratory Function Tests Flashcards
What does spirometry measure
Expired and inspired air
What 3 related measurements is spirometry based on
Volume
Time
Flow
What can spirometry be used for
Assess lung disease
Quantify lung impairment
Monster effects of occupational or enviro exposures
Determine effects of medications
How should patient be positioned in spirometry
Sit upright
Feet flat on floor
Legs uncrossed
Spirometry technique
Deep breath taken -> mouth tightly around mouthpiece -> exhale hard and fast min 6 secs
What is the minimum length of expiration for spirometry
6 secs
Tidal volume
Amount of air moved into or out of lungs at rest
Forced vital capacity
Max volume of air forcibly exhaled after deep full breath
Inspiratory reserve volume
Volume of air you can draw into your lungs
Expiratory reserve volume
Volume of air you can expel from your lungs
Residual volume
Volume of air that remains in lungs even after maximal exhalation
What 3 things are added to make forced vital capacity
Inspiratory reserve vol + tidal vol + expiratory reserve vol
FEV1
Forced expiratory volume in 1 sec
How many attempts are needed for PEF
3
Peak expiratory flow
Max airflow after completely filling lungs and exhaling hard and fast
What factors effect predicted spirometry values for a patient
Height
Weight
Age
Sex
Ethnic origin
Smoking
Environment
What are spirometry results compared against
Reference values
Predicted values
How do FEV1 and FVC change with height
Incr w height
How do FEV1 and FVC change with age
Decr w age
Which asthma patients may have normal spirometry
Well managed asthma
How does unmanaged asthma appear on spirometry
Decr FEV1 and FVC
How can an asthma patients spirometry be improved short term
Bronchodilator
How does asthma effect flow rate
Decrease
Are the volume time traces and flow volume traces of an an asthma patient above or below range of normalcy
Below
What FEV1/FVC ratio is normal
Above 70%
What percentile of the population sets the lower limits of normality for spirometry
95th
What does DLCO/TLCO assess
How efficient lungs are at exchanging gases
Does haemoglobin preferentially bind to CO or O2
CO
What does DLCO measure
Quantity of CO transferred per minute from alveolar gas to RBCs
DLCO single breath hold technique
Unforced exhalation -> rapid inhalation of CO/helium to TLC -> breath hold 10 sec -> unforced exhalation less than 4 sec -> exhaled breath sampled
How can DLCO be calculated
Lung surface area available for gas exchange x rate of capillary blood CO uptake
What % of the predicted value is normal for DLCO
75%+
What do exercise tests assess
How much exercise a patient can manage
Benefit of extra O2 to help w daily activities
Pre operative fitness
3 types of exercise test
6 min walk
Shuttle walk
Cardio pulmonary exercise
