Pulmonary Function Tests Lecture Powerpoint Flashcards
2 functions of the sinuses and how do we learn to breath first?
- Lighten the weight of the head
- Moisten and filter air
-through the nose
Because of the respiratory system’s ability to filter upon inspiration, most pneumonias are the result of…
….reflux and aspiration
Further down in the respiratory tract, we see more smooth muscle and less cartilage tissue making it….
…more capable of partial collapse or complete collapse in disease states (this increases residual volume in the lungs as everything distal to the collapse is affected)
Functions of PFT’s (3)
- add to diagnosis of disease (pulmonary and cardiac)
- monitor progression of disease and effectiveness of treatment
- aid in pre op assessment of certain patients
Different components of PFTs (8)
- spirometry
- flow volume loop
- bronchodilator response
- lung volumes
- diffusion capacity (DLCO)
- bronchoprovocation testing
- max respiratory pressures
- simple and complex cardiopulmonary exercise testing
6 min walk test
Test to evaluate physical function or assess therapeutic response in COPD and pulmonary fibrosis patients, considered positive if oxygen saturation falls by >4% ending below 93% after 6 minutes of walking and indicates need for confirmatory ABG’s
Indications for PFTs (6)
- Signs and symptoms of pulmonary distress
- screening at risk population (smokers current or former >45 years of age)
- monitoring drug toxicity
- abnormal study such as CXR or EKG
- environmental exposure monitoring
- preoperative assessment and risk stratification
PFT’s are beneficial but…
….they only support or exclude a diagnosis
Steps to performance of an FVC maneuver in spirometry
- Prep patient (results are VERY effort dependent)
- cover nose with clip
- elevate chin slightly and extend neck slightly
- put mouthpiece in mouth after inhaling and then exhale hard and fast as possible
- need to avoid coughing, variable flow, or early termination
Spirometry’s goal is to measure ____, it cannot (directly) measure ____
Vital capacity, residual volume
Body plethysmography
Used to measure total lung capacity by placing patient in a small airtight room while taking measurements to determine residual volume and total lung capacity
Flow (flow volume loop) definition
Volume of a substance moved thru a structure or space over a period of time in L/s
Flow volume loop, what is it sometimes referred to as?
- A measurement of flow during pulmonary function testing that should have a rounded inhalation and a sharp spike in expiration (this height should represent 90% of what can be exhaled) followed by continuous drop straight line
- also referred to as a spirogram
Volume time loop
A measurement of flow during pulmonary function testing that determines FEV1 and should have 90% of the volume (in L) released in the first second before quickly tapering off to a flat line
Lung properties that affect spirometry (2)
- mechanical properties (compliance and elastic recoil)
- resistive properties (affected by airway diameter predominantly)
% predicted in spirometry
What a patient performed based on what is predicted based on age, gender, height, weight, ethnicity to determine some fraction value which is then interpreted (low % is worse for the patient)
Spirometry % FVC predicted value interpretation
80-120% normal
70-79% mild reduction
50-69% moderate reduction
<50% severe reduction
Spirometry % FEV1 predicted value interpretation
> 75% normal
60-75% mild obstruction
50-59% moderate obstruction
<49% severe
Spirometry % FEF 25-75% predicted value interpretation
> 60% normal
40-60% mild
20-40% moderate
<10% severe
Obstructive disease pattern loss with spirometry % predicted values
- FEF 25-75 decreased
- FEV1 decreased
- FVC normal to decreased in late stage (last thing to go)
- FEV1/FVC <70% predicted
Obstructive lung disease list (5)
- asthma (reversible obstructive dz)
- COPD (chronic bronchitis and emphysema)
- bronchiectasis
- bronchiolitis
- upper airway obstruction
Restrictive disease pattern loss with spirometry % predicted values
- TLC decreased
- FVC decreased
- Normal or increased FEV1/FVC ratio
Restrictive lung disease list (4)
- Parenchymal disease (interstitial lung disease)
- pleural disease
- chest wall disease
- neuromuscular disease
Scooped out vs witch’s hat on volume/flow diagram
Scooped out is characteristic of obstructive disease, witch’s hat is characteristic of restrictive disease
