Respiratory Flashcards
What are morphologic pulmonary assessment tools?
radiology, bronchoscopy, biopsy, sputum
What are physiologic pulmonary assessment tools?
PFTs, blood gas analysis
Bronchoscopy
direct visualization of the airway
Biopsy
obtaining a tissue sample
Sputum
lower airway mucus produced by inflammation
Radiology
CXR
CT scan
VQ (ventilation/perfusion)
MRI- not commonly used
PET scan- nuclear scan that looks at metabolic changes on a molecular level
What can be visualized in a bronchoscopy?
proximal airways. distal airways are often not accessible
What is bronchoscopy used for?
Obtain biopsies, retrieve foreign bodies, control bleeding or remove secretions, can place stents in the event of obstructing lesion
What are the two types of sputum studies and what do they evaluate?
- culture- evaluates bacteria or fungal organisms causing infection. Helps target antibiotic therapy, detects TB via an acid-fast bacilli (AFB) smear and culture
- cytology- look for abnormal cells under a microscope. noninvasive way to evaluate for cancerous cells-not typically used alone. Sensitivity is low, specificity nears 100%
What is a CT scan?
series of XR images taken at different angles and then manipulated by a computer screen to create cross-section images. 3D view.
What does a CT scan rely on?
relies on densities of different tissues- variations of grey.
bone=white
air=black
When do you need to have contrast for a CT scan?
need contrast to evaluate pulmonary elbolism.
if looking for infection, edema, effusion, nodules, it is not required
What is a VQ scan?
uses radioactive substance to evaluate the flow of air and blood through the lungs (inhaled and injected)
What is a VQ scan most commonly used for?
- To evaluate for pulmonary embolism
V>Q because there are blood clots blocking the flow of blood - Can see changes in other lung diseases
- For patients who cannot have IV contrast for CT scan (renal insufficiency or allergy)
What does a pulse ox estimate?
how saturated with oxygen peripheral blood is
What are ways in which the pulse ox can be wrong?
nail polish
darker skin
smoking
cold extremities
When in doubt when using a pulse ox, what would be a more reliable test to do?
ABG
What does a PFT measure?
measures ventilatory function or gas diffusion
illustrates effects of disease on lung function
allows for assessment of disease progression
evaluates efficacy of treatment
What does ventilatory function tests measure?
- lung volumes and lung capacities. Volume of gas in the lungs during different parts of the respiratory cycle. Some are measured and some are calculated.
- diffusion capacities
- restrictive disease (lung expansion problems) or obstructive disease (flow problems)
- measured by spirometry and formulas
Tidal volume (TV)
amount of air inhaled/exhaled in 1 breath at rest (normal breathing)
Inspiratory reserve volume (IRV)
max amount of air inhaled above TV inhalation
Expiratory reserve volume (ERV)
max amount of air exhaled below TV expiration
Residual volume (RV)
amount of air left after maximum exhalation. Tested by inhaling 100% oxygen or helium and taking measurements
What are the four lung capacities that are measured?
Vital capacity (VC): forced vital capacity (FVC) is the max amount of air exhaled after max inhalation
Total lung capacity (TLC): max amount of air in the lungs after max amount inhalation (also equals VC plus RV)
Inspiratory capacity (IC): max amount of air inhaled after normal exhalation
Functional reserve capacity (FRC): volume of air remaining in the lungs after a normal total volume exhalation
Forced capacity/volume is useful in evaluating __________________
obstructive disease
Which two measurements are useful in evaluating obstructive disease?
- forced vital capacity (FVC): max amount of air displaced from lung during a forced exhalation after maximum inhalation
- Forced expiratory volume at 1 second (FEV1): taken from FVC during 1st second measurement
FEV/FVC is clinically important
FEV1/FVC is a specific measure of ____________. What is the normal ratio?
airway obstruction. normal is >75% and values less than that suggest obstructive disease
Chronic obstructive: chronic bronchitis, emphysema. What is the VC, RV, FEV;FVC
VC: normal or decreased
RV: normal or increased
FEV;FVC: decreased
Reversible obstructive: asthma. What is the VC, RV, FEV;FVC
VC: normal or decreased
RV: increased
FEV;FVC: decreased
Restrictive(extrapulm,intrapulm). What is the VC, RV, FEV;FVC
VC: decreased
RV: decreased
FEV;FVC: normal
Combined obstructive and restrictive. What is the VC, RV, FEV;FVC
VC: decreased
RV: decreased
FEV;FVC: decreased
What is diffusion capacity? When is diffusion capacity decreased?
the ability of a gas to cross the alveolocapillary membrane. decreased in membrane thickening, losses of alveoli, poor ventilation
What is diffusion capacity testing? How is it measured?
evaluates diffusion across membrane. Measured by diffusion capacity of carbon dioxide (DLco). Patient inhales CO;measurements of gases are taken and diffusion is calculated.
Diffusion testing is used to separate _______ from _______
COPD, asthma
What is blood gas analysis useful for?
for determining current gas exchange status.
When do you want to obtain a blood gas analysis?
acute respiratory problems, hypoxemia, cardiac arrest, altered mental status
What are lab studies?
ABG- arterial blood gas
Partial pressure of oxygen (PO2) amount of oxygen dissolved in the blood
Partial pressure of carbon dioxide (PCO2) amount of carbon dioxide dissolved in the blood
pH
Bicarb (HCO3)
Oxygen saturation- how much of the hemoglobin is carrying oxygen
ABG values
PaCO2: 34-45 mmHg
PaO2: 80-100mmHg
SaO2: 97% saturation
pH: 7.35-7.45
HCO3: 22-26 mEq/L
Respiratory acidosis
pH is low, pCO2 high
hypoventilation
Respiratory alkalosis
pH is high, pCO2 is low
hyperventilation
