Intro and Diagnostics to Pulm Flashcards
Define tidal volume
The volume of air inspired or expired with each normal breath at rest
Define inspiratory reserve volume
Maximum volume of air that can be inspired over and above the tidal volume.
Define expiratory reserve volume
ERV) is the volume of air that can be expired after the expiration of the tidal volume (about 1L)
Define residual volume
(RV) is the volume of air that remains in the lungs after maximal exhalation
so that they don’t collapse
Define Vital capacity (VC)
The greatest volume of air that can be expelled from the lungs after taking the deepest possible breath
Forced vital capacity
the amount of air that can be forcibly exhaled from the lungs after taking the deepest breath possible
Forced expiratory volume in one second
the amount of FVC you can forcibly exhale in 1 second
Peak expiratory flow (PEF) rate
the maximal speed at which air can be exhaled with force
What do you inspect for lung conditions?
- Pattern, depth of breathing
- Time spent in inspiration and expiration
- Symmetry of expansion (squeeze back together and look for movement of thumbs)
- Retractions
- Digital clubbing¹ (long term hypoxia, and nail bed becomes rounded)
- Acrocyanosis (blue/gray skin d/t problems with blood flow - common in smokers, and can change with position)
Always inspect first, can look for retractions if clothes are removed
Can you document retractions with clothes on? Why are retractions a concern?
ABSOLUTELY NOT
Your muscles can fatigue and go into respiratory failure and cannot compensate for lung movement, leading to death. NEED TO IMMEDIATELY ADDRESS
What is the RR of Bradypnea?
<12
Where do you palpate for tracheal allignment and what are you looking for?
Suprasternal notch
Looking for tracheal deviation in tension
Tactile tremitus and what you are looking for
Vibrations, if you don’t feel it, the lung collapsed or there is fluid buildup
Where do you palpate for heaves? What are you looking for?
Chest
Can feel if heart is enlarged or deviated
Where do you asscess the point of maximal impulse? What is abnormal?
Midclavicular intercostal space 4.
Should be in left lateral decubitus and tilted towards the front so that the heart shifts to the side.
Abnormal is if you feel it at the 5th, or at a different location
What is resonance and what do you do to hear it? What if it is dull instead? What if the lung collapses?
Percussion
Resonant if air moves through it, it will be dull if there is something dense.
Will hear hyperresonance if the lung collapses because there is not tissue there
What is Pulmonary Function Testing (PFT? and the two primary ones?
Measures lung expiration and inspiration
Spirometry and Plethysmography
What is Spirometry, Plethysmography based on?
measured against predicted values derived from large studies of healthy people of same height, weight, sex and race.
What is diffusion capacity a type of?
a type of PFT
What are the indications of a PFT?
If there is chronic lung condition, not acute pulmonary complaints.
- Evaluate patients with respiratory symptoms or rib fracture (to prevent complications such as pneumonia)
- Assess progression of previously diagnosed lung disease
- Monitor the efficacy of treatment
- Evaluate patients preoperatively (make sure that they are good candidates for surgery)
- Monitor for potentially toxic side effects of certain drugs
What are the considerations for PFTs? Why does this exclude young patients?
Requires cooperations - need to follow directions, which is why <5 yo is not indicated
How much air can your lungs hold?
6L
What are spirometers? What does it tell you?
Tells you how much a patient can force in and force out. Performed bedside.
There will be a goal based on body habitus (marked by a yellow line)
Tell to exhale as much as possible after deepest inhalation
When is a spirometer used for bronchodilators?
May be performed pre- and post bronchodilator
assesses reversibility of airflow 10-15 minutes after bronchodilator to see if it is useful for management
How does spirometry prevent pneumonia?
Patients experience pain during deep breaths, and default shallow breaths instead, but spirometry can be used to keep lungs healthy by setting goals
What are the indications for spirometry?
- diagnostic and monitoring of lung and neuromuscular diseases that affect breathing
- prevention of post-surgical/traumatic pulmonary complications
What are the contraindications for spirometry and why? What are some minor complications that are not CI?
- recent (<6wks) since abdominal, intracranial, or eye surgery or a pneumothorax (don’t want to reopen a wound)
- thoracic, abdominal and cerebral aneurysms
- unstable angina or a recent MI
- acute severe asthma (actively struggling to breathe - and using the test may cause them to pass out), acute respiratory distress, active TB (can cause airborne transmission of disease)
can cause dizziness and syncope, but these are not CI
What is the gold standard of PFT? When is this done? What does this allow you to do?
Plethysmography (glass air-tight container)
Done if decreased FVC on spirometry (as spirometry is easier to perform)
Tells us total lung capacity
What is functional residual capacity?
The volume of air in the lungs following expiration of the tidal volume (ERV + RV)
What are the two categories of lung disease? What are the complications of these?
Obstructive: difficulty exhaling air from the lungs. Air builds up in lungs and there is more reserved volume, leading to barel chest (1:1 ratio)
Restrictive: difficulty expanding the lungs during inhalation. Typically caused by scarring and lungs can’t open up
What are the three numbers that you look at for the 2 types of lung diseases?
FVC - amount of air exhaled after the deepest breath possible
FEV₁ - amount of air exhaled in the first 1 second of a FVC maneuver
TLC - total amount of air in the lungs at maximal inspiration during the FVC maneuver
What are the three values of PFT and why are these important?
- Actual value - what the patient performed
- Predictive values - what the patient should have performed
Based upon healthy patients of the same height, age, sex, ethnicity - Percent predicted - a comparison of the actual value to the predicted value
Look for these with pre and post-bronchilator response
What values do you need to show that there is a reversible lung condition in adults and kids?
Adults: increase in FEV1 > 12% AND FVC > 0.2 L
need both of these to indicate bronchodilator
Age 5-18: just an increase in FEV1 > 12%
What is normal flow loop?
Start with 2L, inhale an additional 4L, and very quickly you exhale in one second, then the rest of the 2 L.
What is the obstructive flow loop
Start with 4L (due to accumlation of air over time), get up to 8L, exhaling you can’t get air out.
What is a restrictive flow loop?
Start with 1L, can’t take in air (only to 4L total), but can get rid of air quickly like healthy lungs.
What percent predicted is considered normal for PFT values?
> 80%
What are the steps to interpreting PFTs?
- Is FVC > 80%? If yes, no restriction. If no, restriction or obstruction with air trapping
- If FVC > 80%, check FEV1/FVC. If > 0.7, there is no obstruction, if it is <0.7, then there is an obstruction. If there is a restriction or obstruction, look TLC (with plethysmography) . If TLC > 80%, then there is an obstruction (because there is enough air in lungs). If TLC is < 80% then there is a restriction (because they did not get air).
- If there is an obstruction, look at severity FEV1
A 65 year-old man undergoes PFTs as part of a routine health-screening test. He had no pulmonary complaints. He is a non-smoker but had a prior history of asbestos exposure while serving in the Navy.
His pulmonary function test results are as follows:
FVC = 102%
FEV1/FVC = 91%
FEV1/FVC = 91%
this means there are no obstruction and no need to do anything further
A 60 year-old man presents to his primary care provider with complaints of increasing dyspnea on exertion. He has a 40 pack-year history of smoking and is retired following a career as a building contractor.
His pulmonary function testing is as follows:
FVC: percent predicted 41%
Post bronch FVC = 112%
FVC is low, so we take bottom path, because
FEV1 = 25% predicted, meaning that it is severe
Step 4 = bronchodilator, it is reversible
A 30 year-old woman presents for evaluation of dyspnea on exertion which has been present for 2 months. She is a life-long non-smoker with no prior history of asthma or other pulmonary problems. She works as a receptionist at a publishing company. She has two cats and several parakeets at home.
Her pulmonary function testing is as follows:
FVC: 40%
FVC is < 80%, so follow bottom
TLC is < 80%, so restrictive
Severity = 44% TLC
Bronchodilator = FVC 4%, so bronchotherapy is not useful
Maximal respiratory pressures and what it is used for
You blow and hold up cheeks, and measures respiratory muscles to look for neurologic problems
What is the most sensitive PFT for diffusing capacity and how does it work?
Diffusing capactity,
A patient has a tracer gas, and normally the lung retains 80% or more, and 20% or less should be blown out.
If you blow out more (high reading), than your alveoli is not retaining gas appropriately
What is the 6 minute walk test and when is it used?
To see if they need to get supplemental oxygen therapy.
Mark a flat surface 100 feet of of length, and you should be able to walk 1300-2300 feet without O2 dropping 95% - otherwise it is failed.
If passed document Passed 6MWT or Failed 6MWT
What do you use to monitor asthmatic patients? How is this used?
Peak flow
Determine what you should be able to blow out normally (based on age, gender). Used to see if therapy is working, and then it is charted.
There are markers that are green, yellow, and red.
What does green, yellow, and red mean for peak flow and when are these done?
Green = 80-100% of (p) predicted expiration volume
Yellow = 50-80% of (p) expiration volume: caution
Red = below 50% (p) expiration volume: medical alert
done at different times of the day and then graphed to see how asthma treatment/therapy is going
Pulse oximetry and how it works.
When is it used?
What is a normal reading?
You have rays that come throw the skin, pick up the Hemogloblin in blood, and the amount of rays that goes to the other side is what determines your O2 sat. Also gives pulse and because it senses how quickly the hemoglobin is moving through the blood.
Used if cardio/pulm issues
Normal reading is >95%
What is important for placement of a pulse ox? Where are these put on? What are some limitations of this that may show an artificially low reading?
Location and fit matter
Finger, big toe, ear, feet, cheek
avoid too tight or loose probes
Nail polish may obstruct, leading to lower readings. Can’t be used in cold extremities because there is not blood getting there as it is shunted to the core. CO poisoning cannot be detected as it only reads O2
What is capnography? What does it measure indirectly?
Amount of CO2 expired per breath. Shows metabolic rate through cellular respiration.
What drops first, CO2, or O2 during hypoxia?
CO2 - 30-60 seconds before
What is normal End-tidal CO2 EtCO2 levels? What are the possible etiologies if it is above vs below this range?
normal EtCO₂ levels are 35-45 mmHg (meaning you expire 35-45 mmHg per breath)
EtCO₂ < 35 mmHg = Hypocapnia
Etiologies:
1. hypothermia (which lowers metabolic rate)
2. low cardiac output (leading to less O2 to tissues and thus lower metabolic rate and CO2 production)
3. pulmonary embolism (prevents blood from getting into alveoli)
4. hyperventilation (breathing too fast and shallow, leading to too much CO2 retention)
EtCO₂ > 45 mmHg = Hypercapnia
Etiologies:
1. Malignant hyperthermia (increasing basal metabolic rate)
2. shivering (increasing metabolic rate through muscle use without length-change)
3. fever (leading to higher demands on the body and higher metabolic rate)
4. sepsis (leading to greater metabolic demand)
5. severe hypothyroidism (leading to hypoventilation - remember, thyroid hormone increases cellular activity)
6. hypoventilation (breathing too slow)
What is the waveform of an obstructive air disease in capnography?
CO2 does not come out as rapidly, so there is not a rapid movement of CO2, and there is a less steep drop in the curve (such as in asthma)
known as shark-fin deformity
What is the waveform of hypoventilation?
Just longer, because you are breathing slower but there is no restriction
When do you typically use capnography?
Typically if incubated
Can be used during CPR to make sure you are getting at least 10 mmHg.
Ensuring proper ventilation during:
general anesthesia
procedural sedation
Confirmation of proper ET tube placement and ventilator settings
What are the two indications for ordering a sputum culture?
If a patient will be admitted to the hospital, if a patient fails outpatient empiric therapy.
What are collection instructions for sputum culture?
- collect before initiating antibiotics
preferred early morning collection - rinse mouth out with plain water
breathe deeply to stimulate coughing and expectoration - refrigerate the container until processing takes place
- culture specimen prepared within 2 hours of collection is preferred
avoid adding saliva or nasopharyngeal secretions to the sputum sample to make sure that it is coming from the lungs
What is sputum cytology used in?
Look for abnormal cells in:
Pulmonary cancer
Non-cancerous conditions
Pneumonia
Inflammatory disease
TB
Asbestosis
Lung computed tomography (CT) helical (spiral) and why it is preferred over conventional CT
MC CT used
patient is moved through a rotating x-ray beam
image obtain in the holding of one breath
Allows for cardiac imaging
Eliminates respiratory artifact during breathing
Sharper, more high-definition 3D images
allows you to get an image in minutes!
What are the advantages of a Lung CT over conventional radiography?
- Anatomic structures in different planes not superimposed on each other
- Better contrast resolution
- Can be reconstructed to provide different visual planes
What is a CXR radiation exposure? How is this different from a CT?
Measured in mSv (1 mSv is aprox equivalent to 100 days of background radiation)
CXR - 0.1 mSv (10 days of natural background radiation²)
CT is MUCH higher:
Standard Radiation CT chest - 7 mSv (2 years of natural background radiation)
Low-dose CT chest - 1.5 mSv (6 months of natural background radiation)
When is a lung CT used?
- Inconclusive x-rays or abnormality on physical examination
- Assess cardiothoracic space for tumors and other lesions
monitor response of tumors to treatment - Intrathoracic injury/bleeding
- Infections
- Unexplained chest pain
- Obstructions
- Provide guidance for biopsies and/or aspiration of the tissue from the chest
What are the risks/CI of a CT
Pregnancy
Non-life threatening condition
What is the limitations of CT?
Too heavy (can’t fit in the CT)
Can’t have metals
Barium in esophagus
When is contrast used or not used?
Can they ingest by mouth (PO), IV, inhaled (rarely used)?
Indicated if assessing vascular disease or to delineate area of concern from adjacent structures
Most common type of dye used in CT scans is IODINE……patient allergies is very important information
CTA or chest CT with contrast??
Difference between CTA and Chest CT w/ contrast
CTA primarily focuses on imaging blood vessels and blood flow, with a particular emphasis on identifying vascular abnormalities.
Chest CT with contrast is more comprehensive and focuses on imaging the entire chest area, including the lungs, heart, and surrounding structures, to diagnose a broader range of conditions.
What are you looking for in a pulmonary angiography?
Looking for pulmonary emboli defects, which is a change in color from black (showing blood flow), to gray/white
Describe the procedure of a VQ scan and what a normal scan looks like.
Part 1: radioactive material is INHALED - images are taken to look at the AIR FLOW in the lungs
Part 2: radioactive material is INJECTED IV and additional images taken to assess the BLOOD FLOW in the lungs
Normal scan involves lungs that look dark evenly throughout the lungs as radioactive tracer is distributed evenly
What are the 3 different abnormal VQ scans, and what are the possible etiologies of each?
- Ventilation scan = abnormal but perfusion scan = normal. This indicates ABNORMAL AIRWAYS in all or parts of lung (not getting enough ventilation). COPD or asthma likely. (V = abnormal, Q = normal)
- Ventilation scan = normal but perfusion scan = abnormal. This means there is INADEQUATE BLOOD FLOW, because air is able to travel through the lungs properly, but some parts of the lungs are not getting adequate blood flow. Likely a PE.
- Ventilation scan and perfusion scan = abnormal. Likely PNEUMONIA (most likely), COPD, or PE.
What are the risks of a VQ scan and ways to address such risks? Is there more or less radiation than CTs?
Pregnancy (can use less radioactive dye)
Breastfeeding (must discard milk for 24 hours post scan)
Mild and rare chance of allergic reaction (MC HIves)
Much less radiation than CT and can get rid of often w/in a few days
What is the Gold Standard for imaging blood vessels of the lungs? Is this also the first-line imaging?
The gold standard/ definitive diagnostic technique is pulmonary angiography. This is the most sensitive and specific imaging for a PE.
This is NOT first-line though - a CTA is. It is not first-line because it is invasive.
Apart from dx a PE, what is a pulmonary angiography also indicated in?
- AV malformation of the lung
- Congenital narrowing of pulmonary vessels
- Pulmonary artery aneurysms
- Pulmonary hypertension
What are the risks for pulmonary angiography and ways to possibly address these?
- Allergic rxn (prophylactic Benadryl)
- Damage to blood vessel or nerve from needle or catheter
- Excessive bleeding, blood clot or hematoma formation
- MI or stroke (if plaque buildup)
- Injury to nerves at puncture site
- Kidney damage from contrast dye (similar to CT scans)
When do you use a pulmonary angiography over a CTA?
Only if CTA is non-diagnostic for suspected PE
Certain conditions where CTA is not useful (such as pulmonary hypertension)
Explain bronchoscopy and what the two types of bronchoscopes
A procedure used to DIRECTLY visualize the airways and diagnose lung disease
2 types of bronchoscopes
flexible - MC used (can use procedural sedation where they are unconscious)
rigid (generally need to be sedated and intubated)
Can be inserted into the nose or mouth if flexible, needs to be inserted into the mouth if not flexible
What are the indications of bronchoscopy?
Foreign body removal
Bronchogenic carcinoma (get a biopsy)
Evaluate source of hemoptysis
Pulmonary infections
Transbronchial lung biopsy
Bronchoalveolar lavage (inject saline and suction out to thin secretions)
What are the contraindications for bronchoscopy and potential rare complications?
Contraindications
SEVERE bronchospasm or bleeding diathesis
Complications - Rate of major complications is less than 1%
Common
Transient hypoxemia, pneumothorax (through poking a hole), hemorrhage
Less common
Infection, nasal/laryngeal trauma, bronchospasm, cardiorespiratory arrest
Needs informed consent because of the risks!
