Diagnostic and Therapeutic Skills - Pulmonology Flashcards
measured against predicted values derived from large studies of healthy people of same height, weight, sex and race.
what type of PFT is this?
Spirometry, Plethysmography
what are the Types of PFTs
- Spirometry, Plethysmography
- Diffusing Capacity, 6 Minute Walk Test, Peak Flow
indications for PFTs
- Evaluate patients with respiratory symptoms or rib fracture
- Assess progression of previously diagnosed lung disease
- Monitor the efficacy of treatment
4.Evaluate patients preoperatively - Monitor for potentially toxic side effects of certain drugs
considerations for PFTs
- Patient cooperation and consistent effort is essential
- > 5 y/o can perform
volume of air inspired or expired with each normal breath at rest
tidal volume
maximum volume of air that can be inspired over and above the tidal volume
Inspiratory reserve volume (IRV)
volume of air that can be expired after the expiration of the tidal volume
Expiratory reserve volume (ERV)
volume of air that remains in the lungs after maximal exhalation
Residual volume (RV)
Non-invasive assessment of maximum inspiratory and expiratory volume as well as maximal expiratory effort
- Spirometry
- Completed bedside, in pulmonary lab or as an incentive spirometer
- May be performed pre- and post bronchodilator
indications for spirometry
- diagnostic and monitoring of lung and neuromuscular diseases that affect breathing
- prevention of post-surgical/traumatic pulmonary complications
CI/cautions for spirometry
- recent (<6wks) since abdominal, intracranial, or eye surgery or a pneumothorax
- thoracic, abdominal and cerebral aneurysms
- unstable angina or a recent MI
- acute severe asthma, acute respiratory distress, active TB
Minimal risk - dizziness, rarely syncope occurs
what Lung volumes are assessed with spirometry
- Vital capacity (VC)
- Forced vital capacity (FVC)
- Forced expiratory volume in one second (FEV₁)
- FEV₁/FVC
- Peak expiratory flow (PEF) rate
- Forced expiratory volume over the middle half of expiration (FEF25-75)
Measures the total volume of air held in the lungs
Gold standard for PFTs
Plethysmography
Indicated if decreased FVC on spirometry
Plethysmography
volume measurements in plethysmography
- Total Lung Capacity¹ (TLC)
- RV+VC = TLC - Vital capacity (VC)
- Functional Residual Capacity² (FRC)
- ERV + RV = FRC - Expiratory reserve volume (ERV)
5.Residual Volume (RV) - RV/TLC
difficulty exhaling air from the lungs during PFT
what is your interpretation?
obstructive
difficulty expanding the lungs during inhalation during PFT
what is you interpretation?
Restrictive
3 lung volumes to initiate plethysmography interpretation
- FVC - amount of air moved after the deepest breath possible
- FEV₁ - amount of air moved in the first 1 second
- TLC - total amount of air in the lungs at maximal inspiration
what are the 3 values reported in a PFT
- 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
Assessed during plethysmography
Measures respiratory muscle strength
what is this PFT
Maximal respiratory pressures
Pre- and Post-bronchodilator Responsiveness during PFT
- Adults: increase in FEV1 > 12% AND FVC > 0.2 L
- 5-18 y/o: increase in FEV1 > 12%
indications for Maximal respiratory pressures
unexplained decrease in VC or suspected respiratory muscle weakness
Procedure: forced expiration (with cheeks bulging) through a blocked mouthpiece after a full inhalation.
most sensitive PFT
assesses the transfer of oxygen and carbon dioxide
Diffusing Capacity (DLCO)
procedure of Diffusing Capacity (DLCO)
- patient inhales carbon monoxide (CO) + tracer gas (methane or helium)
- holds for 10 sec, exhales forcefully
- exhaled air tested to determine amount of tracer gas remaining
A result a >80% is normal
assesses oxygenation during exertion and the distance a patient can walk
6 minute walk test (6MWT)
patients walks back and forth on flat surface 100 ft in length
with 6 minute walk test (6MWT), you must monitor:
symptoms (dyspnea and fatigue) at rest and progression of symptoms with walking
oxygen saturation at rest and while walking
what is a normal 6MWT
1300 - 2300 feet, asx with pulse ox maintained above 95%
Measures peak expiratory flow (PEF) rate
Utilized to determine adequate control of asthma
Peak Flow
how are predicted values of peak flows determined?
- Height and Age
- Predicted values for African American and Hispanic are appx 10% less
interpretation of peak flow
- GREEN = 80-100% (p) “All clear”
- YELLOW = 50-80% (p) - “Caution”
- Implement treatment plan prescribed by PCP - RED = Below 50% (p) - “Medical Alert”
- Contact provider and start bronchodilator therapy immediately
Noninvasive, non-risky, continuous or intermittent measurement of arterial hemoglobin saturation
Pulse Oximetry
Indications:
- CC of pulmonary or cardiac etiology
- chronic pulmonary or cardiac disease
Normal: 95% or higher
limitations with pulse ox
- nail polish, pigmented skin
- bright lighting
- movement, improper placement
- poor perfusion - hypothermia, anemia, PAD
- CO poisoning
- unable to differentiate between CO and O2 bound to hgb
the measurement and monitoring of the concentration of CO₂ in expiratory gases
Capnography
what is the Early warning of impending hypoxia
CO₂ will rise 30-60 seconds before O₂ drops in respiratory depression
what is A-B?
Phase 1: Dead space ventilation
represents beginning of exhalation
What is B-C?
Phase 2: Ascending phase
represents a rapid rise in CO2 as air is exhaled
What is C-D?
What does D represent?
Phase 3: Alveolar plateau
- represents CO2 reaching a uniform level during the entire breath stream
- point D = maximum (measured) CO2 concentration at the end of expiration
What is D-E?
inspiration
what is the normal range for Capnography
EtCO₂ levels 35-45 mmHg
capnography you see EtCO₂ < 35 mmHg
what is your interpretation?
causes?
Hypocapnia
hypothermia, low cardiac output, pulmonary embolism, hyperventilation
capnography you see EtCO₂ > 45 mmHg
what is your interpretation?
causes?
Hypercapnia
Malignant hyperthermia, shivering, fever, sepsis, severe hypothyroidism¹, hypoventilation
obstructed diseases would change the capnography how?
The waveform results in a rounded ascending phase and upward slope in the alveolar plateau
indications of capnography
- Ensuring proper ventilation during:
- general anesthesia
- procedural sedation - Confirmation of proper ET tube placement and ventilator settings
- Ensuring adequacy of chest compressions in cardiac arrest
A collection of expectorated sputum for the purpose of detecting the bacterial cause of lower respiratory infections
Sputum Culture
(pneumonia, bronchiectasis, bronchitis, or pulmonary abscess)
Collection instructions for sputum cx
- 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
- cx specimen prepared within 2 hr of collection preferred - avoid adding saliva or nasopharyngeal secretions to the sputum sample
Sputum collection for microscopic evaluation to determine the presence of abnormal cells
Sputum Cytology
indications for Sputum Cytology
- Pulmonary cancer
- Non-cancerous conditions
- Pneumonia
- Inflammatory disease
- TB
- Asbestosis
Noninvasive diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce horizontal, or axial images called slices
Lung Computed Tomography (CT)
what are the 2 major types of CT scans
-
Conventional
- obtains one image at a time in slices as patient moves through the gantry
- requiring 30-45 minutes to complete -
Helical (Spiral) - MC
- pt is moved through a rotating x-ray beam
- image obtain in the holding of one breath
Advantages of lung CT in general over conventional radiography
- Anatomic structures in different planes not superimposed on each other
- Better contrast resolution
- Can be reconstructed to provide different visual planes
pros and cons of Helical (spiral) CT
Pros
1. Faster and more anatomic coverage
2. Allows for cardiac imaging
3. Eliminates respiratory artifact during breathing
4. Sharper, more high-definition 3D images
Cons
1. Radiation exposure - measured in millisievert (mSv)
- CXR - 0.1 mSv (10 d of natural background radiation²)
- Standard Radiation CT chest - 7 mSv (2 yrs)
- Low-dose CT chest - 1.5 mSv (6 months)
indications for lung CT
- 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
CI/caution with lung CT
- Pregnancy - first trimester
- Hx of large amounts of radiation exposure
- non-life threatening conditions
- If contrast is indicated
- Allergy to contrast dye (give meds for allergy)
- Severe renal impairment - GFR < 20 mL/min, BUN/Cr should be obtained before contrast
- Hyperthyroidism or thyroid goiter - may potentiate thyrotoxic crisis
- Pheochromocytoma - may induce HTN crisis
- Metformin use - drug must be discontinued prior to contrast and held for 48 hours after
Limitations with lung CT
- body habitus/weight
- wt limit for most CT tables are 450 lbs - artifact
- metal objects - pacemakers, surgical clips, body piercings
- barium in esophagus from recent barium study
things to consider about using contrast during CT or not
- Ingested by mouth (PO), IV, inhaled (rarely used)
- Indicated if assessing vascular disease or to delineate area of concern from adjacent structures
- Iodine: MC dye type - allergies
A nuclear medicine scan that uses radioactive material to examine air flow (ventilation) and blood flow (perfusion) in the lungs
Lung Ventilation and Perfusion Scan
(V-Q scan)
what tool to use to diagnose or r/o a pulmonary embolism (PE) when CT is contraindicated
V-Q scan
PEs cause significant low blood oxygen levels and can lead to lung damage and/or death
detects poor blood flow in the pulmonary vascular and uneven air distribution
V-Q scan
what is the procedure for V-Q scans
- radioactive material is inhaled - images are taken to look at the airflow in the lungs
- radioactive material is injected IV and additional images taken to assess the blood flow in the lungs
radioactive tracer is evenly distributed throughout lungs during ventilation and perfusion
what is this V-Q scan showing
normal lung scan
V-Q scan shows ventilation scan is abnormal but the perfusion scan is normal
what are you suspecting
COPD
asthma
V-Q scan shows perfusion scan is abnormal but he ventilation scan is normal
what are you suspecting
PE
both ventilation and perfusion scans are abnormal during V-Q scan
what are you suspecting
pneumonia, COPD, or PE
risks with V-Q scan
- Radiation is very minimal and usually out of system in a few days
- Pregnancy
- will use a smaller amount of radioactive dye - Breastfeeding
- mother must discard milk for 24 hours post scan - Mild and rare chance of allergic reaction - MC hives
Definitive diagnostic technique or GOLD STANDARD in the diagnosis of acute PE
High sensitivity and specificity of dx in a PE
what is this diagnostic tool
Pulmonary Angiography
procedure of Pulmonary Angiography
- Usually performed by interventional radiologist
- Pt is mildly sedated with local anesthesia
- Inject contrast into a pulmonary artery branch after percutaneous catheterization usually via the femoral vein
- Images are obtained via fluoroscopy (x-ray movie)
in a pulmonary angiography, a filling defect or abrupt cutoff of a small vessel is indicative of ?
embolus
a negative pulmonary angiography will exclude what?
clinically relevant PE
additional indications for Pulmonary Angiography
- AV malformation of the lung
- Congenital narrowing of pulmonary vessels
- Pulmonary artery aneurysms
- Pulmonary hypertension
risks for Pulmonary Angiography
- Allergic rxn
- Damage to blood vessel or nerve from needle or catheter
- Excessive bleeding, blood clot or hematoma formation
- MI or stroke
- Injury to nerves at puncture site
- Kidney damage from contrast dye
CTA vs Pulmonary Angiography
- CT angiography
- less invasive, faster, safer
- provides most of the same diagnostic info with benefit of visualizing the lung tissue and other structures - Pulmonary angiography
- Gold standard for PE
- Utilized in cases where CTA is nondiagnostic
A procedure used to directly visualize the airways and diagnose lung disease
Bronchoscopy
2 types of Bronchoscopy
- flexible (MC)
- rigid
procedure of bronchoscopy
- Patient is sedated
- general anesthesia if rigid scope is used
-procedural sedation is utilized for flexible scopes - Scope is passed through the mouth or nose and advanced into the lungs
indications for bronchoscopy
- Evaluation and removal of airway FB’s or other obstructions
- Diagnosis and staging of bronchogenic carcinoma
- Evaluation of hemoptysis
- Diagnosis of pulmonary infections
- Transbronchial lung biopsy
- Bronchoalveolar lavage
CI for bronchoscopy
SEVERE bronchospasm or bleeding diathesis
complications with bronchoscopy
Rate of major complications is less than 1%
1. Common
- Transient hypoxemia, pneumothorax, hemorrhage
2. Less common
- Infection, nasal/laryngeal trauma, bronchospasm, cardiorespiratory arrest
