Pulmonary Flashcards
If a patient has ongoing pulmonary disease, then they should really be cleared by
their pulmonologist or medical doctor prior to surgery
A person usually (underestimates/overestimates) how much they smoke per day?
Underestimates
During auscultation, patients should take ____ breaths first, and then ___ breaths
quiet, then deep
Describe bronchial breath sounds
Normal breath sounds of the tracheobronchial tree (large airways).
Heard best at: Trachea, sternoclaviular joint, and the right posterior interscapular space
Sounds like: High pitch and rapid/loud air movement
With bronchial breath sounds there is a ____ between inspiration and expiration
Pause
Describe vesicular breath sounds
Normal sounds you should hear over lung tissue
Softer and lower pitched than bronchial
No pause between inspiration and expiration.
Expiration is shorter (meaning we will hear more during inspiration)
When are bronchial breath sounds abnormal
Whenever they are heard somewhere they shouldn’t be (in the periphery)
What is lung consolidation?
Lung tissue that has been filled with liquid
What type of breath sounds should you hear in consolidation?
Low pitched-bronchial (more bronchial because the tissue that should be making vesicular sounds are not opening)
What is cavitary disease?
Disease where normal lung tissue is replaced by a cavity
What type of breath sounds should you hear in cavitary disease?
High pitched bronchial, because the lung tissue that should be making vesicular sounds is replaced by a cavity (essentially a large-airway).
When are crackles insignificant?
If they clear with deep breathing
What is wheezing?
Musical noise as air passes through constricted bronchioles. Usually heard on expiration (when the airways constrict), but can be heard on inspiration as well.
What is stridor?
High pitched sound on inhalation due to narrowing of the larynx. Think about how hard you would be truing to breathe in if your larynx was constricted!
Can PFTs be used alone to make a diagnosis?
No, they must be taken into consideration with other factors
What are PFTs used for?
Diagnosis
Evaluate disease progression and treatment
Assessing risk of pulm compliations
Who are good candidates for PFTs?
COPD Smokers with persistent cough Wheezing or dyspnea on exertion Morbid obesity (once they have pulm HTN or OHS) Thoracic surgery patients (lung surgery) Open upper abdominal procedures Those > 70
Remember that PFTs are NOT routinely recommended. Just for those you questions how well they will do from a pulm standpoint post-op
Tests that assess abnormalities of gas exchange
ABG
Pulse-ox
Capnography
Spirometry
Tells you:
1) Volume (Normal is 80-120% of predicted value)
2) Flow (normal is 80-100% of predicted value)
Predicted values for spirometry are based on
Age
Height/weight
Gender
Race
Asthma is a disease of
inflammation
What happens to lung volumes in restrictive disease?
A proportional decrease in ALL lung volumes
What is the most commonly measured parameter in spirometry
Vital capacity
What is normal VC?
60-70mL/kg
Normal is >80% of predicted value
What is FVC?
Forced vital capacity (max inspiration followed by a FORCED expiration–meaning the patient has to cooperate with the test).
It graphs volume vs. time (meaning that it measures FLOW).
Test measures resistance to flow: 80-120% is normal 70-79% = mild 50-69% = moderate <50% = severe
In COPD, FVC will be
Reduced (even if their VC is normal)
This is because the small airways close early and cause gas trapping
What is FEV1?
The amount of air you can forcefully expire in 1 second.
FEV1/FVC values
70-80% = normal 60-75% = mild obstruction 50-59% = moderate obstruction <50% = severe obstruction
What is FEF25-75%?
Forced expiratory flow during the middle portion of FVC.
May reflect effort independent expiration and small airway status.
Sensitive in early stages of obstructive disease
What is more reliable in early disease, FEF25-75% or FEV1/FVC?
FEF25-75%
- Remember that this is the effort independent portion and is sensitive to the status of small airways, especially early in disease
Interpretation of FEF25-75% values
> 60% of predicted value = normal
40-60% = mild
20-40% = moderate
<10% = severe obstruction
What is maximum voluntary ventilation (MVV)?
The largest volume of air a person is able to inhale and exhale in one minute (although test is only performed over 10, 12, or 15 seconds)
MVV is ____ in obstructive disease
decreased
MVV is ____ in restrictive disease
Normal (although someone with restrictive disease d/t to paralysis will have a decreased MVV)
What information does FRC tell you?
Tells you about compliance and how well someone can tolerate apnea.
Someone with a low FRC will have a harder time maintaining their sats during apnea.
How is FRC measured?
Nitrogen wash-out
Basically, someone breathes 100% O2 until the nitrogen analyzer attached to the spirometer detects a nitrogen concentration < 7%. Then all the nitrogen the person breathed out is added together to calculate FRC.
Appearance of the flow/volume loop in obstructive disease
Scooped out expiration d/t air trapping
FV Loop in restrictive disease
Basically a normal loop, but skinnier d/t reduced volumes (volume is on the x axis)
Flattened upstroke in a FV loop indicates
Some sort of upper airway obstruction such as tracheal stenosis.
In the anesthetized patient, this could be a mucus plus, kinked ET tube, etc.
PA, Pa, and Pv pressures and Lung Zones
Zone 1: PA > Pa > Pv
Zone 2: Pa > PA > Pv
Zone 3: Pa > Pv > PA
Does Zone 1 type V:Q normally occur in the awake and spontaneously breathing patient?
NO! Normally, we should have enough BP to force blood into the apices.
However, this type of V:Q may occur if BP drops or alveolar pressure increases (like in PPV!)
Does Zone 3 type V:Q normally occur in the awake and spontaneously breathing patient?
NO! Normally a nice deep breath should provide enough PA to overcome the arterial and venous pressures.
Zone 3 is an example of a
Shunt. Because there is a lot of blood flow, but little ventilation.
In the awake and spontaneously breathing patient, where is ventilation the smallest?
At the highest portion of the lung
In the awake and spontaneously breathing patient, where is ventilation the best?
In the more dependent parts of the lung. Here, the alveoli are compressed d/t gravity and the lung tissue has good compliance.
Pulmonary risks of PPV
Atelectasis (if not enough TV)
Increased blood flow to the dependent lung
Increased ventilation in the independent lung
(^^ above two cause worsened V:Q mismatch)
Dead space (apparatus)
Potential for barotrauma
How to counteract the pulm risks of PPV
Set PAW pressures to 15cm above what their normal PAW is
Deliver an adequate TV (to prevent atelectasis)
Maintain BP to perfuse the lung well
PEEP (prevent atelectasis)
FiO2
CV risks of PPV
Decreased preload and BP
(decreased preload will decrease CO, which decreases BP)
Can cause right to left shunt if the person has an atrial-septal defect
Counteract these effects with positioning, fluids, alpha and beta stimulants, and inotropes
Who may cancel a case if the patient has been smoking?
Plastics or ortho, because it will interfere with wound healing.
How to maximize pulm function before surgery?
Smoking cessation
Mobilize secretions and treat infections
Treat bronchospasm
Improve motivation ad stamina
Effects of smoking cessation
12-24 hours = carboxyhemoglobin levels return to normal, and patient is able to oxygenate better
2-3 weeks = mucociliary function returns and the patient has an increase in secretions and airway irritability
4 weeks = secretions reduce
8 weeks = rate of post-op pulmonary complications decrease** ideal amount of time to stop smoking before surgery
How can we help mobilize secretions?
Hydrate!!
Vibration/percussion
Aerosol therapy
Mucolytic agents?? (may increase secretions and cause irritable airways)
Meds used to treat/prevent bronchospasm
B2 agonists
Anticholinergics (atrovent)
Methylxanthines
Corticosteroids (will probably need a booster dose of this before surgery)
Point to note with FRC and restrictive disease
FRC will be reduced, so less safe apnea time. Be careful with your pre-op sedation.
Also, this decrease in FRC accelerates uptake of inhaled agents
Restrictive disease and regional anesthesia
Be careful of block > T10. This will cause loss of accessory muscles that they need to breath!!
Restrictive disease and PPV
Expect increased PAW pressures
Decrease TV to 4-8 mL/kg
Increase RR to 14-18 (to normalize MV)
Give PEEP (but remember this will decrease preload)
Affect of anesthesia on FRC
Normally, there is a 10-15% decrease in supine position
Additional 5-10% with GA
Plateau of FRC occurs after 10 minutes, regardless of ventilation
Can take up to 3-7 days for FRC to recover after upper abdominal surgery
VC may have up to a ___% reduction after an upper abdominal procedure, and take up to __ days to return to normal
40%
14 days
And this is for a healthy patient! Will be even worse for someone with pulmonary disease
How can we reduce airway reactivity?
Aggressive bronchodilator therapy
High alveolar concentrations of inhaled anesthetics (remember that IAs are bronchodilators!!)
IV opioids/lidocaine prior to AW manipulation
Single-dose corticosteroids
Vent management for obstructive disease
Large TV (remember their lung volumes are increased!)
Slow resp rate
Longer exp-time
Keep PIP below 40cmH20
Intrinsic PEEP may occur due to air trapping
In obstructive disease, MVV is
reduced
In restrictive disease, MVV is
normal
although it depends on cause, obviously someone with muscle disease will have reduced MVV
What does FRC tell you about?
Safe apnea time and pulmonary compliance
Effect of obstructive disease on FEF25-75%
Reduced
Remember that this test tells you about the small airways, and small airways close early in obstructive disease
When may zone 1 occur?
PPV or drop in BP
In PPV, you get increased ventilation to the ______ lung
Independent
Vent settings for restrictive disease
Lower TV (4-8mL/kg)
Increased RR (14-18bpm)
Give PEEP
Expect high peak airway pressures
In obstructive disease, we should avoid PIP above
40
Remember that their airways have thinned, and we want to avoid high pressures.
