L11 PFTs and Asthma Flashcards
FVC
forced vital capacity
FVC
forced vital capacity
FEV1
forced expiratory capacity in the first second of expiration
FEF 25-75%
forced expiratory flow 25-75%, the middle half of forced expiration
SVC
slow vital capacity
IC
inspiratory capacity
ERV
expiratory reserve volume
TLC
total lung capacity
VC
vital capacity
RV
residual volume
TV
tidal volume
IRV
inspiratory reserve volume
FRC
functional residual capacity
perform spirometry ________ because ______
sitting
less likelihood of syncope
spirometry is done at least
3 times
most useful information for obstruction on spirometry
FEV1
defines severity of obstruction, assists in differentiationg obstructive vs restrictive
FEV1/FVC
FEV1/FVC ratio indicative of obstructive pattern
curve quality control involves
- volume time curve plateaus
- expiration lasts >6 secs
- Two best efforts within .2 L
- Flow volume loop are free of artifact
TV
tidal volume
diffusion capacity has a false reduction when _______
to compensate ________
anemic
adjust for hemoglobin level
defines severity of obstruction, assists in differentiationg obstructive vs restrictive
FEV1/FVC
FEF 25-75%
nonspecific for small airway obstruction but may be an early indicator of disease
how long after administering 2-4 puffs of bronchodilator do you wait to repeat testing
15 minutes
how many rounds of bronchodilator testing are done?
3-8 rounds
possibly repeated during flare
bronchodilator may be given by
nebulizer
inhaler
methacholine is given by
nebulizer
after givign methacholine, spirometry is conducted at
30 seconds
90 seconds
a positive methacholine challenge is
FEV1 decreases by 20%
problems with methacholine challenges
risky, must be closely monitored
false positives
expiration makes a triangle
normal flow volume loop
goes up and then has a weird dip on the way back down
obstructive flow volume loop
total lung capacity =
residual volume + vital capacity
diffusion capacity measures
ability of lungs to transfer gas and saturate hemoglobin using CO instead of O2
after diagnosis, retest FEV1
after 3-6 months of controller treatment
periodically every 1-2 years
asthma
- Chronic airway inflammations
- Intermittent and reversible airway obstruction
- Bronchial hyper-responsiveness
obstructive disease inspiration is
normal
obstructive disease expiration is
limited
lung volumes of obstructive disease
high
airway of obstructive disease
narrowed
Normal in obstructive disease
VC
Increased in obstructive disease
TLC
RV
decreased in obstructive disease
FEV1
FEV1/FVC
lung volume in restrictive disease
reduced
Samter’s triad
- sinus disease with nasal polyps
- ASA sensitivity
- severe asthma
inspiration and expiration in restrictive disease
appear normal but flow and volume are significantly reduced
decreased in restrictive disease
TLC
FVC
RV
FEV1
normal or increased in restrictive disease
FEV1/FVC
normal FEV1 value
rules out obstruction/restriction
indicative of obstructive disease
FEV1 < 80% predicted
TLC increased by 15-20%
an alternative to FEV1, as it is more sensitive for detecting early airway obstruction
FEF 25-75%
if ratio of FEV1/FVC is .7-lower limit normal
may have mild obstruction
refer FEV1 and FEF 25-75%
asthma symptoms
- Coughing: nocturnal, seasonal, triggered, longer than 3 weeks
- Wheezing: inspiratory and expiratroy
Chest pain/pressure, dyspnea, SOB
step 4
severe persistant asthma
medications which can trigger an asthma attack
beta blockers
aspirin
NSAIDS
risk factors for asthma
Atopy ASA/NSAID intolerance food allergies GERD RSV family history maternal smoking obesity
pulmonary function tests in intermittent asthma
Normal pulmonary function tests between exacerbations, no limits on activities
associated signs of asthma
rhinitis sinusitis conjunctivitis URI atopic dermatitis
chest of an asthmatic
increased AP diameter
samter’s triad aka
ASA triad
moderate persistent asthma symptoms/SABA use
daily
some activity limitations
atopic triad
- Atopic dermatitis
- Allergic rhinitis
- Asthma
atopic march
atopic dermatitis → food allergy → allergic rhinitis → asthma
moderate persistant asthma FEV1/FVC
reduced by 5%
severe persistent asthma symptoms/SABA use
daily, throughout the day
extremely limited physical activity
severe persistent asthma nighttime awakenings
0-4: more than once a week
5+: nightly
FEV1/FVC in asthma
normal or decreased relative to predicted values
reversibility with bronchodilaotr in young kids
> 8% in young children
step 1
intermittent asthma
step 2
mild persistant asthma
step 3
moderate persistant asthma
step 4
severe persistant asthma
intermittent asthma nighttime awakenings
0-4: none
5+: less than two nights/month
intermittent asthma symptoms/SABA use
less than 2 days/week
cromolyn
mast cell stabilizer
Symptoms/SABA use in mild persistent asthma
more than 2 days/week
mild persistent asthma pulmonary function tests
Normal pulmonary function tests with minor limitation in activity
step 5 treatment
High dose ICS + LABA (or LTRA in ages 0-11)
step 6 treatment
High dose ICS + LABA (or LTRA in ages 0-11) + oral steroids
moderate persistent asthma FEV1
60-80%
*******
if positive for any condition of rule of 2
asthma is not under control
severe persistent asthma symptoms/SABA use
daily, throughout the day
well controlled asthma symptoms/SABA
less than 2x/week
severe persistent asthma FEV1
<60%
severe persistent asthma FEV1/FVC
reduced by more than 5%
montelukast
leukotriene receptor antagonist
used ages 0-4
in chilren older than 12, use _________ to assess control instead of ____________
3 validated questionnaires
FEV1/FVC
benralizumab
monoclonal anti-IL5 receptor a antibodies
not well controlled asthma nighttime awakenings
0-4: >1x/month
5-11: >2x/month
12+: 1-3x/week
used in all stages of asthma PRN
SABA
step 1 treatment
SABA prn
step 2 treatment
Low dose ICS daily
-or-
LTRA or cromolyn
step 3 treatment
Medium dose ICS
Or
Low dose ICS + LABA (or LTRA)
Rule of 2:
- symptoms more than 2x a week
- awaken with asthma more than 2x a month
- refil rescue inhaler more than 2x a year
- peak flow meter measure less than 20% from baseline
how often to follow up asthma
initially: every 1-3 months
then every 3-12 months depending on severity
yellow PFER should
use SABA and increase meds
well controlled asthma FEV1
> 80%
well controlled asthma FEV1/FVC
> .8 for ages 5-11
not well controlled asthma symtoms/SABAA
> 2 days/week
not well controlled asthma FEV1
60-80%
not well controlled asthma FEV1/FVC
75-80%
very poory controlled asthma symptoms/SABA
daily
very poory controlled asthma FEV1
<60%
very poory controlled asthma FEV1/FVC
<75%
signs of severe obstruction
tachypnea tachycardia tripod positioning accessory muscle use pulsus paradoxus
useful handheld on the go measurement of asthma control
peak flow expiratory rate (PFER)
green: good control PFER
> 80%
yellow: caution PFER
50-80%
red: medical alert PFER
<50%
GO TO ED
when to use a CXR for asthma
may show
ruling out infection or obstruction
hyperinflation
treatment for asthma exacerbation
- O2
- SABA (albuterol/xopenex) +/- ipratropium bromide
- Systemic corticosteroids: prednisolone 1mg/kg/day
+/- abx, respiratory monitoring, CPAP, BiPAP, intubation
xopenex
saba
