Clin Med (Pulm)

lung volumes

a mesure of the amount of air in the lungs at different points during breathing

breathing frequency (f)

breaths taken/min ie respiratory rate

minute ventilation (Vm)

vol of air inhaled & exhaled in a min

Vt * f

tidal volume

amount of air inhaled & exhaled during normal, quiet breath

inspiratory reserve volume

the extra air you can forcefully inhale after normal tidal breath

expiratory reserve volume

the extra air you can forcefully exhale after normal tidal breath

residual volume

air that is left in lungs after full foceful exhalation

keep the lungs from collapsing

closing volume

vol of air that you can still exhale AFTER small airways begin closing

lung capacities

2+ lung volumes

functional residual capacity

vol of air in lungs @ resting end-exhalation

ERV + RV = FRC

inspiratory capacity

max vol of air that can be inhaled from resting expiratory level

Vt + IRV = IC

total lung capacity

vol of air in lungs @ max inflation

IRV + Vt + ERV + RV = TLC

vital capacity

largest vol where respiratory bronhioles begin to collapse during expiration

CV + RV = CC

respiratory bronchioles & alveoli

these stay open via pul. interstitium/lung tissue

spirometry

measures airflow; rate at which the lungs vol changes during forced breathing maneuvers

starts w full inhalation → fast, forced exhalation (for as long as possible)

forced vital capacity (FVC)

total vol air that can be exhaled during a max forced exhalation

forced expiratory volume in 1 sec (FEV1)

vol air exhaled in 1st sec after max inhalation

FEV1/FEC ratio

% of FVC exhaled in 1 sec

FEF25-75

avg airflow speed during the middle half of a forced exhalation

specifically reflecting the function of middle → small peripheral airways

maximal voluntary ventilation

max amount of air that can be inhaled & exhaled in 1 min

methacholine challenge

specialized test to diagnose asthma by inhaling methacholine (a bronchoconstrictor)

CO diffusion test (DLCO)

measures how well you lungs transfer O2 from breath → blood

peak flow meter

measures how fast you can blow air out of lungs to help MONITOR conditions

V/Q mismatch

happens when airflow (ventilation) in lungs doesn’t equal blood flow (perfsion) in capillaries

shunt

normal blood flow but reduced/blocked airflow

EX: pneumonia

physiological shunt

small airways close due to disease, airway closure, & atelectasis (aka lung collapse) → dilutes O2 saturation of L atrial blood

hypoxic pulmonary vasoconstriction

pulmonary arterioles reflexively vasoconstricts → moves blood to better ventilated alveoli (which results in pulmonary hypertension)

anatomic shunt

a structural condition where deoxygenated blood bypass lung’s gas exchage → enters arterial system directly

ie blue blood diluted red blood, a little bit..

bronchial circulation

feeds lung tissue itself w O2 therefore blood from bronchial arteries slowly become deoxygenated & drains into pulmonary veins

Thebesian circulation

thebesian veins drain deoxygenated blood directly into heart chambers

dead space

normal airflow but reduced/missing blood flow

EX: pulmonary embolism

alveolar dead space (aka respiratory zone)

normal airflow @ alveoli but reduced/missing blood flow

anatomic dead space (aka conducting zone)

normal airflow but don’t participate in gas exchange

EX: trachea, bronchi

physiological dead space

combo of alveoloar & anatomci dead space

reasons for hepatological V/Q mismatch

pathological conditions of liver → liver fails to clear vasoactive substance from blood prod → V/Q mismatch

hepato-pulmonary syndrome

diseased liver fails to clear vasodilators which counteract HPV → physiological shunt

porto-pulmonary hypertension

diseased liver fials to clear vasoconstrictors which causes increased pulmonary artery pressure & R ventricular dysfunction → alveolar dead space

cor pulmonale

altered structure &OR imparied function of R ventricle due to pulmonary HTN

pulmonary HTN

caused by ddisease in lung, vasculature, upper airway, or chest wall

incrase pulmonary arterial pressure → SECONDARY RV failure

PAP > 25mmHg at rest (normal PAP = 8-20mmHg)

findings of cor pulmonale

dyspnea on excurtion, fatigue, lethargy, exertional syncope & angina, hypoxemia, anorexia & RUQ discomfort (due to passive congestion of liver & bowel)

workup for cor pulmonale

EKG, 2D echo, right heart catheterization

causes for pulmonary HTN (arteriolar)

idiopathic, hereditary, drugs like cocane, connective tissue disease like SLE

causes for pulmonary HTN (outside arterioles)

mitral valve disease, LV failure, congenital heart disease like shunting, COPD, interstitial lung disease, obstructive sleep apnea, chronic thromboembolic disease

findings in pulmonary HTN

1. P2 louder bc PA diastolic pressure increase → valve close more forcefully

2. initially wider S2 split bc RV still strong therefore takes longer to eject blood

3. later narrower S2 split bc RV is fialing therefore ejects less blood

4. holosystolic murmur @ LLSB (lower left sternal border) bc tricuspid regurgitation

5. diastolic murmur @ ULSB (upper left sternal border) bc pulmonic insufficiency

treatment for pulmonary HTN

1. reduction of RV afterload (ie decrease PA pressure) by giving supplemental O2 or medication

2. decrease RV pressure preload by increase prod of urine

3. improve RV contractility by giving IV dobutamine/milrinone

4. heart-lung transplant

asthma

chronic, INFLAMMATORY lung diseas that increase airway responsiveness → airway obstruction BUT can be partially/completely reversed

features of asthma

airflow obstruction, aggrevateion increases @ night, remodeling of airway (VERY RARE)

associated coditions to asthma in adults

atopic dermatitis/allergy

obesity

chronic sinusitis

GERD

OSA

stress/depression

exercise

food allergies

vocal cord dysfunction

ABPA (very rare)

associated condition to asthma in children

RSV

foreign body aspiration

bronchopulmonary dysplasia

cystic fibrosis

obesity

risk factors for asthma

host (genetics, gender, race like blacks & hispanics), environmental, asprin/NSAIDs hypersensitivity, use of beta-blockers

intermitten asthma category

1. symptoms occur during the day (days/wk): </= 2 days/wk

2. awaken @ night by symptoms (nights/mo): </= 2 nights/mo

3. use of rescue inhaler/wk: </= 2x/wk

4. # of rescue inhaler refill/yr: </= 2x/yr

5. # of exacerbations that require oral glucocorticoids: < 2x/yr

6. interference w/normal activity: none

7. FEV1 & FEV1/FVC ratio between exacerbations: >/= 80%

rules of 2

mild persistent asthma category

1. symptoms occur during the day (days/wk): 2+ days/wk

2. awaken @ night by symptoms (nights/mo): 3-4 nights/mo

3. use of rescue inhaler/wk: 2+ x/wk BUT NOT DAILY

4. # of rescue inhaler refill/yr: > 2x/yr

5. # of exacerbations that require oral glucocorticoids: 2+ x/yr

6. interference w/normal activity: minor

7. FEV1 & FEV1/FVC ratio between exacerbations: >/= 80%

moderate persistent asthma category

1. symptoms occur during the day (days/wk): daily

2. awaken @ night by symptoms (nights/mo): 1+ nights/wk

3. use of rescue inhaler/wk: daily

4. # of rescue inhaler refill/yr:

5. # of exacerbations that require oral glucocorticoids: 2+ x/yr

6. interference w/normal activity: moderate

7. FEV1 & FEV1/FVC ratio between exacerbations: 60-80%

severe persistent asthma category

1. symptoms occur during the day (days/wk): all day

2. awaken @ night by symptoms (nights/mo): every night

3. use of rescue inhaler/wk: multiple times/day

4. # of rescue inhaler refill/yr:

5. # of exacerbations that require oral glucocorticoids: 2+ x/yr

6. interference w/normal activity: extreme

7. FEV1 & FEV1/FVC ratio between exacerbations: < 60%

blood test (testing for asthma)

elevated eosinophilia/serum IgE levels → asthma

spirometry & bronchodilator (testing for asthma)

if FEV1/FVC ratio improves by >/= 12% & >/=200mL after bronchodilator → asthma

bronchoprovacation (testing for asthma)

(+) spirometry after deliverately causing bronchoconstriction → asthma

peak expiratory flow

useful for MONITORYING variability/control of asthma

CXR (testing for asthma)

used to exculde alt/complicating diagnoses other than asthma

treating asthma

1. control triggers

2. avoid beta-blockers (ESPECIALLY non-selective beta-blockers bc they nullify bronchodilators)

3. avoid aspirin & non-COX2 selective NSAID anti-inflammatory drug (can cause triad asthma)

4. avoid sulfite compounds found in food (like shrimp)

rescue inhaler (asthma)

drug that gives quick relief of symptoms; consists of beta2-agonists & steroid OR pure SABA

examples of beta2-agonist & steroid medications

formoterol/budesonide → Symbicort

formoterol/beclomethasone → Fostair

scheduled medication (asthma)

in addition to rescue inhaler bc pt has persistent asthma

forms of inhalers

powder & nebulizer

tier 1 asthma medication (SABAs)

short-acting beta agonist

stimulates beta2 receptors → relaxes bronchial smooth muscle → rapid bronchiodilation delivered via HFA MDI

EX: albuterol

frequent use → reduced responsiveness therefore ONLY USE IN EMERGENCY

HFA MDI

HydroFluoroAlkane Metered Dose Inhaler

tier 2 asthma medication (ICS)

inhaled corticosteroids/glucocorticoids

suppress the airway inflamtion & decrease bronchial hyperresponsiveness to disease

EX: budesonide (Pulmicort)

must be used w SABAs bc it has slower onset of relief

tier 3 asthma medication (LABAs)

long acting beta agonist

stimulates beta2 receptors → bronchodilation but happens MUCH slower (EX: formoterol/Foradi), therefore it must be used w ICS (EX: Advair)