m6 (4/?) - ARDS, ARF, age-related issues

ARDS

acute respiratory distress syndrome - life threatening condition where alveolocapillary membrane becomes injured and acute lung inflammation occurs

hyaline membrane

a layer of debris surrounding alveoli air sacs, composed of dead cells, fluids, residual surfactant, proteins. impairs gas exchange

what ARDS leads to

severe pulmonary edema and severe hypoxemia

causes of ARDS

sepsis and trauma, pneumonia, drug overdose or smoke inhalation, inspiration of gastric acid contents

describe the development of ARDS

1. neutrophil and platelets release inflammatory chemicals that damage the alveolocapillary membrane

2. the membrane permeability increases and blood leaks into the interstitial spaces → leads to edema

3. alveoli collapse from surfactant inactivation, and gas exchange decreases further

4. hyaline membrane forms and impairs gas exchange more

5. tissue repair may produce fibrosis

ARDS clinical manifestations

severe onset respiratory distress, severe hypoxemia

ARDS treatment

supplying high concentrations of oxygen via assisted ventilation, until the lungs heal

mortality rate of ARDS

50-70% - needs to be treated promptly

ARF (types)

acute respiratory failure from inadequate gas exchange

• hypercapnic: due to ventilation failure

• hypoxemic: due to gas exchange failure within lungs

hypercapnic respiratory failure

due to ventilation failure causing increased arterial CO2 and hypoxemia

treatment of hypercapnic respiratory failure

mechanical ventilation

hypoxemic respiratory failure

vital capacity and respiratory muscle peaks between what ages?

20-25

after 40 yrs old, […] decreases

alveolar surface area

after 50 yrs old, […] lose elasticity and decrease in chest wall […]

[alveoli] [motility]

list alterations of pulmonary function in children

• croup

• bronchiolitis

• epiglottitis

• IRDS - respiratory distress syndrome in infants

croup (overview, classic symptoms/signs)

inspiratory stridor (wheezing tone) from obstruction, inflammation. hoarseness, barking cough

virus most commonly causing croup

LTB - laryngotracheobronchitis

retractions

indentations of skin around ribs, sternum, from accessory respiration muscles. seen in severe croup cases

bronchiolitis

inflammation of bronchioles from viral infection. wheezing, dyspnea, cough

epiglottitis

swelling of larynx and epiglottis from bacterial infection. causes sore throat and fever, and inspiratory stridor

inspiratory stridor

harsh high pitched breathing sound during inspiration, from partial airway obstruction or narrowing

IRDS

seen in premature infants due to surfactant deficiency