Week 6: NR283:Pathophysiology: NR283 Pathophysiology
What are the causes of dyspnea? - ANSWER:Diffuse or focal disturbances of ventilation, gas exchange,
ventilation-perfusion relationships, increased work of breathing, diseases that damage lung tissue (lung
parenchyma)
Causes of PND - ANSWER:PND = paroxysmal nocturnal dyspnea
Wake up at night gasping for air, must sit or stand to relieve SOB
Causes: heart failure or lung disease correlated with HF
Pathophysiology of PND - ANSWER:Laying flat -> body redistributes body water, causing abdominal
contents to exert pressure on diaphragm, decreasing efficiency of the respiratory muscles
Why only when asleep? Decreased responsiveness of respiratory center in the brain and decreased
adrenergic activity in myocardium during sleep
Symptomatic relief of: orthopnea - ANSWER:Sitting up in a foward-leaning posture or supporting the
upper body with pillows
Symptomatic relief of: dyspnea - ANSWER:(Depends on cause)
Reduce anxiety, anger, emotions. Decrease amount of effort put forth to induce the dyspnea
Correct decreased pH, hypercapnia or hypoxemia
Symptomatic relief of: hyperpnea - ANSWER:Depends on cause
avoid or stop strenuous exercise, treat underlying condition causing metabolic acidosis
Symptomatic relief of: dyspnea on exertion - ANSWER:reduce amount of exertion
Kussmaul respirations - ANSWER:(Hyperpnea) - slightly increased ventilatory rate, very large TV, no
expiratory pause. Caused by strenuous activity or metabolic acidosis
Cause of respiratory acidosis - ANSWER:d/t hypoventilation
CO2 removal doesn't keep up with CO2 production, paCO2 increases, hypercapnia, increased H+ in
blood, decreased pH, respiratory acidosis
Often overlooked until severe. Can present as somnolence or disorientation, can cause secondary
hypoxemia
Cause of respiratory alkalosis - ANSWER:d/t hyperventilation
Lungs remove CO2 faster than it is produced (decreases paCO2) - hypocapnia, increased pH, respiratory
alkalosis
, Can only be determined by ABGs
Presents w/ anxiety, acute head injury, conditions that cause insufficient oxygenation of the blood
Clubbing (What is it? Causes?) - ANSWER:selective bulbous enlargement of the digits. Can be graded 1-5
based on nail bed hypertrophy and changes in nails. Not typically painful and reverses when the
underlying condition is treated
Cause: low O2
Diseases presenting with clubbing - ANSWER:Bronchiectasis, cystic fibrosis, lung abscess, pulmonary
fibrosis, congenital heart disease, lung CA
Hypoxia - ANSWER:Reduced oxygenation of cells in tissue
Pulmonary edema S/S - ANSWER:dyspnea, orthopnea, hypoxemia, increased work of breathing,
inspiratory crackles, dullness to percussion over base of lung, ventricular dilation
Causes of pulmonary edema - ANSWER:Valvular dysfunction, coronary artery disease, left ventricular
dysfunction (MC) -> increases L atrial pressure, increases pulmonary hydrostatic pressure leading to
pulmonary edema
Injury to capillary endothelium (ARDS) -> causes increased capillary permeability and disruption of
surfactant production by alveoli (movement of fluid into interstitial space and alveoli)
Blockage of lymphatic vessels (fluids can't be removed from interstitial space for it accumulates)
How does pulmonary edema cause hypoxia? - ANSWER:In lungs and alveoli, causes inadequate
ventilation of alveoli to capillaries (low V/Q, shunting) resulting in minimally oxygenated blood returning
back to heart to be circulated to body
Thickening alveolocapillary membrane impairs diffusion of O2, increased time needed to diffuse across
membrane, so less O2 diffuses.
How does fibrosis cause pulmonary edema? - ANSWER:Formation of fibrous lesions increase the time for
diffusion across alveolocapillary membrane
Marked loss of lung compliance, lung difficult to ventilate, decreased V/Q -> shunting
Diseases w/ fibrosis - ANSWER:ILD and asthma
Bronchiectasis, bronchiolitis obliterans, idiopathic pulmonary fibrosis, exposure to toxins,
pneumoconiosis (silicosis, coal worker's lung, asbestosis), allergic alveolitis
Pulmonary conditions that cause dead space - ANSWER:(V/Q ratio is off balance d/t good air ventilation
but low perfusion).
Blood is unable to reach normal functioning alveoli, such as in pulmonary hypertension and pulmonary
embolisms
V/Q is increased
Increased paO2, decreased paCO2
What are the causes of dyspnea? - ANSWER:Diffuse or focal disturbances of ventilation, gas exchange,
ventilation-perfusion relationships, increased work of breathing, diseases that damage lung tissue (lung
parenchyma)
Causes of PND - ANSWER:PND = paroxysmal nocturnal dyspnea
Wake up at night gasping for air, must sit or stand to relieve SOB
Causes: heart failure or lung disease correlated with HF
Pathophysiology of PND - ANSWER:Laying flat -> body redistributes body water, causing abdominal
contents to exert pressure on diaphragm, decreasing efficiency of the respiratory muscles
Why only when asleep? Decreased responsiveness of respiratory center in the brain and decreased
adrenergic activity in myocardium during sleep
Symptomatic relief of: orthopnea - ANSWER:Sitting up in a foward-leaning posture or supporting the
upper body with pillows
Symptomatic relief of: dyspnea - ANSWER:(Depends on cause)
Reduce anxiety, anger, emotions. Decrease amount of effort put forth to induce the dyspnea
Correct decreased pH, hypercapnia or hypoxemia
Symptomatic relief of: hyperpnea - ANSWER:Depends on cause
avoid or stop strenuous exercise, treat underlying condition causing metabolic acidosis
Symptomatic relief of: dyspnea on exertion - ANSWER:reduce amount of exertion
Kussmaul respirations - ANSWER:(Hyperpnea) - slightly increased ventilatory rate, very large TV, no
expiratory pause. Caused by strenuous activity or metabolic acidosis
Cause of respiratory acidosis - ANSWER:d/t hypoventilation
CO2 removal doesn't keep up with CO2 production, paCO2 increases, hypercapnia, increased H+ in
blood, decreased pH, respiratory acidosis
Often overlooked until severe. Can present as somnolence or disorientation, can cause secondary
hypoxemia
Cause of respiratory alkalosis - ANSWER:d/t hyperventilation
Lungs remove CO2 faster than it is produced (decreases paCO2) - hypocapnia, increased pH, respiratory
alkalosis
, Can only be determined by ABGs
Presents w/ anxiety, acute head injury, conditions that cause insufficient oxygenation of the blood
Clubbing (What is it? Causes?) - ANSWER:selective bulbous enlargement of the digits. Can be graded 1-5
based on nail bed hypertrophy and changes in nails. Not typically painful and reverses when the
underlying condition is treated
Cause: low O2
Diseases presenting with clubbing - ANSWER:Bronchiectasis, cystic fibrosis, lung abscess, pulmonary
fibrosis, congenital heart disease, lung CA
Hypoxia - ANSWER:Reduced oxygenation of cells in tissue
Pulmonary edema S/S - ANSWER:dyspnea, orthopnea, hypoxemia, increased work of breathing,
inspiratory crackles, dullness to percussion over base of lung, ventricular dilation
Causes of pulmonary edema - ANSWER:Valvular dysfunction, coronary artery disease, left ventricular
dysfunction (MC) -> increases L atrial pressure, increases pulmonary hydrostatic pressure leading to
pulmonary edema
Injury to capillary endothelium (ARDS) -> causes increased capillary permeability and disruption of
surfactant production by alveoli (movement of fluid into interstitial space and alveoli)
Blockage of lymphatic vessels (fluids can't be removed from interstitial space for it accumulates)
How does pulmonary edema cause hypoxia? - ANSWER:In lungs and alveoli, causes inadequate
ventilation of alveoli to capillaries (low V/Q, shunting) resulting in minimally oxygenated blood returning
back to heart to be circulated to body
Thickening alveolocapillary membrane impairs diffusion of O2, increased time needed to diffuse across
membrane, so less O2 diffuses.
How does fibrosis cause pulmonary edema? - ANSWER:Formation of fibrous lesions increase the time for
diffusion across alveolocapillary membrane
Marked loss of lung compliance, lung difficult to ventilate, decreased V/Q -> shunting
Diseases w/ fibrosis - ANSWER:ILD and asthma
Bronchiectasis, bronchiolitis obliterans, idiopathic pulmonary fibrosis, exposure to toxins,
pneumoconiosis (silicosis, coal worker's lung, asbestosis), allergic alveolitis
Pulmonary conditions that cause dead space - ANSWER:(V/Q ratio is off balance d/t good air ventilation
but low perfusion).
Blood is unable to reach normal functioning alveoli, such as in pulmonary hypertension and pulmonary
embolisms
V/Q is increased
Increased paO2, decreased paCO2
