6.Neonatal respiratory distress syndrome -ards -sleep apnea - pneum.ipertasi Flashcards
A newborn dies of neonatal respiratory distress syndrome. Lung tissue examined in the lab will reveal a deficiency of what chemical?
Surfactant
• How does the lack of surfactant in neonatal respiratory distress syndrome impair gas exchange in the lungs?
Surfactant deficiency leads to an increase in surface tension, resulting in collapse of the alveoli
What is used as a measure of lung maturity in neonates? What values are expected in neonatal respiratory distress syndrome (NRDS)?
The lecithin:sphingomyelin ratio in amniotic fluid;
What vascular pathology is associated with persistently low oxygen tension due to neonatal respiratory distress syndrome?
Patent ductus arteriosus
A newborn is cautiously administered oxygen by a neonatologist, who also performs serial eye exams. What is the physician worried about?
Retinopathy of prematurity (a side effect of therapeutic supplemental oxygen administration in newborns with NRDS)
A newborn receives supplemental oxygen therapy for neonatal respiratory distress syndrome. This can lead to what three complications?
Retinopathy of prematurity, Intraventricular hemorrhage, and Bronchopulmonary dysplasia (RIB)
What are three risk factors for neonatal respiratory distress syndrome?
Prematurity, maternal diabetes (due to elevated insulin), and cesarean delivery (due to decreased release of fetal glucocorticoids)
A premature infant born to a diabetic mother exhibits intercostal retractions and appears hypoxic. What is the most likely diagnosis?
Neonatal respiratory distress syndrome
A newborn diagnosed with neonatal respiratory distress syndrome is at risk of what complications?
Metabolic acidosis, PDA, necrotizing enterocolitis
Medical treatment for neonatal respiratory distress syndrome includes what treatments for the mother and child?
Steroids for the mom prior to birth, and artificial surfactant for the newborn
A patient hospitalized for acute pancreatitis suddenly has difficulty breathing. PaO2:FiO2 ratio is decreased. Diagnosis?
Acute respiratory distress syndrome
Name seven conditions known to cause acute respiratory distress syndrome.
Trauma, sepsis, shock, gastric aspiration, acute pancreatitis, amniotic fluid embolism, and uremia
Despite many etiologies, what pathophysiology is seen in all cases of acute respiratory distress syndrome?
Alveolar damage leads to capillary permeability, fluid leakage into alveoli, and pulmonary edema, resulting in thickened (hyaline) membranes
In acute respiratory distress syndrome, acute alveolar damage leads to a(n) ____ (decrease/increase) in alveolar capillary permeability.
Increase
Name three molecular mechanisms that contribute to the initial damage to alveoli in acute respiratory distress syndrome.
Neutrophilic toxins, activation of the coagulation cascade, and oxygen-derived free radicals
An alcoholic man with acute pancreatitis and oxygen desaturation is having trouble breathing. What put him at risk for this disorder?
Pancreatitis, which triggers acute respiratory distress syndrome
What obstetric complication can result in adult respiratory distress syndrome?
Amniotic fluid embolism
A patient is diagnosed with dyspnea characterized by a decreased PaO2:FiO2 ratio. Management?
Low tidal volume mechanical ventilation, and treat underlying cause (trauma, sepsis, uremia) (this is acute respiratory distress syndrome)
A man has daytime sleepiness; his wife attributes it to disrupted sleep from breathing pauses. His daytime PaO2 is ____ (normal/low/high).
Daytime PaO2 would be normal (this patient likely has sleep apnea)
A patient is diagnosed with sleep apnea. What complications may arise from the hypoxia he experiences at night?
Arrhythmias (atrial fibrillation or flutter), systemic or pulmonic hypertension, sudden death
What is the difference between central and obstructive sleep apnea?
Central apnea is due to a lack of CNS-derived respiratory effort, obstructive apnea is due to a mechanical airway obstruction
An obese man complains of chronic fatigue. His wife says he is an especially loud snorer. What treatments can you offer?
Treat with weight loss, continuous positive airway pressure, surgery (this is obstructive sleep apnea)
A child is diagnosed with obstructive sleep apnea. What anatomic abnormality is this associated with? Adults?
Adenotonsillar hypertrophy in children; excess parapharyngeal tissue in adults
Name five conditions potentially associated with sleep apnea.
Obesity, loud snoring, pulmonary/systemic hypertension, arrhythmias, and possible sudden death
An obese patient has daytime somnolence, disrupted sleep, and loud snoring. CBC shows elevated hematocrit. Why is his hematocrit high?
Increased erythropoietin and increased red blood cells (the patient likely has sleep apnea causing chronic hypoxia)
• What is the normal pulmonary arterial pressure?
10&8211;14 mmHg
What is the cutoff value for pulmonary hypertension?
≥25 mmHg during rest
What three pathologic changes in the vasculature are caused by pulmonary hypertension?
Medial hypertrophy, arteriosclerosis, and intimal fibrosis of the pulmonary arteries
A man is diagnosed with pulmonary hypertension. What undesirable outcome is possible when he finds himself in severe respiratory distress?
• Cyanosis and RVH, followed by death from cor pulmonale that is decompensated
A patient with pulmonary hypertension is lost to follow up. Is he at risk for sequelae from his untreated pulmonary hypertension?
Yes (severe respiratory distress causing right ventricular hypertrophy and cyanosis, resulting in decompensated cor pulmonale and death)
Name the five classification groups of pulmonary hypertension.
Pulmonary arterial hypertension, chronic thromboembolic PH, PH from left heart disease, PH from lung disease/hypoxia, and multifactorial
Hereditary pulmonary arterial hypertension is caused by what?
An inactivating mutation in the BMPR2 gene, which normally inhibits vascular smooth muscle proliferation
What is the prognosis for a patient diagnosed with pulmonary arterial hypertension?
Poor
Name conditions that cause pulmonary arterial hypertension.
Persistent newborn HTN, pulmonic vein occlusion, HIV, schistosomiasis, drugs, connective tissue disease, portal HTN, congenital heart issues
A patient with narcolepsy is prescribed amphetamines. What pulmonary side effect would you watch out for? Which other drug has this effect?
Pulmonary arterial hypertension; cocaine
What are some of the potential causes of secondary pulmonary hypertension?
COPD, systolic/diastolic issues, mitral stenosis, recurrent microthrombi, sleep apnea, high altitudes, hematologic/metabolic/systemic illness
Name conditions of the heart that can lead to pulmonary hypertension.
Systolic or diastolic dysfunction, valvular disease (e.g., mitral stenosis)
A patient has mitral stenosis. How might this pathology ultimately cause pulmonary hypertension?
Increased resistance to flow in the left heart causes backup of pressure from the left atrium into the pulmonary vasculature
Name primary conditions of the lungs that lead to pulmonary hypertension.
Lung parenchyma destruction (e.g., COPD), hypoxemic vasoconstriction (e.g., living in high altitudes, sleep apnea)
A patient has chronic obstructive pulmonary disease (COPD). How might this pathology ultimately lead to pulmonary hypertension?
By the destruction of lung parenchyma, and subsequent vasoconstriction due to hypoxia
How does obstructive sleep apnea or living at high altitudes cause pulmonary hypertension?
Obstructive sleep apnea and living at high altitudes cause hypoxia, which in turn causes pulmonary vasoconstriction
A cancer patient has recurrent microthrombi and is repeatedly in the hospital. Could this cause him to develop pulmonary hypertension?
Yes (pressures increase because the emboli decrease the total cross-sectional area of the pulmonary vascular bed)
Hematologic, metabolic, and systemic disorders cause what type of pulmonary hypertension?
Multifactorial
A patient has autoimmune disease, but the exact type is unknown. Nonetheless, do you worry about pulmonary hypertension in this patient?
Yes (processes such as systemic sclerosis cause inflammation, leading to intimal fibrosis and medial hypertrophy in pulmonary vessels
