Podcast
Questions and Answers
What is the primary pathophysiologic mechanism leading to impaired gas exchange in Acute Respiratory Distress Syndrome?
What is the primary pathophysiologic mechanism leading to impaired gas exchange in Acute Respiratory Distress Syndrome?
- Diffuse alveolar damage causing surfactant deficiency
- Increased permeability of the alveolar-capillary membrane (correct)
- Inflammation leading to destruction of type II pneumocytes
- Protein-rich edema causing compression of alveoli
Which of the following is a risk factor for developing Acute Respiratory Distress Syndrome?
Which of the following is a risk factor for developing Acute Respiratory Distress Syndrome?
- Asthma
- Hypertension
- Chronic alcohol abuse (correct)
- Hyperlipidemia
What is the characteristic radiographic finding in Acute Respiratory Distress Syndrome?
What is the characteristic radiographic finding in Acute Respiratory Distress Syndrome?
- Acute onset, bilateral opacities on CXR/CT (correct)
- Pneumothorax
- Bilateral pleural effusions
- Unilateral opacities on CXR/CT
Which of the following is an example of indirect lung injury leading to Acute Respiratory Distress Syndrome?
Which of the following is an example of indirect lung injury leading to Acute Respiratory Distress Syndrome?
What is the characteristic laboratory finding in Acute Respiratory Distress Syndrome?
What is the characteristic laboratory finding in Acute Respiratory Distress Syndrome?
In childhood, which gender is more likely to develop asthma?
In childhood, which gender is more likely to develop asthma?
What is a common allergen exposure that can trigger asthma?
What is a common allergen exposure that can trigger asthma?
Which diagnostic test is used to identify specific allergens?
Which diagnostic test is used to identify specific allergens?
What does blood eosinophilia indicate in asthma patients?
What does blood eosinophilia indicate in asthma patients?
What is the purpose of pulmonary function tests (PFTs) in asthma diagnosis?
What is the purpose of pulmonary function tests (PFTs) in asthma diagnosis?
What does spirometry measure during a pulmonary function test?
What does spirometry measure during a pulmonary function test?
Which factor is a trigger for asthma exacerbations?
Which factor is a trigger for asthma exacerbations?
What is the purpose of a chest radiograph (CXR) in asthma diagnosis?
What is the purpose of a chest radiograph (CXR) in asthma diagnosis?
What is the term for the measurement of oxygen and carbon dioxide levels in the blood?
What is the term for the measurement of oxygen and carbon dioxide levels in the blood?
Which of the following is NOT a host factor that contributes to asthma risk?
Which of the following is NOT a host factor that contributes to asthma risk?
Study Notes
Acute Respiratory Distress Syndrome (ARDS)
- Major cause of respiratory failure in critically ill patients
Pathophysiology
- Diffuse alveolar damage leads to increased permeability
- Increased permeability causes protein-rich edema
- Protein-rich edema impairs gas exchange
Etiology
- Direct Lung Injury:
- Pneumonia (bacterial, viral, aspiration)
- Pulmonary contusion
- Gastric aspiration
- Inhalational injury (smoke, toxins)
- Indirect Lung Injury:
- Sepsis
- Severe trauma (multiple fractures, burns)
- Acute pancreatitis
- Drug overdose/toxicity
Risk Factors
- Age > 65 years
- Chronic alcohol abuse
- Obesity
- Chemotherapy (bleomycin)
- Diabetes mellitus
Clinical Presentations
- Progressive dyspnea
- Acute onset, bilateral opacities on CXR/CT
- Hypoxemia refractory to O2 (P/F ratio)
Risk Factors of Asthma
- Host factors include genetics, with a higher risk of asthma in males during childhood and females during adulthood
- Environmental factors that contribute to asthma include allergen exposure, respiratory infections, pollution, smoking, and occupational factors
Triggers of Asthma
- Respiratory infections
- Physical activity
- Hormonal fluctuations
- Medications such as non-selective beta-blockers, aspirin, and other NSAIDs
- Inhaled irritants like tobacco smoke, pollution, cold dry air, and hot humid air
- Inhaled allergens
Diagnosis of Asthma
- Allergen testing through skin test to identify specific allergens
- Complete Blood Count (CBC) to check for total and differential leucocytic count
- Blood eosinophilia may indicate severe forms of asthma
- Sputum examination to check for cellular content or pathogens
- Chest Radiograph (CXR) to show air tapering in severe cases
- Blood Gas Analysis to monitor oxygen and carbon dioxide levels
- Pulmonary function tests (PFTs) to assess severity of the disease and monitor its course and treatment
Pulmonary Function Tests (PFTs)
- Spirometry measures lung volume by recording the amount and rate of air breathed in and out over a specified time
- Primary PFTs used in asthma diagnosis include forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC)
- FEV1 is the volume of air forcefully exhaled in one second, approximately 3-4 L
- FEV1 percentages:
- 80% or above: normal
- 60-80% predicted: mild
- 50-60% predicted: moderate
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Description
Learn about the pathophysiology and etiology of Acute Respiratory Distress Syndrome (ARDS), a major cause of respiratory failure in critically ill patients.
