Definition: A cough is a forceful spasm of the bronchus that expels air from the lungs.
Purpose: To remove any foreign material or irritants from the airway.
Sputum: Mucus that is coughed up during the act of coughing.
- Clinical Relevance: Sputum sampling can be crucial for diagnosing conditions like pneumonia; samples may be analyzed or cultured to identify pathogens.
Hemoptysis
Definition: Coughing up blood.
Hypoxemia and Hypoxia
Hypoxemia
- Definition: Low oxygen levels in the blood, measured as partial pressure of oxygen (PaO2).
Hypoxia
- Definition: Low oxygen levels in the tissues.
- They often occur together, but can be separate; for example, myocardial infarction leads to localized hypoxia in cardiac myocytes even if overall blood oxygen levels are normal.
Hypercapnia
Definition: Elevated levels of carbon dioxide (CO2) in the blood.
Dyspnea
Definition: Subjective feeling of shortness of breath or difficulty breathing.
- Dyspnea on Exertion: Specifically related to physical activity.
- Orthopnea: Difficulty breathing while lying down, commonly experienced in conditions like pneumonia or severe respiratory illness.
Respiratory Distress
Definition: Clinical finding rather than a diagnosis, indicating a patient is struggling to breathe.
Assessment Signs:
- Accessory muscle use (e.g., straining neck and abdominal muscles while breathing).
- Tripoding position: leaning forwards to ease breathing.
- Nasal flaring: noticeable widening of nostrils during inhalation.
Cheyne-Stokes Respirations: Crescendo-decrescendo breathing pattern followed by apneas.
Acute Respiratory Failure
Definition: When lungs cannot properly oxygenate the blood or ventilate CO2.
Causes include:
- Overdose on narcotics (e.g., opioids, fentanyl) which depresses the central respiratory drive.
- Lung diseases (e.g., severe asthma, COPD).
- Brain injuries affecting the respiratory centers.
Patients may require interventions such as non-invasive ventilation (e.g., CPAP, BiPAP) or more aggressive therapy like mechanical ventilation or ECMO (extracorporeal membrane oxygenation).
Pneumothorax
Definition: Abnormal accumulation of air in the pleural space, leading to lung collapse.
- Causes: May involve trauma (e.g., rib fractures) or rupture of blisters on the lungs (particularly in young smokers).
- Diagnosis: Chest x-ray can detect outlines of the pneumothorax; look for lack of lung markings or costophrenic angles.
- Symptoms: Sudden chest pain and dyspnea, with pleuritic chest pain characteristics.
Pleural Effusion
Definition: Excess fluid in the pleural space.
- Classifications:
- Transudative Effusion: Watery fluid, often due to fluid overload.
- Exudative Effusion: Protein-rich fluid due to infections or inflammatory processes.
- Hemothorax: Blood in pleural space.
- Empyema: Pus in pleural space due to severe infection.
Definition: Conditions that decrease lung compliance, making it hard for lungs to expand.
- Examples:
- Aspiration Pneumonitis: Inhalation of food or liquid into lungs, leading to inflammation and reduced lung stretch.
- Atelectasis: Collapsed alveoli, often post-surgery; use incentive spirometry to encourage lung inflation postoperatively.
- Pulmonary Fibrosis: Scarring that reduces lung elasticity, impeding normal function.
Acute Respiratory Distress Syndrome (ARDS)
Definition: A severe, life-threatening form of acute respiratory failure characterized by poor oxygen exchange, bilateral infiltrates on chest x-ray, and decreased PaO2 despite supplemental oxygen.
Clinical Findings: Patients often present with severe respiratory distress, tachypnea, and may progress to multiple organ failure due to hypoxia.
Obstructive Lung Diseases
Overview: Conditions that cause obstruction of airflow. Main types:
- Asthma: Chronic condition characterized by reversible airway obstruction due to inflammation and bronchoconstriction, often triggered by allergens.
- Symptoms: Chest tightness, wheezing, coughing, and dyspnea; treatment involves bronchodilators (e.g., albuterol) especially during acute attacks.
- COPD (Chronic Obstructive Pulmonary Disease): Primarily associated with long-term smoking or exposure to inhaled irritants.
- Subtypes:
- Emphysema: Destruction of alveolar walls leads to trapped air and irreversible obstruction.
- Chronic Bronchitis: Characterized by chronic mucus production leading to airflow obstruction.