pulm lecture 2/27

Introduction

  • Emphysema was not previously discussed; focus shifted to mid-term preparation topics.

Pulmonary Embolism (PE)

  • Occurrence: Mainly in pulmonary arteries.

  • Definitions:

    • Embolism: Small clot.

    • Thrombus: Larger organized clot.

  • Effects of thrombus:

    • Thrombus in pulmonary artery causes pulmonary hypertension.

    • Blood flows from superior/inferior vena cava ➡ right atrium ➡ right ventricle ➡ pulmonary arteries ➡ lungs.

    • Blockage requires stronger heart contractions, resulting in pulmonary hypertension.

  • Hemodynamic changes:

    • Normal pulmonary circulation has low resistance.

    • Obstruction increases resistance ➡ increased pressure needed to push blood through.

Risk Factors for Clots

  • Heart disease

  • Cancer

  • Immobility (e.g., long flights)

  • Obesity

  • Genetic factors (e.g., Factor V, prothrombin mutation)

  • OCPs (oral contraceptive pills)

  • Pregnancy

  • Indwelling catheters

Clinical Presentation of PE

  • Wedge-shaped infarcts can be seen on chest x-ray.

  • Symptoms include:

    • Chest pain

    • Dyspnea (shortness of breath)

    • Hemoptysis (coughing blood)

    • Pleural friction rub

  • PE may cause hypoxemia due to impaired gas exchange.

Diagnostic Imaging

  • VQ scan (ventilation/perfusion scan):

    • Identifies mismatches between air movement and blood flow.

    • Key Finding: Ventilated region with no perfusion points to PE.

  • CT pulmonary angiogram: Currently preferred method for diagnosing PE.

Right-sided Heart Failure and Cor Pulmonale

  • Cor pulmonale: Right-sided heart failure due to pulmonary hypertension.

  • Often secondary to chronic lung diseases like COPD and idiopathic pulmonary fibrosis.

    • Increased pulmonary resistance leads to right ventricular dilation.

  • Symptoms of right-sided heart failure:

    • Jugular venous distension (JVD)

    • Pedal edema

    • Hepatic congestion.

Types of Chronic Obstructive Pulmonary Disease (COPD)

  1. Emphysema:

    • Primarily linked with smoking and pollution.

    • Types:

      • Central acinar emphysema: Affected upper lobes, associated with smoking.

      • Panacinar emphysema: Genetic factor (alpha-1 antitrypsin deficiency).

    • Symptoms:

      • Barrel chest

      • Prolonged expiration

      • Pink puffers (predominantly emphysematous).

  2. Chronic Bronchitis:

    • Often seen in smokers.

    • Symptoms:

      • Blue bloaters (cyanosis, hypoxia).

      • Increased PCO2 leads to respiratory acidosis.

Respiratory Acidosis and Alkalosis

  • Respiratory Acidosis:

    • Low pH (< 7.35), elevated PCO2 (> 45 mmHg).

    • Common in COPD, pneumonia, and respiratory depression.

  • Respiratory Alkalosis:

    • Elevated pH (> 7.45), decreased PCO2 (< 35 mmHg).

    • Often due to hyperventilation (e.g., anxiety, pain).

Arterial Blood Gases (ABGs)

  • Components include:

    • pH

    • Partial pressures of O2 and CO2

    • Bicarbonate concentration.

  • Normal ranges:

    • pH: 7.35 - 7.45

    • PCO2: 35 - 45 mmHg

    • HCO3 (bicarbonate): 22 - 26 mmol/L.

Allen Test

  • Used to assess blood flow prior to arterial puncture.

  • Both radial and ulnar arteries must provide adequate supply.

Acute Bronchitis

  • Often follows upper respiratory infections.

  • Symptoms:

    • Cough (typically non-productive)

    • Mild dyspnea without hypoxia.

  • Common pathogens:

    • Influenza, Mycoplasma pneumonia, Chlamydia pneumonia.

  • Treatment:

    • Rest, hydration, symptom relief (e.g., beta agonists, cough suppressants).

Ventilator-Associated Pneumonia (VAP)

  • Develops 48 hours post-intubation.

  • Frequent pathogens: Pseudomonas, MRSA.

  • Symptoms include fever, increased respiratory rate.

  • Diagnosis: Chest x-ray; treatment often involves antibiotics like piperacillin and levofloxacin.

Conclusion

  • This review has covered key aspects of pulmonary embolism, cor pulmonale, chronic obstructive pulmonary disease, bronchitis, and related complications while stressing the importance of proper diagnosis and treatment modalities.