RESPIRATORY FAILURE.pptx FAILURE OF GAS EXCHANGE

RESPIRATORY FAILURE

1. BASICS OF RESPIRATORY FAILURE BY MUTEGEKI ADOLF

2. Definition Respiratory failure occurs when the respiratory system fails to maintain adequate gas exchange, resulting in hypoxia (low oxygen levels), hypercapnia (elevated carbon dioxide levels), or both. It can be classified into Type I (hypoxemic) and Type II ( hypercapnic ) respiratory failure.

3. The inability of the respiratory system to adequately oxygenate the blood with or without a concurrent alteration in carbon dioxide elimination. It can be acute or Chronic depending on the cause. Acute eg : drug overdose, pneumonia, pneumothorax Chronic eg : severe COPD

4. TYPES Type I hypoxemic respiratory failure Type II hypercapneic respiratory failure Type III perioperative respiratory failure

5. Type I - Hypoxemic Failure Oxygenation failure PaO 2 < 60 mmHg OR < 8 kpa PaCO 2 normal or < 35 mmHg pH normal or elevated ventilation (V A ) and perfusion (Q) mismatching is the most common cause of hypoxemia. Either by increasing the dead space or by wasted ventilation

6. Type II ( Hypercapnic Respiratory Failure) Ventilation failure PaO 2 < 60 mmHg PaCO 2 > 45 mmHg OR >6.7 kpa pH < 7.35

7. Aetiology Type I (Hypoxemic Respiratory Failure): Pneumonia Pulmonary Edema: Fluid accumulation in the lungs due to heart failure or acute respiratory distress syndrome (ARDS). Pulmonary Embolism Interstitial Lung Disease: Diseases causing scarring and inflammation of lung tissue. Acute Respiratory Distress Syndrome (ARDS): Severe inflammation and fluid buildup in the alveoli.

8. COPD Asthma Pneumothorax Pulmonary fibrosis Obesity Lymphatic carcinamatosis Pnueumoconiosis Granulomatous lung disease Cyanotic cong heart disease Bronchiectasis Crush lung injury FAT embolism

9. Type II ( Hypercapnic Respiratory Failure) COPD Asthma Drug overdose/Poisoning Myasthenia gravis Polyneuropathy Poliomyelitis Myopathy,Porphyria Head/ cervical cord injury Primary alveolar hypoventilation Sleep apnoea syndrome Pulmonary edema ARDS Myxedema Laryngeal edema Tetanus Foreign body

10. Type III (perioperative respiratory failure) Perioperative respiratory failure , also known as Type III respiratory failure, is a condition that occurs in the perioperative period (around the time of surgery) due to complications arising from anesthesia, surgery, or the underlying health status of the patient. This type of respiratory failure is often associated with atelectasis (collapse of lung tissue) and is commonly seen in patients undergoing major surgeries, especially abdominal or thoracic procedures.

11. Causes of type III Atelectasis Aspiration Pulmonary Edema Pneumonia Pulmonary Embolism Airway Obstruction Hypoventilation : Due to the effects of anesthetics, sedatives, or neuromuscular blockers. Acute Respiratory Distress Syndrome (ARDS) : Severe inflammation and lung injury postoperatively.

12. Pathophysiology

13. Pathophysiology Hypoxemic Respiratory Failure (Type I): Impaired Diffusion: Due to thickening or damage to the alveolar-capillary membrane (e.g., interstitial lung disease). Ventilation-Perfusion Mismatch: Areas of the lung receive oxygen but not enough blood flow (or vice versa), common in pulmonary embolism and pneumonia. Shunt: Blood bypasses ventilated areas of the lung, leading to unoxygenated blood circulating through the body.

14. Hypercapnic Respiratory Failure (Type II): Alveolar Hypoventilation: Due to airway obstruction, respiratory muscle fatigue, or reduced respiratory drive. Increased CO2 Production: Often secondary to increased metabolic demand or fever. Reduced CO2 Clearance: Seen in COPD where there is obstruction to airflow.

15. Type III (perioperative respiratory failure) Reduced Functional Residual Capacity (FRC) : Anesthesia and supine positioning reduce FRC, making the lungs more prone to collapse. Impaired Ventilation-Perfusion (V/Q) Matching : Collapsed alveoli lead to areas of the lung being perfused but not ventilated (shunt), causing hypoxemia. Impaired Gas Exchange : With alveolar collapse and fluid accumulation, the surface area for gas exchange is reduced, leading to hypoxemia and hypercapnia . Decreased Respiratory Muscle Function : Pain, sedation, and muscle relaxants impair the ability to take deep breaths or cough effectively.

16. Clinical Presentations Hypoxemia Symptoms: Dyspnea (shortness of breath), cyanosis, restlessness, confusion, tachypnea (rapid breathing). Hypercapnia Symptoms: Dyspnea, headache, confusion, lethargy, asterixis (flapping tremor), and in severe cases, coma. General Symptoms: Tachycardia, hypertension, use of accessory muscles for breathing, nasal flaring, and diaphoresis (sweating).

17. Investigations Arterial Blood Gas (ABG) Analysis: Key investigation to confirm respiratory failure, showing hypoxemia, hypercapnia , or both. Chest X-ray: To identify causes such as pneumonia, pulmonary edema, or pneumothorax. Pulmonary Function Tests: Useful in chronic respiratory conditions like COPD. CT Scan of the Chest: Detailed imaging for interstitial lung disease, pulmonary embolism, or lung masses. Blood Tests: Complete blood count (CBC), electrolytes, and biomarkers (e.g., BNP for heart failure). Electrocardiogram (ECG) and Echocardiogram: To assess cardiac function, especially in cases of pulmonary edema.

18. Management Oxygen Therapy: Low-Flow Systems: Nasal cannula or simple masks for mild hypoxemia. High-Flow Systems or Non- Rebreather Mask: For moderate to severe hypoxemia. Mechanical Ventilation: Invasive (intubation) or non-invasive (CPAP/ BiPAP ) for severe cases or hypercapnia .

19. Treat Underlying Cause: Antibiotics: For pneumonia or sepsis. Diuretics: For pulmonary edema due to heart failure. Bronchodilators and Steroids: For asthma or COPD exacerbations. Anticoagulation: For pulmonary embolism. Ventilatory Support: Invasive ventilation if respiratory muscle fatigue or severe hypoventilation occurs.

20. Supportive Care: Fluids and Nutrition: Manage fluid balance and provide nutritional support. Physiotherapy: To aid with secretion clearance and improve ventilation.

21. Prognosis Best predictor of mortality in patients with acute on chronic respiratory failure is degree of acidemia . pH< 7.26 is associated with higher mortality. Long term mortality of patients who survive an episode of acute respiratory failure depends on underlying illness. Eg : COPD, 50% survival at end of 3 years

22. Prevention Smoking Cessation: To reduce the risk of COPD and lung cancer. Vaccinations: Influenza and pneumococcal vaccines to prevent respiratory infections. Management of Chronic Conditions: Proper management of asthma, COPD, heart failure, and diabetes. Avoidance of Respiratory Depressants: Careful use of sedatives and opioids in at-risk patients. Regular Monitoring: For patients with neuromuscular disorders or at risk of respiratory failure