29(1).Respiratory insufficiency.pdf

Types of Lung disease Professor Indu Nanayakkara Department of Physiology Faculty of Medicine Peradeniya Types of Lung diseases The most important clinical division of lung disease → Obstructive lung disease...

Types of Lung disease Professor Indu Nanayakkara Department of Physiology Faculty of Medicine Peradeniya Types of Lung diseases The most important clinical division of lung disease → Obstructive lung disease Restrictive lung disease Obstructive lung disease → Problem of expiring air out eg – Bronchial asthma Chronic bronchitis & emphysema Bronchiectasis Bronchiolitis FOR 22/23 BATCH - AUGUST 2024 Obstructive lung disease There is bronchial narrowing Compliance There is destruction of elastic tissue Recoil Inspiration not so bad, expiration difficult. Therefore – Air trapping (barrel chested) Tidal volume – may be normal IRV, ERV – low TLC – high VC - low Normal Obstructive FOR 22/23 BATCH - AUGUST 2024  Types of Lung diseases Restrictive lung disease → Problem of expanding lungs (taking in air) Lung causes – Lung fibrosis – due to autoimmune disease, drug induced, occupational, idiopathic Pneumonia ARDS Non-lung causes – chest wall deformities abdominal problems neurological causes like diaphragm paralysis respiratory center depression idiopathic causes FOR 22/23 BATCH - AUGUST 2024 Restrictive lung disease Something is restricting the lungs ability to expand Compliance Recoil Inspiration is difficult. Small puffs of breath, rapidly taken Tidal volume – may be normal IRV, ERV – low RV - low Normal Restrictive TLC – low VC - low FOR 22/23 BATCH - AUGUST 2024 FOR 22/23 BATCH - AUGUST 2024  Respiratory Failure Professor Indu Nanayakkara Department of Physiology Faculty of Medicine Peradeniya  Topics covered Definition Classification of RF Distinction between Acute and Chronic RF Pathophysiologic causes of Acute RF Diagnosis of RF Causes Clinical presentation  Arterial Blood Gases (ABG) Normal values at sea level pH 7.35-7.45 ↓pH - Acidosis PaO2 >70 mmHg ↑pH - Alkalosis PaCO2 35-45 mmHg ↓ PaO2 - Hypoxemia HCO3 22-28 mmol/l ↑PaCO2 - Hypercapnia ↓pH+ ↑PaCO2 R. acidosis ↑HCO3 ↑pH+↓PaCO2 R. Alkalosis ↓HCO3  Respiratory Failure (RF) Definitions Clinical conditions in which PaO2 < 60 mmHg while breathing room air or a PaCO2 > 50 mmHg Failure of oxygenation and carbon dioxide elimination Acute and chronic Type 1 or 2  Type 1 vs Type 2 Type 1 respiratory failure occurs when the respiratory system cannot adequately provide oxygen to the body, leading to hypoxemia. Type 2 respiratory failure occurs when the respiratory system cannot sufficiently remove carbon dioxide from the body, leading to hypercapnia.  Classification of RF Type 1 Type 2 (Hypoxemic RF) (Hypercapnic RF) PaO2 < 60 mmHg with PaCO2 > 50 mmHg normal or ↓ PaCO2 Drug overdose, Associated with acute neuromuscular disease, diseases of the lung chest wall deformity, COPD, and Bronchial asthma Pulmonary edema (Cardiogenic, non- cardiogenic (ARDS), pneumonia, pulmonary hemorrhage, and collapse  Distinction between Acute and Chronic RF Acute RF Chronic RF Develops over minutes Develops over days to hours ↑ in HCO3 ↓ pH quickly to 45 mmHg due to respiratory pump failure or increased CO2 production Depending on the cause of respiratory failure, the PaO2 may be normal or decreased In addition, Alveolar hypoventilation may progress to Type 2 respiratory failure  Type 2 Respiratory failure Due to Respiratory pump failure The respiratory pump is comprised of the chest wall, the pulmonary parenchyma, the muscles of respiration, the central and peripheral nervous systems The inability to ventilate can occur if any of the components  Type 2 Respiratory failure Causes of pump failure: Decreased central drive Altered neural and neuromuscular transmission Chest wall and pleural disorders Dead space ventilation Muscle abnormalities  Type 2 Respiratory failure Due to Increased CO2 production High CO2 production may occur due to fever exercise hyperalimentation sepsis, and thyrotoxicosis  Diagnosis of RF Clinical (symptoms, signs) Hypoxemia Hypercapnia Dyspnea, Cyanosis ↑Cerebral blood flow, and Confusion, somnolence, fits CSF Pressure Tachycardia, arrhythmia Headache Tachypnea (good sign) Papilloedema Use of accessory muscles Warm extremities, collapsing pulse Nasal flaring Acidosis (respiratory, and Recession of intercostal metabolic) muscles ↓pH, ↑ lactic acid Polycythemia Pulmonary HTN, RT HF  Complications of ARF Pulmonary Infections Pulmonary embolism Nosocomial infection barotrauma Pneumonia, UTI, catheter related sepsis pulmonary fibrosis (ARDS) Nosocomial pneumonia Renal Cardiovascular ARF (hypoperfusion, nephrotoxic drugs) Hypotension, ↓COP Poor prognosis Arrhythmia Nutritional MI, pericarditis Malnutrition, diarrhea GIT hypoglycemia, electrolyte disturbances Stress ulcer, ileus, diarrhea, hemorrhage  Prognosis of ARF Mortality rate for ARDS → 40% Younger patient