1. Difficult Weaning

2. Indications for mechanical ventilation: A) Global pathophysiological indications: - Apnea - Acute ventilatory failure - impending failure - Refractory hypoxemia - Signs of respiratory failure B) Common clinical conditions when need for ventilatory support is high: - ARDS - Asthma - COPD - Chest trauma - Overdose - Post cardiac surgery - Pneumonia - Sepsis - Head Trauma

3. -Preparing the Patient for Weaning: - Electrolyte Disturbance - Volume Overload - Altered Mental status - Fatigue of the diaphragm - Adequacy of sleep and sleep deprivation - Malnutrition

4. -Criteria to consider Patients for Weaning: - Reversal of underlying pathology - Po2, PEEP, FiO2, PH - ABG - Vital Data - CXR -Parameters Predicting successful Weaning: - Respiratory rate - Tidal Volume - Minute Ventilation - Negative inspiratory force - Maximal Inspiratory pressure - RSBI - RSBI rate

5. Algorithm for weaning Protocol

6. New Advances in Ventilators to assist Weaning: - Automated tube compensation (ATC) - Proportional Assisted ventilation (PAV)

7. Causes of Difficult Weaning Imbalance Respiratory muscle pumpRespiratory muscle load A) Increased Ventilatory Needs Increased resistive loadIncreased chest Wall LoadIncreased parenchyma load -Bronchospasm - Airway edema - Airway obstruction - Tube kinking - Sleep Apnea - Secretions - Circuit resistance - Pleural effusion - Pnumothorax - Flail chest - Obesity - Ascites - Distension -Hyperinflation - Inflammation - Atelectasis - Alveolar edema

8. B) Decreased Neuromuscular compliance: Decreased Drive Muscle WeaknessImpaired Transmission Drug overdose - Electrolyte derangement - Critical illness polyneuropathy Brain-stem lesion - Malnutrition - Neuromuscular blockers Sleep deprivation - Myopathy - Aminoglycosides Hypothyroidism - Hyperinflation - Guillain–Barré syndrome Starvation/malnutrition - Drugs, corticosteroids - Mysthenia gravis Metabolic alkalosis - Sepsis - Phrenic nerve injury Myotonic dystrophy

9. How to Wean Difficult to Wean Patients Correction of Causes Choice of appropriate mode Tracheostomy

10. Neuromuscular Weakness in Critically Ill Critical illness polyneuropathy (CIP):Disorders of neuromuscular transmission: Myopathy: Critical illness Polyneuropathy Definition Course Causes Diagnosis: - EPS: shows reduced compound motor and sensory nerve action potential amplitudes with normal conduction velocities. - Needle EMG reveals fibrillation potentials and positive sharp waves indicating denervation Treatment

11. Disorders of neuromuscular transmission: - Prolonged use of neuromuscular blockers - Decreased Metabolism - Decremental Response - Aminoglycosides, Polypeptide antibiotics

12. Myopathy : 1. Critical illness myopathy: - Histological Pattern - Normal CPK levels - Type II myofibres - IL-1, TNF 2. Thick filament myopathy: - Selective loss of myosin - Absent neuropathy - Increased steroid receptors - Triggering factors: NMBA, Denervation - Diagnosis: EPS, CPK, Muscle biopsy

13. 3. Necrotizing myopathy: - Prominent muscle necrosis - CPK elevated - Correlated with NMBA, Steroids - Diagnosis: - difficult to diagnose - Direct muscle stimulation and calculation of the ratio of nerve and muscle evoked compound muscle action potential amplitudes. - Muscle biopsy is of choice -No specific treatment is available

14. Prevention of neuromuscular weakness in ICU: - Appropriate treatment of sepsis - Minimize use of NMBA - Check serum electrolytes - Avoid Pharmacological agents causing weakness - Early EPS

15. Thank You