1. Mechanical Ventilation Tariq Alzahrani M.D Assistant Professor College of Medicine King Saud University

2. Anatomy

3. Lung has weight -8 P pl = -2 -5 Apex Base Chest Wall

4. Mechanical Ventilator Definition Indication Types Classification Modes Goals Monitor Weaning Complication

5. Indication Support of oxygenation –Oxygen responsive hypoxemias Pneumonia Sepsis Inhalation injury –Oxygen refractory hypoxemias Atelectasis Aspiration / Drowning Adult Respiratory Distress Syndrome (ARDS)

6. Support of ventilation –Airway compromise –Muscle fatigue / weakness –Paralysis / spinal cord injury –Neuromuscular disease –Chest wall injury

7. Types

8. Non invasive Ventilation Invasive Ventilation ETT tracheostomy

9. Classification Volume controlled ventilation Pressure controlled ventilation Time controlled ventilation

10. CMV IPPV SIMV MMV BIPAP CPAP SPONT PCV VCV APRV PLV PS ASB ILV PRVC VAPS PAV Modes? Auto Mode AutoFlow PPS VS

11. Modes CMV AC PCV SIMV PSV Spo. V

12. Goals Maintain patient comfort Allow a normal, spontaneous breathing pattern whenever possible Maintain a PaCO2 between 35-50 mmHg Maintain a PaO2 sufficient to meet cellular oxygen demands but avoid oxygen toxicity Avoid respiratory muscle fatigue and atrophy

13. PATIENT COMFORT SCALE + - Spontaneous Breathing Controlled Mechanical Ventilation Assist Control Ventilation Synchronized Intermittent Mechanical Ventilation Pressure Support Ventilation Pressure Control Ventilation SEDATIVES, ANALGESICS AND MUSCLE RELAXANTS

14. Monitor

15. Weaning Factors to consider: Awake, and off sedation (as much as possible). Adequate nutrition, fluid status. Free of infection. Hemodynamically stable (preferably off pressors, angina controlled, no active bleeding) Normal acid-base status Bronchospasm controlled Normal electrolyte balance Oxygenation (O2 requirements <0.5 and PEEP <5 cmH20) Weaning Parameters: Inspiratory negative pressure of -25 cmH2O RR<30 Vt >6-8 ml/Kg ABG status near normal

16. Causes of failure to wean: 1. Hypoxemia Diffuse pulmonary disease Focal pulmonary disease (Pneumonia) Pulmonary edema (removal of positive pressure can increase preload and lead to worsening heart failure) 2.Insufficient Ventilatory Drive: response to metabolic alkalosis Inadequate function of CNS drive (Ex: sedatives, malnutrition) 3. Excessive Ventilatory Drive: Excessive CO2 production (sepsis, agitation, fever, high carbohydrate intake) 4. Respiratory Muscle Weakness: Neuromuscular disease Malnutrition Drugs (Neuromuscular blocking agents, Corticosteroids,aminoglycosides)

17. 5. Excessive Work of Breathing: Airway obstruction Bronchospasm Secretions Increased Raw (ETT) ETT too small Chest motion restriction (pain, bandages) 6. Acid base disorders 7. Phrenic nerve Injury (especially with contralateral pulmonary disease)

18. Complication Ventilation-related complications: Disconnection Malfunction Hemodynamic effects: decreased cardiac output due to impaired venous return to the right heart and increased pulmonary venous resistance due to positive pressure alveolar distension AutoPEEP Barotrauma or Atelectasis Oxygen toxicity Respiratory alkalosis Increased intracranial pressure

19. Suctioning-related complications: Hypoxemia a) patients should always be pre-oxygenated with 100% oxygen prior to suctioning b) suction time should be limited Arrhythmias Nosocomial infections

21. Non-invasive ventilation Invasive vs. Non-invasive ventilation Invasive  Good control of airway  Suitable for higher pressures Non-invasive  Avoidance of complications of intubation  Avoidance of complic of invasive ventilation ( sinusitis…)  If tolerated, more comfortable to awake pts. Breaks possible  No sedation (or less sedation)

22. Indication –Acute settings –Chronic disease

23. Goals Relieve symptoms Reduce work of breathing Improve gas exchange Minimize risk Avoid intubation

24. Exclusion criteria 1.Respiratory arrest 2.Medically unstable 3.Unconscious, unable to protect airways 4.Excessive secretions 5.Significant vomiting 6.Agitated or uncooperative 7.Facial trauma, burns, surgery or anatomic abnormalities interfering with mask application