1. A&E(VINAYAKA) MECHANICAL VENTILATION IN ARDS / ALI Dr. V.P.Chandrasekaran,

2. A&E(VINAYAKA) ARDS Clinical syndrome of  Severe dyspnea of rapid onset  Hypoxemia  Diffuse pulmonary infiltrates leading to respiratory failure.

3. A&E(VINAYAKA) ALI A less severe disorder but has the potential to evolve into ARDS

4. A&E(VINAYAKA) DIAGNOSING CRITERIA Acute onset Chest X Ray - Acute Bilateral alveolar or interstitial infiltrates Pa O2 /FI O2 < 300 mmHg - ALI Pa O2 /FI O2 < 200 mmHg - ARDS PCWP < 18 mmHg or CVP < 12 mmH2O

5. A&E(VINAYAKA) ARDS:Pathogenesis

6. A&E(VINAYAKA) CLINICAL COURSE

7. A&E(VINAYAKA) NEEDS AGGRESSIVE MANAGEMENT

8. A&E(VINAYAKA) VENTILATOR STRATEGIES Non Invasive Ventilation Invasive ventilation

9. A&E(VINAYAKA) Goals of ventilation To improve O 2 & CO 2 gas exchange Alveolar recruitment To assist respiratory muscles To improve the lung compliance

10. A&E(VINAYAKA) SCENARIO - 1 Mr. X, 30 year male Fever x 5 days Cough with expectoration x 5 days Breathlessness Grade IV x 2 hours

11. A&E(VINAYAKA) Chest X Ray

12. A&E(VINAYAKA) ABG @ FiO2 0.4 Measured Data Ph -7.513 pCO2-25.4 pO2-66.5 Na+-136 K+-3.54 Cl--101 Calculated Data HCO3 (act)-19.9 HCO3 (std)-23.4 BE (ect) -3.1 BE (B) -1.3 ctCO2 -20.7 AnionGap -18.8 O2 Sat -98% ACUTE RESPIRATORY ALKALOSIS

13. A&E(VINAYAKA) PaO 2 / FiO 2 = 66.5 / 0.4 = 166.25 CVP 8 cm Hep Saline

14. A&E(VINAYAKA) ARDS:Treatment Recent decrease of mortality  Treatment of underlying cause  Better supportive ICU Care  Prevention of infections  Appropriate nutrition  GI prophylaxis  Thromboembolism prophylaxis

15. A&E(VINAYAKA) BiPAP Pressure Support – 15 PEEP – 8 FiO2 – 0.4

16. A&E(VINAYAKA)

17. Contraindications to BiPAP Apnoea Active ischemic cardiac disease Unable to handle secretion Homodynamic instability Facial trauma No respiratory drive Claustrophobia Poor cooperation

18. A&E(VINAYAKA) ADMISSIONDISCHARGE

19. A&E(VINAYAKA) SCENARIO - 2 40 year male Cellulitis of Left leg Breathlessness grade IV since morning

20. A&E(VINAYAKA) Chest X Ray

21. A&E(VINAYAKA) Not co operative for Bi-PaP PaO 2 / FiO 2 = 60.0 / 0.4 = 150 CVP 7 cm Hep Saline

22. A&E(VINAYAKA) Requires Mechanical ventilation Goals? To improve oxygenation Alveolar recruitment To assist respiratory muscles To improve the lung compliance

23. A&E(VINAYAKA) To improve Oxygenation More inspiratory time Optimum PEEP Higher FiO2 - initially

24. A&E(VINAYAKA) Alveolar recruitment Optimum PEEP More inspiratory time Low rate

25. A&E(VINAYAKA) Protective ventilation Smaller tidal volumes  Avoid overdistention  Tolerate “permissive hypercarbia” “Open lung” ventilation with PEEP  Avoid alveolar collapse and reopening

26. A&E(VINAYAKA) Collapse/ atelectosis/ ARDS Increases Surface area for gas exchange Opens the collapsed lung Collapsed alveoli After PEEP PEEP

27. A&E(VINAYAKA) To assist respiratory muscles Ventilator support If needed to rest respiratory muscles with paralysis

28. A&E(VINAYAKA) To improve the lung compliance To keep the PEEP above the lower inflection point Paralysis Pressure control mode

29. A&E(VINAYAKA) Optimal “PEEP” Positive end-expiratory pressure should be high enough to shift the end-expiratory pressure above the lower inflection point by 2-3 cm H 2 O (usually 12-15 cm H 2 O)  Allows maximal alveolar recruitment  Decreases injury by repeated opening and closing of small airways

30. A&E(VINAYAKA)

31. Settings Pressure control – to reach Vt 400ml ( 65 x 6 = 390 ml ) Rate : 10-12/min I:E : 1:1 PEEP: 10-15CMH 2 O FiO2 : 100% -  40%

32. A&E(VINAYAKA) Will it result in Respiratory acidosis? Yes. But still needed…!

33. A&E(VINAYAKA) ARDS:Permissive Hypercapnoea Permissive hypercapnia  pH >7.2  PCo2 <80mmHg Contraindication  Hypotension  Brain injury  Barotrauma

34. A&E(VINAYAKA) Watch for Barotrauma / pneumothorax Hypercapnoea Respiratory acidosis

35. A&E(VINAYAKA) What to do if PCo2 raises above 80 mmHg or pH <7.2 Increase Vt Decrease PEEP Increase rate Decrease inspiratory time And reassess

36. A&E(VINAYAKA) If signs of pneumothorax appears ICD If tension pneumothorax – needle decompression -  ICD

37. A&E(VINAYAKA) What to do if saturation does not improve? Increase PEEP Increase Inspiratory time (Inverse) Increase FiO2 Increase Vt

38. A&E(VINAYAKA) Why should I aim for low FiO2 <60 High FiO2 can result in oxygen toxicity and free radical injury and further precipitate ARDS and MOF

39. A&E(VINAYAKA) Treat the cause Avoid frequent suctioning Frequent ABG assesment

40. A&E(VINAYAKA) Adjuncts Paralyze & Sedate CVP guided fluids Vasopressers DVT prophylaxis Stress ulcer/Bed sore prophylaxis Nutrition

41. A&E(VINAYAKA) ARDS Treatment Prone positioning Steroids Anti oxidant Nitric oxide Surfactant Anti-inflammatory Strategies  Prostaglandin agonist/inhibitors  Lisofylline and pentoxifylline  Anti IL-8 ?

42. A&E(VINAYAKA) THANK YOU