1. Newer Modes of Mechanical Ventilation Timothy A. Morris, M.D. Division of Pulmonary and Critical Care Medicine Medical Director, Respiratory Care University of California, San Diego

2. How to Assess Ventilator Modes l Inhalation »what is controlled during the breath »what is targeted (how much is enough?) »how does it adjust to changes

3. How to Assess Ventilator Modes l Exhalation »what is controlled »when does it end »how does it adjust

4. How to Assess Ventilator Modes l Inhalation »what is controlled »what is targeted »how does it adjust

5. Simple Pressure System Pressure 20 cm H 2 O Pressure 20 cm H 2 O

6. Time Constant l time it takes to get 1/2 way to equilibrium l total resistance x total compliance

7. Increased Compliance Pressure 20 cm H 2 O Pressure 20 cm H 2 O

8. Increased Resistance Pressure 20 cm H 2 O Pressure 20 cm H 2 O Obstruction

9. Volume 500 ml Pressure 3500 cm H 2 0 Simple Volume System Volume 500 ml

10. Volume 2000 ml Pressure 3500 cm H 2 0 Pop! Simple Volume System

11. Big Secret! l Ventilator modes are simulations »pressure control »volume control l Microprocessors control the simulation

12. Dadmobile

13. Minivan Tire

14. High Pressure Pump

15. Filling the Tire

16. Tire Pressure

17. Toy Balloon: deflated

18. Toy Balloon: inflated

19. Toy Balloon: popped

20. Flow Control

21. Control of Resistor

22. Pressure 3500 cm H 2 0 High Pressure System valve Pressure 35 cm H 2 0 Tidal volume 500 ml

23. Volume Control Deflated Volume Inflated Volume

24. Pressure Control Deflated PressureInflated Pressure

25. What controls the adjustments? Volume? (flow control) Pressure?

26. Pressure 3500 cm H 2 0 Microprocessor Control Inhalation valve (resistor) solenoid Microprocessor exhale valve Tidal volume 500 ml Pressure 35 cm H 2 0

27. Quality of the control l hardware: »how frequently is the flow/pressure measured »how rapidly are adjustments made »how are adjustments made l software »timing and patterns of control

28. How to Assess Ventilator Modes l Inhalation »what is controlled »what is targeted »how does it adjust

29. Targeting l How much breath is enough?

30. Targeting Control l Flow l Pressure Target l Time l Pressure l Volume Volume control

31. Targeting Control l Flow l Pressure Target l Time l Pressure l Volume Time-cycled pressure control

32. Targeting Control l Flow l Pressure Target l Time l Pressure l Volume Volume targeted pressure control

33. How to Assess Ventilator Modes l Inhalation »what is controlled »what is targeted »how does it adjust

34. Patients generate pressures l Negative pressure »inhalation efforts l Positive pressure »“bucking”

35. Negative pressure: Adjustments l No adjustment l Increase in pressure/flow to match demand l Decrease in pressure/flow to foster weaning

36. Positive pressure: Adjustments l No adjustment l End inhalation, open exhalatory valve l Adjust inspiratory and expiratory valves to maintain control

37. How to Assess Ventilator Modes l Exhalation »next year

38. Coming up next... Reality