Tr igger/Limit/Cycle/Baseline

1. Trigger/Limit/Cycle/Baseline Mechanical Ventilation

2. Trigger • All breaths on a ventilator need to be triggered

3. Trigger • All breaths on a ventilator need to be triggered • They can be • Time triggered

4. Trigger • All breaths on a ventilator need to be triggered • They can be • Time triggered • Patient triggered

5. Trigger • All breaths on a ventilator need to be triggered • They can be • Time triggered • Patient triggered • Flow triggered

6. Trigger • All breaths on a ventilator need to be triggered • They can be • Time triggered • Patient triggered • Flow triggered • Pressure triggered

7. Time triggering • Time triggering means the ventilator starts the breath

8. Time triggering • Time triggering means the ventilator starts the breath • This will happen when there is no patient effort

9. Time triggering • Time triggering means the ventilator starts the breath • This will happen when there is no patient effort • This is based on the set respiratory rate

10. Patient Triggering • A breath can be triggered by the patient

11. Patient Triggering • A breath can be triggered by the patient • Flow triggering is the most common

12. Patient Triggering • A breath can be triggered by the patient • Flow triggering is the most common • Pressure triggering is another option

13. Flow Triggering • Flow triggering starts with a base flow • This flow is continuously flowing through the circuit

14. Flow Triggering • Flow triggering starts with a base flow • This flow is continuously flowing through the circuit • The ventilator knows how much flow is going through the circuit • The liter flow leaving the ventilator should be the same as the liter flow coming back

15. Flow Triggering • As the patient inhales some of the flow goes into the patient lungs • This means less flow is returning to the ventilator • The ventilator senses that as a patient effort and starts a breath

16. Flow Triggering • The difference in the flow coming out of the ventilator and coming back to the ventilator is how sensitivity is determined • The less flow needed to be deflected by the patient the more sensitive it is • The more flow needed to be deflected by the patient the more difficult it is to trigger, i.e. less sensitive

17. Flow Triggering • 10 lpm is leaving the ventilator • 10 lpm is returning to the ventilator • As a patient inhales and takes in 2 lpm • 8 lpm is returning to the ventilator • This reduction in returned flow tells the ventilator to start a breath

18. Flow Triggering • If you increase the amount of flow needed to be inhaled by the patient the less sensitive the machine is • 10 lpm is leaving the ventilator • 10 lpm is returning to the ventilator • As a patient inhales and takes in 4 lpm • 6 lpm is returning to the ventilator

19. Pressure Triggering • Negative pressure is generated when a patient inhales

20. Pressure Triggering • Negative pressure is generated when a patient inhales • This negative pressure is in both the patients lungs and the ventilator circuit

21. Pressure Triggering • Negative pressure is generated when a patient inhales • This negative pressure is in both the patients lungs and the ventilator circuit • The ventilator senses the negative pressure as a patient effort and starts a breath

22. Pressure Triggering • So the patient needs to generate -2cmH2O to start a breath • If you increase the amount of negative pressure needed the more difficult it is for the patient to trigger, i.e. less sensitive

23. Limiting • Limiting is what contols are in effect during the inspiratory phase

24. Limiting • Limiting is what contols are in effect during the inspiratory phase • After a breath is initiated certain limits will be in effect depending on which type of breath is being delivered

25. Limiting • Limiting is what contols are in effect during the inspiratory phase • After a breath is initiated certain limits will be in effect depending on which type of breath is being delivered • Limiting factors are what define a type of breath

26. Limiting • Limiting is what contols are in effect during the inspiratory phase • After a breath is initiated certain limits will be in effect depending on which type of breath is being delivered • Limiting factors are what define a type of breath • The two most common limits are

27. Limiting • Limiting is what contols are in effect during the inspiratory phase • After a breath is initiated certain limits will be in effect depending on which type of breath is being delivered • Limiting factors are what define a type of breath • The two most common limits are • Pressure

28. Limiting • Limiting is what contols are in effect during the inspiratory phase • After a breath is initiated certain limits will be in effect depending on which type of breath is being delivered • Limiting factors are what define a type of breath • The two most common limits are • Pressure • Flow

29. Pressure Limited • Pressure limited breaths have a set peak airway pressure

30. Pressure Limited • Pressure limited breaths have a set peak airway pressure • The pressure in the patients lungs will not go over the set pressure

31. Pressure Limited • Pressure limited breaths have a set peak airway pressure • The pressure in the patients lungs will not go over the set pressure • The following breaths are pressure limited

32. Pressure Limited • Pressure limited breaths have a set peak airway pressure • The pressure in the patients lungs will not go over the set pressure • The following breaths are pressure limited • PCV • PSV • PRVC

33. Pressure Limited • Pressure Control Ventilation (PCV) • Pressure is set with the intention of reaching the peak pressure and holding the pressure for part of the inspiratory time

34. Pressure Limited • Pressure Control Ventilation (PCV) • Pressure is set with the intention of reaching the peak pressure and holding the pressure for part of the inspiratory time • Pressure Support Ventilation (PSV) • Pressure is set to augment a patients own tidal volume

35. Pressure Limited • Pressure Control Ventilation (PCV) • Pressure is set with the intention of reaching the peak pressure and holding the pressure for part of the inspiratory time • Pressure Support Ventilation (PSV) • Pressure is set to augment a patients own tidal volume • Pressure Regulated Volume Control (PRVC) • Pressure changes with each breath with the intention of reaching a specific volume

36. Flow Limited • Flow limiting is used when a specific volume needs to be delivered

37. Flow Limited • Flow limiting is used when a specific volume needs to be delivered • Each breath has a rigid flow rate and pattern that will deliver the specific volume

38. Flow Limited • Flow limiting is used when a specific volume needs to be delivered • Each breath has a rigid flow rate and pattern that will deliver the specific volume • Therefore the breath is limited to a predetermined flow • Volume Control is a type of flow limited breath

39. Pressure vs. Flow Limiting • Pressure limited breaths have a variable flow which allows better gas distribution

40. Pressure vs. Flow Limiting • Pressure limited breaths have a variable flow which allows better gas distribution • The pressure is limited therefore if lung conditions change the volume will change

41. Pressure vs. Flow Limiting • Pressure limited breaths have a variable flow which allows better gas distribution • The pressure is limited therefore if lung conditions change the volume will change • If lungs become stiffer the volume will go down as the pressure remains the same

42. Pressure vs. Flow Limiting • Flow limiting will deliver a volume no matter what the lung conditions

43. Pressure vs. Flow Limiting • Flow limiting will deliver a volume no matter what the lung conditions • Volume will be consistent but pressures will change

44. Pressure vs. Flow Limiting • Flow limiting will deliver a volume no matter what the lung conditions • Volume will be consistent but pressures will change • If the lungs become stiffer the pressures will go up

45. Pressure vs. Flow Limiting • PRVC uses pressure limiting but will automatically adjust the pressure to deliver a volume

46. Pressure vs. Flow Limiting • PRVC uses pressure limiting but will automatically adjust the pressure to deliver a volume • So the pressure is not set, the volume is set

47. Pressure vs. Flow Limiting • PRVC uses pressure limiting but will automatically adjust the pressure to deliver a volume • So the pressure is not set, the volume is set • The ventilator will adjust the pressure to achieve the volume

48. Pressure vs. Flow Limiting • PRVC uses pressure limiting but will automatically adjust the pressure to deliver a volume • So the pressure is not set, the volume is set • The ventilator will adjust the pressure to achieve the volume • This allows for the variable flow which is better for gas distribution

49. Pressure vs. Flow Limiting • PRVC uses pressure limiting but will automatically adjust the pressure to deliver a volume • So the pressure is not set, the volume is set • The ventilator will adjust the pressure to achieve the volume • This allows for the variable flow which is better for gas distribution • If the lungs become stiffer the pressures will go up

50. Cycling • Cycling is what determines how the breath will stop and allow the patient to exhale