mechanical ventilation. trigger all breaths on a ventilator need to be triggered

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Trigger/Limit/Cycle/ Baseline Mechanical Ventilation

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  • Slide 1
  • Mechanical Ventilation
  • Slide 2
  • Trigger All breaths on a ventilator need to be triggered
  • Slide 3
  • Trigger All breaths on a ventilator need to be triggered They can be Time triggered
  • Slide 4
  • Trigger All breaths on a ventilator need to be triggered They can be Time triggered Patient triggered
  • Slide 5
  • Trigger All breaths on a ventilator need to be triggered They can be Time triggered Patient triggered Flow triggered
  • Slide 6
  • Trigger All breaths on a ventilator need to be triggered They can be Time triggered Patient triggered Flow triggered Pressure triggered
  • Slide 7
  • Time triggering Time triggering means the ventilator starts the breath
  • Slide 8
  • Time triggering Time triggering means the ventilator starts the breath This will happen when there is no patient effort
  • Slide 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
  • Slide 10
  • Patient Triggering A breath can be triggered by the patient
  • Slide 11
  • Patient Triggering A breath can be triggered by the patient Flow triggering is the most common
  • Slide 12
  • Patient Triggering A breath can be triggered by the patient Flow triggering is the most common Pressure triggering is another option
  • Slide 13
  • Flow Triggering Flow triggering starts with a base flow This flow is continuously flowing through the circuit
  • Slide 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
  • Slide 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
  • Slide 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
  • Slide 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
  • Slide 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
  • Slide 19
  • Pressure Triggering Negative pressure is generated when a patient inhales
  • Slide 20
  • Pressure Triggering Negative pressure is generated when a patient inhales This negative pressure is in both the patients lungs and the ventilator circuit
  • Slide 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
  • Slide 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
  • Slide 23
  • Limiting Limiting is what contols are in effect during the inspiratory phase
  • Slide 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
  • Slide 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
  • Slide 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
  • Slide 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
  • Slide 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
  • Slide 29
  • Pressure Limited Pressure limited breaths have a set peak airway pressure
  • Slide 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
  • Slide 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
  • Slide 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
  • Slide 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
  • Slide 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
  • Slide 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
  • Slide 36
  • Flow Limited Flow limiting is used when a specific volume needs to be delivered
  • Slide 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
  • Slide 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
  • Slide 39
  • Pressure vs. Flow Limiting Pressure limited breaths have a variable flow which allows better gas distribution
  • Slide 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
  • Slide 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
  • Slide 42
  • Pressure vs. Flow Limiting Flow limiting will deliver a volume no matter what the lung conditions
  • Slide 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
  • Slide 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
  • Slide 45
  • Pressure vs. Flow Limiting PRVC uses pressure limiting but will automatically adjust the pressure to deliver a volume
  • Slide 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
  • Slide 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
  • Slide 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
  • Slide 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
  • Slide 50
  • Cycling Cycling is what determines how the breath will stop and allow the patient to exhale
  • Slide 51
  • Cycling Cycling is what determines how the breath will stop and allow the patient to exhale Most breaths are time cycled
  • Slide 52
  • Cycling Cycling is what determines how the breath will stop and allow the patient to exhale Most breaths are time cycled Any breath type that requires a set Ti is time cycled These include the following breath types
  • Slide 53
  • Cycling Cycling is what determines how the breath will stop and allow the patient to exhale Most breaths are time cycled Any breath type that requires a set Ti is time cycled These include the following breath types PRVC
  • Slide 54
  • Cycling Cycling is what determines how the breath will stop and allow the patient to exhale Most breaths are time cycled Any breath type that requires a set Ti is time cycled These include the following breath types PRVC PCV
  • Slide 55
  • Cycling Cycling is what determines how the breath will stop and allow the patient to exhale Most breaths are time cycled Any breath type that requires a set Ti is time cycled These include the following breath types PRVC PCV Volume Control
  • Slide 56
  • Cycling Flow is also used to cycle a breath off
  • Slide 57
  • Cycling Flow is also used to cycle a breath off Pressure Support Ventilation (PSV) is flow cycled
  • Slide 58
  • Cycling Flow is also used to cycle a breath off Pressure Support Ventilation (PSV) is flow cycled As the inspiratory flow starts to slow down the ventilator will sense that the lungs are getting full and cycle off allowing the patient to exhale
  • Slide 59
  • Cycling Flow is also used to cycle a breath off Pressure Support Ventilation (PSV) is flow cycled As the inspiratory flow starts to slow down the ventilator will sense that the lungs are getting full and cycle off allowing the patient to exhale During that same breath it is being pressure limited
  • Slide 60
  • Cycling Flow is also used to cycle a breath off Pressure Support Ventilation (PSV) is flow cycled As the inspiratory flow starts to slow down the ventilator will sense that the lungs are getting full and cycle off allowing the patient to exhale During that same breath it is being pressure limited So pressure is being held in the lungs until the flow slows down at which time the ventilator will release the pressure and the patient exhales
  • Slide 61
  • Baseline Baseline is what limits are in effect during exhalation Exhalation is passive The only limit will be added pressure, i.e. PEEP The baseline should be assessed via total PEEP to accurately measure the baseline
  • Slide 62
  • Rise Time or Slope Rise time is part of the inspiration so could be considered a limiting factor
  • Slide 63
  • Rise Time or Slope Rise time is part of the inspiration so could be considered a limiting factor It is usually not included in the definition of a breath
  • Slide 64
  • Rise Time or Slope Rise time is part of the inspiration so could be considered a limiting factor It is usually not included in the definition of a breath Rise time adjusts the initial flow rate of a breath
  • Slide 65
  • Rise Time or Slope Rise time is part of the inspiration so could be considered a limiting factor It is usually not included in the definition of a breath Rise time adjusts the initial flow rate of a breath It determines how much time is allowed for the breath to reach the peak flow needed to deliver the breath in the allotted time (Ti)
  • Slide 66
  • Rise Time/Slope The less time the Rise time is the faster the breath ramps up to full speed
  • Slide 67
  • Rise Time/Slope The less time the Rise time is the faster the breath ramps up to full speed The longer the Rise Time is the slower the breath reaches peak flow
  • Slide 68
  • Rise Time/Slope So if you have an inspiratory time of 1 second and you set your Rise Time at 0.2 seconds the peak flow will be reached in 0.2 seconds creating a blast of air at the beginning of the breath
  • Slide 69
  • Rise Time/Slope So if you have an inspiratory time of 1 second and you set your Rise Time at 0.2 seconds the peak flow will be reached in 0.2 seconds creating a blast of air at the beginning of the breath If you increase the Rise Time to 0.5 seconds the breath will not reach peak flow until half way through the breath creating a slower overall flow
  • Slide 70
  • Rise Time/Slope A short Rise Time may be helpful in patient with high inspiratory demands, such as asthma
  • Slide 71
  • Rise Time/Slope A short Rise Time may be helpful in patient with high inspiratory demands, such as asthma A longer Rise Time is usually more comfortable because there is not the blast of air at the beginning
  • Slide 72
  • Rise Time/Slope A short Rise Time may be helpful in patient with high inspiratory demands, such as asthma A longer Rise Time is usually more comfortable because there is not the blast of air at the beginning Where it is set is very patient dependent
  • Slide 73
  • Inspiratory Cycle Off Inspiratory cycle off is part of the flow cycling breath
  • Slide 74
  • Inspiratory Cycle Off Inspiratory cycle off is part of the flow cycling breath Pressure Support Ventilation (PSV)
  • Slide 75
  • Inspiratory Cycle Off Inspiratory cycle off is part of the flow cycling breath Pressure Support Ventilation (PSV) Flow cycling is used to end a PSV breath
  • Slide 76
  • Inspiratory Cycle Off Inspiratory cycle off is part of the flow cycling breath Pressure Support Ventilation (PSV) Flow cycling is used to end a PSV breath Normal inspiration goes to zero flow and then reverses the flow to exhale
  • Slide 77
  • Inspiratory Cycle Off Inspiratory cycle off is part of the flow cycling breath Pressure Support Ventilation (PSV) Flow cycling is used to end a PSV breath Normal inspiration goes to zero flow and then reverses the flow to exhale Because it is difficult to achieve a tight seal on the circuit and patient, it is impractical to require the patient to get to zero flow before exhaling
  • Slide 78
  • Inspiratory Cycle Off Inspiratory cycle off is part of the flow cycling breath Pressure Support Ventilation (PSV) Flow cycling is used to end a PSV breath Normal inspiration goes to zero flow and then reverses the flow to exhale Because it is difficult to achieve a tight seal on the circuit and patient it is impractical to require the patient to get to zero flow before exhaling Flow cycling allow the breath to end prior to reaching zero flow
  • Slide 79
  • Inspiratory Cycle Off Some ventilators have a preset flow rate that will cycle the PSV breath into exhalation
  • Slide 80
  • Inspiratory Cycle Off Some ventilators have a preset flow rate that will cycle the PSV breath into exhalation Some ventilators allow the flow rate to be adjusted
  • Slide 81
  • Inspiratory Cycle Off Some ventilators have a preset flow rate that will cycle the PSV breath into exhalation Some ventilators allow the flow rate to be adjusted When setting Inspiratory Cycle Off it is a percentage
  • Slide 82
  • Inspiratory Cycle Off Some ventilators have a preset flow rate that will cycle the PSV breath into exhalation Some ventilators allow the flow rate to be adjusted When setting Inspiratory Cycle Off it is a percentage The percentage is based on the peak inspiratory flow achieved during the breath
  • Slide 83
  • Inspiratory Cycle Off Some ventilators have a preset flow rate that will cycle the PSV breath into exhalation Some ventilators allow the flow rate to be adjusted When setting Inspiratory Cycle Off it is a percentage The percentage is based on the peak inspiratory flow achieved during the breath The percent is what determines when the breath will release the pressure and allow exhalation
  • Slide 84
  • Inspiratory Cycle Off If you set the Inspiratory Cycle Off at 25% the inspiratory breath will end when the flow is 25% of the peak flow during that breath
  • Slide 85
  • Inspiratory Cycle Off If you set the Inspiratory Cycle Off at 25% the inspiratory breath will end when the flow is 25% of the peak flow during that breath If the peak flow was 60 lpm the breath will end at 25% of that or 15 lpm
  • Slide 86
  • Inspiratory Cycle Off If you set the Inspiratory Cycle Off at 25% the inspiratory breath will end when the flow is 25% of the peak flow during that breath If the peak flow was 60 lpm the breath will end at 25% of that or 15 lpm The higher the % set the sooner the breath will be cycled off
  • Slide 87
  • Inspiratory Cycle Off If you set the Inspiratory Cycle Off at 25% the inspiratory breath will end when the flow is 25% of the peak flow during that breath If the peak flow was 60 lpm the breath will end at 25% of that or 15 lpm The higher the % set the sooner the breath will be cycled off This may cut off a patient breath early