APRV stuff Flashcards
Initial Settings for APRV?
When transferring form conventional ventilation:
- Phigh match Plat on current mode (max 30)
- Plow set to 0
- Thigh 4
- T low 0.5-1 (often 0.8)
What do you need to ensure is adjusted after setting initial settings?
Adjust end expiratory flow to 75% of PEFR
What are you goals for Phigh?
Ensure a ratio of 4:1 or greater; want 90-95% of time spent at Phigh
Add slide 19 (APRV vent quirks)
What are other names for APRV?
Bivent or Bilevel
How do you adjust APRV settings to increase ventilation?
- Increase Phigh or decrease Thigh
- Increase or decrease Tlow
How do you adjust APRV settings to increase oxygenation?
Increase Phigh or Thigh
- Decrease Tlow
Weaning APRV?
Achieved by: decreasing Phigh then increasing Thigh
- The goal is to wean the patient to a low level of CPAP
- Decreasing Thigh decreases RR which allows the patient to breath
Contraindications for APRV?
Air leak syndromes and condition of TBI/high ICP
What is Phigh?
Phigh represents the high continuous positive airway pressure (CPAP) level during the inspiratory phase of the ventilator cycle.
- Determines the level of positive pressure applied to the airways to recruit and maintain alveolar inflation
- Set above baseline PEEP to support lung recruitment and oxygenation
What is Plow?
Plow represents the low CPAP level during the expiratory phase of the ventilator cycle.
- Determines the level of positive pressure maintained in the airways during the expiratory phase to prevent alveolar collapse and maintain functional residual capacity (FRC)
- Plow is usually set below Phigh to allow for passive expiration and CO2 elimination.
What is Thigh?
High pressure time; duration of time which the vent maintains Phigh (High CPAP pressure) in the inspiratory phase.
- Determines the duration of time allocated for lung recruitment and oxygenation.
What is Tlow?
Low pressure time; duration of time during which the ventilator maintains the Plow level (low CPAP pressure) in the expiratory phase
- Determines time allowed for passive expiration and CO2 elimination
- Prevents air trapping
In Airway Pressure Release Ventilation (APRV), the settings that primarily affect the I:E (inspiratory to expiratory) ratio and respiratory rate include?
Primarily Thigh and Tlow; RR is also connected and could be manipulated
How does Thigh affect the I:E ratio?
Thigh determines the duration of time during which the ventilator maintains the Phigh (high CPAP pressure) level in the inspiratory phase.
- Increasing Thigh will prolong the inspiratory phase, thereby increasing the I:E ratio and potentially decreasing the respiratory rate.