APRV By Kellianne McCaffrey and Rowena Eason
What is it? • Airway Release Pressure Ventilation is a method of ventilation that provides two levels of continuous positive airway pressure (CPAP) and allows spontaneous breathing at both levels. • It is time triggered and time cycled • Ideally, promote higher MAP and improve oxygenation
Auto-PEEP and APRV • Release time does not allow the patient to expire entirely, intentionally causing an intrinsic PEEP air trapping to keep alveoli open
When is APRV used? • APRV is beneficial to patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) • This is because these patients are difficult to oxygenate based on their inadequacy of gas exchange
How does it help? • APRV provides consistent lung recruitment, prolonged and improved oxygenation through the increased mean airway pressure • It does NOT increase PIP.
Set up • What is set? • Time-hi (inspiratory) • Time-lo is the time that Low pressure is held (AW pressure release time to allow for CO2 release ie. expiratory) • Pressure-hi • Pressure-lo • FiO2
What does that mean?!? • Pressure-Hi is the high pressure given on inspiration • Pressure-Lo is the Low pressure given on expiration • Time-Hi is the amount of time the High pressure is held • Time-Lo is the time that the Low pressure is held
Basic Parameters • Low Pressure 0 cmH2O, High Pressure 20-30 cm H2O • Low Time 0.4-0.6 seconds, High Time 4-6 seconds • adjust accordingly to maintain Vt between 4-6 ml/kg
Oxygenation status • Different measures will be taken depending on whether or not the patient is oxygenating and ventilating well. • T-hi must be increased if patient remains severely hypoxemic after beginning APRV • If oxygenation is adequate, the patient may be ready to be weaned
Weaning • Can be weaned to pressure support. • FiO2 is always weaned FIRST. • Inspiratory time is increased • Pres-lo is increased gradually to 8-10 cmH2O • Pres-hi is decreased, typically 2-3 cmH2O at a time
Weaning (cont’d) • Inspiratory time is increased while the high pressure is decreased in order to reduce the total number of release phases. • Ultimately the two pressures are set to match the MAP and allow the patient to breathe spontaneously on CPAP
Other names • Each ventilator has a different name for the same thing • Servo calls it BiVent • Puritan Bennet calls it BiLevel • Drager and Hamilton both call it APRV
APRV rocks! • Rowena’s favorite part about APRV is that it continuously recruits the lungs and really helps the ARDS patients. • Kellianne’s favorite part about APRV is the simplicity of the weaning process.
References http://www.americannursetoday.com/airway-pressure-release-ventilation-a-boost-for-spontaneous-breathing/http://www.ncbi.nlm.nih.gov/pubmed/24093118 http://www.ccjm.org/content/78/2/101.long#abstract-2 www.respiratorytherapyfiles.net Pilbeam’s Mechanical Ventilation 5th edition 2012 http://www.ncbi.nlm.nih.gov/pubmed/24093118 http://www.ccmtutorials.com/rs/mv/strategy/page14.htm