APRV is a ventilation mode that applies CPAP at a high pressure for a prolonged period of time to recruit and maintain lung volume, followed by brief releases to a lower pressure to allow for exhalation and CO2 removal. It aims to preserve spontaneous breathing. APRV is indicated for ARDS management and postoperative atelectasis and has benefits like improved oxygenation and reduced sedation needs but risks include increased work of breathing and worsening of air leaks. Studies comparing APRV to other modes in ARDS patients have found similar outcomes but more research is still needed to determine its full utility.

1. AIRWAY PRESSURE RELEASE
VENTILATION
APRV
Ahmed Al Gahtani, BSRC, RRT.
Associate Director Clinical Education & Instructor
Chairman, RTS Advisory Committee
Dept. of Respiratory Therapy Program
Inaya Medical College
SSRC Central & Northern Chapter Board Member for RC Education

2. APRV
• What
• When
• How

3. What When How

4. What is APRV
■ Airway pressure release ventilation (APRV) was described more than 20 years ago by
Stock & Down in 1987 as a CPAP with an intermittent release phase.
■ APRV is a time-cycled alternant between two levels of positive airway pressure, with
the main time on the high level and a brief expiratory release to facilitate ventilation
allows spontaneous breathing throughout the ventilation cycle
■ APRV applies CPAP (P high) for a prolonged time (T high) to maintain adequate lung
volume & alveolar recruitment, with a time cycled release phase to a lower set of
pressure (P low) for a short period of time (T low) or (release time) where most of the
ventilation & CO2 removal occurs

5. ■ The Dräger Evita was the first ventilator in the United
States to provide APRV. Subsequently other intensive
care unit (ICU) ventilators, such as the Hamilton G-5,
the Puritan Bennett 840, the DrägerV500, the
CareFusion AVEA, and the Maquet Servo-i,
incorporated APRV.
■ Servo-i refers to APRV as Bi-vent
■ Puritan Bennett 840 uses the term Bi-level
■ Hamilton G5 refers to APRV as Duo-PAP.
■ The function of APRV may also be different with each
ventilator.
■ ‘APRV’ is common to users in North America, biphasic
positive airway pressure (BIPAP) was introduced in
Europe
What is APRV
Henzler CriticalCare 2011, 15:115

7. APRV Set Parameters
■ P high.
■ P low
■ T high
■ T low
■ (10% to 30%)

8. HOW

9. When
■ APRV indicated for ARDS management and atelectasis after major surgery.
■ APRV presents many attractive benefits as an alternative mode of mechanical
ventilation in patients who do not respond to conventional modes.
■ APRV contraindicated with COPD & Asthma, Deep sedation, and NMD

10. ■ This study is the largest reported randomized trial of APRV to date.Trauma patients at
risk for ARDS ventilated with
■ APRV had similar outcomes as those treated with LOVT
■ APRV seems to be a safe alternative ventilator modality that provides increased mean
airway pressure as a potential recruitment mechanism.
■ Sedation requirements seem to be similar to SIMV.
■ Additional trials in patients with documented ARDS will be necessary for further
clarification of its ultimate utility.

11. ■ The preemptive ventilation strategy presented in our study has the potential to change the
current clinical practice paradigm from treating ARDS once it manifests to preventing it
from ever developing.
■ Clinical application can begin without delay with an immediate impact on patient care.
■ If successful, our ventilation strategy would be the first prophylactic intervention of any kind
to prevent ARDS.

14. PROS AND CONS
Advantages
■ alveolar recruitment and improved
oxygenation
■ preservation of spontaneous breathing
■ reduction of left ventricular transmural
pressure and therefore reduction of
left ventricular afterload
■ potential lung-protective effect
■ better ventilation of dependent areas
■ lower sedation requirements to allow
spontaneous breathing
Disadvantages
■ risks of volutrauma from increased transpulmonary
pressure
■ increased work of breathing due to spontaneous
breathing
■ increased energy expenditure due to spontaneous
breathing
■ worsening of air leaks (bronchopleural fistula)
■ Increased right ventricular afterload, worsening of
pulmonary hypertension
■ Reduction of right ventricular venous return: may
worsen intracranial hypertension, may worsen
cardiac output in hypovolemia
■ Risk of dynamic hyperinflation

15. Four HypothesesAre Possible
1, APRV/BIPAP is better than A/C;
2, APRV/BIPAP is worse than A/C;
3,there is no difference between APRV/BIPAP and A/C;
4,it is undetermined whether there is a difference between APRV/BIPAP
and A/C.
Henzler Critical Care 2011, 15:115
Finally