For the majority of patients admitted to ICU with hypoxic respiratory failure, a conventional ventilatory strategy using volume, pressure or dual control modes with PEEP is usually very effective. With severe lung injury it may be necessary to administer neuromuscular blockade, turn the patient prone and increase the mean airway pressure using PEEP or inverse ratio ventilation (IRV). If these interventions are unavailable, ineffective or inadequate, rescue therapies may be required.

One easily available rescue therapy is Airway Pressure Release Ventilation (APRV). APRV is an extreme version of IRV that looks analogous to using CPAP at high airway pressure levels (e.g. 28cmH2O). Intermittently that high airway pressure is released to remove CO¬ – the release time (less than 1 second) being too short to cause lung derecruitment. Using modern ventilators it is possible utilize the inspiratory capacity to oxygenate the patient (flipping the respiratory cycle from expiration as the primary time of gas exchange to inspiration) and allow the patient to breath spontaneously.

The spontaneous efforts have been shown to improve both gas exchange and cardiovascular performance – but they are not necessary when using this ventilator strategy. Gasping should be avoided. This tutorial covers the science behind APRV, how to set it up, how to use it as part of a ventilator strategy in ARDS, the strengths and limitations of this approach and how to wean it.

I guarantee you will learn something. @ccmtutorials http://www.ccmtutorials.org