#TARGET CO2 WITH TIDAL VOLUME CALCULATOR DRIVER#

T-high is the main driver of the release frequency.

Reduction in driving pressure and expiratory flow velocity may reduce secretion clearance.

Will reduce tidal volume and thereby promote hypercapnia.

May allow for management of severe hypoxemia without increasing the P-High to dangerous levels.

Should make APRV more lung-protective, by avoiding atelectasis and wide fluctuations in airway pressure which drive large tidal volumes (Mireles-Cabodevila 2016 Chatburn 2016).

Most APRV protocols in use set P-low to zero, but some do use positive P-low of ~5 cm ( Zhou 2017).

Inadequate P-high may cause inadequate ventilator support, causing increased work of breathing.

P-high is what provides the driving pressure for the release breath, which is the mechanism whereby APRV provides mechanical support to the work of breathing.

Low minute ventilation and hypercapnia.

May impair hemodynamics by causing cor pulmonale.

Excess driving pressure and large release breaths may cause lung injury.

However, for patients with severe obesity, may need to increase higher. Patients with severe obstructive lung disease aren't ideal candidates for APRV (e.g., they were excluded by Zhou 2017). The guideline below is designed for patients with predominantly hypoxemic respiratory failure (e.g. Slightly suboptimal settings are unlikely to cause harm.

This is evidence that APRV is a relatively forgiving ventilator mode. When in doubt, different settings may need to be trialed to determine which works the best.Ī review of small APRV trials dating back to 1988 found that none of them caused harm, although many used protocols that are horrific by modern standards ( Jain 2016). Each patient is different, so ventilator settings will need to be titrated to the individual patient.

#TARGET CO2 WITH TIDAL VOLUME CALCULATOR HOW TO#

These guidelines are intended as a basic scaffold for how to approach APRV. The most successful clinical trial of APRV to date is Zhou 2017, which has influenced the guidelines below. There has never been a human trial comparing two different APRV protocols, so it's impossible to dogmatically say whether any protocol is better than any other protocol. Numerous protocols and articles recommend different approaches. Let's admit it, nobody knows exactly how to set APRV.

Target co2 with tidal volume calculator