Table 1 MV strategies previously, or currently, studied to address the major problems facing clinical utilization of MV. The intuition behind the strategy, the aims of recent studies, and the limitation of current methods are briefly summarized

Recruitment manoeuvres

 Stepwise recruitment, maximum recruitment

Research the role, safety, clinical feasibility, and adverse effects of single, and/or regular, recruitment manoeuvres

Recruiting lung volume early improves ventilation and prevents atelectrauma but excessive pressures may further injure the lung

Each patient will respond differently to recruitment depending on the condition of their lung, the RM procedure could be routine but the ventilation settings determined afterwards should be specific to the patient at that moment in time

Compliance/elastance

 Setting MV using maximum or inflection compliance

Employ clinical protocols to determine an optimal ventilation PEEP using a patient’s static compliance/elastance and inflection

The best way to model a patient’s lung condition is to measure its compliance in a static PV curve

However, doing so is invasive and an impediment to continuing ventilation and is not feasible for frequent reassessment

 Dynamic monitoring

Employ clinical protocols to determine an optimal ventilation PEEP using a patient’s dynamic compliance/elastance and inflection and often mathematical methods

Patient airway dynamics are going to change overtime (e.g. pre- and post-recruitment or PEEP change), modelling compliance/elastance from pressure/volume data can enable incremental improvements to ventilation settings without large digressions from ventilation

Reliance on mathematical models may cause adverse effects to be ignored. Moreover, to ensure the current setting remains optimal, small perturbations are necessary which may disrupt ventilation

Lung protective strategy

 ARDSNet, OLA, EXPRESS

Employ clinical protocols that can be used to select ventilation parameters all within acceptable ranges to prevent further lung injury

To prevent further lung injury, ventilation should be set within canonically safe ranges of tidal volumes, plateau pressure, driving pressures, PEEP etc

Unfortunately, respiratory failure patients are diverse and what may be safe for the majority may be detrimental for some

Variable ventilation

 NAVA

Improve patient-ventilator interaction by promoting patient spontaneous breathing

Healthy breathing is variable over time and without this variability a patient’s breathing efforts may be suppressed. To promote breathing effort, variable breaths are delivered either artificially or using the electrical activity of the diaphragm

Each patient may respond differently to variation and relatively little comprehensive protocols or guidelines exist

High mean pressure modes

 HFOV, APRV

Development of clinical protocols to prevent atelectasis with continually high airway pressures

To prevent collapse or atelectasis, continually high airway pressures are used which result in a healthy to high end-expiratory lung volume

Neither HFOV nor APRV are patient-specific. Moreover, the small tidal volumes at high pressures create dead space and reduce minute ventilation and CO₂ clearance over alternatives