From the Guidelines
The protocol for managing hyperinflation in mechanically ventilated patients should prioritize the use of low tidal volumes (4–8 ml/kg predicted body weight) and target plateau pressure <30 cmH2O, as recommended by recent guidelines 1. To manage hyperinflation, the following steps can be taken:
- Decrease tidal volumes to 6-8 mL/kg of ideal body weight to minimize overdistension, as suggested by the evidence from the ARDSnet trial 1
- Use positive end-expiratory pressure (PEEP) titration guided by the Fraction of Inspired Oxygen (FiO2) required to achieve a desired arterial oxygen saturation (SpO2), with settings derived from the ARDSnet trial 1
- Consider early airway pressure release ventilation and prone ventilation in certain patients, as recommended by the guidelines 1
- Permissive hypercapnia may be considered if haemodynamically satisfactory parameters are maintained, as opposed to forms of ventilation which may cause further lung damage 1 The goal of these interventions is to reduce air trapping and improve ventilation, while minimizing the risk of lung damage and hemodynamic compromise. Key considerations include:
- Monitoring of plateau pressure and adjustment of tidal volumes as needed
- Titration of PEEP to achieve optimal oxygenation while minimizing lung injury
- Early consideration of alternative ventilation strategies, such as airway pressure release ventilation and prone ventilation, in patients who do not respond to conventional therapy.
From the Research
Hyperinflation Protocol
The hyperinflation protocol in mechanically ventilated patients involves strategies to minimize dynamic hyperinflation and intrinsic positive end-expiratory pressure (PEEPi).
- The application of external PEEP during assisted ventilation can reduce inspiratory effort and facilitate ventilatory triggering 2.
- To minimize the risk of hyperinflation, it is advisable to limit the level of external PEEP during assisted ventilation to about 70% of the level of PEEPi (measured during passive ventilation) 2.
- The use of lower tidal volumes and PEEP may limit pulmonary inflammation in mechanically ventilated patients without preexisting lung injury 3.
Ventilatory Strategies
Ventilatory strategies to manage hyperinflation include:
- Setting positive end-expiratory pressure (PEEP) to reduce dynamic hyperinflation and PEEPi 2, 4.
- Using small tidal volumes to minimize dynamic hyperinflation and auto-PEEP 4.
- Preserving expiratory time to reduce the risk of hyperinflation 4.
- Applying low levels of external PEEP to minimize work of breathing and facilitate ventilator triggering 2.
Monitoring and Treatment
Monitoring and treatment decisions should be guided by ventilator graphics and patient-ventilator interaction 4.