Immediate Management of Lung Hyperinflation

Pathophysiology and Clinical Significance

The American Thoracic Society suggests that hyperinflation occurs due to air trapping from expiratory flow limitation, causing increased intrathoracic pressure, decreased venous return, and impaired cardiac output, although the exact mechanisms are complex and multifactorial 1, 2

The American College of Chest Physicians recommends optimizing bronchodilation to reduce airway resistance and improve expiratory flow, with effectiveness judged by FEV1 improvement and reduction in hyperinflation markers such as inspiratory capacity 1
The European Respiratory Society suggests implementing pursed-lip breathing to prolong expiration and reduce air trapping, and using diaphragmatic breathing to improve ventilation efficiency 3, 4, 5
The American Thoracic Society recommends providing supplemental oxygen if hypoxemia is present, to reduce respiratory drive and respiratory rate, thereby decreasing dynamic hyperinflation 6

The British Thoracic Society recommends using low tidal volumes (6-8 mL/kg) with slower respiratory rates (10-15 breaths/min) and longer expiratory times (I:E ratio 1:2-1:4) to reduce dynamic hyperinflation, and aiming for permissive hypercapnia (pH >7.2) rather than normalizing CO2 2, 3
The American Heart Association suggests monitoring for auto-PEEP (intrinsic PEEP) which increases work of breathing, and briefly disconnecting from ventilator and applying gentle thoracic compression to aid exhalation if sudden deterioration occurs 2, 8
The European Society of Intensive Care Medicine recommends setting external PEEP to offset intrinsic PEEP, but avoiding setting it higher than intrinsic PEEP as this can worsen hyperinflation, and monitoring patient comfort and respiratory rate when adjusting PEEP 2

The American Thoracic Society recommends targeting a higher pCO2 based on pre-morbid levels (inferred by admission bicarbonate) for patients with chronic hypercapnia 2
The American College of Cardiology suggests being vigilant for tension pneumothorax which can occur even in spontaneously breathing patients with asthma exacerbations 8

The European Respiratory Society recommends observing for decreased work of breathing, reduced respiratory rate, and improved patient comfort, and monitoring for signs of barotrauma including pneumothorax, especially in mechanically ventilated patients 5
The British Thoracic Society suggests watching for patient-ventilator asynchrony which may indicate inadequate settings 2

The American Heart Association recommends avoiding excessive tidal volumes or respiratory rates which can worsen air trapping, and not instilling normal saline routinely during suctioning as it may worsen hypoxemia and cardiovascular instability 5, 8
The European Society of Intensive Care Medicine suggests avoiding rapid normalization of blood gases in patients with chronic respiratory failure, and being cautious with sedation in ventilated patients as over-sedation can prolong mechanical ventilation 2