Transrespiratory Pressure in Mechanical Ventilation

Fundamental Concepts

Transrespiratory pressure is the total pressure difference across the entire respiratory system, calculated as the difference between airway opening pressure and body surface pressure, representing the sum of transpulmonary pressure and transchest wall pressure, as defined by the European Respiratory Society 1, 2
The mathematical relationship between transrespiratory pressure, transpulmonary pressure, and transchest wall pressure is: Transrespiratory pressure = Transpulmonary pressure + Transchest wall pressure, according to the American Thoracic Society 1, 2
Transpulmonary pressure is the pressure difference between alveolar pressure and pleural pressure, representing the distending pressure across the lung tissue alone, as stated by the Society of Critical Care Medicine 3

In ARDS patients, understanding transrespiratory pressure is critical because high chest wall elastance can substantially alter the relationship between airway pressures and actual lung distension, as noted by the European Society of Intensive Care Medicine 3, 4
Esophageal pressure measurement allows clinicians to partition transrespiratory pressure into its lung and chest wall components, enabling more precise assessment of actual lung stress, as recommended by the American College of Chest Physicians 3
The goal of setting PEEP is to achieve positive end-expiratory transpulmonary pressure to maintain alveolar recruitment, according to the National Institutes of Health 3

Esophageal pressure serves as a surrogate for pleural pressure, measured via balloon catheters positioned 35-40 cm from the nostril in adults, as described by the American Thoracic Society 5
Transpulmonary pressure can be calculated as: PL = Airway pressure - Esophageal pressure, as stated by the Society of Critical Care Medicine 3

Assuming that airway plateau pressure alone reflects lung stress can lead to inadequate lung recruitment or overdistension, as warned by the European Society of Intensive Care Medicine 3
Patient self-inflicted lung injury can occur during spontaneous breathing efforts in ARDS, requiring deep sedation or neuromuscular blockade to prevent, as noted by the Society of Critical Care Medicine 3, 4
Lung driving pressure (ΔPL = end-inspiratory PL - end-expiratory PL) reflects the tidal distending pressure and may be the most important predictor of ventilator-induced lung injury, as stated by the American Thoracic Society 6