Advances in achieving lung and diaphragm-protective ventilation

Abstract

Purpose of review: Mechanical ventilation may have adverse effects on diaphragm and lung function. Lung- and diaphragm-protective ventilation is an approach that challenges the clinician to facilitate physiological respiratory efforts, while maintaining minimal lung stress and strain. Here, we discuss the latest advances in monitoring and interventions to achieve lung- and diaphragm protective ventilation.

Recent findings: Noninvasive ventilator maneuvers (P0.1, airway occlusion pressure, pressure-muscle index) can accurately detect low and excessive respiratory efforts and high lung stress. Additional monitoring techniques include esophageal manometry, ultrasound, electrical activity of the diaphragm, and electrical impedance tomography. Recent trials demonstrate that a systematic approach to titrating inspiratory support and sedation facilitates lung- and diaphragm protective ventilation. Titration of positive-end expiratory pressure and, if available, veno-venous extracorporeal membrane oxygenation sweep gas flow may further modulate neural respiratory drive and effort to facilitate lung- and diaphragm protective ventilation.

Summary: Achieving lung- and diaphragm-protective ventilation may require more than a single intervention; it demands a comprehensive understanding of the (neuro)physiology of breathing and mechanical ventilation, along with the application of a series of interventions under close monitoring. We suggest a bedside-approach to achieve lung- and diaphragm protective ventilation targets.

Box 1

no caption available

FIGURE 1

Monitoring parameters and interventions to achieve lung- and diaphragm-protective ventilation. Schematic representation of the monitoring parameters and interventions available to achieve lung- and diaphragm-protective ventilation in relation to the time course of respiratory failure and ventilatory support. In the early/acute phase of respiratory failure, lung-protective ventilation should be given priority, thereafter this priority gradually shifts to diaphragm-protective ventilation. Dashed arrows indicate experimental interventions that should not routinely be used in clinical practice. ΔPaw, airway driving pressure; ΔPdi, transdiaphragmatic pressure swing; ΔP_L, static transpulmonary driving pressure; ΔP_L,dyn, dynamic transpulmonary driving pressure; ΔPmus, respiratory muscle pressure swing; EAdi, electrical activity of the diaphragm; EIT, electrical impedance tomography; HFNO, high-flow nasal oxygen; NIV, noninvasive ventilation; NMBA, neuromuscular blocking agents; NRD, neural respiratory drive; PEEP, positive end-expiratory pressure; PMI, pressure muscle index; Pocc, airway occlusion pressure; SGF, sweep gas flow; TFdi, diaphragm thickening fraction; V_T, tidal volume. vv-ECMO, veno-venous extracorporeal membrane oxygenation.

FIGURE 2

Bedside approach to achieve lung- and diaphragm-protective ventilation based on the occluded inspiratory airway pressure. In this approach the occluded inspiratory airway pressure (Pocc) is measured to estimate both lung stress and diaphragm effort. Pinsp is the inspiratory pressure set on the ventilator without including the rise in pressure that can sometimes be observed during the latter part of inspiration. The protocol can be repeated hourly, or when patient breathing effort has likely changed such as after changing ventilator settings. Note that prospective studies are required to assess whether using this protocol results in lung stress and effort in purported safe ranges. Figure adapted from [^▪▪].