It’s Not the Wand; It’s the Wizard: It’s Not Just the Mode but the Method Used to Set and Adjust the Mode that Is Lung Protective

The current protective ventilation strategies for patients with acute respiratory distress syndrome (ARDS) (Brower et al., N Engl J Med 351:327–36, 2004) that have been tested in randomized controlled trials (RCTs) were analyzed for physiologic correctness and patient outcome in Chap. 6 (Tables 6.1 , 6.2 , and 6.3 ). Regrettably, none of the current protective ventilation methods demonstrated a significant reduction in ARDS-related mortality, much below that in the high tidal volume (VT) control group in the ARDSNetwork Acute Respiratory Management Approach (ARMA) study. Given this lack of improved patient outcomes, Chaps. 8 and 9 will analyze novel ventilation strategies that have the potential to mitigate ventilator-induced lung injury (VILI) and lower ARDS-related mortality. These innovative ventilator methods will leverage applied physiology to construct a protective mechanical breath profile (MBP). The goal is to minimize lung pathophysiology predisposing the lung to secondary VILI. The MBP encompasses airway volumes, pressures, flows, rates, and the timing of their application during inspiration and expiration. The chapters will scrutinize highly specific methods for setting and adjusting various ventilator modes based on the components of the MBP to determine the optimal protective breath. This chapter emphasizes the significance of the methods used to set a mode and why it is crucial to inquire whether the mode’s configuration is grounded in sound physiology when evaluating a study involving a novel ventilation mode. In essence, it highlights the importance of the method over the mode itself—“It’s not the wand, it’s the wizard.” The ARMA study serves as a pertinent example revealing that the choice of mode alone does not determine its efficacy for ARDS patients; instead, it is the method of setting and adjusting the mode that dictates whether a ventilation strategy is lung protective or injurious. The ARMA study, which utilized the assist–control ventilation (VCV) mode, compared ARDS patients ventilated with high VT to those with lower VT. The study found an 8.8% reduction in mortality with the low VT method. The key takeaway was not that the VCV mode is not inherently “good” for ARDS patients but that the low VT method outperforms the high VT method. This chapter underscores the need to avoid lumping studies conducted with a specific mode, irrespective of the method, into a single group for meta-analysis, as this practice can yield a wide range of results. To illustrate the method’s critical role in patient outcomes, the chapter will compare the ARMA method for setting and adjusting the VCV mode with the Time-controlled Adaptive Ventilation (TCAV) method for setting and adjusting the airway pressure release ventilation (APRV) mode.