Closed-Loop Control of Mechanical Ventilation: Description and Classification of Targeting Schemes

TLDR

Ventilation modes have proliferated over the past 30 years, driven by a desire to improve safety, efficiency, and synchrony, yet the many names make understanding capabilities difficult. The authors describe the six basic targeting schemes—set‑point, dual, servo, adaptive, optimal, and intelligent—used in commercially available ventilators. These control systems are designed to achieve the primary goals of mechanical ventilation: safety, comfort, and liberation. Clinicians can understand the basic operations of these schemes without engineering expertise, facilitating better mode selection for synchrony, while engineers can use the descriptions to communicate more effectively with end users.

Abstract

There has been a dramatic increase in the number and complexity of new ventilation modes over the last 30 years. The impetus for this has been the desire to improve the safety, efficiency, and synchrony of ventilator-patient interaction. Unfortunately, the proliferation of names for ventilation modes has made understanding mode capabilities problematic. New modes are generally based on increasingly sophisticated closed-loop control systems or targeting schemes. We describe the 6 basic targeting schemes used in commercially available ventilators today: set-point, dual, servo, adaptive, optimal, and intelligent. These control systems are designed to serve the 3 primary goals of mechanical ventilation: safety, comfort, and liberation. The basic operations of these schemes may be understood by clinicians without any engineering background, and they provide the basis for understanding the wide variety of ventilation modes and their relative advantages for improving patient-ventilator synchrony. Conversely, their descriptions may provide engineers with a means to better communicate to end users.