Controlled mechanical ventilation in equine anaesthesia: Classification of ventilators and practical considerations (Part 2)

Controlled mechanical ventilation (CMV) is routinely used in equine anaesthesia, with many different options available to facilitate the delivery of mechanical breaths. The complexity of equine respiratory pathophysiology and the wide range of devices available is described in the two parts of this scoping review. The second part of this review provides an overview of commercially available and hand-made devices that can be used to deliver CMV in large animals. A short overview of basic physics for mechanical ventilation is given. Working principles are discussed and, where relevant, connected to the pathophysiological background of equine ventilation. The objective of this review is to demystify ventilation modes and ventilators used in equine anaesthesia over the last two decades. In addition, this review aims to provide a practical guide to what the anaesthetist needs to consider before using CMV, how CMV can be delivered and monitored, and which principles need to be applied are included. Comparison of the clinical effects between spontaneous breathing and CMV is included.