Ventilators for Nonintensivists. Basic Modes and Breath Types.

Ventilator modes and breath types.

As coronavirus disease (COVID-19) has rapidly evolved into a pandemic, many physicians without prior critical care training are being called upon to help manage severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–infected patients who develop respiratory failure and require mechanical ventilation. This video is intended to provide a brief and simplified approach to mechanical ventilation for nonintensivists with an overview of major ventilator modes and breath types. For acutely ill patients, the most commonly used mode is the Assist Control (AC) mode. Therefore, we primarily focus on the AC mode in this video. The AC mode requires the clinician to set the FiO, the positive end-expiratory pressure (PEEP), and the respiratory rate. The patient is able to breathe above, but not below, the set respiratory rate. In addition to selecting the above parameters, a breath type, most commonly either volume control (VC) or pressure control (PC), must also be chosen. In VC, the tidal volume (Vt) is directly selected by the clinician. In PC, the clinician chooses a pressure level above PEEP and the Vt is determined indirectly. As there are advantages and disadvantages for both VC and PC, one is not intrinsically better than the other and the breath type selected is typically dictated by institutional preferences. Whether the clinician uses VC or PC, it is important that the set Vt (in case of VC) or the resulting Vt (in case of PC) is 4–8 ml/kg of predicted body weight.