Background: The purpose of this study was to determine the functional relationship between tidal volume (VT) and 4 other ventilator parameters.
Methods: The following parameters were collected from an AVEA ventilator operating in the volume-controlled ventilation mode: VT (in L), peak flow (Vmax, in L/min), breath rate (f, in bpm), inspiratory-to-expiratory time ratio (I:E) and plateau time (TP, in s). The relationship between VT and each of the other variables was determined.
Results: When the other parameters were held constant, VT was positively correlated with Vmax and I:E, but negatively correlated with f and TP. When the velocity versus time curve was a 50% linearly decreasing wave, the functional relationship among the 5 parameters was governed by the equation: VT = 180 Vmax (60f - 60f [1 + I:E] - TP).
Conclusions: The functional relationship among the 5 parameters for the AVEA ventilator in the volume-controlled ventilation mode was determined. The parameters should be controlled in accordance with the patient's pathophysiological needs.