inspiratory waveform, one of several flow patterns during inspiration associated with mechanical ventilation. These patterns include a square wave, in which the inspiratory flow rises rapidly to a preset level and stays at that level until expiration begins; a sinusoidal wave, in which the flow gradually increases and decreases throughout inspiration; and a descending ramp wave, in which the flow increases very rapidly and then decreases gradually until the end of inspiration. The last pattern is most similar to normal breathing.