Ventilators from Hamilton Medical offer the volume-targeted modes APVcmv/APVsimv (Adaptive Pressure Ventilation) as an alternative Time-Cycled Pressure Limited (TCPL) and Pressure-Controlled Ventilation (PCV) for neonates. There is strong evidence in the literature for the use of volume-targeted ventilation in neonates (see references below).
The TCPL mode was commonly used in previous generations of ventilators. In this mode, the gas flow is constant over the whole breath cycle and the operator sets the flow according to the preferred gradient of the slope/ramp on the pressure curve. In neonates the flow would be decelerating and the targeted form would resemble a shark’s fin to avoid pressure overshoots. However, if lung compliance changes abruptly to a change in patient condition (e.g. when surfactant is administered or mucus is suctioned), there may be a possibility of volutrauma. Compliance increases but inspiratory pressure stays the same, resulting in increased tidal volume.
In PCV (pressure controlled ventilation), the gas flow is variable and the operator can adjust the shape by adjusting the P-ramp setting in the controls’ menu. The longer he sets the ramp, the more gradual the rise of the pressure curve will be.
PCV and TCPL theoretically carry the same risk of causing volutrauma.
Hamilton Medical ventilators provide the volume-targeted modes APVcmv and APVsimv. In these modes, the gas flow is variable and the working principle is the same as in a pressure controlled mode. The operator sets the tidal volume and the ventilator regulates the pressure breath by breath to maintain the target tidal volume, so there is a lower risk of barotrauma and hypo/hypercapnia. Keeping the tidal volume constant also avoids the risk of volu- and atelectrauma.
Klingenberg, C., Wheeler, K. I., McCallion, N., Morley, C. J., & Davis, P. G. (2017). Volume‐targeted versus pressure‐limited ventilation in neonates. The Cochrane Library.
Peng, W., Zhu, H., Shi, H., Liu, E. (2014). Volume-targeted ventilation is more suitable than pressure-limited ventilation for preterm infants: a systematic review and meta-analysis. Arch Dis Child Fetal Neonatal Ed. 2014 Mar;99(2):F158-65.