Ventilación controlada por volumen vs. ventilación controlada por presión en pacientes sometidos a ventilación de un solo pulmón

Abstract

The one lung ventilation (OLV) have problems as well increase of pressures in the airway and the shunt. This changes can be influenced by the ventilation mode choice. The ventilation controlled by pressure (VCP) is an alternative way widely used in patients with respiratory failure by its characteristics of flow and pressure. In this study the VCP was used in the patients who required OLV and their effects on the pressures in the airway, oxygenation and hemodynamics state were compared with the controlled ventilation by volume (VCV). We studied 41 patients who needed OLV. After ventilating two lungs with volume the patients were randomized to one of two groups. In first group (n=19) OLV it was initiated with VCV and after passed 30 minutes the patients they were changed to VCP, where the ventilation by the same time stayed. In the other group (n=21) the patients initiated in VCP 30 minutes and them they were changed to VCV with same duration. The pressures in the airway, arterial blood gases and variable hemodynamics were measured during OLV in each ventilatory mode previous to the change. We observed that the beginning of OLV generates an increase of the inspiratory pressure peak (PIP) (p=0.0002) and pressure plateau (p=0.005). This increase is greater in the group than was VCV (p=0.008) that in the group that was VCP (p=0.003). There was no significant statistically difference in the other varibles studied between the groups. We concluded that the VCP can be an alternative to VCV in patients who require OLV because diminishes the pressures in the airway and although it does not improve oxygenation, can decrease the ventilador induced lung injury in risk high poblation.