the study purpose was to evaluate the efficacy of the IntelliVent-ASV mode in maintaining the target range of PaCO2 in patients with severe TBI.
The study included 12 severe TBI patients with the wakefulness level scored 4-9 (GCS). This was a crossover design study. Two ventilation modes were consecutively used: IntelliVent-ASV and P-CMV, for 12 h each. When using the P-CMV mode, the ventilation parameters were set to maintain PaCO2 in a range of 35-38 mm Hg. The IntelliVent-ASV mode involved the Brain Injury ventilation algorithm. The target range of EtCO2 was set in accordance with the delta PaCO2-EtCO2 to maintain PaCO2 in a range of 35-38. At the beginning of each ventilation period and every 3 hours, the arterial blood gas composition was analyzed. When PaCO2 occurred out of the 35-38 range, appropriate adjustments were made to the ventilation parameters. In the P-CMV mode, the Pinsp and RR parameters were adjusted to achieve the target PaCO2 range. In IntelliVent mode, a shift of the target EtCO2 range was adjusted in accordance with a changed PaCO2-EtCO2 difference. In all patients, ICP, blood pressure, and EtCO2 were monitored; the arterial blood gas composition was analyzed every 3 h; the frequency of manual settings of ventilation parameters was recorded.
The EtCO2 and PaCO2 parameters were found not to be significantly different in the P-CMV and IntelliVent modes, but the spread in these parameters was significantly lower in the IntelliVent ventilation mode. The PaCO2 parameter occurred out of the target range significantly less often in the IntelliVent mode than in the P-CMV mode. The mean frequency of manual respirator settings needed to maintain the target EtCO2 range was significantly lower in the IntelliVent-ASV mode than in the P-CMV mode.
The IntelliVent-ASV mode provides more efficient maintenance of PaCO2 in the target range compared to traditional artificial ventilation using fewer manual settings of the ventilation parameters.