Effectiveness of the volume guarantee software algorithm on tidal volume stability in preterm neonates recovering from RDS

Objective. The volume guarantee software algorithm attempts to deliver a tidal volume as close as possible to what the clinician selects as the target volume. To check the effectiveness of the algorithm we compared the interaction between patient and ventilator, and tidal volume variability in premature infants. Methods. Seven infants born before the 32nd week of gestation in the recovery phase of RDS were enrolled in the study. Infants were switched to SIPPV + VG for a 15-minute period, then back to SIMV for 15 minutes. They were then switched to PSV + VG, to SIMV again, and finally to SIMV + VG. Real time monitoring allowed us to download 500 observation points for each parameter. Results. Fewer large breaths and greater stability of tidal volume were observed in SIPPV & PSV modes compared to SIMV (p <0.0001). Lower peak inspiratory pressure was observed in all ventilator modes combined with VG than what was delivered by the ventilator during SIMV alone. The results of blood gas analyses after each ventilation mode were comparable. Conclusions. Our results suggest that the VG option complies very closely to the proposed theoretical algorithm. Modes that support every breath (SIPPV/PSV) are likely to be more effective in delivering stable tidal volumes than modes in which unsupported breaths are present (SIMV).