Analysis of peak inflating pressure and inflating pressure limit during neonatal volume guaranteed ventilation

Objectivesto report how peak inflating pressure (pip), tidal volume (vt) and low-tidal volume alarms are affected by maximum allowed inflating pressure (pmax) during volume guarantee (vg) ventilation.study designventilation data were analysed with 1 hz sampling rate from 25 neonates receiving synchronised intermittent positive pressure ventilation with vg for >12 h.resultsthe difference between pmax and pip (pdiff) ranged between 5 and 20 mbar (median = 11 mbar) despite a protocol to keep pmax 5 mbar above the “working pip”. pmax was reached in 5.2% of inflations. computational modelling demonstrated that had pdiff been kept at 5 mbar more consistently, >10% of inflations would have reached pmax. the frequency of low-tidal volume alarms showed inverse correlation with pdiff.conclusionsit is difficult to implement a simple pmax strategy due to variability of pip. setting pmax close to the “working pip” limits vt delivery and triggers frequent alarms.