Introduction The Babylog VN500 ventilator (Draeger, Lubeck, Germany) in High frequency oscillation mode (HFOV) has the ability to control tidal volume (VThf) using a Volume Guarantee function. However, appropriate VThf values during this mode of ventilation has not been established.
Aim The aim of this study was to establish normative data for VThf/kg during HFOV and explore its correlation with FiO2, day of life (DOL), gestational age (GA) and frequency (Freq).
Methods Newborns admitted to the level III NICU from January 2012 till September 2013 treated with VN-500 in HFOV mode according to strict clinical protocol were included. Indications for HFOV were: PCO2 > 65 on two consecutive blood gases and RR > 60. Blood gases with corresponding vent settings, time, patient’s weight and clinical diagnosis, were prospectively recorded. Measured VThf values were included only when PCO2 was in the ‘normocapneic range’ of 40–55 torr. Univariate analysis for FiO2, DOL, GA and Freq as well as Spearman’s rank correlation coefficient was done.
Results 37 patients were treated with rescue HFOV; BW = 875.9 g ± 163.7 and GA = 26.4 ± 1.4 (mean ± SD). 201 of 425 sets of blood gases met normocapnic criteria. The PCO2 was 46.5 ± 3.7 mmHg and VThf/kg 2.00 ± 0.59 mL/kg (mean ± SD). Correlation with GA, DOL, FiO2 and Freq are shown in the Table (*p < 0.05 in univariate correlation).
Conclusions The mean VThf during normocapnia on HFOV is 2 mL/kg but its value is affected by GA, DOL, FiO2 and Freq.