Effects of High-Frequency Oscillatory Ventilation With Volume Guarantee During Surfactant Treatment in Extremely Low Gestational Age Newborns With Respiratory Distress Syndrome: An Observational Study

Abstract

Objective: To evaluate the effect of volume guarantee (VG) combined with high-frequency oscillatory ventilation (HFOV) on respiratory and other physiological parameters immediately after lung recruitment and surfactant administration in HFOV elective ventilated extremely low gestational age newborns (ELGAN) with respiratory distress syndrome (RDS).

Design: Observational study.

Setting: Tertiary neonatal intensive care unit.

Patients: Twenty-two ELGANs of 25.5 ± 1.1 weeks of gestational age requiring invasive mechanical ventilation and surfactant administration for RDS during the first 6 h of life.

Interventions: All infants intubated in delivery room, were managed with elective HFOV and received surfactant after a lung recruitment manoeuver. Eleven infants received HFOV + VG and were compared with a control group of 11 infants receiving HFOV alone. HFOV was delivered in both groups by Dräger Babylog VN500 ventilator (Dräger, Lubeck, Germany).

Main outcome measures: Variations and fluctuations of delivered high-frequency tidal volume (VT_hf), fluctuation of pressure amplitude (ΔP) and partial pressure of CO₂ (pCO₂) levels after recruitment manoeuver and immediately after surfactant administration, in HFOV + VG vs. HFOV ventilated infants.

Results: There were no significant differences in the two groups at starting ventilation with or without VG. The mean applied VT_hf per kg was 1.7 ± 0.3 ml/kg in the HFOV group and 1.7 ± 0.1 ml/kg in the HFOV + VG group. Thirty minutes after surfactant administration, HFOV group had a significant higher VT_hf/Kg than HFOV + VG (2.1 ± 0.3 vs. 1.6 ± 0.1 ml/kg, p < 0.0001) with significantly lower pCO₂ levels (43.1 ± 3.8 vs. 46.8 ± 1.5 mmHg, p = 0.01), 54.4% of patients having pCO₂ below 45 mmHg. Measured post-surfactant ΔP values were higher in HFOV group (17 ± 3 cmH₂O) than in HFOV + VG group (13 ± 3 cmH₂O, p = 0.01).

Conclusion: HFOV + VG maintains pCO₂ levels within target range and reduces VT_hf delivered variations more consistently than HFOV alone after surfactant administration.

Keywords: ELGAN; HFOV; lung recruitment; respiratory distress syndrome; volume guarantee.

Figure 1

Flow diagram.

Figure 2

Evaluation of VT_hf (ml/kg), amplitude level (ΔP) and pCO₂ in HFOV and HFOV + VG groups. (A) At start: no significant differences of the three parameters between the two groups were observed. (B) Pre-surfactant administration (after completing the lung recruitment maneuver): there is a significant difference between the two groups in terms of VT_hf/kg (p = 0.03). (C) Post-surfactant administration: there are significant differences between the two groups in terms of VT_hf/kg (p < 0.0001), ΔP (p = 0.005), and pCO₂ (p = 0.006). ^*Represents statistically significant differences.

Figure 3

Pearson correlation analysis between VThf/kg, pCO2 significant correlation between all VThf/kg and pCO2 levels (Pearson coefficient: r = −0.69, p < 0.0001).