P52
ELECTIVE HIGH FREQUENCY JET VENTILATION VS CONVENTIONAL VENTILATION FOR
RESPIRATORY DISTRESS SYNDROME: SYSTEMATIC REVIEW AND META-ANALYSIS
Bhuta T1, Henderson-Smart D J2
1
NSW newborn and paediatric Emergency Transport Service, Sydney
2
NSW Centre for Perinatal Health Services Research, Sydney
Objective: To determine whether the elective (commencing soon after initiation of mechanical ventilation) use
of high frequency jet ventilation (HF JV), as compared to conventional ventilation (CV) in preterm infants with
the respiratory distress syndrome (RDS) would decrease the incidence of chronic lung disease (CLD) without
adverse effects.
Methods: Systematic search in accordance with Cochrane reviews. All randomised controlled trials of elective
high frequency jet ventilation versus conventional ventilation in preterm infants < 35 weeks GA or <2000 gms
with respiratory distress were included in the systematic review. Trials, which used HF JV to "rescue" preterm
infants usually beyond 24 hours, and trials that used HF JV for a mandatory time period and then switched back
to CV, were not included in this review. Data analysis was conducted according to the standards of the
Neonatal Cochrane Review Group using relative risk (RR), risk difference (RD). From 1/RD number needed to
treat (NNT) for benefits and number needed to harm (NNH) for adverse outcomes, were calculated. Preplanned
subgroup analyses: 1) Trials with and without surfactant replacement therapy, 2) Ventilator strategies aimed at
maintaining effective lung volume such as use of high mean airway pressures, manoeuvres to recruit alveolar
volume after suctioning and weaning of Fi02 before pressure called high volume strategy (HVS) versus trials
that did not use the strategy (LVS), 3) Infants at different gestational ages and birth weight and 4) Trials with
and without adequate humidification.
Results: Three publications were included in the meta-analysis1-3. Overall analysis of the three trials showed
that HF JV is associated with a reduction in CLD at 36 weeks post menstrual age (PMA) in survivor 2,3 [RR
0.58 (0.34, 0.98), NNT 7(4, 90)]. Home 02 was assessed in only one study 3 where a lower rate was found in the
HF JV group [RR 0.24 (0.07, 0.79), NNT 5 (3, 21)]. Overall there is a trend towards an increase in risk of PVL
in the HF JV group, which was not significant. Subgroup analysis shows a significant increase in risk of PVL
in the trial by Wiswell 19962 [RR 5.0 (1.19, 21.04), NNH 4 (2.3,14.5)] where a 'low volume strategy' was in the
protocol for HF JV. In the other trial by Keszler 19973, where the intention was to use a 'high volume strategy',
there is no significant difference in the incidence of PVL, RR 0.42 (0.14, 1.30). In the overall analysis, there
were is no significant differences in the incidence of neonatal mortality, IVH all grades and grades 3 or 4 IVH.
In the subgroup where low volume strategy was used there was a non-significant trend toward an increase in
risk of IVH all grades and grades 3 or 4 IVH. Subgroup analysis of infants at different gestational age,
birthweight and with or without humidification could not be performed.
Conclusions: The overall analysis show a benefit in pulmonary outcomes (CLD at 36 wks PMA 2,3 Home 02,3)
in the group electively ventilated with HFJV. Of concern is the significant increase in PVL in one single centre
trial, which used lower mean airway pressures when ventilating with HFJV 2. There are as yet no long term
pulmonary or neurodevelopmental outcomes from any of the trials. Until further studies ascertain the most
appropriate strategy to ventilate premature infants with HFJV safely, routine use of HF JV cannot be
recommended for ventilated preterm infants with RDS.
1
Carlo WA, Siner B, Chatburn RL, Robertson S, Martin RJ. Early randomised intervention with high-frequency jet ventilation in
respiratory distress syndrome. J Pediatr 1990;117:765-70.
2
Wiswell et al. High-Frequency jet ventilation in the early management of respiratory distress syndrome is associated with a greater risk
for adverse outcomes. Pediatrics 1996;98:1035-1043.
3
Keszler et al. Multicenter controlled clinical trial of high frequency jet ventilation in preterm infants with uncomplicated respiratory
distress syndrome. Pediatrics 1997;100 (4):593-597.