Meta-analysis of elective high frequency ventilation in preterm infants with respiratory distress syndrome

Abstract

Aim-To summarise the evidence on the eYcacy of elective high frequency ventilation compared with conventional ventilation in preterm infants with respiratory distress syndrome. Methods-A search from 1987 onwards was made on Embase, Medline, and the Cochrane Library. A questionnaire was also circulated during an international meeting on high frequency ventilation. To be included in the data synthesis, studies had to be randomised controlled trials comparing elective high frequency ventilation with conventional ventilation in preterm infants with respiratory failure due to respiratory distress syndrome; indices of mortality, chronic pulmonary morbidity, and other clinically relevant outcomes were compared. Studies were assessed for methodological validity according to explicit criteria. Results-Ten studies (a total number of 1345 preterm infants) were considered for data synthesis. No diVerence in mortality at 28 or 30 days, nor in oxygen dependency at 28 days was found between both types of ventilation. Reduced oxygen dependency at the postconceptional age of 36 weeks (RR 0.50, 95% CI 0.32-0.78) was found, but so was an increase in grades 3 and 4 intraventricular haemorrhage (IVH) (RR 1.31, 95% CI 1.04-1.66). Those studies using a high lung volume ventilatory strategy showed a significant decrease in oxygen dependency at the postconceptional age of 36 weeks (RR 0.44, 95% CI 0.27-0.73), but no increase in severe IVH (RR 0.78, 95% CI 0.45-1.37). Conclusions-Although high frequency ventilation reduces chronic lung disease, it seems to increase the risk of severe IVH. These results are dominated by an early study where the absence of benefit on pulmonary outcomes, and the increase in adverse neurological events, could be related to the low volume ventilatory strategy used. Recent studies, using a high lung volume approach, show better pulmonary outcomes without any increase in intracranial morbidity. Still, uncertainty remains about long term pulmonary and neurodevelopmental outcome. (Arch Dis Child Fetal Neonatal Ed 1999;80:F15-F20) Keywords: elective high frequency ventilation; respiratory distress syndrome; intraventricular haemorrhage Despite advances in management, such as the use of surfactant, the mortality and morbidity of respiratory distress syndrome in premature infants remain high. Chronic pulmonary morbidity after mechanical ventilation is still a major clinical problem. In particular, very low birthweight infants are at high risk of chronic lung disease: at least one in four infants between 500 and 750 g is oxygen dependent at the postconceptional age of 36 weeks.1 It is now thought that this lung damage is largely caused by repetitive collapse and overexpansion of surfactant deficient lungs, creating shear forces, with subsequent epithelial injury and inflammatory responses.2 3 In an attempt to avoid such lung injury alternative ventilation modalities were examined.High frequency ventilation (HFV) was first described by Bohn et al in 1980. 4 Animal studies showed that it could obtain eVectiv...

Risk Factors for Intraventricular Hemorrhage in Very Low Birth Weight Premature Infants: A Retrospective Case-Control Study

“…34 Potentially, a lower Paco 2 may reduce the risk of IVH by causing arterial vasoconstriction. However, low Paco 2 has been described as a risk factor for periventricular leukomalacia and a poor neurologic prognosis, 19 so there is a need for caution in interpreting this finding.…”

“…19 Pregnancy-induced hypertension is associated with a lower rate of IVH. 5,20 For reducing the incidence of IVH, several pharmacological interventions have been proposed, including antenatal steroids, 5,8,10,15,21,22 prenatal tocolytic therapy, 8,23 postnatal administration of low-dose indomethacin, 24,25 and surfactant.…”

High-Frequency Oscillatory Ventilation in the Management of Respiratory Distress Syndrome

“…HFOV reduced the incidence of CLD at 36 weeks in 2 studies [9,13], in contrast with other trials including our own [2,10,11]. A meta-analysis of the studies using HVS based on the results of the 2 studies discussed above [9,13] concluded that HFOV reduced the incidence of CLD at 36 weeks [18].…”

Multicentre trial of high frequency ventilation

“…E ditor —Cools and Offringa’s recent meta-analysis of elective high frequency ventilation (HFV) in preterm infants with respiratory distress syndrome1 concludes that HFV reduces the risk of chronic lung disease (CLD) at 36 weeks of postconceptional age, but may be associated with an increased risk of severe intraventricular bleeding. Several areas of uncertainty remain, however, and they suggest that new clinical trials should be done in very preterm infants to evaluate the usefulness of elective HFV, using a high lung volume strategy, started as soon as possible after birth.…”