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 Journal
Review
The
Sy-Fi Study
Craft
AP, Bhandari V, Finer NN. The Sy-Fi Study: A randomized prospective
trial of synchronized intermittent mandatory ventilation versus
a high-frequency flow interrupter in infants less than 1000 g. J
Perinatol 2003;23:14–19.
by
Ketan Kasangra, MD
Introduction:
Mechanical ventilation has been the mainstay of treatment for
respiratory distress syndrome (RDS), but it is associated with
the potential development of bronchopulmonary dysplasia (BPD)
and air leak syndrome, especially in the preterm infant who is
less than 1000 grams. Clinical trials of high-frequency flow interruption
(HFFI) have shown equivocal results regarding efficacy and complications.
This study tested the hypothesis that (HFFI) would reduce the
incidence of BPD in preterm infants less than 1000 grams when
compared to synchronized intermittent mandatory ventilation (SIMV),
which has been reported to have a lower incidence of BPD compared
to conventional mechanical ventilation (CMV).
Methods:
From January 1999 to May 2000, patients between 24 and 34 weeks’
gestation and less than 1000 grams were recruited from two nurseries
(San Diego and Philadelphia) after informed consent was obtained.
Infants were randomized to SIMV or HFFI and stratified into two
weight categories (500–750 grams [I] and 751–1000 grams [II])
and remained on the assigned mode until extubation (at MAP <7
cm H2O) or, if on high frequency, until changed to CMV or extubation.
The Infant Star® ventilator was used in both groups. Standard
approach to ventilator management was utilized for both groups.
Primary outcome was the incidence of BPD, defined as having an
oxygen requirement at 36 weeks’ postconceptual age, as well as
multiple secondary outcomes. Recruitment was stopped early due
to declining enrollment, and an interim analysis was performed.
Results:
No differences were noted in demographic data between the two
groups, nor in BPD or ventilator days between groups, nor in any
other secondary outcomes. Center differences included increased
air leak in Center A for all weight categories and increased ventilator
days for Group II, and increased continuous positive airway pressure
(CPAP) days for Center B in Group I.
Discussion:
No differences were seen in the measured outcomes between the
two groups. The most important limitation of this study is that
it lacked power to reject the null or alternate hypotheses. Thus,
this study can not answer which mode of therapy is better. Despite
apparent advances in ventilator strategies, ventilator-induced
lung injury continues to be a cause of significant morbidity in
the extremely low birth weight infant. Strategies to avoid mechanical
ventilation entirely might hold the greatest promise to reduce
the incidence of lung injury.
(Infant
Star is a registered trademark of Nellcor Puritan Bennett, Inc.,
Pleasanton, PA.)
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