Abstract 201 Clinical Bioethics Poster Symposium, Tuesday, 5/4

High-Frequency oscillatory ventilation (HFOV) has been touted as a significant improvement over conventional mechanical ventilation (CV) in the care of newborn infants with respiratory failure. We wondered whether the benefits of HFOV, if any, might be associated with burdens as well. Specifically, we wondered whether non-surviving infants treated with HFOV spent longer in the NICU before their death compared to doomed infants treated with CV.

Methods: We identified infants who died in our NICU for 3 years after introduction of optional HFOV. We abstracted birthweight (b.w.), gestational age (g.a.), length of stay (LOS), and type of ventilation (CV vs HFOV) for all non-survivors. In addition, to account for the possibility that the two populations differed in illness-severity, we calculated the Score for Neonatal Acute Physiology (SNAP) on DOL 1 for infants in each group.

Results: Records from 135 infants who died in our NICU after receiving mechanical ventilation during the three-year study period were analyzed. 104 infants received CV, and 29 received HFOV. Two infants died within 48 hours, having received 1 day each of CV and HFOV, and were not assigned to either group. There were no significant differences in b.w. or g.a. for non-survivors receiving HFOV (median 773 g, 25 weeks) vs CV (median 852 g, 26 weeks). SNAP scores for non-surviving HFOV infants (28 ± 8; median 27) did not differ significantly from SNAP scores for non-surviving CV infants (25 ± 10; median 24). However, median LOS for non-survivors ventilated with HFOV was 15 days (quartiles 5 - 22 days), approximately five times longer than median LOS for non-survivors ventilated with CV, 2.5 days (quartiles 1 - 9 days)(p<0.001; Mann-Whitney). Analysis of a sub-population of ELBW (b.w.<1500 g; n = 54) infants matched for illness-severity (median SNAP 27 vs 27), birthweight (median 743 v 770g), and gestational age (median 25 v 25 wks) revealed the same phenomenon - LOS for non-surviving HFOV infants (median 15 days) was significantly longer than non-surviving CV infants (median 3.5 days; p<0.03; Mann-Whitney).

Conclusions: 1) HFOV ventilation significantly prolonged the dying of doomed newborns in our NICU, independent of initial mortality risk assessed by b.w., g.a., or SNAP illness-severity score, both for ELBW infants and for the overall population of non-survivors. 2) In the absence of compelling data demonstrating improved survival and/or decreased morbidity with HFOV, CV may be preferable as it appears to be less burdensome.