Objectives: To determine whether improved
oxygenation indicates a valid response to inhaled nitric oxide (iNO)
therapy in patients with pediatric ARDS, and to establish an analytic
tool to differentiate the iNO effects from those of other interactive
factors in pediatric patients with ARDS.
Consecutive case series evaluated by post hoc analysis
Patients and methods: Nineteen patients treated
with iNO for ARDS or pulmonary hypertension were enrolled in our study.
We evaluated the Pao2/fraction of inspired
oxygen ratio (PF ratio), oxygenation index (OI), patient position
(prone vs supine), Paco2, pH, and vasoactive
drug support, and classified patients’ responsiveness to iNO into
three categories: (1) possible response, an increase in PF ratio, with
no alteration of the aforementioned variables in a direction known to
improve oxygenation; (2) nonspecific response, an increase in PF ratio
with no increase in OI, and alteration of one or more of the other four
criteria in a direction known to improve oxygenation; and (3)
undetermined response, an increase in both the PF ratio and OI,
indicating a deliberate augmentation in ventilator support.
Results: A total of 119 data points were evaluated. Fifty
data points (42%) exhibited no response to iNO. Thirty-two data points
(27%) were classified as having possible responses, 35 data points
(29%) as nonspecific, and 2 data points (2%) as undetermined
responses to the iNO treatment.
Conclusions: In ARDS,
improved oxygenation amid iNO treatment is multifactorial. In only 27%
of our evaluated data points could the increase in PF ratio be
attributed to iNO. We suggest that when clinically utilizing iNO, the
interactive factors described by us should be taken into account for