Objective: To estimate mortality risk in pediatric patients with acute
hypoxemic respiratory failure (AHRF). Design: Retrospective chart rev
iew. Setting: Forty-one pediatric ICUs. Subjects: Four hundred seventy
children with AHRF. We defined AHRF as mechanical ventilation with po
sitive end-expiratory pressure greater than or equal to 6 cm H2O and f
raction of inspired oxygen greater than or equal to 0.5 for 12 or more
hours. Measurements: Physiologic and treatment variables were recorde
d every 12 h for 14 days. Cases were randomly assigned to score develo
pment and score validation subsets. Variables were assessed for their
association with mortality in the development subset by logistic regre
ssion analysis. The analysis generated a series of logistic equations,
which we called the Pediatric Respiratory Failure (PeRF) score, to es
timate mortality risk at 12-h intervals over the first ? days of treat
ment for AHRF, The predictive ability of the score was assessed in the
validation subset by receiver operating characteristic curve area and
goodness-of-fit chi(2). Results: Mortality of the collected cases was
43%. The PeRF score included age, operative status, Pediatric Risk of
Mortality score, fraction of inspired oxygen, respiratory rate, peak
inspiratory pressure, positive end-expiratory pressure, PaO2, and PaCO
2. Area under the receiver operating characteristic curve was 0.769 at
entry and increased to greater than 0.8 after 36 h, When the score wa
s applied to the validation subset of patients, goodness-of-fit chi(2)
showed no significant difference between estimated and actual mortali
ty between 0 and 96 h. Conclusions: The PeRF Score accurately estimate
d mortality risk in this retrospectively sampled group of high-risk pe
diatric patients with AHRF, This score may be useful in studies of new
er therapies for pediatric AHRF, though prospective validation is nece
ssary before it could be used to make clinical decisions.