Interactive effects of high-frequency oscillatory ventilation and inhaled nitric oxide in acute hypoxemic respiratory failure in pediatrics.
OBJECTIVE
High-frequency oscillatory ventilation (HFOV) and inhaled nitric oxide (iNO) have been reported to improve oxygenation in children with acute hypoxemic respiratory failure (AHRF), but their roles in the treatment of AHRF remains unknown. The use of HFOV improves oxygenation by increasing lung recruitment. iNO can improve oxygenation in AHRF, but it may have limited efficacy in patients with poor lung inflation. Based on these findings, we hypothesized that the combined treatment of HFOV and inhalation of low-dose NO would improve oxygenation and survival in children with severe AHRF compared with children treated with conventional mechanical ventilation (CMV) or either treatment alone.


METHODS
Tertiary pediatric intensive care units at seven academic centers.


METHODS
Post hoc analysis of data from children enrolled in a multicenter, randomized, masked study of the use of iNO in the treatment of AHRF.


METHODS
A total of 108 pediatric patients with AHRF defined as an oxygenation index of >15 twice within 6 hrs. Mode of ventilation (HFOV or CMV) was determined by the patient's physician based on guidelines to maximize oxygenation. The patient was then randomized to treatment with or without iNO. Comparisons were made between patients who were treated with HFOV plus iNO (n = 14), HFOV alone (n = 12), CMV plus iNO (n = 35), and CMV alone (n = 38).


METHODS
Ventilation with CMV or HFOV with or without iNO.


RESULTS
We found that the change in Pao /Fio ratio was greatest in the HFOV plus iNO group compared with the other treatment groups at 4 hrs (p =.02) and 12 hrs (p =.01). After 24 hrs of treatment, both HFOV plus iNO and HFOV alone resulted in greater improvement in Pao2/Fio2 ratio than either CMV alone or CMV plus iNO (p =.005). After 72 hrs, treatment with HFOV alone resulted in a greater improvement in Pao2/Fio2 ratio than either CMV alone or CMV plus iNO (p =.03). There was no difference in predefined treatment failures between treatment groups.


CONCLUSIONS
We conclude that the combination of HFOV with iNO causes a greater improvement in oxygenation than either treatment strategy alone in children with severe AHRF. We speculate that the enhanced lung recruitment by HFOV enhances the effects of low dose iNO on gas exchange.
Dobyns
Emily L
EL
Department of Pediatrics at the Children's Hospital University of Colorado School of Medicine, Denver, USA.
Anas
Nick G
NG
Fortenberry
James D
JD
Deshpande
Jayvant
J
Cornfield
David N
DN
Tasker
Robert C
RC
Liu
Paul
P
Eells
Patricia L
PL
Griebel
Jeffery
J
Kinsella
John P
JP
Abman
Steven H
SH
D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D005260:Female; D006612:High-Frequency Ventilation / Q000379:methods*; D006801:Humans; D000860:Hypoxia / Q000628:therapy*; D007223:Infant; D008297:Male; D009569:Nitric Oxide / Q000627:therapeutic use*; D012128:Respiratory Distress Syndrome / Q000628:therapy; D012131:Respiratory Insufficiency / Q000628:therapy*; D012189:Retrospective Studies; D018709:Statistics, Nonparametric
D001993:Bronchodilator Agents; D009569:Nitric Oxide