Hypoxic respiratory failure in term newborns: clinical indicators for inhaled nitric oxide and extracorporeal membrane oxygenation therapy.
OBJECTIVE
The criteria for starting extracorporeal membrane oxygenation (ECMO) therapy in term newborn patients with hypoxemic respiratory failure consist of an oxygenation index (OI) of 25 or higher and alveolar-arterial oxygen (Aao(2)) gradient of more than 600 at sea level. In such conditions, inhaled nitric oxide (iNO) may improve oxygenation and reduce the need for ECMO therapy. We studied early changes in OI and Aao(2) gradients in response to iNO treatment that may indicate a need to continue iNO treatment or the necessity to start an ECMO therapy.


METHODS
In this prospective study, we used 34 outborn neonatal patients that were referred to our pediatric critical care unit in a children's hospital for ECMO therapy with diagnosis of hypoxemic respiratory failure. In all patients, iNO therapy, starting at 80 ppm, was instituted either during transport or on arrival to hospital. Response to iNO was assessed after 1 hour, at which time, iNO concentration was reduced to 40 ppm, provided there was more than 20% improvement in either or both oxygenation indices. Patients who did not respond positively to continuous iNO therapy and met ECMO criteria were given ECMO therapy.


RESULTS
Inhaled nitric oxide therapy alone was successful in 10 (29%) of 34 patients. Eighteen patients (53%) required ECMO therapy within the first 10 hours of iNO treatment (early ECMO therapy), whereas 6 other neonates (18%) became eligible for ECMO therapy after prolonged (2-4 days) iNO treatment (late ECMO therapy). No mortality occurred with any treatment. Within 4 hours after iNO therapy, patients who required early ECMO therapy had significantly higher OI and Aao(2) gradients than patients who were treated with iNO therapy alone (P<.01, analysis of variance followed by Tukey-Kramer multiple comparison test). Six of 34 patients (18%), categorized as late ECMO therapy, on the average, had initially higher levels of OI and mean airway pressure than neonates in iNO treatment and early ECMO therapy.


CONCLUSIONS
Persisting levels of OI of more than 20 or Aao(2) gradients of more than 600 after 4 hours of iNO therapy could be indicative of an immediate need for ECMO therapy.
Fakioglu
Harun
H
Division of Critical Care Medicine, Miami Children's Hospital, Miami, FL 33155-3009, USA.
Totapally
Balagangadhar R
BR
Torbati
Dan
D
Raszynski
Andre
A
Sussmane
Jeffrey B
JB
Wolfsdorf
Jack
J
D015199:Extracorporeal Membrane Oxygenation; D006801:Humans; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric; D008471:Meconium Aspiration Syndrome; D009569:Nitric Oxide / Q000627:therapeutic use*; D010547:Persistent Fetal Circulation Syndrome / Q000150:complications; D011446:Prospective Studies; D012127:Respiratory Distress Syndrome, Newborn / Q000209:etiology / Q000628:therapy*
D009569:Nitric Oxide