BACKGROUND:
Respiratory failure in term and near term
infants is often associated with persistent
pulmonary hypertension of the
newborn and contributes to
hypoxemia in these
infants. Inhaled
nitric oxide (iNO) is currently used as a pulmonary
vasodilator to improve
oxygenation in
neonates with severe
respiratory failure.
OBJECTIVE:
To determine outcome of
administration of iNO in severe hypoxic
respiratory failure. MATERIAL AND
METHOD:
The present study was conducted from 1999 to 2004 in the
neonatal intensive care unit (NICU) at Queen Sirikit National Institute of
Child Health.
Patients were selected from all
infants > or = 34 weeks
gestational age who required high frequency oscillatory
ventilation (SLE 2000 HFO, SLE, UK) or conventional
mechanical ventilation for
hypoxemic respiratory failure caused by PPHN.
Diagnosis was confirmed by 2-D echocardiogram visualization with right to left shunt through the
foramen ovale or
patent ductus arteriosus. Inhaled
nitric oxide was given as standard
therapy in
patients who had two
oxygenation indices > or = 20 at least 30 minutes apart after being on a
mechanical ventilator.
RESULTS:
Fifty-five cases were enrolled and
male to
female ratio was 22.2 tol. The
survival rate was 76.4 percent. Inhaled
nitric oxide significantly improved
oxygenation index, arterial alveolar
oxygen tension ratio (a/A O2), and alveolar arterial
oxygen gradient in
survivors at one hour
after treatment. The earliest improvement in
oxygen saturation was within ten minutes.
Meconium aspiration syndrome was the most common underlying cause of PPHN. No acute complication was found during
nitric oxide administration. Chronic
lung diseases, delayed development and severe
hearing loss in long-term follow up were found in 10, 5, and 2 cases, respectively.
CONCLUSION:
Inhaled
nitric oxide should be used early in severe hypoxic
respiratory failure with
persistent pulmonary hypertension of newborn and can improve
survival rates without any major immediate side effects.