Material & Methods:
This retrospective study was conducted in five tertiary care neonatal intensive care units (NICU) of South India over 29 months (January 2018 to May 2020). All neonates (both inborn and outborn) above 35 weeks of gestation born by meconium-stained amniotic fluid with the onset of distress within 12 hrs of life, requiring respiratory support beyond 24 hrs of life and chest x-ray showing features of MAS ((hyper-inflated lung fields with diffuse non-homogenous opacity or reticulonodular pattern or low volume lungs with reticulogranularity and air-bronchograms)12 were eligible for enrolment. Newborns with major life-threatening congenital malformations were excluded. The Institutional Ethics committee approved the study at all the centres.
Of the five centres participated, two centres were private sector hospitals, one was public sector hospital, two were trust hospitals. All the centres catered to sick term and preterm infants, both intra and extra mural. The five centres had similar protocols in the respiratory management of neonates with MAS. The primary respiratory support was defined as the highest respiratory support required within the first 6 hours of admission. Surfactant was administered if FiO2 was above 40% on CPAP or mechanical ventilation. Only one centre had access to inhaled nitric oxide. The data was retrieved with the discharge diagnosis of “Meconium aspiration syndrome” from the computerized database or admission registers. The data was collected with respect to respiratory support, timing of initiation of CPAP, timing of surfactant administration, number of doses of surfactant, severity of PPHN, vasodilators usage , antibiotic usage, indication for antibiotic usage and number of days, length of stay in hospital till discharge and survival outcomes were collected. The primary support beyond oxygen included either CPAP or mechanical ventilation. The data were entered into a web database and coded for each centre separately.
The prolonged hospital stay was arbitrarily defined as a stay beyond 7 days of life for the study purpose as there was no clear definition from previous studies. Neonatal sepsis was diagnosed if the blood culture was positive. Hypoxic Ischemic Encephalopathy (HIE) was classified using Sarnat and Sarnat staging13. Persistent pulmonary hypertension was diagnosed based on 2D-Echocardiographic findings of elevated pulmonary artery systolic pressure (PASP). The PASP greater than three quarters of systolic pressure was defined as moderate-severe PPHN14. The hypoxemia in PPHN was stratified based on the Oxygen saturation index (OSI). The OSI values correspond to half of the oxygenation index (OI)15, and severity of hypoxemia in PPHN was graded as mild < 7.5, moderate ≤ 7.5- 12.5, and severe >12.5.
The primary outcome measure was to identify morbidities predicting prolonged length of stay (>7days). The secondary outcome was to evaluate the proportion of associated morbidities in our cohort.