Material and methods
This retrospective study was conducted involving 6 tertiary care NICU of South India over a period from August 2019 to December 2022. Both inborn and outborn preterm neonates born between 24- 34 weeks of gestation having RDS and requiring rescue surfactant were enrolled. Exclusion criteria included babies with antenatally or postnatally suspected or diagnosed structural lung disease, major congenital malformations and where death or discharge (against medical advice) or referred to other NICU occurred within 24 hours of life. The Institutional ethics committee approved the study at all centres.
Of the 6 tertiary centres that participated, one was a trust hospital, while the other 5 were private sector hospitals. All the centres catered to both inborn and outborn neonates. All the centres started delivery room CPAP with settings of 5 PEEP and 30% FiO2 using a T piece resuscitator in spontaneously breathing infants. Surfactant was administered predominantly using INSURE technique when the baby continued to have respiratory distress on settings of ≥ 6 cm PEEP and FiO2 >30%.1 All units either used porcine surfactant (Curosurf, Chiesi, USA Inc) at 200 mg/kg or bovine (Neosurf, Cipla/Survanta, Abbott) at 100 mg/kg. The choice of surfactant was individual clinician based, however there was inclination towards usage of porcine for extreme preterm owing to smaller volume of the dose. Redosing was considered when the baby continued to have respiratory distress needing ≥ 6 cm PEEP and FiO2 >30%, after 12 hours of first dose. Nasal mask was used as a nasal interface in 5 centres and Ram’s cannula was used in one centre. All centres had nurse:patient ratio of 1:2. Overall the protocols of managing RDS were similar across centres.
The data were identified from the unit specific registers/database. Case records of NICU admissions across the hospitals in the collaboration were retrieved. Data retrieved included demographic, antenatal, perinatal parameters related to RDS and neonatal morbidities and mortality. A standardised data collection proforma was used across all units. Data was entered into a common database with coding of the centres. Chronic lung disease (CLD) was defined as need for supplemental oxygen at 36 weeks i.e., moderate to severe CLD as per the NICHD criteria6.
The primary outcome measure studied was combined outcome of Mortality or Chronic Lung Disease (CLD). The secondary outcome measures which were studied are proportion of babies requiring redosing of surfactant, Air leaks, invasive ventilation, ROP requiring LASER, PDA requiring treatment, Intraventricular hemorrhage (IVH) (>Grade 3 or 4), Necrotizing enterocolitis (NEC) (>Stage 2B) and duration of hospital stay.