Sustained Lung Inflation in the Delivery Room in Preterm Infants at High Risk of Respiratory Distress Syndrome

BACKGROUND Sustained lung inflation (SLI) applied at birth in the delivery room has been demonstrated to lead to clearance of lung fluid and achievement of a precocious functional residual capacity (FRC) both in animal and human studies. SLI associated to an adequate positive end expiratory pressure (PEEP) may help the efficacy of the respiratory effort in lung of preterm infants at risk for respiratory distress syndrome (RDS) and reduce need of mechanical ventilation (MV).

OBJECTIVES Our aim will be to demonstrate the hypothesis that the introduction of SLI in the delivery room protocol may reduce the need of MV in the first 72 hours of life in preterm infants at risk for RDS improving their respiratory outcome.

STUDY DESIGN This is a multicenter prospective randomized controlled trial. The study will be carried out at the neonatal care units of the Careggi University Hospital of Florence, the "V. Buzzi" Children Hospital of Milan, IRCCS Ospedale Maggiore Policlinico of Milan,the Catholic University of the Sacred Heart of Rome, the "S. Giovanni" Hospital of Rome, the Regional Hospital of Bozen, the Hospital of Varese, the the Sant'Anna University Hospital of Pisa, the "Maggiore" Hospital of Bologna, the "Di Venere" Hospital of Bari, the University Hospital of Foggia.

Inborn infants with a gestational age between 25 and 28 weeks will be eligible and randomized at birth in two groups. Group A: (SLI group) in this group the preterm infants will receive SLI with mask for initial alveolar recruitment using a pressure control system (Neopuff, Fisher \& Paykel, Inc) in addition to American Academy of Pediatrics (AAP) guidelines for neonatal resuscitation. Peak inflation pressure (PIP) of 25 cm H2O will be delivered for 15 seconds and then reduced to a PEEP of 5 cm H2O. A second SLI manoeuvre will be repeated in case of persistent hearth failure (HR <100 bpm.Group B (control group: in this group the preterm infants will be resuscitated at birth according to AAP guidelines without SLI manoeuvre.

Infants in both the groups who will not be able to reach a good respiratory and/or cardiac effort, they will undergo tracheal intubation to start MV. Then, in neonatal intensive care unit (NICU), infants who will continue to breath spontaneously will be supported by nasal continuous positive airway pressure (NCPAP), bi-level positive airway pressure (BiPAP) or nasal intermittent mandatory ventilation (N-IMV) (PEEP at 5-7 cmH2O). Surfactant (Curosurf ®, Chiesi, Parma, Italia) will be administered (200 mg/kg) to newborns with FiO2 >0.40 or mechanically ventilated. MV will be started if blood pH <7.20, PCO2 >65 mm Hg, pO2 <50 mm Hg with a fraction of inspired oxygen (FiO2) >0.50 or in case of severe apnea; the objective of MV will be to maintain a PaCO2 45-65 mmHg and a PaO2 50-75 mmHg. Preterm infants will be extubated from MV when airway pressure will be <7 cmH2O, FiO2 <0.30, and in absence of severe apnea after caffeine therapy. After extubation it will be allowed to support infant with oxygen-therapy, NCPAP, BiPAP or N-IMV.

ENDPOINTS. Primary endpoint will be the need of MV within the first 72 hrs of life [(excluding the transient tracheal intubation for surfactant replacement: e.g. Intubation-SURfactant-Extubation (INSURE)]. Success criteria will be the lack of MV in the first 72 hrs of life. Secondary endpoints will be the occurrence of MV >3 hrs of life, length of MV and other non invasive respiratory supports (NCPAP/BiPAP/N-IMV), need of surfactant and number of doses, mortality, occurrence of bronchopulmonary dysplasia (BPD:oxygen-therapy at 36 post- conceptional age), intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), retinopahty of prematurity (ROP) and necrotizing enterocolitis (NEC), sepsis, and length of NICU and hospital stay.

STATISTICAL ANALYSIS. Failure of treatment will be considered the need of MV during the first 72 hrs of life in both groups.

Population size: hypothesizing that SLI maneuver might decrease the need of MV during the first 72 hours of life from 35 to 20% we calculated that 138 newborns must be enrolled in each groups to detect this difference statistically significant with 80% power at 0.05 level.

Clinical characteristics of the two groups will be described by mean values and standard deviation, or median values and range, or by rate and percentage. The t-test, Wilcoxon rank-sum test, and Fisher's exact test will be used to compare continuous normally distributed data, nonparametric continuous data, and categorical data, respectively.

Multiple regression analysis will be performed to assess the possible influence of confounding variables (i.e.: gestational age, birth weight, etc.) on the primary endpoint predictive factors. Effect estimates will be expressed as relative risk (RR) with profile likelihood-based 95% confidence limits.