Tracheal intubation is a common and critical procedure in neonatal intensive care units (NICU). Despite its clinical importance, first-attempt success rates remain low (approximately 50%), and adverse events - including oxygen desaturation, bradycardia, and airway trauma - are frequent. Premedication with neuromuscular blocking agents has been associated with improved intubation conditions and fewer adverse events in neonates.

This randomized, double-blind, parallel-group clinical trial (NEORIN) aims to evaluate whether the addition of rocuronium (0,6 mg/kg IV) to standard fentanyl premedication (1 mcg/kg IV) improves first-attempt success rates of tracheal intubation in newborns admitted to the NICU of Maternidade Ana Braga, Manaus, Brazil. The control group will receive fentanyl plus saline placebo. Sugammadex (16 mg/kg IV) is available as a reversal agent in case of prolonged neuromuscular blockade.

A secondary aim is to assess neonatologists' and residents' knowledge of and barriers to the use of neuromuscular blocking agents in neonatal intubation.

Neonatal tracheal intubation is performed in approximately 15-20% of NICU admissions. First-attempt success rates are approximately 49%, and adverse tracheal intubation-associated events (TIAEs) occur in up to 18% of procedures, with severe oxygen desaturation in up to 48% (NEAR4NEOS registry, Foglia et al., 2019). Premedication with neuromuscular blocking agents has been independently associated with a 62% reduction in adverse events (aOR 0.38; 95% CI 0.25-0.57).

Rocuronium is a non-depolarizing neuromuscular blocking agent with rapid onset, stable hemodynamic profile, and full reversibility with sugammadex, making it a safe choice for neonatal premedication.

The NEORIN trial will enroll 102 newborns (51 per group) with postnatal age ≤28 days or corrected gestational age <44 weeks, requiring non-emergent tracheal intubation. Randomization will be performed in variable-sized permuted blocks (4 and 6), with allocation concealment through sequential opaque sealed envelopes.

Intervention group: fentanyl 1 mcg/kg IV + rocuronium 0.6 mg/kg IV. Control group: fentanyl 1 mcg/kg IV + saline placebo (equivalent volume). Sugammadex is available at the bedside throughout the study as a mandatory safety requirement.

The primary composite outcome is first-attempt intubation success without physiological instability, defined as correct tube placement on the first laryngoscopy attempt confirmed by colorimetric CO2 detection, with no SpO2 drop >20% from baseline and no bradycardia (HR <100 bpm). All procedures will be video-recorded for blinded outcome assessment.

A secondary descriptive study will assess neonatologists' and residents' knowledge of and barriers to neuromuscular blocking agent use in neonatal intubation, using a structured questionnaire applied before the start of the clinical trial.

Inclusion Criteria:

• Newborns admitted to the NICU, ≤28 postnatal days OR corrected gestational age <44 weeks
• Indication for non-emergent orotracheal intubation (≥5 minutes between decision to intubate and start of laryngoscopy)
• Informed consent signed by legal guardians

Exclusion Criteria:

• Upper airway malformations
• Use of neuromuscular blocking agent in the 24 hours prior to enrollment
• Known hypersensitivity to fentanyl or rocuronium
• Severe hemodynamic instability (ongoing shock)
• Anticipated difficult airway (micrognathia, cleft palate, or similar)
• Cyanotic congenital heart disease with critical instability
• Neonatal abstinence syndrome
• Concurrent enrollment in another interventional clinical trial

Complete masking is not feasible because rocuronium produces clinically detectable neuromuscular blockade. Partial masking is adopted: the primary outcome assessor, who reviews video recordings, and the data analyst are blinded to group allocation. The intubating physician is aware of the allocated group.