New Formula for Nasal Endotracheal Intubation in Extremely Low–Birth Weight Infants in the Emergency Transport Setting: The “Genoa Formula”

Objective: The purpose of this study was to find a predictive equation for estimating the optimal nasal endotracheal tube insertion depth in extremely low–birth weight infants (ELBWs) requiring invasive ventilation in the critical care interfacility transport setting. Methods: We retrospectively calculated the optimal tube insertion depth in a cohort of neonates ≤ 1,000 g born at our neonatal intensive care unit and nasally intubated within the first 24 hours of life from January 2019 to May 2020. Results: A total of 75 ELBW infants were included, with a median gestational age of 26.6 weeks (range, 22.1-32.6 weeks) and a median birth weight of 780 g (range, 410-990 g). The linear regression of the estimated optimal endotracheal tube insertion depth showed a good correlation when plotted against weight (R2 = 0.491); thus, a new weight-based formula was obtained. Conclusion: The proposed weight-based formula (the “Genoa formula”) may help in predicting optimal insertion depths for nasal intubation in ELBW neonates, especially when a prompt radiologic confirmation of the tube position is not available, as during neonatal critical care transport.