RESUMO
Objective: To derive normative data of the distance betweenoptimally placed endotracheal tube tip and arch of aorta byultrasound in neonates across different weight and gestation.Design: Cross-sectional study.Setting: Tertiary care neonatal intensive care unit from April 2015to May 2016.Participants: All neonates requiring endotracheal intubation wereeligible for the study.Methods: During intubation, insertional length was determinedusing weight-based formula. The distance between endotrachealtube tip and arch of aorta was measured by ultrasound.Endotracheal tube position was confirmed by chest radiograph.Results: Out of 133 enrolled infants, 101 (75.9%) had optimallyplaced endotracheal tubes. The mean (SD) distance betweenendotracheal tube tip and arch of aorta by ultrasound was 0.78(0.21) cm in infants <1500 g and 1.04 (0.32) cm in infants ≥1500 g.The regression equation to estimate insertional length fromweight, crown heel length (CHL), occipito-frontal circumference(OFC), nasal tragus length (NTL) and sternal length (SL) wereWt(kg)+4.95, 0.15×CHL(cm)+0.57, 0.22×OFC(cm)+0.49, 0.82×NTL(cm)+1.24 and 0.75×SL(cm)+2.26, respectively.Conclusion: Our study reports normative data of the distancebetween optimally placed endotracheal tube tip and arch of aortaby ultrasound in neonates. The distance between endotrachealtube tip and arch of aorta increases with increase in weight andgestation. Insertional length correlates strongly with all theanthropometric parameters