Randomised trial of estimating oral endotracheal tube insertion depth in newborns using weight or vocal cord guide

Abstract

BackgroundWhen intubating newborns, clinicians aim to position the endotracheal tube (ETT) tip in the midtrachea. The depth to which ETTs should be inserted is often estimated using the infant’s weight. ETTs are frequently incorrectly positioned in newborns, most often inserted too far. Using the vocal cord guide (a mark at the distal end of the ETT) to guide insertion depth has been recommended.ObjectiveTo determine whether estimating ETT insertion depth using the vocal cord guide rather than weight results in more correctly positioned ETT tips.DesignSingle-centre randomised controlled trial.SettingLevel III neonatal intensive care unit (NICU) at a university maternity hospital (National Maternity Hospital, Dublin, Ireland).PatientsNewborn infants without congenital anomalies intubated in the NICU.InterventionsParticipants were randomised to have ETT insertion depth estimated using weight [insertion depth (cm) = weight (kg) +6] or vocal cord guide.Main outcome measureCorrect ETT position, that is, tip between the upper border of the first thoracic vertebra (T1) and the lower border of the second thoracic vertebra (T2) on a chest X-ray as determined by one paediatric radiologist masked to group assignment.Results136 participants were randomised. The proportion of correctly positioned ETTs was similar in both groups (weight 30/69 (44%) vs vocal cord guide 27/67 (40%), p=0.731). Most incorrectly positioned ETT (69/79, 87%) were too low.ConclusionEstimating ETT insertion depth using the vocal cord guide did not result in more correctly positioned ETT tips.Trial registration numberISRCTN39654846.