Leak around endotracheal tubes in ventilated newborns: an observational study

The study aims to determine the incidence and magnitude of leak around endotracheal tubes (ETTs) in ventilated babies in our unit, and to identify any relationship between weight, gestation, head position or ETT tip position, and the amount of leak.

Ventilated infants in the neonatal unit of the Royal Brisbane and Women's Hospital were observed. Data were collected on ETT size, ventilator settings, body position, head position and amount of leak. Also recorded were weight, post-menstrual age and radiological position of the ETT tip.

Two hundred ninety-six sets of data were collected from 60 infants. At the time of recruitment, infants had a median (interquartile range) post-menstrual age of 32(+3) (28(+4) -36(+3)) years. Minimal leak (defined as <10% measured leak) and a small leak (10-25% leak) were observed on 162 occasions (55%) and 77 occasions (26%), respectively. A large leak of more than 25% was observed on 57 (19%) occasions. The odds of having a large leak with the head turned to the right, or midline, was greater than with the head turned to the left (odds ratio = 2.0; 95% confidence interval: 1.0 to 4.1 and 6.8; 1.4 to 31.5, respectively). Infants lying prone were more likely than those lying supine to have a leak >25% (odds ratio = 2.1; 95% confidence interval: 1.1 to 3.8). There was no association between leak and distance from carina, or weight.

Few babies in our unit had a large leak around the ETT, and many had minimal leak. A leak was less likely when a baby's head was turned to the left. Further study is required to clarify the reasons for this. Weight and post-menstrual age were not associated with the extent of leak.