Insertion Depth of Endotracheal Tube in Extremely Low-Birth-Weight Infants

Objective: To elucidate the relationship between gestational age, body weight, body length, head circumference, chest circumference, and depth of oral ETT in ELBW infants.

Materials and Methods: This retrospective study was conducted at the Far Eastern Memorial Hospital in New Taipei city, Taiwan using data collected from January 2012 to December 2016.We enrolled newborn infants who were intubated in the delivery room or neonatal intensive care unit and who had a body weight of ≤1000 g at birth. The following data were retrieved from medical records: gestational age, birth body weight, body length (crown–heel length), head and chest circumferences, and final ETT depth. Data were analyzed using the SPSS version 20.0 software. Linear regression analysis was performed to assess the associations between each variable and the ETT placement depth. Results were considered to be statistically significant if the P value was <0.05.

Results: A total of 52 candidates were enrolled. The mean (range) gestational age was 25.1 weeks (22 to 32 weeks) and mean body weight (range) was 724.5 g (400─1000 g). There were 8 (15%), 22 (42.5%), and 22 (42.5%) patients with body weights of 500 g or less, 501─750 g, and 751 g─1000 g, respectively. In linear regression, the relationships of ETT depth to gestational age, body weight, head circumference, chest circumference, and body length were all significant (P < 0.001). Regarding the coefficient of determination (r2), body weight ranked first (0.497) and body length second (0.458), and all other parameters fell below 0.4.

Conclusion: In ELBW infants, linear associations were observed between ETT insertion depth and assessed variables that are typically available at birth, including gestational age, body weight, body length, and head and chest circumferences. Although body weight is the most accurate parameter for predicting ETT insertion depth, body length is an equally useful alternative that is preferable during delivery room resuscitation.