Methods for Estimating Endotracheal Tube Insertion Depth in Neonates: A Systematic Review and Meta-analysis
Introduction: There are various methods to estimate the endotracheal tube insertion depth in infants. However, the best method for estimating the ETT tip insertion depth in newborn infants remains unknown. The objective of the review is to systematically review the methods for estimating ETT insertion depth in neonates and to recognize the effect of gestational age on various methods.
Methods: Medline, Embase, Cochrane Central, and CINAHL databases searched for randomized clinical trials (RCT’s). RCT’s comparing two or more different methods to estimate ETT insertion depth were included. Two co-authors independently extracted the data and assessed the risk of bias. The primary outcome includes the proportion of optimally placed ETT tips identified on chest X-ray.
Results: Eight RCTs evaluating seven different estimation methods were included. Trials varied defining the optimal position of the ETT tip. Overall, the percentage of optimal position ranged from 8.8 to 93 percent. The weight, gestation-nomogram, and vocal-cord estimation methods resulted in mal-positioning of ETT tips in more than half of infants <30 weeks GA. The rates of optimal ETT tip placement with the digital-palpation method differ between moderately (83-93%; 2 RCT’s) and extremely (47%; 1 RCT) preterm infants (Table 1). Meta-analysis showed no difference between weight-based and digital-palpation method (relative risk=0.88; 95% confidence interval=0.75-1.04; 3 RCT’s; participants=205; I2=0%; quality of evidence-low).
Conclusion: Commonly used estimation methods for ETT tip placement are inaccurate and unreliable. Further research is required to improve the accuracy of estimation methods and also to identify the usefulness of the digital-palpation method in large clinical trials.