In infants and neonates, suprasternal ultrasound of the endotracheal tube cuff may improve the positioning accuracy and precision of the endotracheal tube tip at T2, researchers have found.
“Appropriate depth of endotracheal tube placement in children is difficult, with rates of malposition as high as 74%,” said Jeffrey A. Wharton, MD, a pediatric anesthesia fellow at Emory University, in Atlanta. “Improper endotracheal tube depth increases the risk of accidental extubation, vocal cord injury and endobronchial intubation.
“Recent research described using ultrasound to identify the endotracheal tube cuff in the suprasternal notch as a method to confirm appropriate endotracheal tube depth in children and adults [Pediatr Crit Care Med 2020;21(7):e393-e398; Anesthesiology 2016;124(5):1012-1020],” Wharton explained. “However, there is limited data in infants and neonates.”
Wharton and his colleagues identified a cohort of patients younger than 1 year of age who underwent suprasternal ultrasonography to ascertain the correct depth of endotracheal tube placement, along with an age-matched auscultation cohort. In all patients, chest x-ray was used to confirm the depth of the endotracheal tube.
The final study cohort comprised 34 patients (median age, 4.2 months; median weight, 5.3 kg), 17 in each of the ultrasound and auscultation groups. There were no differences between groups with respect to age, weight and sex.
Ausculation Falls Short
As Wharton reported during Pediatric Anesthesiology 2021, a joint virtual meeting of the Society for Pediatric Anesthesia and American Academy of Pediatrics (abstract RRR-3), the researchers found a statistically significant difference between groups with respect to the variability of endotracheal tube placement from the ideal location at T2 (Figure). Indeed, while the standard deviation of such variability was only 0.42 levels for patients in the ultrasound group, it was 1.28 levels for their counterparts in the auscultation group (P<0.001).
Similarly, while 76.5% of endotracheal tubes were placed at least one vertebral level away from T2 in the auscultation cohort, this was found to occur in only 11.8% of ultrasound patients (P<0.001).
The audience followed up the presentation with some questions.
“Did you use saline in the cuff to more easily identify the cuff?” asked Rebecca S. Isserman, MD, an attending anesthesiologist in at Children’s Hospital of Philadelphia.
“No saline, just air,” replied study co-investigator Thomas Austin Jr., MD, an associate professor of anesthesiology at Emory. “But adding saline may definitely help with visualization.”
“What do you do if there is contention about placement?” asked Vidya T. Raman, MD, a clinical assistant professor of anesthesiology at The Ohio State University College of Medicine, in Columbus.
“We have never had the ultrasound indicate a depth that brought contention,” Austin replied. “It has always seemed to be within a reasonable range, and the confidence of seeing the cuff in that position makes us certain that it is at least well below the glottis. We also listen for bilateral breath sounds to be more certain we have avoided endobronchial intubation.”
The findings, the researchers explained, demonstrate the utility of ultrasound in confirming endotracheal tube placement in even the smallest of patients. “These results support the hypothesis that suprasternal ultrasound of the endotracheal tube cuff in infants and neonates improves the accuracy and precision of tip positioning,” Wharton said.
Saline Not Used
For Atim (Uya) Ekpenyong, MD, the study is a welcome addition to the literature. “It’s always encouraging to see more and more material coming out regarding the use of ultrasound in endotracheal tube confirmation,” said Ekpenyong, an associate professor of pediatrics at the University of California, San Diego.
Ekpenyong found it interesting that the researchers were able to visualize cuff placement without the use of saline, which she and her colleagues had used in their investigation (Pediatr Crit Care Med 2020;21[7]:e393-e398). “In our investigation, we went through quite a few different methods before eventually settling on saline,” she told Anesthesiology News. “We found it wasn’t particularly easy to see the cuff without saline.”
Either way, Ekpenyong said the successful use of ultrasound is at least partly dependent on provider expertise. “When it comes to using ultrasound itself, there is certainly a learning curve,” she said. “But that learning curve can be made less steep depending on the method you teach. And for me, putting saline in the cuff definitely made it much easier for people to learn to identify the cuff.”
—Michael Vlessides
Wharton and Ekpenyong reported no relevant financial disclosures.
Comment on This Article
Thank you very much for this interesting article. I hope you can provide some ultrasound images.
Much obliged
Post your comment here