P2C075: Point-of-care Ultrasound Confirmation of Endotracheal Tube Positioning: Accurate Enough to Have a Role in Neonates?

Background: Endotracheal intubation is a common procedure in the NICU and often needed in an emergent situation for neonatal resuscitation. While a universally agreed upon estimation technique doesn’t currently exist, ETT placement verification includes multiple modalities, including auscultation, colorimetry or capnography, and subsequent imaging. Chest radiography remains the imaging gold standard in neonates but does expose patients to ionizing radiation and can be delayed based on urgent needs in other areas of the hospital. POCUS can be used for ETT placement and position confirmation.

Methods: Primary

Aim: Determine if ETT tip location in neonates can correlate between POCUS and chest radiography in >90% of cases. Secondary

Aim: To investigate interrater reliability by calculating a kappa coefficient for multiple ultrasound operators who have local training in the use of POCUS.

This prospective observational study evaluated the correlation between chest x-ray and POCUS for ETT position as defined as “not-deep” on chest x-ray by being above the carina, or on POCUS by being visualized and located above the superior aspect of the right pulmonary artery. Ultrasound images were obtained using a General Electric LOGIQ E Machine (8-18 MHz Linear Array probe) and a midsagittal approach. Images were obtained during the same episode as a chest x-ray but prior to viewing the radiograph and prior to any ETT position changes prompted by the primary care team. Ultransonographer 1 (Neo 1) and ultrasonographer 1 (Neo 2) worked independently, but in succession and were blinded to their counter part's scanning results and ETT position determination. Afterwards, each ultrasonographer interrupted the ETT position on the correlating x-ray.

Results: 15 were patients enrolled (Sept 2022-Jan 2023) with 13 patients scanned between 1-5 times (n=35). Demographic data showed a median GA of 25+4 a range of 22+2-27+3. Birth weight range of 365g-2860g with 77% being ELBW. ETT sizes ranged from 2.0-3.5 and predominantly sized at 2.5 (85.7%).
The ETT was visualized during all scanning attempts (35/35). Neo 1 had 91.4% agreement between the radiographs and her own POCUS images with a Cohen’s Kappa of 0.72, which is substantial agreement. Neo 2 had 100% agreement between radiographs and her own POCUS images, which gives a Cohen’s Kappa of 1. Neo 1 and Neo 2 were in agreement on ETT tube position on 85.7% of scans with a Cohen's Kappa of 0.58 demonstrating moderate to borderline substantial agreeability.

Conclusion: POCUS is feasible for ETT depth determination in the NICU and is valid across gestational ages and birth weights. The utilization of POCUS for ETT depth determination is generalizable for non-expert physician ultrasonographers. The use of POCUS in the neonatal population, particularly the extremely low birth weight infant, is safe with no infants in this study demonstrating adverse reactions or worsening clinical status after imaging.