# A Prospective Observational Study to Assess the Diagnostic Accuracy of Suprasternal Versus Subxiphoid Ultrasonography for Endotracheal Intubation in Patients Undergoing Elective Surgery

## TL;DR

This study compares suprasternal and subxiphoid ultrasonography for confirming endotracheal tube placement during surgery, finding both methods accurate and faster than capnography.

## Contribution

The study introduces a direct comparison of suprasternal and subxiphoid ultrasound for ETT confirmation in elective surgery patients.

## Key findings

- Suprasternal ultrasound was significantly faster than capnography and auscultation for ETT confirmation.
- Both suprasternal and subxiphoid ultrasound showed 100% agreement with capnography.
- No false positives or false negatives were observed with either ultrasound method.

## Abstract

Objective: This study compared the diagnostic accuracy and time efficiency of suprasternal versus subxiphoid ultrasonography for endotracheal tube (ETT) confirmation.

Methodology: A prospective observational study was conducted on 50 patients classified as American Society of Anesthesiologists Physical Status (ASA-PS) 1 or 2 who were scheduled for elective surgical procedures under general anesthesia. After endotracheal intubation (ETI), tube placement was verified using three methods: suprasternal ultrasonography, visualizing the characteristic “bullet sign”; subxiphoid ultrasonography, assessing diaphragmatic motion; and continuous waveform capnography. The time required for confirmation and the diagnostic accuracy of each method were systematically recorded.

Results: Suprasternal ultrasound was significantly faster (5.58 ± 1.14 seconds) than capnography (31.50 ± 4.84 seconds) (p < 0.001) and auscultation (33.38 ± 4.58 seconds) (p < 0.001). Subxiphoid ultrasound took 20.32 ± 4.60 seconds (p < 0.001). No false positives or false negatives were observed. Both ultrasound methods showed 100% agreement with capnography.

Conclusion: Suprasternal and subxiphoid ultrasonography are equally accurate but faster than capnography for ETT confirmation in low-risk surgical patients. Due to its speed, suprasternal ultrasound may be preferable in time-critical scenarios.