Ultrasound confirmation of endotracheal tube placement

Abstract

Real-time B-mode ultrasound imaging was performed in 24 intubated patients in order to confirm the correct placement of endotracheal tubes. The large acoustic impedance mismatch between the air within the endotracheal tube cuff and the tracheal wall could be bypassed by (1) use of a foam-cuffed Bivona endotracheal tube, or by (2) cuff inflation with saline instead of air. Optimal repositioning of the endotracheal tube could be done under direct visualization. Imaging of the foam-filled and saline-filled cuffs was easier in the longitudinal (sagittal) than in the transverse view, was enhanced by a slight longitudinal to-and-fro motion of the tube, and was often improved with the use of a stand-off pad. Cases of esophageal intubation were not considered. Use of a noninvasive imaging modality such as ultrasound will spare selected patients from the radiation exposure associated with a chest x-ray. This is of value in pregnant patients and in those requiring frequent chest radiographs for the sole purpose of confirming correct endotracheal tube placement. Limitations of the techniques are discussed.

Inflating the endotracheal tube cuff with saline to confirm correct depth using bedside ultrasonography

“…It requires lifting of the patient to place the x-ray film under them, a procedure well known for causing dislodgment of the ETT. 9,27 It requires interruption of chest compressions during resuscitation and involves ionizing radiation. The chest x-ray result also only reflects the position of the ETT at the time of the radiograph, and the tip is known to move 1 6 4 cm during flexion and extension of the neck.…”

“…A pioneering anesthesiology study in 1987 reported the use of saline rather than air to allow cuff visualization by ultrasonography. 27 This technique was not adopted into clinical practice, however, perhaps due to the limited availability of bedside ultrasonography at the time. A more recent report in a cadaver study showed that novice sonographers could accurately identify a saline-inflated ETT cuff at the level of the suprasternal notch.…”

“…12 Previous reports suggest that inflating the ETT cuff with liquid rather than air (an established and safe practice with applications in many areas of medicine [15][16][17][18][19][20][21][22][23][24][25][26] ) allows the cuff to be visualized on a sonogram. 27,28 An ETT cuff at the level of the suprasternal notch correlates with correct depth of the tip (i.e., just deep to the clavicles. [29][30][31][32] Therefore, sonographic identification of a liquid-filled cuff at the suprasternal notch should confirm the correct depth of intubation.…”

“…Previous reports of this technique have been limited to cadaver studies 28 or the operating room and a single radiologist. 27 We describe filling the ETT cuff with saline to verify both endotracheal position and correct endotracheal depth during emergency resuscitation.…”

Identification and Description of Esophageal Intubation Using Ultrasound

“…2 The second study, in adults, evaluated the use of foam and saline-filled ETT cuffs to aid in ultrasonic imaging of ETT placement in the operating room. 3 A third study describes a technical innovation in visualizing the ETT in six neonates in the ICU. 4 A recently presented abstract found ultrasound to be a ''potentially rapid and accurate method of confirming esophageal intubation'' but did not describe the ultrasonographic findings.…”