Tracheal rapid ultrasound saline test (T.R.U.S.T.) for confirming correct endotracheal tube depth in children

Abstract

Objective: We evaluated the accuracy of tracheal ultrasonography of a saline-inflated endotracheal tube (ETT) cuff for confirming correct ETT insertion depth.

Methods: We performed a prospective feasibility study of children undergoing endotracheal intubation for surgery. Tracheal ultrasonography at the suprasternal notch was performed during transient endobronchial intubation and inflation of the cuff with saline, and with the ETT at a correct endotracheal position. Ultrasound videos were recorded at both positions, which were confirmed by fiberoptic bronchoscopy. These videos were shown to two independent blinded reviewers, who determined the presence or absence of a saline-inflated cuff. The primary outcome was accuracy of tracheal ultrasonography for appropriate ETT insertion depth.

Results: Forty-two patients were enrolled. For correct endotracheal versus endobronchial positioning, pooled results from the reviewers revealed a sensitivity of 98.8% (95% CI=90-100%), a specificity of 96.4% (95% CI=87-100%), a PPV of 96.5% (95% CI=87-100%), a NPV of 98.8% (95% CI=89-100%), a positive likelihood ratio of 32 (95% CI=6-185), and a negative likelihood ratio of 0.015 (95% CI=0.004-0.2). Agreement between reviewers was high (kappa co-efficient=0.93; 95% CI=0.86 to 1). The mean duration of the ultrasound exam was 4.0s (range 1.0-15.0s).

Conclusions: Sonographic visualization of a saline-inflated ETT cuff at the suprasternal notch is an accurate and rapid method for confirming correct ETT insertion depth in children.

Keywords: Diagnostic accuracy; Endobronchial intubation; Endotracheal tube; Intubation; Pediatrics; Ultrasound.