Pre-Extubation Ultrasound Measurement of In Situ Cuffed Endotracheal Tube Laryngeal Air Column Width Difference: Single-Center Pilot Study of Relationship With Post-Extubation Stridor in Under 5 Years Old.

OBJECTIVES: Post-extubation stridor (PES) is difficult to predict before extubation. We therefore evaluated the potential diagnostic performance of pre-extubation laryngeal air column width difference (LACWD) measurement, as assessed by intensivist-performed point-of-care laryngeal ultrasound, in relation to clinically important PES.

DESIGN: Prospective observational cohort study.

SETTING: Single quaternary care PICU (July 19, 2021, to October 31, 2022).

PATIENTS: Included subjects were younger than 5 years old, intubated with a cuffed endotracheal tube, requiring invasive mechanical ventilation for greater than 24 hours, and nearing extubation. Subjects at high risk for supraglottic airway obstruction were excluded.

INTERVENTIONS: Laryngeal ultrasound with measurement of laryngeal air column width with the endotracheal tube cuff inflated and deflated. Clinically important PES was defined as a high-pitched inspiratory respiratory noise suspected to be from a subglottic focus necessitating received medical intervention or reintubation.

MEASUREMENTS AND MAIN RESULTS: Among 53 enrolled subjects, 18 of 53 (34%) experienced PES and three of 53 (6%) were reintubated because of severe subglottic upper airway obstruction. Median LACWD was significantly lower in the stridor group compared with the nonstridor group (∆ 0.41 mm; 95% CI, 0.37-0.48; p < 0.001). The area under the receiver operating characteristic curve for LACWD as a diagnosis of PES was 0.94 (95% CI, 0.89-1.00; p < 0.001). The LACWD cutoff for PES was less than or equal to 0.47 mm, which yielded a diagnostic sensitivity of 91.4% and specificity of 88.9%. In this population, the pre-to-post-test change in probability of PES for LACWD less than or equal to 0.47 mm is 0.34 to 0.81.

CONCLUSIONS: Pre-extubation LACWD is a novel, noninvasive assessment that can be performed and interpreted by the intensivist at the bedside. There is, however, diagnostic uncertainty in the use of this measurement for identifying those at-risk of PES and larger validation studies are needed.