Abstract P-574: FEASIBILITY STUDY OF CLINICIAN-PERFORMED ULTRASONOGRAPHIC ASSESSMENT OF AIRWAY OF INTUBATED PATIENTS TO PREDICT POSTEXTUBATION AIRWAY OBSTRUCTION

Abstract

Aims & Objectives: Post-extubation airway obstruction (PEAO) is common in children. We hypothesized that Intracricoid Peritubal Free Space (IPFS) between inner circumference of cricoid and outer circumference of tracheal tube (TT) may inversely correlate to cricoid edema, and thus development of PEAO. Methods • Design: Prospective observational study. • Setting and Participants: 15-bed PICU at a tertiary care hospital in a lower middle income economy during Aug’2016 to Dec’2017. Ninety-three patients (3mo-12yrs) intubated for >48h and planned for extubation were included. Patients with pre-existent upper airway conditions, chronic respiratory diseases and poor airway reflexes were excluded. • Measurements: Cricoid was imaged just prior to planned extubation, and inner cricoid diameter (ICD) was ascertained. Outer diameter of TT was deducted from ICD to obtain IPFS-diameter. Similarly, difference of cross-sectional area of inner cricoid and of outer TT circumference was calculated (IPFS-area). PEAO was defined by Westley’s Croup Score, >4. Results 34%(32/93) patients developed PEAO, while 18%(17/93) needed reintubation. Baseline disease characteristics were similar between patients with and without PEAO. IPFS-diameter (4.16 + 1.18mm vs 5.28 + 1.51mm) and IPFS-area (56.72 + 24.25mm2vs 80.93 + 33.91mm2) were significantly lower in patients with PEAO compared to those without. ROC AUC of IPFS-diameter and IPFS-area were 0.713 (95% CI, 0.608 -0.819) and 0.713 (95%CI, 0.606–0.819). Sensitivity and specificity at IPFS-diameter of 5.2mm were 84% and 50%; and at IPFS-area of 75mm2 were 88% and 50%. Conclusions It is feasible to perform airway ultrasound by clinician to evaluate Intracricoid Peritubal Free Space (IPFS). It may help predict PEAO among intubated children. However, a larger study is needed to confirm these initial findings.