Viamo

The diameter of the left common carotid artery was assessed by ultrasound (Toshiba Viamo, Toshiba Medical Systems Corporation, Japan) by an experienced evaluator. The image of the common carotid artery, proximal to the carotid bulb, was optimized so that the artery walls were well-defined. Doppler velocity was also recorded at the smallest possible insonation angle (always <60°). Carotid artery diameter was evaluated at rest (1 min) and during CPT (3 min). The mean carotid diameter at rest was considered the basal diameter. During the CPT, the carotid diameter was averaged every 10 s, and the value of the greatest relative change in diameter, above or below the diameter at rest, was used to calculate the CAR in percentage (Peace et al., 2020 (link)). The video analyses were performed by a blinded evaluator using FloWave software run in MATLAB 2012b (Coolbaugh et al., 2016 (link)).

All ultrasonography (US) examinations were performed using a focused assessment with sonography for trauma (FAST) by Japanese board-certified attending emergency physicians. A US imaging unit (Viamo, Toshiba, Tokyo, Japan) with a 5.0-MHz convex probe was used. All CT scans were performed using 64 multidetector CT scanners (Aquilion CT scanner; Toshiba, Tokyo, Japan) at the initial management. Intravenous contrast medium (iohexol, Omnipaque 300; Daiichi Sankyo, Tokyo, Japan) was used in all patients unless contraindicated. CT images were reviewed retrospectively, with agreement between an attending radiologist and an experienced faculty emergency radiologist. The following CT features were assessed: extraluminal air, free fluid, bowel wall thickening, contrast extravasation, and the presence of solid organ injury. These findings were based on a study by Fakhry et al.^{[2 (link)]}