The ultrasound assessment of the inferior vena cava collapsibility in the prone volunteers through a new acoustic window: a prospective observational study

INTRODUCTION: Ultrasound assessment of inferior vena cava (IVC) collapsibility is used in clinical practice to assess patients' volume status. Finding the subject in the prone position limits the ability to assess IVC collapse by the traditional method, which requires the use of alternative methods. OBJECTIVE: Conducting a comparative assessment of the IVC collapse index in healthy volunteers in the back position and in the pro position using a new acoustic window. MATERIALS AND METHODS: Ultrasound observation was performed in 25 adult healthy volunteers of both sexes. Ultrasound measurement of IVC was carried out sequentially in the position of volunteers on the back and abdomen. The mean (M) and standard deviation (SD) of the maximum and minimum IVC size. The values of the collapsing index (CI) obtained during the study are presented as a median (Me) and quartiles (Q1–Q3). Wilcoxon's nonparametric test was selected for comparative analysis (significance level accepted 0.05). RESULTS: Measurements of the diameter of the inferior vena cava obtained the following results: the average maximum and minimum vein size in volunteers in the supine position were 1.58 ± 0.37 cm and 1.30 ± 0.36 cm, respectively; in prone — 1.51 ± 0.37 cm and 1.24 ± 0.36 cm, respectively. Me (Q1–Q3) IVC-CI values (%) in volunteers in the supine and in the prone position of the voice were 16.84 (8.86–24.39) and 15.63 (10.23–24.77), respectively. Statistical analysis of the obtained results did not reveal a significant difference between CI values (p = 0.861). CONCLUSIONS: The absence of a statistically significant difference in IVC-CI values in the supine and abdominal volunteers demonstrates the possibility of using a new acoustic window to assess volume status in the clinical setting in patients in the prone position.