Correlation of Baseline Inferior Vena Cava Diameter and Collapsibility with Age and Sex in Normovolaemic Children: A Cross-sectional Study

Introduction: Ultrasound measurement of Inferior Vena Cava (IVC) diameter and collapsibility is increasingly used for volume status assessment and fluid responsiveness in paediatric and adult population. There is a wide variation in the age specific IVC diameters in paediatric population, whereas age specific variation in IVC collapsibility in euvolaemic children is not much known.

Aim: To analyse the correlation of baseline IVC diameter and collapsibility with age and sex in euvolaemic children.

Materials and Methods: This cross-sectional study was conducted at Kerala Institute of Medical Sciences, a tertiary care hospital in south Kerala, India, over a study period from June 2014 to May 2016. A total of 80 children in the age group of one month to 15 years, who presented without evidence of volume depletion were enrolled. The IVC was assessed approximately 2 cm distal to IVC-hepatic vein junction, Motion mode (M-mode) measurement of maximum (expiratory) and minimum (inspiratory) width of IVC diameter was measured. Collapsibility Index was also calculated for each subject by measuring difference between the maximum and minimum IVC diameters divided by the maximum diameter. The statistical data was analysed using the statistical software Statistical Package for Social Sciences (SPSS) version 16. All the numerical data was expressed as mean±Standard Deviation (SD). Quantitative analysis was performed using Analysis of Variance (ANOVA) and t-test. The correlation of IVC parameters were assessed using Karl Pearson correlation coefficient. The p-value less than 0.05 was considered as significant.

Results: Eighty euvolaemic children between the age one month and 15 years were enrolled in the study. The mean age of study group was 5±4 years. Males 41 (51.3%) and females 39 (48.8%) were almost equally distributed. A significant strong positive correlation was found between IVC expiratory and inspiratory diameter with age using Karl Pearson correlation, r=0.912, p<0.001; r=0.876, p<0.001, respectively. No significant correlation was found between IVC collapsibility and age, Karl Pearson correlation, r=0.079, p=0.485. No correlation was found between sex and the IVC parameters.

Conclusion: According to the present study results, IVC diameter showed a positive correlation with age but not with sex. The IVC collapsibility had no correlation with either age or sex.