Evaluating Inferior Vena Cava Diameter to Assess Fluid Responsiveness in Icu Patients at the Kenyatta National Hospital

Abstract

Background: For better prognosis of critically ill patients with hypotension or shock, controlling fluid responsiveness is essential. Currently, central venous pressure (CVP) is used as a standard volume status indicator, but CVP monitoring is costly, intrusive, difficult, and there is evidence in recent literature that CVP is an inaccurate volume status predictor. A healthy, non-invasive and potentially more accurate indicator of volume status is an ultrasound of the inferior vena cava (IVC) diameter. It can be used in patients to predict fluid responsiveness. Aim of the study: The clinical utility of ultrasound of the IVC in assessing patients in ICU for fluid responsiveness Materials and Methods: This study used a prospective observational study design of adult patients admitted to the ICU who underwent fluid therapy between February 2021 – May 2021. 79 patients were enrolled after obtaining informed consent. Ultrasound was done by the principal investigator under the supervision of a consultant radiologist. Measurements of the IVC diameter before and after fluid bolus and the distensibility index were calculated. Data was analyzed using SPSS version 23, Microsoft Access and Excel Results: The paired Student t test was used to compare between hemodynamic data before and after a bolus of fluid. The study focused on 79 adult patients admitted to the intensive care unit who were receiving fluid therapy. Out of the 79, 63 patients had an inferior vena cava diameter of less than 1.5cm while 16 of the patients had an inferior vena cava diameter of 1.5-2.5cm. The data was then used to calculate the distensibility index of inferior vena cava (dIVC) to assess for fluid responsiveness. The rate was represented in percentage and 18 patients had a 6 distensibility index of less than 18% while majority represented by 61 had a distensibility index of greater than 18%. Before 500mls of fluid bolus, the pre-hydration mean was 1.25 while after 500mls the mean was 1.53. The difference between the means was 0.28 which indicated that the response was moderate. The t-value was -12.6 while the p-value was represented by a value less than0.001 indicating the study is statistically significant. The pair sample correlation was represented by 0.652 indicating a positive strong relationship between the inferior vena cava diameters to assess fluid responsiveness in ICU patients