Correlation of IVC Diameter and Collapsibility Index With Central Venous Pressure in the Assessment of Intravascular Volume in Critically Ill Patients

OBJECTIVE: The objective of our study is to assess the correlation between inferior vena cava (IVC) diameters, central venous pressure (CVP) and the IVC collapsibility index for estimating the volume status in critically ill patients. METHODS: This cross-sectional study used the convenient sampling of 100 adult medical intensive care unit (ICU) patients for a period of three months. Patients ≥ 18 years of age with an intrathoracic central venous catheter terminating in the distal superior vena cava connected to the transducer to produce a CVP waveform were included in the study. A Mindray diagnostic ultrasound system model Z6 ultrasound machine (Mindray, NJ, USA) was used for all examinations. An Ultrasonic Transducer model 3C5P (Mindray, NJ, USA) for IVC imaging was utilized. A paired sampled t-test was used to compute the p-values. RESULTS: A total of 32/100 (32%) females and 68/100 (68%) males were included in the study with a mean age of 50.4 ± 19.3 years. The mean central venous pressure maintained was 10.38 ± 4.14 cmH2O with an inferior vena cava collapsibility index of 30.68 ± 10.93. There was a statistically significant relation among the mean CVP pressure, the IVC collapsibility index, the mean maximum and minimum IVC between groups as determined by one-way analysis of variance (ANOVA) (p < 0.001). There was a strong negative correlation between CVP and IVC collapsibility index (%), which was statistically significant (r = -0.827, n = 100, p < 0.0005). A strong positive correlation between CVP and maximum IVC diameter (r = 0.371, n = 100, p < 0.0005) and minimum IVC diameter (r = 0.572, n = 100, p < 0.0005) was found. CONCLUSION: There is a positive relationship of CVP with minimum and maximum IVC diameters but an inverse relationship with the IVC collapsibility index.