Ultrasonographic measurement of inferior vena cava diameter as an index of ultrafiltration adequacy in dialysed uraemic patients

ABSTRACT

This study was designed to assess the adequacy of ultrafiltration during dialysis by ultrasonographic measurement of inferior vena cava [IVC] diameter in both normotensive and hypertensive dialysed uraemic patients and to determine whether control of extracellular fluid volume by ultrafiltration is correlated with blood pressure control. Fifty patients were studied; 25 normotensives [group I] and 25 hypertensives [group II]. The patients of the later group were followed for 8 month with gradual increase in ultrafiltration and decrease in the dose and the number of anti-hypertensive agents. In addition to thorough clinical examination including blood pressure body weight sampling for estimation of blood urea pre and post dialysis and calculation of Kt/V which is defined as the rate of urea removal normalized for body surface, serum creatinine, haemoglobin concentration and ultrasonographic measurement of IVC diameter predialysis and 2- hours post dialysis were done. Results showed that body weight and IVC diameter were significantly [p<0.001] higher in group II compared with group I and were significantly lower at post dialysis time compared to predialysis time in both groups while haemoglobin levels and Kt/V showed insignificant changes. At the endof the follow up period for group II patients 10 patients [group IIa] normotensives with ultrafiltration only without antihypertensive drugs, 9 patients [group IIb] became normotensives with ultrafiltration plus antihypertensive drugs and 6 patients [group IIc] remained hypertensives despite ultrafiltration and hypertensive drugs. A significant negative correlations was observed between the duration of dialysis in years and both the systolic and diastolic blood pressures, body weight and Kt/V and IVC diameter and Kt/V. In conclusion ultrasonographic measurement of IVC diameter assessment of adequacy of ultrafiltration to control hypertension in dialysis patients. Thus avoiding the side effects of antihypertensive drugs and decrease the cost. Routine sonographic assessment of IVC diameter in dialysis patients is recommended