Bioimpedance spectroscopy method to determine hypervolemia in maintenance hemodialysis patients.

BACKGROUND

Hypervolemia is a major risk factor for hypertension leading to cardiovascular diseases and also a frequent problem in maintenance hemodialysis (MHD) patients. Fluid overload (FO) can be determined by bioimpedance spectroscopy (BIS) which is a new, practical, and non-invasive method. We tried to determine FO by BIS in MHD patients and find out the relationship between FO and clinical features.

MATERIAL AND METHODS

We studied 100 MHD patients aged between 20 and 85 years and undergoing hemodialysis three times weekly for minimum one year. By using BIS, we estimated FO and extracellular water (ECW). The patients who exhibited a FO/ECW ratio >15% were considered as FO.

RESULTS

Twenty-nine (29.0%) patients had a FO/ECW ratio >15%. In the overhydrated group, the mean pre-hemodialysis systolic blood pressure was 153.3 ± 20.0 mmHg and the mean diastolic blood pressure was 89.1 ± 8.5 mmHg. These were significantly higher than in the non-overhydrated group (113.5 ± 14.5 and 71.0 ± 8.8, p <0.001). FO was significantly correlated with systolic and diastolic blood pressures (r =0.63, p <0.001 and r =0.59, p <0.001). The patients were divided into two groups, i.e. those with cardiothoracic index (CTI) of  >0.5 and those with CTI of ≤0.5. The median FO/ECW ratio was 0.11 L in the former group and 0.08 L in the latter group with a significant difference (p =0.006).

CONCLUSIONS

Hypervolemia is associated with high blood pressure and left ventricular hypertrophy that should be treated effectively to prevent cardiovascular diseases in MHD patients. BIS is useful to assess hydration status in MHD patients. Hippokratia 2015; 19 (4): 324-331.