Factors affecting intradialytic hepatic oxygenation: Associations between ultrafiltration rate and changes in systemic blood pressure.

INTRODUCTION

Hepato-splanchnic circulation influences the oxygenation of abdominal organs and is important in preventing a reduction in intradialytic blood volume. However, the association between changes in intradialytic hepato-splanchnic circulation and clinical factors remain unknown.

METHODS

We enrolled 91 hemodialysis (HD) patients (20 with intradialytic hypotension (IDH) and 71 without IDH). During HD, hepatic regional oxygen saturation (rSO), a marker of hepatic oxygenation reflecting hepato-splanchnic circulation and oxygenation, was monitored. Changes in hepatic rSO at the lowest systolic blood pressure (BP) during HD were analyzed to identify associations with clinical factors.

RESULTS

Hepatic rSO levels were 55.8 ± 15.3% before HD and 53.8 ± 14.9% at the lowest systolic BP; therefore, % changes in hepatic rSO were -2.7 ± 11.3%. These values were significantly lower in patients with IDH than in those without IDH (-13.8 ± 9.3% vs 0.4 ± 9.8%,  < 0.001). Multivariable regression analysis showed that % changes in hepatic rSO were independently associated with % changes in systolic BP (standardized coefficient: 0.416) and ultrafiltration rate (-0.206). Furthermore, % changes in mean BP (0.304) were identified as affecting % changes in hepatic rSO instead of those in systolic BP.

CONCLUSIONS

Changes in intradialytic hepatic oxygenation is associated with ultrafiltration rate and changes in systemic BP. Further studies are required to clarify the directionality of the association between changes in hepatic oxygenation and changes in systemic BP during HD.