Changes in cerebral oxygenation during hemodialysis before and after carotid artery stenting.

A 68-year-old man received hemodialysis (HD) for the treatment of end-stage renal failure for 6 years. Five years prior to carotid artery stenting (CAS), a neck ultrasound performed to screen for carotid atherosclerosis revealed an asymptomatic right internal carotid artery stenosis. One month prior, the stenotic lesion progressed to 74% by cerebral angiography; therefore, CAS was performed. To evaluate the influence of right internal carotid artery stenosis on the intradialytic cerebral circulation and oxygenation, cerebral regional oxygen saturation (rSO2) at bilateral forehead was measured using the INVOS 5100c oxygen saturation monitor (Covidien Japan, Japan) during HD before and after CAS. Before CAS, right cerebral rSO2 was maintained during HD, whereas left cerebral rSO2 gradually increased from the initiation to end of HD. However, the differences of intradialytic cerebral rSO2 changes between bilateral sides disappeared after CAS. In the present case, before CAS, the intradialytic increase in left cerebral rSO2 might reflect the increase in the left cerebral blood flow to compensate for the ultrafiltration-associated decreases in the right cerebral blood flow and perfusion pressure. Furthermore, the preserved right cerebral rSO2 before CAS might reflect the mechanism maintaining the right cerebral blood flow from the collateralized circle of Willis during HD. Throughout our experience, cerebral oxygenation monitoring during HD might disclose intradialytic changes in cerebral blood flow distribution between the ipsilateral and contralateral side in HD patients with carotid artery stenosis.

Continuous monitoring of changes in cerebral oxygenation during hemodialysis in a patient with acute congestive heart failure.

A 71-year-old man undergoing hemodialysis (HD) was admitted to our hospital with congestive heart failure (CHF) and pneumonia. After admission, ultrafiltration with HD was urgently performed because of a lack of respiratory improvement despite the use of noninvasive positive pressure ventilation. During HD, cerebral regional saturation of oxygen (rSO2) was monitored by INVOS 5100c oxygen saturation monitor (Covidien Japan, Japan) to evaluate changes in tissue oxygenation. At HD initiation, cerebral rSO2 was very low at 34% under the fraction of inspiratory oxygen (FiO2) of 0.4. Ultrafiltration was performed at the rate of 0.5 L/h thereafter, cerebral rSO2 gradually improved even as inhaling oxygen concentration decreased. At the end of HD, cerebral rSO2 improved at 40% under a FiO2 of 0.28 as excess body fluid was removed. After pneumonia and CHF improved, he was discharged. Reports of the association between cerebral oxygenation and acute CHF status in patients undergoing HD are limited; therefore, in our experience with this case, cerebral oxygenation deteriorated with the CHF status but was improved by adequate body-fluid management during HD.