Nitric oxide production and blood pressure reduction during haemodialysis

A decrease of systolic blood pressure in excess of 20 mmHg during haemodialysis treatment (IDD) is common for haemodialysis patients. Intradialytic hypotension (IDH) is symptomatic IDD by definition. Overproduction of nitric oxide (NO) is a possible cause of IDD. Dialysate nitrate and nitrite amount can be used as an indicator of intradialysis NO production. Our aim was to find the predictor of NO production in IDD patients.

Partial dialysate samples were collected during the whole haemodialysis session and total dialysate nitrate and nitrite amount was measured to assess the association of intradialysis NO production with blood pressure change.

There were 31 IDD patients and 71 patients who did not develop IDD (NIDD) included in the study. Among the IDD patients, 13 were IDH patients with a mean systolic blood pressure lower than that of the other 18 symptomless IDD patients (96.6 ± 3.4 mmHg vs 125.0 ± 3.8 mmHg, P<0.001). The median value of NO production was higher in the IDD than in the NIDD patients (447.7 μg vs 238.8 μg, P<0.001). The NO production correlated linearly with blood pressure reduction (R=0.487, P<0.001). The multivariate analysis showed that NO production was positively associated with predialysis systolic blood pressure.

Nitric oxide production during haemodialysis was higher in IDD than in NIDD patients. IDH often occurred when systolic blood pressure was reduced to below 100 mmHg. The amount of NO produced during haemodialysis, which may be associated with predialysis systolic blood pressure, can be used to predict intradialysis blood pressure decrease.