Immersion-enhanced fluid redistribution can prevent intradialytic hypotension: A prospective, randomized, crossover...

Intradialytic hypotension (IDH) is an important cause of morbidity and mortality among hemodialysis patients. We used an immersion model to evaluate the role of reduced effective circulating volume, and to examine whether facilitated refilling can prevent IDH.

Ten male hemodialysis patients who had frequent episodes of IDH were randomized to a mid-week "wet" or "dry" hemodialysis session, and subsequently underwent the other session in a crossover manner. The wet sessions were performed while immersed up to the neck in a 34 to 35°C bath, and the dry session was standard hemodialysis. Ultrafiltration goals were determined as the mean ultrafiltration during the 10 sessions preceding the first study session ± 10%.

Mean ultrafiltration was similar for the wet and dry sessions (2.99 ± 0.64 kg vs. 2.96 ± 0.74 kg). Symptomatic hypotension did not develop in any of the patients during the wet session, compared to 4 (40%) during the dry session. Systolic blood pressure adjusted to ultrafiltration was stable during the wet session, 0.22 mmHg/15 min (95% CI -0.27 to 0.70), P = 0.38, and significantly decreased during the dry session, -0.68 mmHg/15 min (95%CI -1.24 to -0.11), P = 0.02. Diastolic blood pressure did not change during the sessions. Mean atrial natriuretic peptide significantly increased in the wet session, by 31.36 pgr/mL (95%CI 8.73-53.99), P = 0.007, and slightly and insignificantly decreased in the dry session, by 21.66 pgr/mL (95% CI -52.59 to 9.25), P = 0.167. Aldosterone blood levels did not change.

Reduced effective circulating volume is a major cause for IDH, which can be prevented using head-out water immersion facilitated redistribution.