Why assistive technology is needed for probing of dry weight.

Despite advancements in dialysis therapy, the subjective clinical examination still remains the standard of care in managing volume removal in chronic dialysis. While there is no definitive trial establishing that dry weight management guided by an assistive technology is superior to the clinical method, there is ample evidence that there is a need for these technologies to be developed. Mortality, cardiovascular morbidity, and sequelae of volume overload remain far too common under the current paradigm. Recent studies indicate that the mortality associated with volume overload is independent of hypertension, suggesting that if mortality is to be improved, then a measure of volume independent of blood pressure must be developed. Even when considered as an integrated whole, the clinical method is inaccurate at setting dry weight when compared to the use of assistive technologies. A recent secondary analysis of a randomized trial showed that relative plasma volume (RPV) slope is responsive to change in volume status and may be useful in guiding therapy for hypertension. The only large randomized trial to investigate the ability of an assistive technology to manage volume removal in hemodialysis patients is the Crit-Line Intradialytic Monitoring Benefit Study, which found harm associated with RPV monitoring. However, the design of this trial did not require the RPV group to actually receive this intervention. Assistive technologies offer an opportunity to improve on the subjective clinical exam for the setting of dry weight, but well designed and adequately powered clinical trials are needed.