Hemodynamic response to fluid removal during hemodialysis: categorization of causes of intradialytic hypotension

Abstract

The hemodynamic profiles clearly define specific hemodynamic mechanisms of cardiac power reduction and/or vasodilatation as underlying intradialytic hypotensive episodes. A reduction in cardiac power (reduction of both blood pressure and cardiac output) could be the result of preload reduction due to a high ultrafiltration rate with not enough refilling or low target weight. A reduction in peripheral resistance (reduction in blood pressure and increase in cardiac output) could be the result of relative vasodilatation as arteries do not contract to compensate for volume reduction due to autonomous dysfunction. As both phenomena are independent, they may appear at the same time. Based on these results, a reduction of ultrafiltration rate and an increase in target weight to improve preload or immediate therapeutic actions to increase peripheral resistance are rational measures that could be taken to maintain blood pressure and prevent hypotensive ischemic complications in dialysis patients.

The Prevalence of Intradialytic Hypotension in Patients on Conventional Hemodialysis: A Systematic Review with Meta-Analysis

“…Three of the 5 studies that used IDH definitions with multiple cutoff values reported an IDH prevalence of 4.5% [30] and 5.4% [19], and 23.3% [27] at session level but did not specify the used definitions (online suppl. File 3).…”

“…Of the 5 studies that used definitions with multiple cutoff values, 2 reported a proportion of patients with frequent IDH was 57% [38] and 26% [27]. In the 5 studies that did not provide detailed information on the IDH definition, the proportion of patients with frequent IDH ranged between 4.8% [26] and 76.4% [6], (online suppl.…”

Intradialytic exercise increases cardiac power index

“…Subjects who are prone to IDH have reductions in overall cardiac contractility, leading to reductions in cardiac power output (11). Cardiac power may be reduced due to reductions in preload from high ultrafiltration rates (15). In the present study, CPI during the EX session was higher compared to the CON session.…”

“…The NICaS device measures CPI (W/m 2 ) (15). CPI may decrease in subjects undergoing hemodialysis treatment due to less contractile force production from impaired coronary blood flow (15).…”

“…The potential for intradialytic exercise to reduce hemodynamic instability, myocardial stunning, and negative outcomes of hemodialysis has not been well studied (3). CPI may be a potential indicator of myocardial perfusion and is measured in watts per meter squared by multiplying MAP by Q (15).…”