Prevalence and risk factors of hypotension associated with preload-dependence during intermittent hemodialysis in critically ill patients

Abstract

Background: Hypotension is a frequent complication of intermittent hemodialysis (IHD) performed in intensive care units (ICUs). Passive leg raising (PLR) combined with continuous measurement of cardiac output is highly reliable to identify preload dependence, and may provide new insights into the mechanisms involved in IHD-related hypotension. The aim of this study was to assess prevalence and risk factors of preload dependence-related hypotension during IHD in the ICU. Methods: A single-center prospective observational study performed on ICU patients undergoing IHD for acute kidney injury and monitored with a PiCCO® device. Primary end points were the prevalence of hypotension (defined as a mean arterial pressure below 65 mm Hg) and hypotension associated with preload dependence. Preload dependence was assessed by the passive leg raising test, and considered present if the systolic ejection volume increased by at least 10 % during the test, as assessed continuously by the PiCCO® device. Results: Forty-seven patients totaling 107 IHD sessions were included. Hypotension was observed in 61 IHD sessions (57 %, CI 95% : 47-66 %) and was independently associated with inotrope administration, higher SOFA score, lower time lag between ICU admission and IHD session, and lower MAP at IHD session onset. Hypotension associated with preload dependence was observed in 19 % (CI 95% : 10-31 %) of sessions with hypotension, and was associated with mechanical ventilation, lower SAPS II, higher pulmonary vascular permeability index (PVPI) and dialysate sodium concentration at IHD session onset. ROC curve analysis identified PVPI and mechanical ventilation as the only variables with significant diagnostic performance to predict hypotension associated with preload dependence (respective AUC: 0.68 (CI 95% : 0.53-0.83) and 0.69 (CI 95% : 0.54-0.85). A PVPI ≥ 1.6 at IHD session onset predicted occurrence of hypotension associated with preload dependence during IHD with a sensitivity of 91 % (CI 95% : 59-100 %), and a specificity of 53 % (CI 95% : 42-63 %). Conclusions: The majority of hypotensive episodes occurring during intermittent hemodialysis are unrelated to preload dependence and should not necessarily lead to reduction of fluid removal by hemodialysis. However, high PVPI at IHD session onset and mechanical ventilation are risk factors of preload dependence-related hypotension, and should prompt reduction of planned fluid removal during the session, and/or an increase in session duration.

Intradialytic hypotension in acute kidney injury requiring renal replacement therapy

“…In a single‐center study of 20 patients with AKI over 57 hemodialysis sessions, Tonelli et al reported that 30% of sessions were complicated by intradialytic hypotension, defined as mean MAP <70 mm Hg for ≥5 minutes duration . Using MAP <65 mm Hg as the definition of intradialytic hypotension, Bitker et al reported a 57% incidence of intradialytic hypotension in a study involving 107 hemodialysis sessions in 47 patients . In a prospective cohort study by Silversides et al, of 492 AKI patients requiring RRT (intermittent HD or CRRT or SLED), 87.3% had intradialytic hypotension—defined as MAP <65 or >20% reduction in MAP—on one or more occasions during the observation period .…”

Clinical Predictors of Mortality of Patients With Acute Kidney Injury Requiring Renal Replacement Therapy

“…Moreover, indicators of hemodynamic failure were retained in the nal multivariable model. Renal replacement therapy may lead to intradialytic hypotension [36][37][38] that aggravated hemodynamic disturbances.…”

Bedside prediction of intradialytic hemodynamic instability in critically ill patients: the SOCRATE study

“…improvement of intermittent hemodialysis management [5,6], intradialytic hemodynamic instability (IHI) remains a common issue [5,[7][8][9][10][11][12] that could account for increased mortality and delayed renal recovery. Optimal timing to initiate RRT in critically ill patients is still uncertain [4, 13,14].…”

“…Determination of risk factors for IHI could help clinicians to identify patients in whom initiation of RRT should be reconsidered in the absence of emergent criteria. However, factors associated with IHI remain poorly explored [8][9][10][11][12]. The pathophysiology of IHI is complex with a reduction of venous return and also an alteration of endothelial function that limits vascular tone adaptation to intermittent hemodialysis-induced hypovolemia [12,[16][17][18].…”