How to Determine Fluid Management Goals during Continuous Kidney Replacement Therapy in Patients with AKI: Focus on POCUS

Abstract

The utilization of kidney replacement therapies (KRT) for fluid management of patients who are critically ill has significantly increased over the last years. Clinical studies have suggested that both fluid accumulation and high fluid removal rates are associated with adverse outcomes in the critically ill population receiving KRT. Importantly, the ideal indications and/or fluid management strategies that could favorably affect these patients are unknown; however, differentiating clinical scenarios in which effective fluid removal may provide benefit to the patient by avoiding congestive organ injury, compared with other settings in which this intervention may result in harm, is direly needed in the critical care nephrology field. In this review, we describe observational data related to fluid management with KRT, and examine the role of point-of-care ultrasonography as a potential tool that could provide physiologic insights to better individualize decisions related to fluid management through KRT.

Fluid Management for Critically Ill Patients with Acute Kidney Injury Receiving Kidney Replacement Therapy

“…Beyond confirming that different models of collaboration exist between intensivists and nephrologists, we report that different factors may affect their decision making while prescribing ultrafiltration. 14 Intensivists tended to incorporate hemodynamic monitoring [15][16][17][18][19] and ultrasound, 20 while nephrologists were more likely to consider preventive interventions to improve tolerance to ultrafiltration, 21 which likely reflects different areas of expertise. In both areas, significant evidence gaps remain, 21,22 which likely contributes to the variability in these practices.…”

Volume Management with Kidney Replacement Therapy in the Critically Ill Patient

“…, repeated presence of B lines on lung ultrasonography or evidence of right ventricular overload on echocardiography). 20,66–68 As these techniques continue to mature, they will likely need to be combined with the metric of net fluid gain to guide optimal management.…”

“…However, catheter-based methods are invasive and can serve as a portal for infection. Point-of-care ultrasound provides a noninvasive technique to estimate stroke volume by measuring aortic valve area and flow 20 but requires significant expertise. As a result, in clinical settings, an increase in systolic BP, pulse pressure, or mean arterial pressure (MAP) immediately after fluid administration is often used as a metric fluid of responsiveness instead of change in cardiac output.…”

“…65 Point-of-care ultrasound has emerged as an important bedside tool to rapidly and noninvasively assess parameters associated with both fluid responsiveness and fluid intolerance (e.g., repeated presence of B lines on lung ultrasonography or evidence of right ventricular overload on echocardiography). 20,[66][67][68] As these techniques continue to mature, they will likely need to be combined with the metric of net fluid gain to guide optimal management.…”

Fluid Management during Continuous Renal Replacement Therapy: A Case-Based Approach

“…When evaluating potential causes of %FB GAP , one should consider the broad spectrum of possibilities related to inadequate prescription or ineffective delivery of the prescription (e.g., interrupted CRRT due to access issues, clotting, machine malfunction, etc. ), as well as patient intolerance, among other factors [18]. Collectively, the critical care nephrology community should recognize that similar to the % gap between prescribed versus achieved total effluent dose of CRRT [19], %FB GAP is a relevant CRRT performance indicator that should be monitored during CRRT [20, 21].…”