*3.2.1 Intermittent vs. continuous*

Although there are substantial variations in practice, hemodynamic instability is the most common reason to choose slow intermittent (PIRRT) or continuous (CRRT)


*\*In all patients randomized.*

*\*\*In patients who survived at ICU discharge.*

*CAVHDF: Continuous arteriovenous hemodiafiltration, p: p-value, NS: Non-significant.*

## **Table 5.**

*Major studies comparing CRRT to IHD.*

therapy. The 2012 KDIGO AKI guidelines suggest using CRRT rather than intermittent RRT for these patients (grade B – moderate quality of evidence) [19]. However, empirical data has not proven what might seems obvious at first to clinicians. In fact, the use of PIRRT or CRRT compared to IHD in randomized trials has failed to demonstrate differences in hard outcomes such as mortality or recovery of renal function [20–26] (see **Table 5**). Still, it is important to note that heterogeneity is found in dosing, CRRT subtypes, delivered blood flow, and that the most unstable patients were excluded for most of them.

As mentioned earlier, in patients with hemodynamic instability, the choice between PIRRT and CRRT mostly depends on local availability. The level of evidence regarding PIRRT is still limited, but advantages compared to CRRT may include: reduced costs and flexible treatment schedule allowing the patient to be more easily mobilized during daytime. As opposed to fixed CRRT solutions, the dialysate composition can be more easily adapted to the patient's needs even during the dialysis session. However, no clear antimicrobial dose adjustments are recommended with that modality. In patients who regain stability, the RRT prescription can be rapidly adapted, from PIRRT to a conventional IHD prescription, using the same technology.
