Sustained Low-Efficiency Dialysis (SLED) — The Hybrid Modality

Also known as Sustained low-efficiency dialysis · SLED · Extended daily dialysis · EDD · Hybrid dialysis · Slow low-efficiency dialysis · SLED-f

Sustained low-efficiency dialysis (SLED) is a hybrid renal replacement therapy that combines features of intermittent haemodialysis (IHD) and continuous renal replacement therapy (CRRT). A standard haemodialysis machine is run slowly — published protocols use blood flows of about 100 to 250 mL/min and dialysate flows of 200 to 350 mL/min over extended 8 to 12 hour sessions on a daily or near-daily schedule, with primarily diffusive clearance. Advantages: versus CRRT it uses the standard IHD machine (cheaper, more available), needs less anticoagulation (many sessions run heparin-free), and allows down-time for procedures and mobilisation; versus IHD it is haemodynamically gentler. Randomised and meta-analytic evidence shows mortality and renal recovery comparable to CRRT. Timing follows Gaudry 2016 and STARRT-AKI — wait for an urgent indication regardless of modality.

medium22 referencesUpdated 8 Oct 202615 min readSource-verified · Oct 2026

Checked against its sources on 8 Oct 2026

Practise this topic

8 MCQs

The one-line answer

SLED is the hybrid RRT — a standard haemodialysis machine run slowly (blood flow about 100 to 250 mL per min, dialysate 200 to 350 mL per min in published protocols) over an extended 8 to 12 hour session, daily or six days a week. It occupies the favourable middle ground between IHD and CRRT: haemodynamics and small-solute clearance comparable to CRRT (Kielstein randomised study, Schwenger randomised trial), mortality and renal recovery non-inferior to CRRT (Schwenger RCT, Dalbhi 2021 meta-analysis), less anticoagulation — most treatments in the Berbece series ran heparin-free — lower cost, and built-in down-time (nocturnal SLED frees the day). The two killer trials to remember: Gaudry 2016 and STARRT-AKI killed the early-start reflex — wait for an urgent indication regardless of modality.^[1]^[2]^[3]^[11]^[14]

Meet the patient

A 68-year-old woman (70 kg) with septic shock from pyelonephritis, on a single low-dose noradrenaline infusion, has developed KDIGO stage 3 AKI. Her triggers for starting renal replacement therapy are exactly those that mandated RRT in the delayed arm of Gaudry 2016 — refractory hyperkalaemia, worsening metabolic acidosis, and cumulative fluid overload — and she is the kind of dialysis-dependent ICU AKI patient in whom SLED was trialled against CRRT.^[1]^[6]

Three questions decide the modality. Is the haemodynamic stability IHD-tolerant, CRRT-needed, or in between? (this patient is in between — single low-dose vasopressor). What is the available resource? (standard haemodialysis machines are universal; CRRT machines may be scarce). How much down-time does the patient need? (the procedures, imaging, mobilisation all favour intermittent therapy). Hold those questions and SLED is the answer.^[1]

References22Show

[1]Schwenger V, Weigand MA, Hoffmann O, et al. Sustained low efficiency dialysis using a single-pass batch system in acute kidney injury - a randomized interventional trial: the REnal Replacement Therapy Study in Intensive Care Unit PatiEnts Crit Care, 2012.PMID 22839577
[2]Kielstein JT, Kretschmer U, Ernst T, et al. Efficacy and cardiovascular tolerability of extended dialysis in critically ill patients: a randomized controlled study Am J Kidney Dis, 2004.PMID 14750100
[3]Berbece AN, Richardson RMA Sustained low-efficiency dialysis in the ICU: cost, anticoagulation, and solute removal Kidney Int, 2006.PMID 16850023
[4]Fliser D, Kielstein JT Technology Insight: treatment of renal failure in the intensive care unit with extended dialysis Nat Clin Pract Nephrol, 2006.PMID 16932387
[5]Joannidis M Good-bye CRRT, here comes SLED? ... not so fast! Crit Care, 2012.PMID 23148709
[6]Gaudry S, Hajage D, Schortgen F, et al. Initiation Strategies for Renal-Replacement Therapy in the Intensive Care Unit N Engl J Med, 2016.PMID 27181456
[7]Bagshaw SM, Wald R, Adhikari NKJ, et al. Timing of Initiation of Renal-Replacement Therapy in Acute Kidney Injury N Engl J Med, 2020.PMID 32668114
[8]Bellomo R, Cass A, Cole L, et al. Intensity of continuous renal-replacement therapy in critically ill patients N Engl J Med, 2009.PMID 19846848
[9]Palevsky PM, Zhang JH, O'Connor TZ, et al. Intensity of renal support in critically ill patients with acute kidney injury N Engl J Med, 2008.PMID 18492867
[10]Roberts JA, Paul SK, Akova M, et al. DALI: defining antibiotic levels in intensive care unit patients: are current β-lactam antibiotic doses sufficient for critically ill patients? Clin Infect Dis, 2014.PMID 24429437
[11]Dalbhi SA, Alorf R, Alotaibi M, et al. Sustained low efficiency dialysis is non-inferior to continuous renal replacement therapy in critically ill patients with acute kidney injury: A comparative meta-analysis Medicine (Baltimore), 2021.PMID 34941056
[12]Russo DS, Eugenio CS, Balestrin IG, et al. Comparison of hemodynamic instability among continuous, intermittent and hybrid renal replacement therapy in acute kidney injury: A systematic review of randomized clinical trials J Crit Care, 2022.PMID 35124346
[13]Zhou X, Dong P, Pan J, et al. Renal replacement therapy modality in critically ill patients with acute kidney injury - A network meta-analysis of randomized controlled trials J Crit Care, 2021.PMID 33836397
[14]Marshall MR, Golper TA, Shaver MJ, et al. Sustained low-efficiency dialysis for critically ill patients requiring renal replacement therapy Kidney Int, 2001.PMID 11473662
[15]Marshall MR, Ma T, Galler D, et al. Sustained low-efficiency daily diafiltration (SLEDD-f) for critically ill patients requiring renal replacement therapy: towards an adequate therapy Nephrol Dial Transplant, 2004.PMID 15031344
[16]Clark JA, Schulman G, Golper TA Safety and efficacy of regional citrate anticoagulation during 8-hour sustained low-efficiency dialysis Clin J Am Soc Nephrol, 2008.PMID 18272829
[17]Kanji S, Roberts JA, Xie J, et al. Vancomycin Population Pharmacokinetics in Critically Ill Adults During Sustained Low-Efficiency Dialysis Clin Pharmacokinet, 2020.PMID 31471789
[18]Oliveira MS, Machado AS, Mendes ET, et al. Pharmacokinetic and Pharmacodynamic Characteristics of Vancomycin and Meropenem in Critically Ill Patients Receiving Sustained Low-efficiency Dialysis Clin Ther, 2020.PMID 32199609
[19]Chou JA, Kalantar-Zadeh K Volume Balance and Intradialytic Ultrafiltration Rate in the Hemodialysis Patient Curr Heart Fail Rep, 2017.PMID 28803369
[20]Thomsen J, Sprogøe U, Toft P Urine neutrophil gelatinase-associated lipocalin and urine output as predictors of the successful discontinuation of continuous renal replacement therapy in critically ill patients with acute kidney injury BMC Nephrol, 2020.PMID 32859163
[21]Felsenfeld AJ, Levine BS Approach to treatment of hypophosphatemia Am J Kidney Dis, 2012.PMID 22863286
[22]Heung M, Mueller BA Prevention of hypophosphatemia during continuous renal replacement therapy-An overlooked problem Semin Dial, 2018.PMID 29405468