Absolute indications (AEIOU), why routine early RRT does not help (STARRT-AKI, AKIKI), and when not to delay further (AKIKI-2).
At the bedside
Timed steps- 1
Check emergency indications (AEIOU)
ImmediateA: acidosis pH < 7.15 (metabolic) refractory; E: K > 6.0-6.5 mmol/L or ECG changes refractory to medical therapy; I: intoxication with dialysable toxin (methanol, ethylene glycol, lithium, salicylate, metformin with lactic acidosis, valproate); O: fluid overload with pulmonary oedema refractory to diuretics; U: uraemic complications (pericarditis, encephalopathy, bleeding).
- 2
If none: watch and wait
Daily (or 12-hourly) review: urine output, fluid balance, K, bicarbonate, urea, creatinine. Optimise haemodynamics, stop nephrotoxins, try diuretics for overload.
- 3
Do not delay beyond reasonable thresholds
AKIKI-2: when oliguria > 72 h or blood urea nitrogen > 112 mg/dL (urea ~240 mg/dL), postponing RRT further gave no benefit and possible harm.
- 4
Consider the whole patient
Severe fluid overload (> 10% body weight) with worsening oxygenation, rising K with ongoing tissue breakdown (rhabdo, tumour lysis), or severe sepsis needing large volumes may justify earlier start.
- 5
Discuss goals
In patients with poor prognosis, discuss whether RRT matches their goals of care before starting.
- 6
Assess for recovery daily
Rising urine output (> 400-500 mL/day without diuretics, or > 2 L/day with diuretics) suggests recovery; trial off CRRT.
Emergency indications for RRT
| Indication | Threshold (refractory to medical therapy) |
|---|---|
| Acidosis | pH < 7.15 metabolic, or rapidly worsening |
| Electrolytes | K > 6.0-6.5 mmol/L or ECG changes; severe hyper/hyponatraemia with AKI; tumour lysis |
| Intoxications | Methanol, ethylene glycol, lithium, salicylates, metformin-associated lactic acidosis, valproate, theophylline, barbiturates |
| Overload | Pulmonary oedema / hypoxaemia not responding to diuretics |
| Uraemia | Pericarditis, encephalopathy, uraemic bleeding; urea very high (e.g. BUN > 112 mg/dL) |
References
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Should we start RRT?
Step 1 of ~3
Decision: Refractory AEIOU indication?
Based on Gaudry S, Hajage D, Schortgen F, et al; Gaudry S, Hajage D, Martin-Lefevre L, et al; STARRT-AKI Investigators. Educational use; follow local protocol.
Pathophysiology
RRT replaces solute clearance and fluid removal but adds risks: catheter infection and thrombosis, hypotension, hypophosphataemia, drug and nutrient removal, and possibly delayed renal recovery from haemodynamic insults.
Evidence
- AKIKI (2016): delayed strategy avoided RRT in 49% with similar mortality [Gaudry 2016].
- ELAIN (2016, single-centre surgical): early RRT reduced 90-day mortality; not replicated [Zarbock 2016].
- STARRT-AKI (2020, n=3,019): accelerated RRT did not reduce mortality and increased RRT dependence at 90 days [STARRT-AKI 2020].
- AKIKI 2 (2021): a more-delayed strategy beyond oliguria > 72 h or BUN > 112 mg/dL offered no benefit and was associated with harm [Gaudry 2021].
Controversies
- Which patients benefit from earlier RRT (e.g. severe overload, ARDS); biomarker-guided timing.
🇮🇳 India notes
- Cost and availability of CRRT shape decisions in India; SLED on a standard dialysis machine is widely used.
- Dialysis for toxins: methanol outbreaks (illicit liquor) need urgent haemodialysis as fomepizole is scarce.
References
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Test yourself
Module quiz · score 70% to complete the module
Educational reference for trained clinicians. Check doses against your hospital protocol and the patient in front of you.