Acute kidney injury

Manage now— do this, in order

• Catheterise early in unexplained AKI — it is both diagnostic and therapeutic: it excludes and relieves bladder outlet obstruction, yields a residual volume (a large residual is diagnostic), gives an hourly output to trend, and supplies urine for dipstick, microscopy and culture.Doctor / Nurse
• If hypovolaemic, give a fluid challenge of 250–500 mL of balanced crystalloid intravenously over 15 minutes, then reassess pulse, blood pressure, JVP, lung bases and urine output — a 250 mL challenge usually establishes whether hypotension is fluid-responsive. Children 10–20 mL/kg over 15–30 minutes (10 mL/kg where cardiac dysfunction or malnutrition is suspected). Use balanced crystalloid (Ringer's lactate/Hartmann's) in preference to 0.9% sodium chloride when large volumes are anticipated, but balanced solutions contain about 5 mmol/L of potassium, so where hyperkalaemia is established or suspected 0.9% sodium chloride is preferred. If bleeding, give blood. If pulse and pressure have not improved after 2 litres, stop and reassess — look for occult blood loss and consider vasodilated sepsis needing a vasopressor rather than a third litre. Hydroxyethyl starch and other synthetic colloids are contraindicated.Doctor / Nurse
• If euvolaemic, prescribe the previous day's urine output plus gastrointestinal and drain losses plus about 500 mL for insensible loss — excessive fluid in AKI causes pulmonary oedema. If overloaded, sit the patient upright, give oxygen, and give furosemide 40–80 mg intravenously, no faster than 4 mg per minute — rapid injection causes deafness; paediatric 0.5–1 mg/kg IV (maximum 2 mg/kg per dose). A diuretic treats fluid overload; it does not treat kidney injury, and renal replacement therapy must never be delayed because a diuretic is being tried.Doctor / Nurse
• Treat hyperkalaemia on the ECG, not the number — the trigger is potassium above 6.5 mmol/L, or above 6.0 mmol/L with ECG changes, or any hyperkalaemia with a broad QRS or arrhythmia — and give the first three agents together, not sequentially (doses in chart).Doctor / NurseNot available at your setup — Serum electrolytes.
• Calcium gluconate 10%, 10 mL IV over 2–5 minutes, repeated at 5 minutes if the ECG is unchanged, up to 3 doses (children 0.5 mL/kg IV over 5–10 minutes, maximum 20 mL); onset 1–3 minutes, duration 30–60 minutes. It stabilises the myocardium and does not lower potassium at all — never treat it as definitive. Calcium chloride 10% 10 mL is an alternative but far more damaging on extravasation.Doctor / Nurse
• Soluble insulin with dextrose: 10 units in 50 mL of 50% dextrose IV over 15–30 minutes, or 10 units in 250 mL of 10% dextrose over 30 minutes (children 0.1 unit/kg with 5 mL/kg of 10% dextrose IV over 30 minutes); onset 15–30 minutes, duration 4–6 hours. Check glucose before, at 30 minutes, then hourly for 6 hours — late hypoglycaemia after insulin-dextrose is a recognised cause of death from this treatment.Doctor / Nurse
• Nebulised salbutamol 10–20 mg over 10 minutes (children 2.5 mg under 5 years; 5 mg at 5 years or older), additive to insulin-dextrose and used cautiously in ischaemic heart disease. Sodium bicarbonate 8.4%, 50 mL (50 mmol) IV over 15–30 minutes into a large vein, or 1.26% 500 mL (children 1 mmol/kg, diluted to 4.2% in infants) — only if acidotic and NOT volume-overloaded, since the sodium load precipitates pulmonary oedema and it may precipitate tetany if hypocalcaemic.Doctor / Nurse
• Add a potassium binder, the only measure short of dialysis that removes potassium from the body: calcium or sodium polystyrene sulfonate 15 g orally 3–4 times daily or 30 g rectally, or sodium zirconium cyclosilicate 10 g orally three times daily for 48 h then 5–10 g daily (children 0.5–1 g/kg per day orally or rectally in divided doses). Stop everything that adds potassium — potassium-containing fluids and supplements, potassium-sparing diuretics, ACE inhibitors, ARBs, trimethoprim, NSAIDs — and recheck potassium and the ECG at 1 hour and at least 2-hourly thereafter, because rebound is the rule.Not available at your setup — Serum electrolytes.
• Stop or withhold the nephrotoxins — this is a treatment, not an administrative task: NSAIDs, ACE inhibitors and ARBs, aminoglycosides, amphotericin B, vancomycin, tenofovir, high-dose bolus aciclovir, cisplatin, calcineurin inhibitors, iodinated contrast, diuretics if hypovolaemic, metformin and SGLT-2 inhibitors during acute illness. Re-dose every remaining drug for the kidney the patient has now (anticoagulants, opioids, gabapentinoids, digoxin, methotrexate, sulphonylureas, renally cleared antimicrobials) — and do not dose from an eGFR printout while creatinine is moving. Relieve obstruction above the bladder with ureteric stenting or percutaneous nephrostomy as soon as possible, then anticipate post-obstructive diuresis. In rhabdomyolysis give early vigorous 0.9% sodium chloride, typically exceeding 4 L in 24 hours in an adult, titrated to a urine output of 1–2 mL/kg per hour.Doctor / NurseNot available at your setup — Ultrasound.
• Ask AEIOU at every reassessment and arrange renal replacement therapy when an indication appears: Acidosis refractory to medical therapy (pH < 7.1, H⁺ > 79 nmol/L); Electrolytes (hyperkalaemia generally > 6.5 mmol/L with ECG changes, uncontrolled by conservative measures); Intoxication with a dialysable poison; Overload (pulmonary oedema unresponsive to diuresis); Uraemia (pericarditis with or without tamponade, encephalopathy, seizures, bleeding diathesis). No number mandates dialysis — but anuria modifies every indication, because a potassium of 6.2 mmol/L in a patient passing 60 mL an hour is manageable while the same value after 12 hours of anuria is a countdown.DoctorNot available at your setup — Dialysis / renal replacement, Arterial blood gas.