Reduced Urine Output

First actions / assessment

• Assess ABCDE first and decide rapidly whether the patient is hypovolaemic, septic, obstructed, or fluid overloaded. Clarify onset, duration, usual urine pattern, exact last urine passed, fluid intake, thirst, vomiting, diarrhoea, bleeding, fever, dysuria, frequency, haematuria, flank pain, suprapubic pain, difficulty voiding, weak stream, lower urinary tract symptoms, new medicines, recent contrast, NSAIDs, ACE inhibitor or ARB use, diuretics, heart failure symptoms, liver disease, pregnancy, and known renal disease. Examine vitals, capillary refill, JVP, mucous membranes, peripheral oedema, crackles, suprapubic fullness, abdominal tenderness, flank tenderness, bladder distension, and signs of sepsis or shock. In possible AKI, note when urine output fell and assess for peripheral oedema, lung crackles, and a palpable bladder. Initial investigations commonly include urine dip, bedside glucose, ECG, CBC, U&E/creatinine, bicarbonate, potassium, CRP if infection suspected, venous or arterial gas if unwell, and bladder scan where retention is possible. If the cause is unclear or obstruction is possible, urgent renal tract ultrasound is indicated
• NICE recommends immediate ultrasound within 6 hours if pyonephrosis is suspected and urgent ultrasound within 24 hours if there is no identified cause or there is risk of urinary tract obstruction.