Synopsis
Recognise excessive urine production after obstruction relief, distinguish physiological recovery from harmful losses and prescribe monitored, individualised replacement.
- Measure newly produced urine after the initially retained volume has drained; an immediate large bag volume is not itself continuing diuresis.
- Common operational criteria are output above 200 ml per hour for two consecutive hours or above three litres in 24 hours after relief.
- Physiological diuresis excretes retained water and solute; pathological losses continue after balance has been restored.
Investigation priorities
Confirm the rate of newly produced urine and calculate a clinically meaningful balance.
Management branches
An adult has substantial ongoing output following relief of urinary obstruction.
- Measure urine hourly at the start and distinguish the initially retained volume from subsequent production. Record baseline observations, weight and blood results, then apply the output threshold to timed new collections.
- Assess whether the patient can drink, obtain fluids independently and communicate symptoms. Continue monitored care when diuresis, renal impairment, abnormal electrolytes or frailty makes unobserved discharge unsafe.
Key medicines
Isotonic crystalloid for hypovolaemic resuscitationFor the general adult CG174 resuscitation pathway, give 500 ml intravenously over less than 15 minutes using crystalloid containing sodium 130–154 mmol/l, then immediately reassess before further fluid.This bolus is not an automatic ongoing hourly replacement prescription. Individualise for cardiac or renal impairment and assess lungs and perfusion; suspected sepsis has separate fluid guidance. Stop and reassess if overload develops.
Hartmann's solution: Aguettant compound sodium lactate IV infusionNorfolk and Norwich local protocol: initially replace 50% of the preceding hour's urine output intravenously, reviewed hourly; 400 ml urine gives 200 ml over the next hour, adjusted to clinical state and oral intake.This locally specified replacement method requires hourly review, including oral intake. The named product is contraindicated in hypervolaemia, severe oliguria or anuria, uncompensated cardiac failure, hyperkalaemia, hypernatraemia, hypercalcaemia, hyperchloraemia, metabolic alkalosis, severe metabolic or lactic acidosis, severe hepatic dysfunction and ascitic cirrhosis, and with digitalis or potassium-sparing diuretic therapy. Select another appropriate fluid if contraindicated; monitor electrolytes and acid–base status.