Intervention with concentrated albumin for resuscitation of undifferentiated sepsis - Multi Day

Immediately after randomisation, the intervention group will receive 20% human serum albumin, infused intravenously at 100mL/hr over 4 hours, concurrently with standard crystalloid-based fluid therapy as deemed appropriate by the treating emergency team. Over the next 10 days (or until discharge if the patient is discharged prior to 10 days), patients will receive a daily dose of 20% albumin, with the dose determined by the serum albumin concentration in the preceding 24 hours. Specifically, patients will receive: 300mL if serum albumin is <25g/L, 200mL if serum albumin is >=25 and <30g/L 100mL if serum albumin unmeasured within 48hrs, or previous measurement <35g/L No dose if previous serum albumin >=35g/L Adherence to the intervention will be monitored using the patient medication chart. Initial doses of crystalloid and albumin will be administered while the patient is in the Emergency Department. This time period is on average 4-6 hours. The remaining doses will be administered while the patient is in a ward within the hospital. Crystalloid fluid therapies will be administered to patients in both study arms according to evidence-based guidelines such as those disseminated by the Surviving Sepsis Campaign. Modern guidelines advocate discrete bolus fluid therapy (most clinicians utilise volumes of 500mL) with frequent reassessment, clinical examination and evaluation of available physiologic variables (heart rate, blood pressure, arterial oxygen saturation, respiratory rate, temperature, urine output, and others, as available) as well as other non-invasive (e.g., capnography) or invasive monitoring (e.g., arterial blood pressure), as available.