Synopsis
Prescribe and reassess intravenous fluid for an adult surgical patient by separating resuscitation, routine maintenance, replacement and redistribution while preventing sodium, chloride, glucose and volume-related harm.
- Start with the five Rs: Resuscitation, Routine maintenance, Replacement, Redistribution and Reassessment. State which indication each prescribed bag is treating.
- For adult resuscitation under CG174, use crystalloid containing sodium 130–154 mmol/L, give 500 mL over less than 15 minutes, then reassess before any further bolus.
- For routine maintenance alone, begin with 25–30 mL/kg/day water, about 1 mmol/kg/day each of sodium, potassium and chloride, and 50–100 g/day glucose; use less in older, frail, renal or cardiac patients.
Key red flags
Persistent instability or worsening lactate after an initial bolus demands diagnostic escalation; repeated litres can delay haemorrhage control or worsen cardiogenic and obstructive shock.
New hypoxaemia, crackles, raised jugular venous pressure or increasing peripheral oedema after fluid suggests overload and requires reassessment rather than completion of the prescription.
Oliguria alone is not proof of intravascular depletion; obstruction, acute kidney injury, sepsis and drug effects must be considered before more fluid.
Severe renal or liver disease, pregnancy, burns and diabetes lie outside CG174 general prescriptions and require matched specialist guidance.
Marked sodium, potassium, glucose or acid-base disturbance cannot be corrected safely by copying a routine maintenance bag.
Active blood loss requires bleeding control, component support and a major-haemorrhage approach when indicated; crystalloid is not a substitute for oxygen-carrying capacity and haemostasis.
Ongoing hypotension, deteriorating perfusion, rising lactate or new pulmonary oedema after a bolus indicates an unsafe trajectory and requires immediate senior diagnostic review.
Reasoning priorities
Estimate perfusion, congestion and potential fluid responsiveness before and after an intervention.
Haemodynamic improvement within about 30–90 seconds supports possible volume responsiveness; breathlessness or deterioration suggests overload, but neither response identifies the cause of shock alone.
Worked reasoning
An adult in recovery is tachycardic and hypotensive with cool peripheries after an operation where blood loss may have been underestimated.
- Perform ABCDE assessment, call senior anaesthetic and surgical help, review theatre fluid and blood loss, inspect drains and wound, and obtain haemoglobin, lactate, acid-base and coagulation data as indicated.
- If hypovolaemia remains likely, give 500 mL crystalloid containing sodium 130–154 mmol/L over less than 15 minutes while arranging haemorrhage control and matched blood support if bleeding is significant.
- Reassess observations, perfusion, lungs, venous pressure, mental state, urine and lactate immediately; do not prescribe the next bolus before deciding whether response supports further fluid.
- If instability persists, escalate source control, haemorrhage management, vasopressor or cardiac assessment according to cause instead of treating every low pressure with crystalloid.
- Once stable, recalculate maintenance and measured replacement separately and document review timing, biochemical monitoring and limits for stopping fluid.
The patient is haemodynamically stable, has no major deficit or abnormal loss and cannot meet needs enterally for the next day.