How fast
Within 1–2 hours
Add to your jobs list; go now if a red flag applies.
Go now if
- Na⁺ under 120 mmol/L
- Confusion, drowsiness, seizures or vomiting
- Fall of 10 or more in 24 hours
Ask on the phone
- Value and previous values?
- Symptoms? Fluid status?
- On thiazides, SSRIs, PPIs, IV hypotonic fluids?
Every bleep: the basics
- Name, ward, bed, age, why they're in hospital.
- Full set of obs and the NEWS2 score — and what it was before.
- Resuscitation status (DNACPR / ReSPECT) and ceiling of care.
Ask the nurse to start
- Stop hypotonic IV fluids pending review.
- Send serum and urine osmolality and urine sodium.
Call your senior if
- Severe symptoms — hypertonic saline is a senior and HDU decision.
When you get there
For healthcare professionals, as an aid to clinical judgement — not a substitute for it. Follow your local policy and ask a senior when in doubt.