The For Kidneys Sake podcast series is brought to you by Imperial College Healthcare NHS Trust and North West London Integrated Care Board (NWL NHS).

In this episode, Jeremy and Andrew discuss one of the most deceptively tricky areas of everyday kidney and general medical practice: assessing fluid balance. From swollen ankles to dizzy spells, from SGLT2-induced polyuria to the eternal mystery of the JVP, our hosts unpack why no single test ever gives “the answer” and why clinical acumen still matters. They explore how to distinguish true fluid overload from ankle oedema caused by amlodipine, when weight matters, and why blood urea creatinine ratios can occasionally point you in the right direction.

They also highlight the subtleties of recognising volume depletion, why 'dehydration' is often the wrong term, and how sick-day rules, medications, polyuria, and patient education all intersect in real life. From emerging technologies like smartphone perfusion video analysis to the humble power of a daily weigh-in, this conversation offers practical wisdom and a forward-looking perspective, a must-listen for anyone navigating the art and science of keeping patients neither too wet nor too dry.

Top 5 Takeaways

1. There’s no single test for fluid balance — Clinical assessment remains king: history, examination, serial weights, blood pressure (including postural changes), and context are indispensable.
2. Not all ankle swelling is fluid overload — Calcium channel blockers frequently cause ankle oedema that doesn’t require diuretics. Always consider medication effects before treating fluid overload.
3. Volume depletion is often subtle — Thirst, dizziness, polyuria (especially in CKD or after starting SGLT2 inhibitors), and weight loss are key clues, but each has confounders.
4. Simple tools beat fancy tech (for now) — Trends in weight, postural blood pressure, and blood urea/creatinine ratio often outperform bioimpedance machines or wearables in real-world clinical value.
5. Prepare patients with sick day guidance — Clear, proactive advice about temporarily holding RAS blockers, diuretics, or SGLT2 inhibitors during vomiting/diarrhoea prevents avoidable AKI.

Resource Links:
NICE GUIDELINES [NG203] chronic kidney disease: assessment and management Overview | Chronic kidney disease: assessment and management | Guidance | NICE

Northwest London CKD guidelines for primary care Chronic kidney disease (nwlondonicb.nhs.uk)

Pumping Marvellous | The UK's Heart Failure Charity

The purpose of this podcast is to inform and educate health care professionals working in the primary care and community setting. The content is evidence based and consistent with NICE guidelines and North West Guidelines available at the time of publication.

The content of this podcast does not constitute medical advice and it is not intended to function as a substitute for a healthcare practitioner’s judgement.

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From fluid overload to volume depletion: tips on how to get it right?