class: RWH_bg_title hide-count count: false # .black[AKI & IV Fluids] <!-- ### Y4 MBChB | June 2026 --> .RWH_footnote_title[ .RWH_footer_bold[ Rob Hunter ] ] .RWH_footnote_right_title[ .RWH_footer_bold[ Y4 MBChB | June 2026 ] ] --- # Learning outcomes #### Acute Kidney Injury - understand **why AKI matters** - recognise and **define AKI** - outline the broad **diagnostic approach** in AKI & list common **causes** - list the principles of AKI **management** <br> #### Intravenous fluid therapy - prescribe IV fluids for: **resuscitation**, **maintenance**, **replacement** - recognise when IV fluids may be harmful ??? --- class: center, middle, inverse # .white[AKI] ??? what is it & why does it matter? --- # AKI definition Any of the following: - rise in serum creatinine by `\(\geq 26.5 \,\mu mol/L\)` within 48 hours - rise in serum creatinine to `\(\geq 1.5 \times \text{baseline}\)` within 7 days - urine volume `\(< 0.5 \, mL/kg/hour\)` for 6 hours .RWH_footnote_right[.RWH_footer_style[[KDIGO Clinical Practice Guideline for Acute Kidney Injury](https://kdigo.org/guidelines/acute-kidney-injury/)]] ??? --- # AKI causes --  ??? Ask: - tell me some common causes - what will you look for in the history, examination, Ix AKI is a syndrome, not a diagnosis. On the ward, common causes include: - dehydration / poor intake - sepsis - diuretics - ACE inhibitors / ARBs - NSAIDs - urinary retention or obstruction - heart failure and congestion **In older adults, AKI is often multifactorial.** --- # Clinical assessment #### History: - oral intake, vomiting, diarrhoea - infective symptoms - urinary symptoms - co-morbidities (HTN, T2DM, heart failure, cirrhosis...) - drugs: - NSAIDs / antibiotics / chemotherapy... - ACE inhibitors / ARBs - metformin / opioids / digoxin... #### Examination: - volume status (BP, JVP, pulse, CRT, oedema, crackles...) - vascular disease (pulses...) - bladder distension / catheter issues ??? Can rattle through having arrived at all of this together already... --- # Investigations #### Core set - U&Es (think broadly about Es) and compare to previous - FBC, CRP, LFTs, Ca²⁺ - urinalysis - ECG? - CXR? - renal tract USS if not obviously pre-reneal #### And sometimes... - blood film, CK - C3, C4, autoantibodies - CT --- # Management of AKI - treat the underlying cause - optimise fluid status (monitor u/o) - review medications - treat complications (e.g. hyperkalaemia) --- class: center, middle, inverse # .white[IV fluids]  [NHSL IV fluid guideline](https://s3.eu-west-2.amazonaws.com/med-assets-docs/resources/quick-reference-guideline-for-iv-fluid-and-electrolyte-prescribing-in-adults.pdf) --- # IV fluids Before prescribing, ask: 1. **Does this patient need IV fluid at all?** 2. **What type?** 3. **How much & how quickly?** 4. **How will I monitor the response?** for efficacy and safety .RWH_footnote_right[.RWH_footer_style[[NICE CG174: Intravenous fluid therapy in adults in hospital](https://www.nice.org.uk/guidance/cg174)]] ---  .RWH_footnote_right[.RWH_footer_style[[Frost (BMJ 2014)](https://pubmed.ncbi.nlm.nih.gov/25569336/)]] ---  ---  ---  ??? NICE says 25 – 30 ml/day for aq (or 20 – 25 if in the caution groups). NHSL says 30 ml/day (or 20 – 25 in caution groups). Maintenance fluid usually 0.18% NaCl / 4% G / 40 mM KCl. --- class: RWH_black  --- class: RWH_black  --- class: center, middle, inverse # .white[Cases] ??? For each case, ask: 1. Does this patient have AKI? 2. What is the likely cause? 3. What investigations are needed now? 4. What immediate management is needed? 5. Does the patient need IV fluids? 6. If yes: **resuscitation, maintenance, or replacement?** 7. If no: what should be done instead? --- # Case 1 An 81-year-old man presents with confusion and lethargy. **HPC**: 3 days of diarrhoea and poor oral intake `|` fever `|` productive cough **PMH**: hypertension `|` T2DM `|` peripheral vascular disease **Drugs**: - ramipril - bendroflumethiazide - metformin - ibuprofen (over-the-counter) **o/e**: BP 92/56 `|` pulse 108 `|` dry mucous membranes `|` right basal crackles **Ix:** SCr 210 mcM (baseline 120) `|` K 5.6 mM `|` CRP 142 ??? Straightforward pre-renal AKI with CKD / vascular background. --- # Case 2 A 76-year-old woman has had a large stroke. - no prior regular medications; started on aspirin & clopidogrel - unsafe swallow - nil by mouth pending speech and language review - haemodynamically stable - euvolaemic - U&Es normal - estimated body weight 60 kg ??? Maintenance fluids. --- # Case 3 An 84-year-old man is admitted with breathlessness. **HPC**: one week of progressive breathlessness `|` 3 kg weight gain **PMHx**: HFrEF `|` CKD `|` AFib **o/e**: BP 158/88 `|` raised JVP `|` bibasal crackles `|` pitting oedema to knees **Ix**: SCr 220 (baseline 170) `|` pulmonary oedema **A&E**: resuscitation IV fluids started for AKI ??? Stop the fluids! --- # Case 4 A 58-year-old woman admitted feeling weak and dizzy. **PMHx:** ileostomy after operation for diverticular disease **HPC:** stoma output much higher than usual for 2 days `|` poor oral intake **o/e**: BP 96/60 `|` HR 104 `|` dry mucous membranes **Ix**: SCr 160 mcM (baseline 90) `|` Na 129 mM `|` K 3.2 mM ??? Ongoing GI losses requiring replacement, with initial resuscitation too. ---  .RWH_footnote_right[.RWH_footer_style[[NICE CG174: Intravenous fluid therapy in adults in hospital](https://www.nice.org.uk/guidance/cg174)]] --- # Take-home messages - AKI is defined by a **rise in creatinine** and / or **reduced urine output** - always ask: **pre-renal vs. intrinsic vs. post-renal?** - prescribe fluids for: **resuscitation** | **maintenance** | **replacement** - some patients with AKI need fluid; some need **less fluid** - monitor the response to IV fluids for efficacy & safety .RWH_footnote_right[.RWH_footer_style[[KDIGO Clinical Practice Guideline for Acute Kidney Injury](https://kdigo.org/guidelines/acute-kidney-injury/)] | .RWH_footer_style[[NICE CG174: Intravenous fluid therapy in adults in hospital](https://www.nice.org.uk/guidance/cg174)]] --- class: center, middle, inverse # .white[Supplemental slides] ---  ---  ---  ---  ---