How to Complete a Fluid Assessment

Being able to assess the fluid status of a patient is a key skill that you will regularly do as a junior doctor. It involves assessing if a patient is hypovolaemic, euvolaemic or hypervolaemic and then using this information to guide your clinical management going forwards.

Factors to consider before examining the patient

Read the notes and take a history!

  • Why is this patient in hospital?
  • Reasons for admission which may affect fluid requirements include:
    • Trauma
    • Burns
    • Fever
    • Surgical patients: pre or post op, NBM?
    • GI losses – vomiting, diarrhoea, stoma output
  • What is their relevant past medical history?
    • Renal disease
    • Heart failure
    • Pre or post op
  • Drug history
    • Diuretics
    • Drugs which can alter bowel habit
      • E.g. antibiotics (diarrhoea), opioids (constipation)
  • Other factors
    • Active bleeding?
    • Vomiting: how much, how often, blood?
    • Stools: how much, how often, blood?
    • Fever
    • Urine output
    • Thirst
    • Light-headedness / dizziness
    • Eating / drinking over the last day or so
    • Are they already receiving IV fluids?
    • Is there a fluid restriction in place?


General Inspection

  • Age of the patient
  • Obvious oedema from end of bed
  • Shortness of breath?
  • Colour – pallor?
  • Anything around the bed space – IV fluids, catheter, stoma, surgical drains etc.
  • Look in patient notes for fluid balance chart and Bristol stool chart – not always filled out but very helpful when it is
  • There may also be a daily weight chart – also very helpful!
  • Use this time to check medications if you haven’t already too


  • Inspect: oedema, peripheral stigmata of disease
  • Temperature
  • Palpate the radial pulse: volume and rate
  • Capillary refill time: should be <2


  • Check blood pressure – often a late sign but still helpful
  • Lying and standing BP
  • Assess skin turgor – gently pinch a fold of skin for a few seconds, assess how long it takes to return to normal


  • Ask patient to open mouth to assess mucous membranes
  • Look to eyes for pallor and sunken eyes


  • Check JVP: if  >3cm consider fluid overload


  • Respiratory rate
  • Listen over 4 heart valves: added S3 gallop rhythm might be heard in fluid overload
  • Auscultate lungs – coarse crackles may indicate pulmonary oedema
  • Assess for sacral oedema at bottom of back


  • Assess for ascites: shifting dullness


  • Assess for peripheral oedema: if so, how far up does it go?


  • Look to catheters, stomas, surgical drains
  • Assess output volume, colour and type of output

Further tests


  • FBC: drop in Hb suggests haemorrhage, raised haemocrit suggest dehydration
  • Urea/creatinine: raised in dehydration, urea raised in upper GI haemorrhage
  • Sodium: raised in dehydration, low in fluid overload (dilutional)


  • Chest X-ray: pulmonary oedema
  • Echocardiogram: heart failure
  • Bladder scan: urinary retention