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Intravenous fluid therapy in adults in hospital – NICE guideline

This National Institute for Health and Care Excellence (NICE) guideline covers the general principles for managing intravenous (IV) fluid therapy in hospital inpatients aged 16 and over with a range of conditions. It aims to help prescribers understand the optimal amount and composition of IV fluids to be administered and the best rate at which to give them, to improve fluid prescribing and outcomes among people in hospital.

The guideline does not cover pregnant women, and those with severe liver or renal disease, diabetes or burns.

Key recommendations

Principles and protocols for intravenous fluid therapy

  • When prescribing IV fluids, remember the 5 Rs:
    • Resuscitation
    • Routine maintenance
    • Replacement
    • Redistribution
    • Reassessment.
  • Offer IV fluid therapy as part of a protocol (see 'Algorithms for IV fluid therapy'):
    • Assess patients' fluid and electrolyte needs following 'Algorithm 1: Assessment'.
    • If patients need IV fluids for fluid resuscitation, follow 'Algorithm 2: Fluid resuscitation'.
    • If patients need IV fluids for routine maintenance, follow 'Algorithm 3: Routine maintenance'.
    • If patients need IV fluids to address existing deficits or excesses, ongoing abnormal losses or abnormal fluid distribution, follow 'Algorithm 4: Replacement and redistribution'.
  • Patients should have an IV fluid management plan, which should include details of:
    • the fluid and electrolyte prescription over the next 24 hours
    • the assessment and monitoring plan.
  • Initially, the IV fluid management plan should be reviewed by an expert daily. IV fluid management plans for patients on longer-term IV fluid therapy whose condition is stable may be reviewed less frequently.

Assessment and monitoring

  • Assess the patient's likely fluid and electrolyte needs from their history, clinical examination, current medications, clinical monitoring and laboratory investigations:
    • History should include any previous limited intake, thirst, the quantity and composition of abnormal losses (see 'Diagram of ongoing losses'), and any comorbidities, including patients who are malnourished and at risk of refeeding syndrome (see 'Nutrition support in adults' [NICE clinical guideline 32]).
    • Clinical examination should include an assessment of the patient's fluid status, including:
      • pulse, blood pressure, capillary refill and jugular venous pressure
      • presence of pulmonary or peripheral oedema
      • presence of postural hypotension.
    • Clinical monitoring should include current status and trends in:
      • National Early Warning Score (NEWS)
      • fluid balance charts
      • weight.
    • Laboratory investigations should include current status and trends in:
      • full blood count
      • urea, creatinine and electrolytes.
  • All patients continuing to receive IV fluids need regular monitoring. This should initially include at least daily reassessments of clinical fluid status, laboratory values (urea, creatinine and electrolytes) and fluid balance charts, along with weight measurement twice weekly. Be aware that:
    • Patients receiving IV fluid therapy to address replacement or redistribution problems may need more frequent monitoring.
    • Additional monitoring of urinary sodium may be helpful in patients with high-volume gastrointestinal losses. (Reduced urinary sodium excretion [less than 30 mmol/l] may indicate total body sodium depletion even if plasma sodium levels are normal. Urinary sodium may also indicate the cause of hyponatraemia, and guide the achievement of a negative sodium balance in patients with oedema. However, urinary sodium values may be misleading in the presence of renal impairment or diuretic therapy.)
    • Patients on longer-term IV fluid therapy whose condition is stable may be monitored less frequently, although decisions to reduce monitoring frequency should be detailed in their IV fluid management plan.
  • Clear incidents of fluid mismanagement (for example, unnecessarily prolonged dehydration or inadvertent fluid overload due to IV fluid therapy) should be reported through standard critical incident reporting to encourage improved training and practice (see 'Consequences of fluid mismanagement to be reported as critical incidents').


  • If patients need IV fluid resuscitation, use crystalloids that contain sodium in the range 130–154 mmol/l, with a bolus of 500 ml over less than 15 minutes. (For more information, see the 'Composition of commonly used crystalloids table'.)

Routine maintenance

  • If patients need IV fluids for routine maintenance alone, restrict the initial prescription to:
    • 25–30 ml/kg/day of water and
    • approximately 1 mmol/kg/day of potassium[1], sodium and chloride and
    • approximately 50–100 g/day of glucose to limit starvation ketosis. (This quantity will not address patients' nutritional needs; see 'Nutrition support in adults' [NICE clinical guideline 32].)
  • For more information see IV fluid prescription for routine maintenance over a 24-hour period.

Training and education

  • Hospitals should establish systems to ensure that all healthcare professionals involved in prescribing and delivering IV fluid therapy are trained on the principles covered in this guideline, and are then formally assessed and reassessed at regular intervals to demonstrate competence in:
    • understanding the physiology of fluid and electrolyte balance in patients with normal physiology and during illness
    • assessing patients' fluid and electrolyte needs (the 5 Rs: Resuscitation, Routine maintenance, Replacement, Redistribution and Reassessment)
    • assessing the risks, benefits and harms of IV fluids
    • prescribing and administering IV fluids
    • monitoring the patient response
    • evaluating and documenting changes and
    • taking appropriate action as required.
  • Hospitals should have an IV fluids lead, responsible for training, clinical governance, audit and review of IV fluid prescribing and patient outcomes.

[1] Weight-based potassium prescriptions should be rounded to the nearest common fluids available (for example, a 67 kg person should have fluids containing 20 mmol and 40 mmol of potassium in a 24-hour period). Potassium should not be added to intravenous fluid bags as this is dangerous.

There is a clear need for guidance on IV fluid therapy for general areas of hospital practice, covering both the prescription and monitoring of IV fluid and electrolyte therapy, and the training and educational needs of all hospital staff involved in IV fluid management.

The aim of this NICE guideline is to help prescribers understand the:

  • physiological principles that underpin fluid prescribing
  • pathophysiological changes that affect fluid balance in disease states
  • indications for IV fluid therapy
  • reasons for the choice of the various fluids available and
  • principles of assessing fluid balance.

In developing the guideline, it was necessary to limit the scope by excluding patient groups with more specialised fluid prescribing needs. It is important to emphasise that the recommendations do not apply to patients under 16 years, pregnant women, and those with severe liver or renal disease, diabetes or burns. They also do not apply to patients needing inotropes and those on intensive monitoring, and so they have less relevance to intensive care settings and patients during surgical anaesthesia. Patients with traumatic brain injury (including patients needing neurosurgery) are also excluded. The scope of the guideline does not cover the practical aspects of administration (as opposed to the prescription) of IV fluids.

It is hoped that this guideline will lead to better fluid prescribing in hospitalised patients, reduce morbidity and mortality, and lead to better patient outcomes.

You can read the guideline on NICE's website.