Intravenous Fluid Therapy: Intravenous Fluid Therapy in Adults in Hospital [Internet]

London: Royal College of Physicians (UK); 2013 Dec.


Many adult hospital inpatients need intravenous (IV) fluid therapy to prevent or correct problems with their fluid and/or electrolyte status. This may be because they cannot meet their normal needs through oral or enteral routes (for example, they have swallowing problems or gastrointestinal dysfunction) or because they have unusual fluid and/or electrolyte deficits or demands caused by illness or injury (for example, high gastrointestinal or renal losses). Deciding on the optimal amount and composition of IV fluids to be administered and the best rate at which to give them can be a difficult task, and decisions must be based on careful assessment of the patient’s individual needs.

Despite the relative complexity of estimating a patient’s IV fluid needs, assessment and prescription is often delegated to healthcare professionals who have received little or no specific training on the subject. Indeed, the task of prescribing IV fluids is often left to the most junior medical staff, who frequently lack the relevant experience. This problem was highlighted by a 1999 National Confidential Enquiry into Perioperative Deaths (NCEPOD) report, which found that a significant number of hospitalised patients were dying as a result of the infusion of too much or too little fluid. The report then recommended that fluid prescribing should be given the same status as drug prescribing. Unfortunately this has not yet occurred, and although inappropriate fluid therapy is rarely reported as being responsible for patient harm, it remains likely that as many as 1 in 5 patients on IV fluids and electrolytes suffer complications or morbidity due to their inappropriate administration.

Errors in prescribing IV fluids and electrolytes are particularly likely in emergency departments, acute admission units, and general medical and surgical wards rather than in operating theatres and critical care units because patients in more general areas usually have less cardiovascular monitoring and the staff may have less experience of fluid prescribing. Indeed, surveys have shown that many staff who prescribe IV fluids in such areas know neither the likely fluid and electrolyte needs of individual patients, nor the specific composition of the many choices of IV fluids available to them. Standards of recording and monitoring IV fluid and electrolyte therapy may also be poor in these settings, and staff may fail to reassess and respond to patients’ inevitable changes in IV fluid and electrolyte status over time.

In addition to the problems above, there is also considerable debate among IV fluid and electrolyte experts about the best IV fluids to use, particularly for more seriously ill or injured patients. There is therefore wide variation in clinical practice. Many reasons underlie the ongoing debate, but most revolve around difficulties in interpretation of both trials evidence and clinical experience, including the following factors:

  1. Many accepted practices of IV fluid prescribing were developed for historical reasons rather than through clinical trials.

  2. Trials cannot easily be included in meta-analyses because they examine varied outcome measures in heterogeneous groups, comparing not only different types of fluid with different electrolyte content, but also different volumes and rates of administration and, in some cases, the additional use of inotropes or vasopressors.

  3. Most trials have been undertaken in operating theatres and critical care units rather than admission units or general and elderly care settings.

  4. Trials claiming to examine best early therapy for resuscitation have actually evaluated therapy choices made after initial resuscitation with patients already in critical care or operating theatres.

  5. Many trials inferring best therapy for resuscitation after acute fluid loss have actually examined situations of hypovolaemia induced by anaesthesia.

In the light of all the above, 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 therefore to help prescribers understand the:

  1. physiological principles that underpin fluid prescribing

  2. pathophysiological changes that affect fluid balance in disease states

  3. indications for IV fluid therapy

  4. reasons for the choice of the various fluids available and

  5. principles of assessing fluid balance.

Publication types

  • Review

Grant support

Funding: National Institute for Health and Care Excellence