Overview #
This guideline will focus on the use of commonly prescribed IV solutions used in resuscitation, replacement and maintenance of hospitalised patients. Electrolyte disturbances are discussed separately. IV fluids carry significant risks, particularly in elderly patients and those with comorbidities and it is important that all junior doctors seek the advice of a senior clinician where necessary.
Key Points:
- Commonly used resuscitation fluids are crystalloids such as 0.9% sodium chloride and Hartmann’s solution
- In adults, crystalloid resuscitation fluids are given as a 500mL bolus over 15 minutes. A lower volume of 250mL should be considered in patients with heart failure, chronic liver disease or chronic kidney disease.
- Patients on IV maintenance therapy should be on a strict fluid balance and have daily assessment of fluid status (including daily weights) and electrolytes. More frequent assessments should be considered in high risk patients.
- The advice of a senior clinician should be sought when prescribing fluids for patients with complex fluid balance or in those not responding to initial resuscitation fluids.
Indications #
Fluid regimen | Indication |
Resuscitation | Fluids are used to maintain perfusion in the acutely hypovolemic/ shocked patient:Significant hypotension/ hypovolaemia Significant blood loss*Sepsis Anaphylaxis Burns |
Replacement | Used to replace existing or ongoing fluid loss where it is not feasible to do so orally Vomiting and nasogastric tube lossDiarrhoea and stomal lossUrinary losses Drain output Ongoing blood loss Insensible losses (eg. sweating, respiratory, stool)- increased in burns, febrile patients |
Maintenance | Provide the baseline daily fluid requirements for patients unable to maintain them orally Nil by mouth patientsProlonged fasting pre-procedurePost major bowel surgeryBowel obstruction Ileus Not tolerating oral intake (eg. significant ongoing vomiting) |
*Patients with significant blood loss should be resuscitated with blood products. Prescribing blood products is discussed in a separate guideline {hyperlink to blood transfusions guideline}
Types of fluids #
Commonly prescribed IV fluids (1,2)
Fluid type | Categorisation | Indication | Composition |
Human Plasma (for reference) | Na+: 135 – 145 mmol/LCl-: 95 – 105 mmol/LK+: 3.5 – 5.5 mmol/LHCO3-: 24 – 32 mmol/L Ca2+: 2.2 – 2.6 mmol/L | ||
0.9% NaCl | Isotonic Crystalloid | Fluid resuscitation Replacement Maintenance | Na+: 154 mmol/LCl-: 154 mmol/L |
Hartmann’s solution | Isotonic Crystalloid | Fluid resuscitation Replacement Routine maintenance | Na+: 131 mmol/LCl-: 111 mmol/LK+: 5 mmol/LHCO3-: 29 mmol/L (lactate)Ca2+: 2 mmol/L |
5% Dextrose | Isotonic (physiologically hypotonic)Crystalloid | Routine maintenance | Glucose: 50 g/L |
4% Albumin* | Colloid | 2nd line fluid resuscitation | Albumin: 40 g/LNa+: 140 mmol/LCl-: 128 mmol/L |
Risks #
While IV fluids are very commonly prescribed by junior doctors, they still have the potential to cause complications, particularly in those who are elderly or who have particular comorbidities. It is important to be aware of these risks and perform a careful fluid assessment of all patients as well as review of serum electrolytes prior to prescribing IV fluids.
Complications of IV fluid therapy (3)
{{Acute pulmonary oedemaPeripheral oedema Hypernatraemia (associated with 0.9% NaCl)Hyponatraemia (associated with 5% dextrose)Hyperkalaemia (associated with solutions with added K+)Hypokalaemia (inadequate K+ replacement)Hyperchloraemic metabolic acidosis (associated with 0.9% NaCl)Hypovolaemia (inadequate fluid replacement)}} |
To reduce risk of complications, all patients on IV fluid therapy should have a daily fluid assessment and blood tests including UEC and CMP to monitor electrolytes. The necessity of ongoing IV fluids should also be constantly reassessed and IV fluids should be ceased when no longer required.
Performing a fluid assessment (3)
Fluid Status | Signs |
Hypovolemic | Vitals: hypotension (SBP <100), tachycardia (HR >100)Peripheries: Capillary refill time >2 secondsCool and pale Decreased skin turgor Weak pulses FaceDry mucous membranesSunken orbits Absent JVPReview fluid balance chartReview blood testsUEC: ↑ Cr, ↓ eGFR, ↑ Ur or ↑ Ur:Cr ratio may indicate pre-renal AKIFBE: ↑ Haematocrit can indicate dehydrationCMP: ↑ Ca can occur in dehydrationAlbumin: ↓ Albumin makes fluid assessment complex as a patient may appear peripherally overloaded despite being intravascularly deplete |
Hypervolemic | Patient weight (ideally with comparison to previous euvolemic baseline weight)Elevated JVP (>3 cm)Signs of pulmonary oedema Vitals: ↑ RR, ↓ SpO2Coarse bibasal cracklesPleural effusion: dullness to percussion, decreased air entry S3 gallop rhythm Ascites Peripheral oedema (sacral, lower limb)Review fluid balance chart including daily weights |
Contraindications #
Several conditions, although not considered absolute contraindications, do increase the risk associated with giving IV fluid therapy and should prompt further consideration of the type, volume and rate of fluid provided. In these patients, junior doctors should #seek the advice of a senior clinician when prescribing IV fluids.
Conditions with increased risks associated with IV fluid therapy (consider reduced rate of infusion)
Condition | Risk |
Heart failure (HF) | Fluid overload |
Chronic liver disease (CLD) | Fluid overload, 0.9% saline should particularly be avoided in patients with CLD |
Chronic kidney disease (CKD) | Fluid overload, electrolyte disturbance |
Diabetic ketoacidosis (DKA) in paediatric patients* | Cerebral oedema |
Hyponatraemia | Osmotic demyelination (if corrected too rapidly) |
*Rehydration is still as key aspect of DKA management and these patients still require resuscitation and replacement fluids however the Royal Children’s Hospital Guidelines recommend this be done at a reduced rate for children (eg. 10ml/kg resuscitation fluids, ⅔ maintenance fluids)
Prescribing #
Resuscitation
Indicated in an acutely hypovolemic patient (see signs above)
Resuscitation fluid regimen for adults (3)
{250-500 ml IV bolus of crystalloid (0.9% NaCl or Hartmann’s) over 15 minutes Reassess status at 15 minutes and if necessary give another bolus, up to 2000 ml in the first 60 minutes. Seek senior advice. |
- A lower volume (250mL bolus) is indicated for those at risk of fluid overload (HF, CKD, CLD) or those at risk of cerebral oedema (DKA), if concerned an even lower volume may be necessary (eg. 100ml bolus) and always seek senior advice
- 5% Dextrose is NOT to be used as a resuscitation fluid as it does not increase intravascular volume
- Always remember to #seek senior assistance in a deteriorating patient, particularly if they are not responding to initial resuscitation fluids (3,4)
- Take particular care when managing the fluid overloaded, hypoperfused patient. In these cases junior doctors should #seek the advice of a senior clinician and consider that these patients may require ICU input and potentially inotropic support.
- When prescribing resuscitations fluids consider undertaking a review of the patient’s medications. Antihypertensives and diuretic may be contributing to hypoperfusion.
The use of albumin in fluid resuscitation
The use of colloid solutions in the resuscitation of hypovolemic patients is controversial. Albumin may be used as a second-line agent for those patients who fail to respond to standard crystalloid solutions, particularly in those for whom hypoalbuminaemia is likely contributing to their intravascular volume depletion such as patients with liver cirrhosis or nephrotic syndrome.
Hyperoncotic albumin, such as 20% albumin solution, may be useful in complex patients with total body fluid overload despite having intravascular volume depletion. The use of albumin in fluid resuscitation is a decision that should be made with the advice of a senior clinician. (4)
Replacement
Replacement fluids are generally added to the routine maintenance fluids schedule in order to account for existing and/ or ongoing losses.
- Those on IV fluid therapy should be kept on a fluid balance chart in order to calculate the necessary replacement fluids
- If a patient’s baseline weight is known, then fluid deficit can be calculated based on this
- Patients with complex fluid redistribution issues (see list below) may require a complex fluid plan. Advice of a senior clinician should be sought in these cases
Conditions associated with complex fluid and electrolytes redistribution (3)
Heart, liver or renal failureHypo/ hypernatraemia Gross oedema Severe sepsis Malnourishment and refeeding syndrome Post-operative fluid redistribution |
Maintenance
Adults
A general rule for prescribing IV maintenance fluids in adults is as follows (3):
25-30 ml/kg of water per day1 mmol/kg of potassium, sodium and chloride per day50-100 g of glucose per day |
Suggested maintenance fluid regime for adults:
- 1-2 L/day of Crystalloid + 1 L/day 5% dextrose (however maintenance fluids should be tailored to each individual patient, with careful consideration the patient’s fluid status and electrolyte requirements) (4)
- Generally to achieve the above regime each 1L bag should be run at a rate of 8-12 hourly
Considerations for adults
- In obese patients, use ideal body weight to calculate fluid and electrolyte needs
- If patient is at risk of fluid overload (see above), consider reducing rate of maintenance fluids
- Potassium may be provided on a check and replace basis (check potassium level and replace as necessary) or by calculating the maintenance requirements for the patient. Take care when replacing potassium in patients with altered renal function.
- Maintenance fluids should only be prescribed for a maximum of 24 hours at any one time (less in higher risk patients) and review of fluid balance, electrolytes and ongoing necessity of IV fluids should be considered prior to prescribing (3)
For information on paediatric fluid management please refer to Royal Children’s Hospital Intravenous Fluids Guideline
References #
- National Institute for Health and Care Excellence [internet]. London, UK: NICE; 2013. Composition of commonly used crystalloids; updated Dec 2016 [cited 2021 Sep 27]: Available from: https://www.nice.org.uk/guidance/cg174/resources/composition-of-commonly-used-crystalloids-table-191662813
- NPS Medicinewise [internet]. Surrey Hills, NSW: NPS MedicineWise; 2019. Consumer medicine information: Albumex 4; published Apr 2020 [cited 2021 Sep 27]: Available from: https://www.nps.org.au/medicine-finder/albumex-4-solution-for-infusion#6.7-physicochemical-properties
- National Institute for Health and Care Excellence [internet]. London, UK: NICE; 2013. Intravenous fluid therapy in adults in hospital; updated May 2017 [cited 2021 Sep 27]: Available from: https://www.nice.org.uk/guidance/cg174/chapter/1-Recommendations#principles-and-protocols-for-intravenous-fluid-therapy-2
- UpToDate [internet]. Waltham, MA: UpToDate Inc; 2019. Maintenance and replacement fluid therapy in adults; updated 2021 [cited 2021 Oct 5]: Available from: https://www.uptodate.com/contents/maintenance-and-replacement-fluid-therapy-in-adults
Contributors
Reviewing Consultant/Senior Registrar
Dr Sam Slater
Dr Adam Steinberg