IV Fluids Flashcards
What are the indications for IV fluids?
IV fluids should only be prescribed for patients whose needs cannot be met by oral or enteral routes. Where possible oral fluid intake should be maximised and IV fluid only used to supplement the deficit. Examples of when IV fluids may be required include:
- A patient is nil by mouth (NBM) for medical/surgical reasons (e.g. bowel obstruction, ileus, pre-operatively)
- A patient is vomiting or has severe diarrhoea
- A patient is hypovolaemic as a result of blood loss (blood products will likely be required in addition to IV fluid)
What are the two major categories of IV fluids?
IV fluids can be categorised into two major groups:
- Crystalloids: solutions of small molecules in water (e.g. sodium chloride, Hartmann’s, dextrose)
- Colloids: solutions of larger organic molecules (e.g. albumin, Gelofusine)
What are the commonly used fluids?
Commonly used fluids include:
- Sodium chloride 0.9% (Normal saline)
- Hartmann’s solution
- Sodium chloride 0.18% / Glucose 4%
- 5% Dextrose
What is the initial assessment for prescribing IV fluids?
The initial assessment involves assessing the patient’s likely fluid and electrolyte needs from their history, clinical examination and available clinical monitoring (e.g. vital signs, fluid balance).
What are the 5 Rs of prescribing IV fluids?
The 5 Rs are:
- Resuscitation
- Routine maintenance
- Replacement
- Redistribution
- Reassessment
What is the initial fluid bolus for resuscitation fluids?
The initial fluid bolus is 500 ml of a crystalloid solution (e.g NaCl 0.9%/Hartmann’s solution) over less than 15 minutes.
What should be done after administering the initial fluid bolus?
(in fluid resus).
After administering the initial 500 ml fluid bolus, the patient should be reassessed using the ABCDE approach, looking for evidence of ongoing hypovolaemia as in the initial assessment. If the patient still has clinical evidence of ongoing hypovolaemia, a further 250-500 ml bolus of a crystalloid solution should be given, then reassessed as before using the ABCDE approach. This process can be repeated if there is ongoing clinical evidence suggestive of the need for fluid resuscitation up until a total of 2000 ml of fluid is given. If hypovolaemia persists despite giving 2000 ml of fluid, expert help should be sought.
What are the daily requirements for IV fluids?
Daily maintenance fluid requirements(as per NICE guidelines):
- 25-30 ml/kg/day of water
- approximately 1 mmol/kg/day of potassium, sodium and chloride
- approximately 50-100 g/day of glucose to limit starvation ketosis (however note this will not address the patient’s nutritional needs)
What should be done for patients with ongoing abnormal fluid or electrolyte losses?
Recognising ongoing abnormal fluid or electrolyte losses can allow for a more tailored fluid prescription to prevent later complications. The amount of ongoing fluid or electrolyte losses should be estimated and added or subtracted from the standard routine maintenance fluid regimen to provide a more tailored fluid prescription.
What should be done for patients with redistribution and other complex issues?
Patients with fluid distribution issues or other complex issues should be prescribed fluids under the guidance of a senior expert to ensure appropriate fluids are prescribed.
When should a more cautious approach be taken to fluid prescribing?
When prescribing IV fluids, a more cautious approach should be taken for the following patient groups:
- Elderly patients
- Patients with renal impairment or cardiac failure
- Malnourished patients at risk of refeeding syndrome
What is the role of reassessment in fluid prescribing?
Reassessment plays a vital role in fluid prescribing, in both fluid resuscitation and ongoing daily maintenance. A patient’s fluid status is highly dynamic, and therefore frequent reassessment will allow for adjustment of the fluid prescription to best suit a patient’s needs. It’s particularly important to review if intravenous fluids are still required, to prevent unnecessary administration.
How should a patient be reassessed?
Reassessing a patient involves repeating the steps in the initial assessment, which includes:
Reviewing the patient’s history
Clinical examination
Clinical monitoring
Laboratory monitoring (blood tests).
What is the preferred method of fluid replacement when maintenance needs are more than 3 days?
Nasogastric fluids or enteral feeding is preferable when maintenance needs are more than 3 days.
What should be done for patients with post-operative fluid retention and redistribution?
Patients experiencing post-operative fluid retention and redistribution should be prescribed fluids under the guidance of a senior expert to ensure appropriate fluids are prescribed.
