Intravenous fluids

Take home messages

• Decide if you're resuscitating or maintaining
• Review what impact your fluids are having
• Don't give colloids

Crystalloids

Crystalloids are water-based solutions with added solutes (electrolytes or glucose). They differ in their composition, which determines their distribution throughout the body.

• Once the glucose is metabolised, 5% glucose effectively becomes free water (i.e. not limited to the extracellular space) and so is not suitable for fluid resuscitation as very little remains in the intravascular compartment
• 'Normal’ Saline and ‘Balanced’ Crystalloids (such as Plasma-Lyte) are retained in the extracellular spaces (in plasma and the interstitium) and so are much more suitable for fluid resuscitation

Normal Saline

5% Dextrose

Plasma-Lyte

Hartmann’s Solution

4% Glucose with 0.18% NaCl

Colloids

Colloids have been popular for their use as plasma volume expanders. This is because they are predominantly retained within the intravascular space (at least initially). They are a crystalloid base with added colloid substance that does not freely diffuse across cell membranes. 

Colloids do eventually leak into the interstitium, especially in:

• Sepsis
• Trauma
• Endothelial glycocalyx injury

And can then have the reverse osmotic effect of dragging fluid out of the vasculature with them, which is distinctly suboptimal.

For various reasons (including anaphylaxis and AKI), their use has fallen out of favour.

However, you should be aware of their chemical classification and the pros and cons associated with each. 

Starches

Dextrans

Gelatins

IV fluid Summary Sheet

Our videos

Useful Tweets and resources

IV Fluid Guidance – don’t drown in confusion!

IV fluid policy Written by: Dr Jonny Wilkinson– Consultant in ITU and Anaesthesia and NICE IV Fluid Lead Dr Lisa Yates – Clinical Fellow in ITU Additions from Dr Ashley Miller (@icmteaching). …

Critical Care NorthamptonView all posts by Jonny Wilkinson

Primary FRCA Toolkit

Members receive 60% discount off the FRCA Primary Toolkit. If you have previously purchased a toolkit at full price, please email anaestheasier@gmail.com for a retrospective discount.

Discount is applied as 6 months free membership - please don't hesitate to email Anaestheasier@gmail.com if you have any questions!

Just a quick reminder that all information posted on Anaestheasier.com is for educational purposes only, and it does not constitute medical or clinical advice.

Member downloads