Fluid therapy is a topic that sometimes gets overlooked by veterinarians, partly because there is a misconception that developing fluid plans can be very difficult.
However, if you keep it simple, you can develop a tailored fluid therapy plan for you patient that is much better than a blanket ‘twice maintenance’ rate.
There are 4 basic components to a fluid therapy plan that you need to think about:
Perfusion deficits need to be corrected immediately. Start with a 10mls/kg IV fluid bolus of buffered crystalloids and repeat as necessary to shock volumes (60mls/kg for cats, 90mls/kg for dogs) until clinical parameters improve.
Once you have corrected your perfusion deficits, then you start correcting dehydration deficits. Correction of dehydration is generally done over a course of 24 hours.
Maintenance requirements are fairly standard and formulas are readily available in many sources.
Determining ongoing losses can be a bit tricky, but you need to try your best to include this in the fluid plan. Patients that are vomiting, have diarrhoea, polyuric etc, will need extra fluid to cover for ongoing losses. These losses can be measured – by weighing the faeces, weighing absorbent bedding if the patient has urinated on it, or by rough estimation.
So when taking these 4 components of a fluid therapy plan into account, you will soon see that twice maintenance is not enough!
The final and most important part of every fluid therapy plan is reassessment. Reassess your patient every couple hours to determine if your plan is appropriate and adjust accordingly.