"421 rule"

Rate of crystalloid per hour=

4mL/kg for first 10kg    (40)
+2mL/kg for next 10kg   (+20)
+1mL/kg for every next kg (+ (wt - 20 kg))

E.g. 110 mL/hr for a 70 kg pt

4-2-1 Maintenance Rate Calculator

Patient's weight in kg:
OR
Patient's weight in lbs:

Calculated maintenance infusion rate=

N.b.

Pediatric fluid bolus is 20mL/kg

Pediatric blood transfusion dose is 10cc/kg

Rates extrapolated for high mass (adults) may be inadequate, always titrate fluids based on patient needs and clinical context.

Avoid overloading patients with heart failure or end stage renal disease.

Avoid underhydrating patients who are dehydrated, in shock or burn victims.

Oliguria is <0.5 mL/kg/hour (see Normal urine output table)

See also:

• Estimated blood loss and initial fluid replacement table
• Crystalloid solutions
• Fluid Management

 

4-2-1 Maintenance Rate Quick Lookup Table

Weight	Weight	Rate
11 lbs	5 kg	20 mL/hr
22 lbs	10 kg	40 mL/hr
33 lbs	15 kg	50 mL/hr
44 lbs	20 kg	60 mL/hr
55 lbs	25 kg	65 mL/hr
66 lbs	30 kg	70 mL/hr
77 lbs	35 kg	75 mL/hr
88 lbs	40 kg	80 mL/hr
99 lbs	45 kg	85 mL/hr
110 lbs	50 kg	90 mL/hr
121 lbs	55 kg	95 mL/hr
132 lbs	60 kg	100 mL/hr
143 lbs	65 kg	105 mL/hr
154 lbs	70 kg	110 mL/hr
165 lbs	75 kg	115 mL/hr
176 lbs	80 kg	120 mL/hr
187 lbs	85 kg	125 mL/hr
198 lbs	90 kg	130 mL/hr
209 lbs	95 kg	135 mL/hr
220 lbs	100 kg	140 mL/hr

 

 

 

Content on this page has not been checked for accuracy. The author's credentials have not been confirmed. Always use multiple peer-reviewed scholarly sources and good clinical judgement in your decision making.

The Compendium platform was created by David Kwinter, MD, CCFP(EM).