Pediatric Anesthesia: 4-2-1 Revisited

In 1957, Holliday and Segar found daily fluid reqs depend on metabolic demand. They derived the original maintenance fluid therapy equation (Holliday M.A., and Segar W.E.: The maintenance need for water in parenteral fluid therapy. Pediatrics 1957; 19: pp. 823-832), the so called 4-2-1 rule. As follows:

Hourly fluid requirements:
First 10kg of child weight x 4ml/kg
Second 10kg (10-20kg) x2ml/kg
every kg above this is 1ml/kg

Not included are fluid deficits, third-spacing, hypo/hyperthermia, or increased metabolic demands.

However, children that are acutely ill or with significant cardiac and renal dysfunction this formula doesn’t work as well. More recent literature recommends:

20-40ml/kg of balanced solution during anesthesia over 2-4hrs
Holliday et al. 2007

Miller also recommends reducing post-operative fluids to 2,1,0.5 rule (following same weights). Then after 12 hrs if patient cannot take PO, convert to 4-2-1 with D5 1/2NS.

If concern for Hypoglycemia, add D5 1/2NS at maintenance rate as piggyback to intra-op fluids. For patients on TPN, Miller recommends remaining on TPN but reducing rate by 1/3 to 40% and check glucose levels intraop.

Remember, mitochondrial disease children cannot get lactate containing solutions! Use glucose solutions instead, even up to 10%.

Newborn Considerations

Reduced fluid requirements in first days of life, as high ECF.

  • Day 1: 70ml/kg
  • Day 3: 80ml/kg
  • Day 5: 90ml/kg
  • Day 7: 120ml/kg

Preemies are slightly higher, and remember to give 10% glucose to prevent hypoglycemia for all newborns. Try not to bolus glucose and monitor BG.