Intraoperative fluid management: infants
Advanced, Clinical Subspecialties
Intraoperative fluid management for infants is complex and often presents challenges to the anesthetic and surgical teams. Typical intraoperative practice involves administration of IV fluids to meet maintenance fluid requirements, replace any fluid deficits as a result of pre-operative fasting and disease-specific loses, in addition to ongoing losses incurred during the surgical procedure. The choice for which IV fluid to administer should be tailored to meet patient-specific requirements; however, isotonic solutions such as lactated ringers or 0.9% normal saline should generally be used intraoperatively. No dextrose should be added to IV solutions in otherwise healthy infants unless there is specific concern for hypoglycemia.
To account for preoperative fasting, Furmen et al (1975) recommended calculating the hourly maintenance requirement, multiplying that by the number of hours the patient was fasting prior to surgery, and administering half of that volume in the first hour of surgery and the rest over the following 2 hours. This was further simplified in 1986 by Berry, who recommended administering a bolus dose of 25mL/kg in children 3 years and younger and 15mL/kg in patients 4 and older within the first hour of surgery.
Updated definition 2020:
There’s no hard and fast rule when it comes to the topic of perioperative fluid management. The following traditional approach is described throughout textbooks and continues to be used today.
Fluid requirements and replacement can be divided into three categories: maintenance, deficit, and replacement. Isotonic solutions (Lactated Ringer’s, Normal Saline, or Plasmalyte) are generally used for intraoperative repletion and boluses. Glucose-containing fluids should NOT be used for boluses. If there is concern for risk of hypoglycemia, D5-0.45%NS can be given as an infusion at maintenance rate.
Maintenance fluids compensate for ongoing normal losses.
The following is the Holliday-Segar formula for estimating maintenance fluid requirements in children. This is the classic “4-2-1” rule taught in pediatrics.
- 0-10 kg —> 4 ml/kg/hr
- Then 11-20 kg —> 40 ml + 2 ml/kg/hr
- Then > 20 kg —> 60 ml + 1 ml/kg/hr
For example, a 25 kg child would have a maintenance rate of 65 ml/hr.
Deficit fluids are for losses prior to surgery (e.g. hours NPO).
This can be estimated by multiplying the child’s hourly maintenance rate (as calculated per 4-2-1) by the number of hours the child has fasted. 50% of this deficit is replaced in the first hour and the remaining 50% in the next two hours.
Replacement fluids are given to meet ongoing intraoperative losses (e.g., insensible losses, increased metabolic demands, blood loss). The recommended rates can range greatly. Minor surgical procedures may require 1 ml/kg/hr while major abdominal procedures may require up to 15 ml/kg/hr.
After further evaluation, the Holliday-Segar rule was found to be inaccurate for acutely ill children or in those with cardiac or renal dysfunction. Therefore, the recommendation for intraoperative fluid resuscitation was changed to a simple 20-40 ml/kg bolus of isotonic fluid over the course of the anesthetic.