As a full scope Family Medicine physician, severely ill infants and children can be some of the most stressful situations in our practice. Although norovirus and rotavirus infections are common, they can make children extremely ill as can other more severe forms of gastroenteritis such as Shigella, Salmonella or E. coli. All of these infections, as well as sepsis and trauma can make a previously healthy child critically ill in a matter of hours — which makes having a pediatric fluid calculator app essential.

Knowing how to replace fluids in children is both art and science. Calculations for bolus therapy, which are first provided to resuscitate the child, are covered in Pediatric Advanced Life Support (PALS). For children, this is typically 20ml/kg of isotonic saline.

For decades, providers have been taught the calculations of maintenance fluids from the paper published by Holliday and Segar in 1957. The Holliday-Segar method is still used to this day with providers utilizing the “4-2-1” rule. The fluid replacement can be calculated for 24hrs or on an hourly basis. The calculations are as follows:

  • 100 ml/kg for the 1st 10 kg of wt
  • 50 ml/kg for the 2nd 10 kg of wt
  • 20 ml/kg for the remaining wt

Which results in the following “4-2-1” rule:

  • 100 ml/kg/24-hours = 4 ml/kg/hr for the 1st 10 kg
  • 50 ml/kg/24-hours = 2 ml/kg/hr for the 2nd 10 kg
  • 20 ml/kg/24-hours = 1 ml/kg/hr for the remainder

The “higher level” calculations above this are those for maintenance and replacement of electrolytes: sodium, chloride and potassium. These are based on the clinical assessment of the child’s volume status.

For providers working in NICU and PICU settings, fluid calculations are second nature. For the rest of us, we have to think about it a bit! Typically, I turn to the various pediatric emergency apps that allow for weight/age/Broslow based treatments for a variety of situations including hypovolemia.

My pediatric emergency app of choice has been Pedi STAT. Here at we have reviewed Pedi STAT previously. We also included it in several “Top 10” app lists for Pediatrics and Family Medicine. Over the years, alternatives to Pedi STAT have come along including PalmPedi, BluCard, Pedi Crisis, Paediatric Emergencies, and most recently Pediatric Anesthesia. The latest entry, Rx Pediatric Dehydration, is focused solely on the calculations for fluid resuscitation for hypovolemic children.

This pediatric fluid calculator app is authored by a group of pediatric intensivists in India. The stated purpose of the app is to highlight the management of both fluids and electrolytes in pediatric dehydration. The description in the iTunes store states that the authors have chosen an “objective and almost mathematical approach” to the problem. The app is designed for pediatric intensivists but can actually be used by any provider in any specialty who may have to perform volume resuscitation on critically ill children.

Clinical Scenario

You are working in the emergency room when a mother brings in her 3 year old daughter who she believes has some type of infectious gastroenteritis. The child has had profuse vomiting and diarrhea for the past three days with poor oral intake. Upon arrival to the bedside, you find a pale appearing female with poor skin turgor and prolonged capillary refill. She is tachycardic and hypotensive. The nursing staff asks you what you would like to do next.

Video Review

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How to use the app in clinical practice

Rx Pediatric Dehydration is clearly meant to be used at the point of care for rapid calculations for volume replacement in a true pediatric emergency. The app is theoretically easy to use, but I found several “bugs” that forced me to close the app and reopen it to get it to reset data. The app could benefit from an intro screen to better explain what is happening in the background. Nonetheless, once you get the hang of it, you can pretty rapidly calculate the fluid replacement rates.

Evidence based medicine

This pediatric fluid calculator app uses accepted calculations for pediatric volume replacement that are evidence based. The app includes a section describing the “math” that the app uses in detail and the logic behind the process. It would be ideal if it had a bit more about that on the opening screen.

What providers would benefit from this App?

Providers who care for critically ill children in and out of the hospital from the original audience of pediatric intensivists to first-responders, students, residents and faculty in emergency medicine, pediatrics, and family medicine.

pediatric fluids app

Disclaimer: The views expressed are those of the author(s) and do not reflect the official policy of the Department of the Army, the Department of Defense or the U.S. Government.

  • Price
    • Free
    • Fills a need for a dedicated fluid calculator for pediatrics.
    • Clean and simple interface for data input and rapid calculations of fluid requirements.
    • Includes a section describing the calculations the app makes at each step.
  • Dislikes
    • Some “bugs” make data input challenging especially if you make an error.
    • Some of these functions are covered in other apps with broader appeal.
    • The app doesn’t reinforce the need for the 20 ml/kg bolus that is used in PALS.
    • The “final” output doesn’t make clear the type of fluid that should be utilized.
  • Overall

    An excellent idea for a dedicated fluid calculator app for pediatrics that is well referenced and initially looks easy to use, but is limited by some interface bugs and some issues with interpretation of the presented results.

  • Overall Score
  • User Interface

    Highly intuitive, but basic interface has data input bugs that must be squashed.

  • Multimedia Usage

    App works quickly and smoothly from one section to the other. No links to outside documents or websites.

  • Price

    Free app which is great, however, the bugs may turn some off.

  • Real World Applicability

    This is a potentially great resource, but hard to recommend for daily use due to the current interface issues and some issues interpreting the output from the calculator. Needs to be more user friendly for point of care use.

  • Device Used For Review

    iPhone 6S running iOS 9.1

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