The Holliday-Segar nomogram offers an estimation of daily fluid loss and consequent fluid requirements with the following guidelines:
- 100 ml per kilogram for the first 10 kilograms of weight.
- 50 ml per kilogram for the next 10 kilograms of weight.
- 20 ml per kilogram for the remaining weight.
Although the consideration of fluid needs is typically done on a 24-hour basis, hospital infusion pumps are designed for hourly programming. Therefore, the 24-hour total is often divided into approximate hourly rates for practicality, giving rise to the “4-2-1” formula:
- 100 ml/kg/24-hours translates to 4 ml/kg/hr for the initial 10 kilograms.
- 50 ml/kg/24-hours corresponds to 2 ml/kg/hr for the subsequent 10 kilograms.
- 20 ml/kg/24-hours equates to 1 ml/kg/hr for the remaining weight.
In most practical cases, especially in critical care settings, calculating the the total daily fluids is of great usefulness.
