Before any IVMT takes place, fluid management should be considered. Water accounts for approximately 60% of the overall body mass of an average 70kg human. 60% accounts for 42 litres of water. This body water is divided into two separate components, intracellular and extracellular.
Intracellular accounts for 2/3rds of that 60% so approximately 40% of body mass (28 litres water). This is water that is kept within cells. Often, lower in an elderly person and a person who is malnourished.
Extracellular accounts for the remaining 1/3rd of the water mass (20%- 14 litres water). This is the amount of water living outside of cells. This is further divided into intravascular (1/4 of extracellular water – 3.5 litres water) and interstitial ((tissue space, ¾ of extracellular water – 10.5 litres water).