fluid
Fluid Balance
Explain in detail the fluid compartments of the body, including distribution of fluid and electrolytes within each compartment and the movement between compartments.
In the average person water constitutes 60% to the total body weight.: 42L in a 70kg individual.
40% is intracellelular fluid, while remaining 20% is extracellular.
The extracellular fluid can be divided into plasma (from intravascular compartment) and interstitial fluid intracellular fluid (28 L, about 35% of lean bodyweight) extracellular - the interstitial fluid that bathes the cells (9.4 L, about 12%) plasma (also extracellular) (4.6 L, about 4-5%).
Fluid can cross from compartment to compartment by osmosis, which depends on solute gradient, and filtration, which is a result of hydrostatic pressure gradient.
Electrolyte composition: intracellular- low sodium and high potassium extracellular- high sodium and low potassium (only 2% of total body potassium is in extracellular fluid) low protein in interstitial fluid compared to high protein in intravascular compartment. Describe normal fluid and electrolyte requirements and increased requirements within common surgical problems such as persistent ileus or vomiting
Normal fluid and electrolyte
Water
Evaporative losses from skin and respiratory tract, sweat, water and electrolyte losses in urine and faeces: Skin 500, Lungs 400, Urine (0.5ml-1 ml /kg/ hr) 1500, Faeces 100. = 2500ml water lost. Usually balanced by an input of: ingested fluid 1500, solid food 800, metabolic water 400.
Estimate usual daily fluid requirement as 1.5ml / kg /hr = 1.5 x 70 x 24 = 2520
i.e. approximately 1.5 to 2.5 l of fluid in per day for a 70kg person.
Electrolytes
Sodium: 1 mmol / kg / day
Potassium 1 mmol / kg / day
i.e. 50 to 80 mmol of Sodium and of Potassium a day.
Abnormal losses
Losses from gut are common (vomiting). Usually replaced with 0.9% saline with 20mmol KCl.
Insensible losses usually equate to 0.5ml / kg
Explain in detail the fluid compartments of the body, including distribution of fluid and electrolytes within each compartment and the movement between compartments.
In the average person water constitutes 60% to the total body weight.: 42L in a 70kg individual.
40% is intracellelular fluid, while remaining 20% is extracellular.
The extracellular fluid can be divided into plasma (from intravascular compartment) and interstitial fluid intracellular fluid (28 L, about 35% of lean bodyweight) extracellular - the interstitial fluid that bathes the cells (9.4 L, about 12%) plasma (also extracellular) (4.6 L, about 4-5%).
Fluid can cross from compartment to compartment by osmosis, which depends on solute gradient, and filtration, which is a result of hydrostatic pressure gradient.
Electrolyte composition: intracellular- low sodium and high potassium extracellular- high sodium and low potassium (only 2% of total body potassium is in extracellular fluid) low protein in interstitial fluid compared to high protein in intravascular compartment. Describe normal fluid and electrolyte requirements and increased requirements within common surgical problems such as persistent ileus or vomiting
Normal fluid and electrolyte
Water
Evaporative losses from skin and respiratory tract, sweat, water and electrolyte losses in urine and faeces: Skin 500, Lungs 400, Urine (0.5ml-1 ml /kg/ hr) 1500, Faeces 100. = 2500ml water lost. Usually balanced by an input of: ingested fluid 1500, solid food 800, metabolic water 400.
Estimate usual daily fluid requirement as 1.5ml / kg /hr = 1.5 x 70 x 24 = 2520
i.e. approximately 1.5 to 2.5 l of fluid in per day for a 70kg person.
Electrolytes
Sodium: 1 mmol / kg / day
Potassium 1 mmol / kg / day
i.e. 50 to 80 mmol of Sodium and of Potassium a day.
Abnormal losses
Losses from gut are common (vomiting). Usually replaced with 0.9% saline with 20mmol KCl.
Insensible losses usually equate to 0.5ml / kg