WHO HYDRATION PLANS - ANATOMY AND PHYSIOLOGY - 2024

The hydration plans of the WHO (World Health Organization) are defined according to this entity as a set of behaviors and measures to be followed whose purpose is to restore and maintain the hydroelectric balance of an individual. They are also called rehydration plans.

These plans are well described and differentiated. They especially take into account the hydration status of the patient through characteristic signs or symptoms. There are many diseases, syndromes, conditions and clinical entities capable of altering the hemodynamics of the human body due to their pathophysiological characteristics.

It is at this point that the importance of hydration plans is denoted, since they prevent dehydration early or treat it immediately, thus avoiding the evolution to states in which the individual's life is compromised.

Physiology of body fluids

Liquids are the fundamental component of the human body, they represent 70% of the total body weight of an individual under normal conditions. However, body fluids are compartmentalized within the human anatomy.

The compartments are named in relation to whether they are inside cells or outside of cells. The two most voluminous compartments are the intracellular compartment and the extracellular compartment.

The intracellular compartment contains two thirds of the total body water; on the other hand, the extracellular compartment has the remaining third.

To his sees; The extracellular compartment is divided into two subcompartments called intravascular (25% extracellular fluids) and interstitial (75% extracellular fluids).

Oral rehydration salts

Oral rehydration salts (ORS) are a set of salts and / or substances used in rehydration plans according to the WHO for the treatment of dehydration.

The WHO describes ORS as the fastest, safest, and cheapest way to prevent and treat electrolyte imbalances. Its most common presentation is in the form of envelopes, inside which are the salts in powder form. These are diluted in a certain amount of water.

Many different laboratories around the world release ORS, but regardless of the source or the brand, oral rehydration salts must be composed of the following elements:

- 20g of anhydrous glucose.

- 3.5 g of sodium chloride.

- 2.5 g of sodium bicarbonate.

- 1.5 g of potassium chloride.

In case of not having ORS available to apply the rehydration plans that include them, the WHO suggests using this recipe: dilution in a liter of water of 6 level tablespoons of sugar and a tablespoon of salt. Some doctors in underdeveloped countries have incorporated the juice of a lemon or ¼ teaspoon of bicarbonate.

However, this last recipe is very controversial and its use has been relegated to cases of extreme need, since it is quite imprecise and on certain occasions it can generate serious complications, such as hyperosomolar coma in pediatric patients.

Crystalloids and colloids

The name of crystalloids is attributed to liquids that in medicine are used to restore or supply the human body's needs for water and electrolytes.

The most widely used today are 0.9% saline solutions (isotonic), 3% saline (hypertonic) and 0.45% saline (hypotonic), lactated ringer's solution and dextrose solution.

For their part, colloid solutions in medicine are those whose oncotic pressure is similar to the oncotic pressure of plasma.

For this reason they are used to retain water in the intravascular space; that is why they are called plasma expanders. The most widely used today is albumin.

Dehydration

Dehydration is defined as a water and electrolyte imbalance whose multifactorial genesis is attributable to two main factors: decreased intake and increased fluid loss. In the context of fluid loss, two mechanisms are described:

Sensitive losses

Fluid that is excreted through urine, feces, or sweat. They are quantifiable.

Insensitive losses

Fluid that is lost through respiration (lungs) or evaporation (skin). It has the characteristic that it is not measurable.

Signs and symptoms

Depending on the severity of dehydration, it will be expressed with a specific symptomatology. From there the following classification arises:

Mild dehydration

In this type of dehydration, the percentage loss of body fluids is <6%. Her clinical examination generally tends to normal; the patient may be thirsty.

Moderate dehydration

In this type of dehydration, the percentage loss of fluids is> 6% to 30%, it presents a decrease in the turgor and elasticity of the skin, sunken eyes, dry mucous membranes, irritability, nausea, vomiting and great thirst.

Severe dehydration

Percentage loss of body fluids> 30%, drowsy, lethargic patient, sunken eyes, dry mucous membranes, tachycardia, hypotension, positive fold sign and anuria. General hemodynamic compromise.

Hydration plans according to the WHO

The World Health Organization classifies rehydration plans depending on the severity of the dehydration state. These plans are applied to individuals with a potentially dehydrating illness or syndrome, such as acute diarrhea.

Plan a

Patient who tolerates the oral route. If it is less than 2 years old, 50 to 100 cc of oral rehydration salts are applied for each liquid evacuation that it presents.

If you are older than 2 years, you should consume 100 to 200 cc of ORS for each fluid evacuation.

Plan A applies to individuals who do not have any symptoms or to patients with mild dehydration.

Plan B

Oral rehydration salts should be administered by virtue of 50 to 100 cc per kg of body weight in a time of 4 to 6 hours, and then reevaluate.

Plan B applies to individuals with moderate dehydration symptoms who tolerate the oral route.

Plan C

It is applied to individuals with symptoms of severe dehydration or to individuals with moderate dehydration who cannot tolerate the oral route.

Moderate dehydration that cannot be tolerated by mouth

25 cc per kg of weight should be administered intravenously of physiological solution in the first hour, and the same amount must be repeated in the second and third hours. Then it must be reevaluated.

Severe dehydration

50 cc per kg of weight should be administered intravenously of physiological solution in the first hour, 25 cc of solution per kg of weight in the second hour and the latter repeated during the third hour. Then reevaluate.

References

1. Treatment of diarrhea. Recovered from: who.int
2. Body fluids and kidneys. Recovered from: dyndns.org
3. WHO articles Oral rehydration salts to reduce mortality from cholera. Recovered from: who.int
4. Dehydration Cienfuegos Health Science Journal. Recovered from: sld.cu
5. Hydration and dehydration. Recovered from: meditip.lat