TERMINAL
LEARNING OBJECTIVE
1.
Given a dehydration casualty in a combat environment and standard field
medical equipment and supplies, manage dehydration casualties, to prevent
further injury or death per the references. (FMST-HSS-1411)
ENABLING LEARNING OBJECTIVE
1.
Without the aid of references, given a description or list, identify
levels of dehydration, per the student handout. (FMST-HSS-1411a)
2.
Without the aid of references, given a description or list, identify
signs and symptoms of dehydration, per the student handout.
(FMST-HSS-1411b)
3.
Without the aid of references, given a description or list, identify
predisposing factors for dehydration, per the student handout.
(FMST-HSS-1411e)
4.
Without the aid of references, given a description or list, identify
treatments for various types of dehydration casualties, per the student
handout. (FMST-HSS-1411c)
5.
Without the aid of references, given a description or list, identify
preventive measures for dehydration, per the student handout.
(FMST-HSS-1411d)
6.
Without the aid of references, given a description or list, identify
the signs and symptoms of hyponatremia, per the student handout.
(FMST-HSS-1411f)
7.
Without the aid of
references, given a description or list,
identify the proper treatment of
hyponatremia, per the student handout. (FMST-HSS-1411g)
1. OVERVIEW
Water
accounts for about 45 to 70% of the average person’s weight. It is a
fundamental component of all cells in the body and is used to carry out normal
functions in the body such as circulation of blood, respiration, and elimination
of waste through the bladder and colon. Water is the basis of blood, lymphatic
fluids, perspiration, mucous, saliva, and digestive juices. Water lubricates
the joints, moisturizes the skin, provides moisture to all of the muscles and
internal organs, and helps regulate body temperature.
2. DEHYDRATION
Dehydration is loss of water and important blood salts like potassium (K+) and
sodium (Na+). Vital organs such as the kidneys, brain, and heart cannot
function without a minimum amount of water and salt. Dehydration is classified
into three levels - mild, moderate, and severe.
Causes:
Vomiting or diarrhea
Excessive urine output due to diuretic use
Excessive sweating, usually from exercises
Fever
Respiration
3. LEVELS OF AND SIGNS AND
SYMPTOMS OF DEHYDRATION
Dehydration is divided into mild, moderate, and severe based upon its
severity. With mild and moderate levels of dehydration, the following
signs and symptoms are most frequently experienced:
Less frequent urination
Thirst
Dry skin, decreased turgor
Fatigue
Light-headedness
Dizziness
Confusion
Dry mouth and mucous
membranes
Increased heart rate and
breathing
Casualties experiencing
severe dehydration may exhibit any of the above signs and symptoms along
with:
Weak, rapid pulse
Cold hands or feet
Hypotension
Dysuria
Lethargy
Cyanotic lips
4. PREDISPOSING FACTORS
Any of the following conditions/factors will predispose a person to increased
risk of suffering from dehydration:
Diseases/injuries, especially fevers, vomiting, diarrhea, heat rash, or sunburn
Use
of alcohol within the last 24 hours
Overweight/unfit
Over
40 years old
Fatigue/lack of sleep
Taking medication (especially for high blood pressure, colds, or diarrhea)
Previous heatstroke/severe heat exhaustion
Lack
of recent experience in a hot environment or improper acclimatization
5.
TREATMENT OF DEHYDRATION
Identify the cause and treat it. (i.e. vomiting/diarrhea)
Assess
the patient’s level of dehydration based on signs or symptoms
Lab Tests - blood tests will assist a clinician
(MO, PA or IDC) in determining imbalances and the best type fluid to give
patients to correct the problem. By obtaining blood tests the clinician can
specify if the problem is a water imbalance or an electrolyte imbalance.
Re-hydrate the patient:
- Oral re-hydration -
drinking fluids usually relieves mild dehydration.
- IV fluids - used for moderate to severe dehydration
6. PREVENTIVE MEASURES
A
common finding in dehydration casualties is that the individuals consume no
fluid or low volumes of fluid during daily activities. We all lose body water
daily through sweat, tears, urine, water vapor exhaled through respirations, and
stool. During heat exposure, body water is primarily lost as sweat.
Individuals can sweat approximately 1 liter per hour. The key to avoiding the
onset of heat illness is to maintain a body fluid balance and to minimize
dehydration during daily activities. A key point to remember is that
individuals normally do not perceive thirst until a deficit of approximately 2%
body weight loss has resulted from sweating. So an individual weighing 200
pounds wound not recognize being thirsty until he or she has lost 4 pounds of
sweat! The following are examples of some measures to prevent dehydration:
During activity -
drink ˝ to 1 quart of fluid per hour (do not exceed 12 canteens per
day)
Maintain a balanced diet
- you can recover fluid loss from the foods you eat as well as from the fluids
you drink. Fruits and vegetables can be a significant source of fluid intake.
MRE’s are formulated to provide the important electrolytes while in the field.
Avoid diuretic beverages
- minimize consumption of alcohol, coffee, tea, and carbonated beverages with
caffeine.
Educate troops -
education of troops is the key to prevention. There are many myths
regarding hydration handed down from Marine to Marine. You need to stress that
once troops are properly acclimatized to hot conditions, it is necessary to
continue to properly hydrate. Hydration is a daily requirement. Just because
they drank enough water yesterday does not decrease their need for today.
Troops should not use salt tablets to assist with dehydration unless directed to
by a Medical Officer.
7. HYPONATREMIA
The word hyponatremia means “to have a low level of sodium in the blood.”
Exertional or exercise hyponatremia, formerly called water intoxication, is a
life-threatening condition that has increasingly been found in recreational
hikers, marathoners, triathletes, and military infantry personnel. Having a low
plasma sodium level disturbs the balance of sodium and water and causes a rapid
influx of water into the brain, which in turn causes cerebral edema. As with
similar signs and symptoms of intracranial pressure (ICP) in head trauma, a
progression of neurologic symptoms with hyponatremia will occur, such as:
Headache
Mental status change
Nausea
Malaise (feeling tired)
Seizures
Coma
Causes: Exertional hyponatremia occurs when sodium and water loss in
sweat results in dehydration and sodium depletion. In trying to account for
this dehydration, the casualty over hydrates solely with water, creating a
dilution of sodium in the blood. Typically, these casualties have not consumed
sport electrolyte drinks or have consumed energy food supplements containing no
salt or in quantities insufficient to balance the loss of sodium in sweat.
Risk factors that may predispose a person to hyponatremia are:
Being a slower runner - slower runners are at a greater risk because of
the greater opportunity to consume water and a greater volume consumed because
they are running for a longer duration.
Chronic NSAID use - people who use nonsteroidal anti-inflammatory drugs
(like Motrin) are at a greater risk than those who do not.
Females - the most common finding in hyponatremia casualties.
Treatment: The first step in treatment is recognizing the disorder and
determining the severity. Management is based on the severity. Treatment of
hyponatremia should only be performed by a Medical Officer. If you suspect a
casualty has hyponatremia, CASEVAC as soon as possible.
REFERENCE
