January 30, 2007
Signs and Symptoms
Hypothermia is one of the more common injuries sustained in an aquatic environment. In fact, many drownings and near-drownings are secondary to hypothermia. Once an individual's core temperature decreases to the point of impairment, many things can happen. As the body's core temperature starts to decrease, various signs and symptoms appear which can be used as indicators for the level of impairment.
Initially, as the core temperature is in the range of 95 - 98 degrees Fahrenheit (mild hypothermia), the individual will usually present with:
When the core temperature drops to between 90 - 95 degrees Fahrenheit (moderate hypothermia), patient presentation will usually include:
If the core temperature reaches the range of 86 - 90 degrees Fahrenheit (severe hypothermia), the situation has taken a very serious turn for the worse. The patient now will most likely present with:
At a core temperature of 86 degrees, the possibility of cardiac arrest first appears, and its likelihood increases with every degree that the individual's core temperature falls below this value. It is possible to resuscitate patients with little or no vital signs due to hypothermia if the core temperature is above 60 degrees. If hypothermia is suspected, resuscitation should be attempted.
Treatment for Hypothermia
Treatment for patients with hypothermia is consistent whether they have severe or mild hypothermia. The first priority is a good patient assessment.
Consider the following:
As is always the case with any patient, a patent airway coupled with adequate breathing and perfusion are a must. Once those have been established, you should begin to assess the level of hypothermia.
NOTE: A simple temperature reading of the core rectal or tympanic temperature is not enough. Individual variations in physiologic responses preclude a simple categorization based on core temperature.
The signs and symptoms should also be considered as should any other injuries that might affect symptom presentation.
NOTE: There are currently two distinct trains of thought regarding hypothermic patient treatments. One states that once the patient is determined to be hypothermic, you should begin compressions and other treatments right away. Be aware, however, that any medications pushed on the patient will be released as a bolus as the patient warms to near normal temperatures. The second train of thought is to withhold most treatments except warming until a patient's core temperature has risen to near normal temperatures. Follow your local protocols.
Advanced treatment for hypothermia.
Severe hypothermia (core temperature 90 or less)
Drowning and Near-Drowning
Drowning can be defined as death by asphyxia due to immersion in water. Drowning does not cause as many deaths as commonly believed. Actually, drownings contribute to only 5% of all adult water related deaths, The majority of adult deaths are caused by deep-water diving accidents and other water sport injuries. Pediatric drownings, however, remain a leading cause of death.
Near-drowning is survival of at least 24 hours from suffocation due to immersion in water.
The treatment for near-drowning and drowning patients is essentially the same for pre-hospital providers. Never assume that a patient has drowned. Instead, treat all submersed non-breathing patients as near-drowning victims. As with all patients, avoid 'tunnel vision' and adequately assess any other injuries the patient might have. If possible, etiology or mechanism of injury can be acquired by asking bystanders.
Injuries that commonly exist with submersion patients are:
§ Gastric distension is the increased gastric pressure/size caused by the influx of either water or air into the stomach cavity. This can lead to decreased patient lung capacity, and must be reduced. Reduction can be performed by either:
· Intubating the patient to maintain airway and inserting a nasogastric tube to relieve the pressure in the stomach. (NOTE: If the presence of a deep-water diving injury cannot be ruled out, inflate both balloons with N.S. in the event that the patient must be placed in a barometric chamber.) or
· Placing your hand on the epigastric area and applying pressure until the distension is relieved. The patient and board should be rolled to the side to facilitate airway drainage. If available, suction should be applied.
· Treat additional injuries
· Perform resuscitative measures: EKG, IV, DEFIB etc.
· Package the patient to prevent hypothermia
Non-breathing patient without pulse.
Jellyfish and Portuguese Man-of-War
Jellyfish and Portuguese Man-of-war are both hollow-bodied animals that sting through nematocysts or stinging cells. These cells are located along the length of the animal's tentacles and inject venom into any organism they come in contact with. The nematocysts remain active even after the animal's death, so exposure to dead animals, or even their slime can cause injury.
Signs of exposure to nematocysts:
Treatment should always start with the ABC's and, once patient stabilization is ensured, removal of additional nematocysts to prevent additional envenomization. This is accomplished by lifting any visible tentacles off the victim with a stick or other object in order to prevent exposure to the rescuer.
Next, remove remaining nematocysts by rinsing the affected area with copious amounts of warm sea water, NOT fresh water. The warmer the sea water the better, but beware of possible thermal injury.
Inactivate whatever nematocysts are still present with vinegar.
Final removal of nematocysts (if necessary) can be accomplished by applying shaving cream (aerosol) and shaving. Be careful not to cause any skin breaks while shaving.
Topical lidocaine will reduce skin discomfort. Do not cover affected areas as this may activate remaining nematocysts, and transport. Beware of patient anaphylaxis.
Venom within the spines and pedicellariea of sea urchins can cause damage to organisms that come into contact with them. Pedicellariea are organs on the surface of the urchin between the spines. The spines may or may not remain in the affected organism, but the pedicellariea most likely will remain and look like cactus thorns. These pedicellariea must be removed as they continue to release venom even after breaking off from the urchin.
A purple stain on and around the wound is a good sign of urchin injury. It is a fluid released by the urchin to ward off predators and stains the skin. Immense pain not commensurate with the wound size, paresthesia, facial edema, and arrhythmias are other signs.
Wound and patient care is mainly supportive. Remove any visible pedicellariea with forceps and irrigate the wound. Standard wound protocols should be applied and patient transport to a definitive care facility to remove any remaining spines should be performed. Beware of anaphylaxis.
Stingrays cause some of the more serious marine life injuries that occur in marine waters. Stingrays are fish with large fins on the sides giving the fish the appearance of butterflies or bats. They also have a long, narrow tail which has poisonous spines near the tip that contain a cardiotoxic venom. These spines can penetrate the skin and, if the ray is stepped on, it will flail around, possibly breaking the spines off into the victim. These spines are barbed and very difficult to remove. Due to the flailing of the ray, the subsequent lacerations can be inordinately large and bleed profusely. Pain is out of proportion with the wound size and will increase during the first 24 days. Vasoconstriction causing blanching and dilatation causing erythema and edema are both reactions to the venom. Systemic effects of the venom are arrhythmias, asystole, slowed respirations, and convulsions.
Treatment should be prompt and aggressive. Irrigation with copious amounts of NS should be initiated. High flow oxygen should also be initiated. Be prepared to intubate. IV calcium gluconate may relieve muscle spasms. Consult medical control. Local IM analgesics and possibly narcotic analgesics may be necessary. Continue irrigation and transport the patient to a definitive care facility.
Deep-Water Diving Injuries
Barotrauma is one common injury that afflicts divers. It is caused by the pressure differential between the diver, the gases inside the diver, and the diver's environment.
Barotrauma is divided into two injuries depending on whether the damage was sustained during descent (the Squeeze) or ascent (the POPS).
Pressure, the nature of gases relating to pressure, and the ability of gases to dissolve into liquids are the root causes of barotrauma.
The relationship between pressure and volume in gases is:
Volume = K
where K is the universal gas constant (i.e. it has a value that does not change).
As pressure increases volume decreases and vice-versa.
A diver at the surface has normalized gas pressure within the body. As the diver descends, the pressure exerted by the water above the diver compresses the gases enclosed in various body spaces, the inner ear, the lungs, sinuses, GI tract etc. These gases compress forming vacuum-like pockets in these spaces. This could cause vascular engorgement, edema, and hemorrhage of the exposed tissues. Most often involved is the eustachian tube and the inner ear leading to perforation of the eardrum. This is called 'barotrauma of descent' or 'the Squeeze'.
During ascent, the reverse process can occur when the gases in the body spaces have equalized to the higher pressures occurring under water. As the diver ascends, if precautions are not taken to equalize the pressure through forced exhalation, or if an obstruction is present, the gases within these spaces expand. This can cause distention and possible rupture. If the lungs are involved, Pulmonary Over-Pressurization Syndrome (POPS) may occur. This is the rupture of the alveoli and subsequent filling of the spaces surrounding the alveoli, and could possibly lead to pneumothorax.
Air embolisms may also be formed during ascent in an manner similar to POPS. As the alveoli rupture and the gases move into the extra-alveolar spaces, pulmonary veins rupture and the gases form bubbles in the bloodstream. These bubbles can lodge in the brain causing ischemia and infarction. If the bubbles lodge in the left ventricle of the heart they may create vapor lock and cause poor cardiac output. The bubbles can also lodge in distal arterioles causing localized effects due to poor oxygen perfusion.
Signs and symptoms of air embolisms are many and varied. Sometimes the only noticeable signs are behavioral changes in the patient. The other signs and symptoms are:
Signs for air embolism include:
Symptoms for air embolism include:
Treatment for air embolisms from a pre-hospital viewpoint is mainly supportive.
First, maintain ABC's and ensure that any accompanying injuries are treated.
Second, locate the nearest facility with a decompression chamber and notify them of the situation.
Decompression sickness (also known as 'the Bends') is a result of partial gas pressure activity. Gases in a mixture such as compressed air follow Dalton's law.
Total pressure = (pressure of gas1) + (pressure of gas2) + (pressure of gas3) + ...
The total pressure of the gas mixture is equal to the sum of the partial pressures of the individual gases.
At the normal pressure of one atmosphere 78% of the air we breathe is nitrogen and 21% oxygen. When air is compressed in diving tanks it too is composed of 78% nitrogen and 21% oxygen.
The law of dissolved gases, or Henry's law, states:
Percentage of a gas dissolved in solution =
of the gas × 100
Now, how does that apply? Well, consider this, if you are breathing normal air at normal pressure, the amount of dissolved nitrogen in your bloodstream is around 78%. As you descend into water, the pressure around you increases and the air you breathe is compressed within your lungs. At a depth of 33 feet the pressure is 2 atmospheres, and the amount of nitrogen and oxygen dissolved into your bloodstream is effectively doubled. These dissolved gases then perfuse into the tissues where the oxygen is used in metabolic processes. Since the nitrogen in the blood is effectively inert - that is, it is not used by tissues as is oxygen - it must be removed through exhalation.
Upon ascending, the pressure exerted by the water decreases and the partial pressure of the dissolved gases increases. This causes bubbles to form because the body tissues can only keep so much dissolved gas in solution. This can have various implications, depending on the tissues involved.
Unlike air embolisms, which cause gas bubbles in the bloodstream, decompression illness causes gas bubbles in other tissues such as the joints and the nervous system. The presence of gas bubbles in the joints causes limb pain due to increased pressure in the joints. It also causes paresthesia and paralysis when gas bubbles affect the nerves and spinal column.
Signs for decompression sickness include:
Symptoms for decompression sickness include:
From a pre-hospital viewpoint, treatment for decompression sickness is, as with air embolisms, mainly supportive.
First, maintain ABC's, and ensure that any accompanying injuries are treated.
Second, locate the nearest facility with a decompression chamber notify them of the situation.
Scuba Diving and Air Travel
SCUBA diving and airplane travel do not mix. The combination of increased amounts of gases in the bloodstream and tissues and the decreased pressure inherent with air travel cause an increased chance of both air embolism and decompression sickness. It is recommended that air travel not follow SCUBA diving by a time of less than 24 hours. If responding to a call involving aircraft passengers, be alert for the warning signs associated with both of these illnesses. Applicable treatment for either illness, if present, should be initiated.
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