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116 Cards in this Set

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What is a Respiratory Cycle?
One complete breath consisting of an inspiration and exhalation, including any pause between the movements.
What is Respiratory Rate?
The number of complete respiratory cycles that take place in 1 minute is the respiratory rate. An adult at rest normally has a respiratory rate of approximately 12 to 16 breaths per minute
What is Total Lung Capacity?
The total volume of air that the lungs can hold when filled to capacity. TLC is normally between five and six liters
What is Vital Capacity?
The volume of air that can be expelled from the lungs after a full inspiration. The average vital capacity is between four and five liters
What is Tidal Volume?
The volume of air moved in or out of the lungs during a single normal respiratory cycle. The tidal volume generally averages about one-half liter for an adult at rest. Tidal volume increases considerably during physical exertion, and may be as high as 3 liters during severe work.
What is Respiratory Minute Volume?
The total amount of air moved in or out of the lungs in a minute. The respiratory minute volume is calculated by multiplying the tidal volume by the respiratory rate. RMV varies greatly with the body’s activity. It is about 6 to 10 liters per minute at complete rest and may be over 100 liters per minute during severe work.
Explain Maximal Breathing Capacity and Maximum Ventilatory Volume.
The greatest respiratory minute volumes that a person can produce during a short period of extremely forceful breathing. In a healthy young man, they may average as much as 180 liters per minute (the range is 140 to 240 liters per minute).
Explain Maximum Inspiratory Flow Rate and Maximum Expiratory Flow Rate
The fastest rates at which the body can move gases in and out of the lungs. These rates are important in designing breathing equipment and computing gas use under various workloads. Flow rates are usually expressed in liters per second.
What is Hypoxia?
An abnormal deficiency of oxygen in the arterial blood. Severe hypoxia will impede the normal function of cells and eventually kill them.
Which part of the body is most vulnerable to the effects of Hypoxia?
The Brain
Air contains approximately 21 percent oxygen and provides an ample ppO2 of about 0.21 ATA at the surface. A drop in ppO2 below _____ ATA causes the onset of hypoxic symptoms.
0.16 ATA
What are the causes of Hypoxia?
The causes of hypoxia vary, but all interfere with the normal oxygen supply to the body. For divers, interference of oxygen delivery can be caused by:
a. Improper line up of breathing gases resulting in a low partial pressure of oxygen in the breathing gas supply.
b. Partial or complete blockage of the fresh gas injection orifice in a semiclosed-circuit UBA. Failure of the oxygen addition valve in MK 16.
c. Inadequate purging of breathing bags in MK 25.
d. Blockage of all or part of the air passages by vomitus, secretions, water, or foreign objects.
e. Collapse of the lung due to pneumothorax.
f. Paralysis of the respiratory muscles from spinal cord injury.
g. Accumulation of fluid in the lung tissues (pulmonary edema) due to diving in cold water while overhydrated, negative pressure breathing, inhalation of water in a near drowning episode, or excessive accumulation of venous gas bubbles in the lung during decompression. The latter condition is referred to as “chokes”. Pulmonary edema causes a mismatch of alveolar ventilation and pulmonary blood flow and decreases the rate of transfer of oxygen across the alveolar capillary membrane.
g. Carbon monoxide poisoning.
h. Breathholding.
Describe the symptoms of Hypoxia.
a. Loss of judgment
b. Lack of concentration
c. Lack of muscle control
d. Inability to perform delicate or skill-requiring tasks
e. Drowsiness
f. Weakness
g. Agitation
h. Euphoria
i. Loss of consciousness
What is the treatment for Hypoxia?
Treat with basic first aid and 100% oxygen. For SCUBA divers, bring the diver to the surface. For surface-supplied mixed-gas divers, shift the gas supply to alternative banks and ventilating the helmet or chamber with the new gas. Refer to Volume 4 for information on treatment of hypoxia arising in specific operational environments for dives involving semi-closed and closed-circuit rebreathers.
What is Hypercapnia?
An abnormally high level of carbon dioxide in the blood and body tissues.
What are the causes of Hypercapnia?
a. Excess carbon dioxide levels in compressed air supplies due to improper placement of the compressor inlet.
b. Inadequate ventilation of surface-supplied helmets or UBAs.
c. Failure of carbon dioxide absorbent canisters to absorb carbon dioxide or incorrect installation of breathing hoses in closed or semi-closed circuit UBAs.
d. Inadequate lung ventilation in relation to exercise level. The latter may be caused by skip breathing, increased apparatus dead space, excessive breathing resistance, or increased oxygen partial pressure.
Symptoms of hypercapnia usually become apparent when divers attempt heavy work at depths deeper then _____ FSW on air or deeper than _____ FSW on helium-oxygen.
120 FSW on air or deeper than 850 FSW on helium-oxygen.
What are the symptoms of Hypercapnia?
a. Increased breathing rate
b. Shortness of breath, sensation of difficult breathing or suffocation (dyspnea)
c. Confusion or feeling of euphoria
d. Inability to concentrate
e. Increased sweating
f. Drowsiness
g. Headache
h. Loss of consciousness
i. Convulsions
What diving related disorder speeds the onset of CNS oxygen toxicity and why?
Hypercapnia. Excess carbon dioxide dilates the arteries of the brain which increases the blood flow through the brain.
What is the treatment for Hypercapnia?
a. Decreasing the level of exertion to reduce CO2 production
b. Increasing helmet and lung ventilation to wash out excess CO2
c. Shifting to an alternate breathing source or aborting the dive if defective equipment is the cause.
What is Asphyxia?
A condition where breathing stops and both hypoxia and hypercapnia occur simultaneously.
What are the causes of Asphyxia?
a. There is no gas to breathe
b. When the airway is completely obstructed
c. When the respiratory muscles become paralyzed
d. When the respiratory center fails to send out impulses to breathe
Describe Carbon Monoxide Poisoning.
Carbon monoxide blocks hemoglobin’s ability to delivery oxygen to the cells, causing cellular hypoxia, and also poisons cellular metabolism directly.
What are the causes of Carbon Monoxide Poisoning?
Carbon monoxide poisoning is usually caused by a compressor’s intake being too close to the exhaust of an internal combustion engine or malfunction of an oil lubricated compressor.
Concentrations of CO2 as low as ______ ata (_______ ppm, or _____ %) can prove fatal.
0.002 ata (2,000 ppm, or 0.2%)
The symptoms of Carbon Monoxide Poisoning are almost identical to what other disorder?
Hypoxia
When Carbon Monoxide Poisoning develops gradually, what are the symptoms?
a. Headache
b. Dizziness
c. Confusion
d. Nausea
e. Vomiting
f. Tightness across the forehead
When will the full effect of Carbon Monoxide Poisoning be felt and why?
When the diver begins to ascend. While at depth, the greater partial pressure of oxygen in the breathing supply forces more oxygen into solution in the blood plasma. Some of this additional oxygen reaches the cells and helps to offset the hypoxia. In addition, the increased partial pressure of oxygen forcibly displaces some carbon monoxide from the hemoglobin. During ascent, however, as the partial pressure of oxygen diminishes, the full effect of carbon monoxide poisoning is felt.
What is the treatment of Carbon Monoxide Poisoning?
a. Get the diver to fresh air and seeking medical attention.
b. 100% Oxygen
c. Transport to a hyperbaric or medical treatment facility
d. Hyperbaric O2 therapy is the definitive treatment of choice and transportation for recompression should not be delayed except to stabilize the serious patient. Divers with severe symptoms (i.e. severe headache, mental status changes, any neurological symptoms, rapid heart rate) should be treated using Treatment Table 6.
What is Barotrauma?
Damage to body tissues from the mechanical effects of pressure, results when pressure differentials between body cavities and the hydrostatic pressure surrounding the body, or between the body and the diving equipment, are not equalized properly.
Barotrauma most frequently occurs during _______ but may also occur during _______.
Descent but may also occur during ascent.
For squeeze to occur during descent what five conditions must be met?
a. There must be a gas-filled space
b. The gas-filled space must have rigid walls
c. The gas-filled space must be enclosed.
d. The space must have penetrating blood vessels
e. There must be a change in ambient pressure
What is the most common type of barotraumas?
Middle ear squeeze
What is vertigo?
A false sensation of motion or spinning. The diver feels that he is moving with respect to his environment or that the environment is moving with respect to him, when in fact no motion is taking place.
What causes alternobaric vertigo of decent?
Frequent oscillations in middle ear pressure associated with difficult clearing may lead to a transient vertigo.
What is the treatment for alternobaric vertigo of decent?
Vertigo usually follows a Valsalva maneuver, often with the final clearing episode just as the diver reaches the bottom. Symptoms typically last less than a minute but can cause significant disorientation during that period. Descent should be halted until the vertigo resolves.
What causes caloric vertigo?
Having cold or warm water enter one ear and not the other
What are the symptoms of a middle ear squeeze?
a. Pain
b. Fullness in the ear
c. Hearing loss
d. Mild vertigo
What is the treatment for a middle ear squeeze?
a. Decongestants
b. Pain medication if needed
c. Cessation of diving until the damage is healed
d. If the eardrum has ruptured antibiotics may be prescribed as well. Never administer medications directly into the external ear canal if a ruptured eardrum is suspected or confirmed unless done in direct consultation with an ear, nose, and throat (ENT) medical specialist.
What is inner ear barotrauma with perilymph fistula?
Where the round window or oval window ruptures spilling inner ear fluids into the middle ear
What is inner ear barotrauma without perilymph fistula?
Where the pressure waves induced in the inner ear during round or oval window movements lead to disruption of the delicate cells involved in hearing and balance
What are the symptoms of inner ear barotraumas?
a. Persistent vertigo. The vertigo of inner ear barotrauma is generally described as whirling, spinning, rotating, tilting, rocking, or undulating. This sensation is quite distinct from the more vague complaints of dizziness or lightheadedness caused by other conditions. Often accompanied by symptoms that may or may not be noticed depending on the severity of the insult. These include nausea, vomiting, loss of balance, incoordination, and a rapid jerking movement of the eyes, called nystagmus. Vertigo may be accentuated when the head is placed in certain positions.
b. Hearing loss. The hearing loss of inner ear barotrauma may fluctuate in intensity and sounds may be distorted. Hearing loss is accompanied by ringing or roaring in the affected ear. The diver may also complain of a sensation of bubbling in the affected ear.
When do symptoms of inner ear barotrauma usually appear?
Abruptly during descent, often as the diver arrives on the bottom and performs his last equalization maneuver. However, the damage done by descent may not become apparent until the dive is over.
What is the treatment for suspected inner ear barotrauma?
They should be referred to an ear, nose and throat (ENT) physician as soon as possible. Treatment of inner ear barotrauma ranges from bed rest with head elevation to exploratory surgery, depending on the severity of the symptoms and whether a perilymph fistula is suspected.
Any hearing loss or vertigo occurring within 72 hours of a hyperbaric exposure should be evaluated as a possible case of _______________________.
Inner ear barotrauma
What precautions should be taken if you can not differentiate between inner ear barotrauma, AGE, or DCS and must treat?
The diver should be placed in a head up position and compressed slowly to allow adequate time for middle ear equalization. Clearing maneuvers should be gentle. The diver should not be exposed to excessive positive or negative pressure when breathing oxygen on the built-in breathing system (BIBS) mask.
What is alternobaric vertigo of ascent?
When the middle ear space on one side is overpressurized while the other side is equalizing normally and affects the inner ear balance mechanism.
What are the five Pulmonary Overinflation Syndromes?
a. Interstitial Emphysema
b. Mediastinal Emphysema
c. Subcutaneous Emphysema
d. Pneumothorax
e. Arterial Gas Embolism
What is Arterial Gas Embolism (AGE)?
An obstruction of blood flow caused by gas bubbles (emboli) entering the arterial circulation.
What are the most common causes of Arterial Gas Embolism (AGE)?
Exhaustion of air supply and the need for an emergency ascent is
What are the symptoms of Arterial Gas Embolism (AGE)?
a. Unconsciousness
b. Paralysis
c. Numbness
d. Weakness
e. Extreme fatigue
f. Large areas of abnormal sensations (Paresthesias)
g. Difficulty in thinking
h. Vertigo
i. Convulsions
j. Vision abnormalities
k. Loss of coordination
l. Nausea and or vomiting
m. Hearing abnormalities
n. Sensation similar to that of a blow to the chest during ascent
o. Bloody sputum
p. Dizziness
q. Personality changes
r. Loss of control of bodily functions
s. Tremors
What is the treatment of Arterial Gas Embolism (AGE)?
a. Basic first aid (ABC)
b. 100 percent oxygen
c. Immediate recompression
d. See Volume 5 for more specific information regarding treatment.
What is Mediastinal Emphysema?
Occurs when gas is forced through torn lung tissue into the loose mediastinal tissues in the middle of the chest surrounding the heart, the trachea, and the major blood vessels.
What is Subcutaneous Emphysema?
Occurs when that gas subsequently migrates into the subcutaneous tissues of the neck.
What are the symptoms of Mediastinal Emphysema?
Mild cases are often unnoticed by the diver. In more severe cases, the diver may experience mild to moderate pain under the breastbone, often described as dull ache or feeling of tightness. The pain may radiate to the shoulder or back and may increase upon deep inspiration, coughing, or swallowing.
What are the symptoms of Subcutaneous Emphysema?
a. Feeling of fullness around the neck
b. May have difficulty in swallowing
c. Voice may change in pitch
d. An observer may note a swelling or apparent inflation of the diver’s neck
e. Movement of the skin near the windpipe or about the collar bone may produce a cracking or crunching sound (crepitation)
What is the treatment for mild cases of Mediastinal and Subcutaneous Emphysema?
a. Nuero to rule out AGE or Pneumothorax.
b. 100 % O2 on the surface
What is the treatment for severe cases of Mediastinal and Subcutaneous Emphysema?
Recompression upon the recommendation of a DMO who has ruled out the occurrence of pneumothorax. Re¬compression is performed with the diver breathing 100 % O2 and using the shallowest depth of relief (usually 5 or 10 feet). An hour of breathing O2 should be sufficient, but longer stays may be necessary. The appropriate air table should be used dictated by the tender’s decompression obligation, but the ascent rate should not exceed 1 fpm. The delay in ascent should be included in bottom time when choosing the proper decompression table.
What is a pneumothorax?
Air trapped in the pleural space between the lung and the chest wall
What is a simple pneumothorax?
A one-time leakage of air from the lung into the chest partially collapses the lung, causing varying degrees of respiratory distress. This condition normally improves with time as the air is reabsorbed. In severe cases of collapse, the air must be removed with the aid of a tube or catheter.
What is a tension pneumothorax?
Leakage of air from the lung into the chest and the damaged lung allows air to enter but not exit the pleural space. Successive breathing gradually enlarges the air pocket eventually totally collapsing the lung. The lung, and then the heart, are pushed toward the opposite side of the chest, which impairs both respiration and circulation.
What are the symptoms of simple pneumothorax?
a. Sudden, sharp chest pain
b. Followed by shortness of breath
c. Labored breathing
d. Rapid heart rate
e. Weak pulse
f. Anxiety
g. Normal chest movements associated with respiration may be reduced on the affected side and breath sounds may be difficult to hear with a stethoscope.
What are the symptoms of tension pneumothorax?
They are similar to simple pneumothorax, but become progressively more intense over time. As the heart and lungs are displaced to the opposite side of the chest, blood pressure falls along with the arterial oxygen partial pressure. Cyanosis (a bluish discoloration) of the skin appears. If left untreated, shock and death will ensue.
What is the treatment for pneumothorax?
Nuero to rule out AGE. Mild pneumothorax can be treated by breathing 100 percent oxygen on the surface. Cases of pneumothorax that demonstrate cardio-respiratory compromise may require the insertion of a chest tube, largebore intravenous (IV) catheter, or other device designed to remove intrathoracic gas (gas around the lung)
What is Nitrogen narcosis?
The state of euphoria and exhilaration that occurs when a diver breathes a gas mixture with a nitrogen partial pressure greater than 4 ata.
For a dive on air, narcosis usually appears at a depth of approximately _____ fsw, is very prominent at a depth of ____ fsw, and becomes disabling at deeper depths.
130 fsw, is very prominent at a depth of 200 fsw
What are the symptoms of nitrogen narcosis?
a. Loss of judgment or skill
b. A false feeling of well-being
c. Lack of concern for job or safety
d. Apparent stupidity
e. Inappropriate laughter
f. Tingling and vague numbness of the lips, gums, and legs
What is the greatest hazard of nitrogen narcosis?
Disregard for personal safety
What is the treatment of Nitrogen Narcosis?
Bring the diver to a shallower depth where the effects are not felt. The narcotic effects will rapidly dissipate during the ascent
What are some ways to prevent Nitrogen Narcosis?
a. Experience
b. Frequent exposure to deep diving
c. Training
d. Use of Helium in place of Nitrogen (Mixed Gas).
Helium-oxygen mixtures should be considered for any dive in excess of _____ fsw.
150 fsw
What are the two types of oxygen toxicity experienced by divers?
a. Pulmonary Oxygen Toxicity
b. Central Nervous System (CNS) Oxygen Toxicity
When can pulmonary oxygen toxicity occur?
Whenever the oxygen partial pressure exceeds 0.5 ata. A 12 hour exposure to a partial pressure of 1 ata will produce mild symptoms and measurable decreases in lung function. The same effect will occur with a 4 hour exposure at a partial pressure of 2 ata. Long exposures to higher levels of oxygen, such as administered during Recompression Treatment Tables 4, 7, and 8.
What are the symptoms of pulmonary oxygen toxicity?
Begin with a burning sensation on inspiration and progress to pain on inspiration.
When can Central Nervous System (CNS) Oxygen Toxicity occur?
Whenever the oxygen partial pressure exceeds 1.3 ata in a wet diver or 2.4 ata in a dry diver. The reason for the marked increase in susceptibility in a wet diver is not completely understood. At partial pressures above the respective 1.3 ata wet and 2.4 ata dry thresholds, the risk of CNS toxicity is dependent on the oxygen partial pressure and the exposure time.
What are the factors affecting the risk of CNS Oxygen Toxicity?
a. Individual susceptibility
b. CO2 Retention. Hypercapnia greatly increases the risk of CNS toxicity probably through its effect on increasing brain blood flow and consequently brain oxygen levels. Hypercapnia may result from an accumulation of CO2 in the inspired gas or from inadequate ventilation of the lungs. The latter is usually due to increased breathing resistance or a suppression of respiratory drive by high inspired ppO2. Hypercapnia is most likely to occur on deep dives and in divers using closed and semi-closed circuit rebreathers
c. Exercise
d. Immersion in Water
e. Depth
f. Intermittent Exposure. Periodic interruption of high ppO2 exposure with a 5-15 min exposure to low ppO2 will reduce the risk of CNS toxicity
What are the symptoms of CNS Oxygen Toxicity?
VENTIDC:
V: Visual symptoms. Tunnel vision, a decrease in diver’s peripheral vision, and other symptoms, such as blurred vision, may occur
E: Ear symptoms. Tinnitus, any sound perceived by the ears but not resulting from an external stimulus, may resemble bells ringing, roaring, or a machinery-like pulsing sound
N: Nausea or spasmodic vomiting. These symptoms may be intermittent
T: Twitching and tingling symptoms. Any of the small facial muscles, lips, or muscles of the extremities may be affected. These are the most frequent and clearest symptoms
I: Irritability. Any change in the diver’s mental status including confusion, agitation, and anxiety
D: Dizziness. Symptoms include clumsiness, incoordination, and unusual fatigue
C: Convulsions. The first sign of CNS oxygen toxicity may be convulsions that occur with little or no warning
What are the three stages of a convulsion?
a. Tonic phase
b. Clonic phase
c. Postconvulsive depression
Describe the tonic phase of a convulsion.
At the height of the seizure, all of the muscles are stimulated at once and lock the body into a state of rigidity.
Describe the clonic phase of a convulsion.
After the tonic phase, the brain soon fatigues and the number of impulses slows and the random impulses to various muscles may cause violent thrashing and jerking for a minute or so.
Describe the postconvulsive depression phase.
After the convulsive phase, brain activity is depressed. During this phase, the patient is usually unconscious and quiet for a while, then semiconscious and very restless. He will then usually sleep on and off, waking up occasionally though still not fully rational. The depression phase sometimes lasts as little as 15 minutes, but an hour or more is not uncommon. At the end of this phase, the patient often becomes suddenly alert and complains of no more than fatigue, muscular soreness, and possibly a headache. After an oxygen-toxicity convulsion, the diver usually remembers clearly the events up to the moment when consciousness was lost, but remembers nothing of the convulsion itself and little of the postictal phase.
What is the treatment of CNS Oxygen Toxicity in the water?
Lower the oxygen partial pressure by ascending, shifting to a breathing mixture with a lower oxygen percentage. If a diver convulses, the UBA should be ventilated immediately with a gas of lower oxygen content, if possible. If depth control is possible and the gas supply is secure (helmet or full face mask), the diver should be kept at depth until the convulsion subsides and normal breathing resumes. If an ascent must take place, it should be done as slowly as possible to reduce the risk of an arterial gas embolism.
What is the Treatment of CNS Oxygen Toxicity in the chamber?
Remove the O2 mask. Keep the individual from thrashing against hard objects and being injured. After the convulsion subsides and the mouth relaxes, keep the jaw up and forward to maintain a clear airway until the diver regains consciousness.
What are some ways to prevent CNS Oxygen Toxicity?
a. Be sure the breathing apparatus is in good order
b. Observing depth-time limits
c. Avoiding excessive exertion
d. Heeding abnormal symptoms that may appear
e. Interruption of oxygen breathing with periodic “air” breaks
What are the symptoms of Type 1 DCS?
a. Itching or burning of skin usually accompanied by a rash
b. Swelling of lymph nodes
c. Pain
What are the symptoms of Type 2 DCS?
Bubble formation in the brain can produce blindness, dizziness, paralysis and even unconsciousness and convulsion. When the spinal cord is involved, paralysis and/or loss of feeling occur. Bubbles in the inner ear produce hearing loss and vertigo. Bubbles in the lungs can cause coughing, shortness of breath, and hypoxia, a condition referred to as “the chokes.” While not attributable to a specific organ system, unusual fatigue is a definite symptom of decompression sickness.
What is Hypothermia?
A lowering of the core temperature of the body
The unprotected diver will be affected by excessive heat loss and become chilled within a short period of time in water temperatures below _____ °F.
72°F
What are the symptoms of mild Hypothermia?
a. Uncontrolled shivering
b. Slurred speech
c. Imbalance
d. Poor judgment
What are the symptoms of severe Hypothermia?
a. Loss of shivering
b. Impaired mental status
c. Irregular heartbeat
d. Very shallow pulse or respirations
e. This is a medical emergency
What are the two methods of treating Hypothermia and describe them?
Passive and active rewarming and should be continued until the victim is sweating.
Passive: Remove all wet clothing, wrap victim in a blanket (preferably wool), place in an area protected from wind, if possible, place in a warm area (i.e. galley).
Active: Warm shower or bath, place in a very warm space (i.e., engine room).
To treat severe hypothermia avoid any exercise, keep the victim lying down, initiate only passive rewarming, and immediately transport to the nearest medical treatment facility.
What is Hyperthermia?
A rising of the core temperature of the body
Hyperthermia should be considered a potential risk any time air temperature exceeds _______ °F or water temperature is above _______ °F.
90°F or water temperature is above 82°F
An individual is considered to have developed hyperthermia when core temperature rises _______ °F above normal (98.6°F, 37°C).
1.8°F
What are the symptoms of hyperthermia?
a. High breathing rate
b. Feeling of being hot, uncomfortable
c. Low urine output
d. Inability to think clearly
e. Fatigue
f. Light-headedness or headache
g. Nausea
h. Muscle cramps
i. Sudden rapid increase in pulse rate
j. Disorientation, confusion
k. Exhaustion
l. Collapse
m. Death
What is the treatment of all cases of hyperthermia?
a. Immediately cool by remove clothing
b. Spray with a fine mist of lukewarm-to-cool water
c. Then fanning
d. Avoid whole body immersion in cold water or packing the body in ice as this will cause vasoconstriction which will decrease skin blood flow and may slow the loss of heat.
e. Ice packs to the neck, armpit or groin may be used.
f. Oral fluid replacement should begin as soon as the victim can drink and continue until he has urinated pale to clear urine several times.
g. If the symptoms do not improve, the victim shall be transported to a medical treatment facility. Severe hyperthermia is a medical emergency. Cooling measures shall be started and the victim shall be transported immediately to a medical treatment facility. Intravenous fluids should be administered during transport.
What is High Pressure Nervous Syndrome (HPNS)?
A derangement of central nervous system function that occurs during deep helium-oxygen dives, particularly saturation dives. The cause is unknown.
What are the symptoms of High Pressure Nervous Syndrome?
a. Nausea
b. Fine tremor
c. Imbalance
d. Incoordination
e. Loss of manual dexterity
f. Loss of alertness
g. Abdominal cramps and diarrhea develop occasionally.
h. In severe cases a diver may develop vertigo, extreme indifference to his surroundings and marked confusion such as inability to tell the right hand from the left hand.
HPNS is first noted between _____ and _____ fsw and the severity appears to be both depth and compression rate dependent.
400 and 500 fsw
What is Compression Arthralgia?
Pain in the joints during compression on deep dives.
What joints most commonly affected by Compression Arthralgia and describe the symptoms?
The shoulders, knees, writs, and hips are the joints most commonly affected. The fingers, lower back, neck, and ribs may also be involved. The pain may be a constant deep ache similar to Type I decompression sickness, or a sudden, sharp, and intense but short-lived pain brought on my movement of the joint. These pains may be accompanied by “popping” or “cracking” of joints or a dry “gritty” feeling within the joint.
The incidence and intensity of compression arthralgia symptoms are dependent on what factors?
a. The depth of the dive
b. The rate of compression
c. Individual susceptibility
What is Immersion Diuresis?
Blood which is normally pooled in the leg veins is translocated to the chest, causing an increase central blood volume. The body mistakenly interprets the increase in central blood as a fluid excess and a reflex is triggered leading to an increase in urination causing a condition called immersion diuresis
What is Immersion Pulmonary Edema?
Immersion in water can cause fluid to leak out of the circulation system and accumulate first in the interstitial tissues of the lungs then in the alveoli themselves.
What are the contributing factors to Immersion Pulmonary Edema?
a. Immersion in cold water
b. Negative pressure breathing
c. Overhydration pre-dive
d. Heavy exercise
What are the symptoms of Immersion Pulmonary Edema and when do they occur?
Consist primarily of cough and shortness of breath. The diver may cough up blood tinged mucus. Chest pain is notably absent. A chest x-ray shows the classic pattern of pulmonary edema seen in heart failure. May begin on the bottom, during ascent, or shortly after surfacing
What is the treatment for Immersion Pulmonary Edema?
Surface 100% O2 and transported immediately to a medical treatment facility. Signs and symptoms will usually resolve spontaneously over 24 hours with just bed rest and 100% O2.
What is middle ear oxygen absorption syndrome?
The negative pressure that may develop in the middle ear following a long oxygen dive
What is your course of action for an injured diver in the water?
A decision must be made as to whether surfacing is possible. If possible, injured divers should be surfaced immediately and treated appropriately. If the decompression obligation is great, the injury will have to be stabilized until sufficient decompression can be accomplished. If an injured diver must be surfaced with missed decompression, the diver must be treated as soon as possible, realizing that the possible injury from decompression sickness may be as severe, or more severe than that from the other injuries.
What is your first priority for a trapped diver who is injured?
The first priority is to ensure sufficient breathing gas is available, then to stabilize the injury.
What is Otitis externa?
Swimmer’s ear is an infection of the ear canal caused by repeated immersion
What are the symptoms of otitis externa?
a. Itching and/or wet feeling in the affected ear
b. Progressing to local pain as the external ear canal becomes swollen and inflamed
c. Local lymph nodes (glands) may enlarge, making jaw movement painful
d. Fever may occur in severe cases
What is the treatment for otitis externa?
a. Discontinue diving
b. Examined and treated by Diving Medical Personnel
What is Hypoglycemia?
An abnormally low blood sugar (glucose) level
What are the symptoms of Hypoglycemia?
a. Unusual hunger
b. Excessive sweating
c. Numbness
d. Chills
e. Headache
f. Trembling
g. Dizziness
h. Confusion
i. Incoordination
j. Anxiety
k. Severe cases, loss of consciousness
What is the treatment for Hypoglycemia?
Giving sugar by mouth relieves the symptoms promptly and proves the diagnosis. If the victim is unconscious, glucose should be given intravenously.