DIVING EMERGENCIES

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DIVING EMERGENCIES
Dr. Ülkümen Rodoplu V. Mediterranean Emergency
Medicine Congress 14-17 September 09, Valencia
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Who is the protector of divers ?
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Oceanus
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Drunken Dionysus
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The second biggest in the World
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St. Pierre
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Introduction

• SCUBA diving accidents are fairly uncommon.
• Inexperienced divers have a higher incident rate
  of injury.
• Emergencies can occur on the surface, one meter
  of water, or at any depth.
• More serious emergencies usually follow a dive.

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History of Scuba

• 1878- Henry Fleuss invents a self contained
  underwater breathing unit.
• 1925- Yves Le Prieur releases a more advanced
  breathing unit.
• 1943 - Jacques-Yves Cousteau and Emile Gagnan
  design and test the first Aqua-Lung.

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Introduction

• SCUBA, self-contained underwater breathing
  apparatus.
• New advances.
• Equipment improvements.
• Behavior of gases and pressure changes during
  descent and ascent.
• Clinical manifestations seen during diving or up
  to 24 h after it.

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Underwater breathing

• Regular breathing makes use of differences in air
  pressure
• The water above a diver increases the atmospheric
  pressure. Therefore,
• Air must be pressurized to be able to breathe at
  a pressure of more than one Atmosphere (air
  pressure at sea level).
• (This is also why you have to pop your ears as
  you descend.)

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Main Pathologies

• Barotrauma
• Decompression ilness
• Pulmonary edema
• Pharmacological and toxic effects of increased
  partial pressures of gases

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Physical Principles of Pressure

• Density of the water can be equated to pressure,
  which is defined as the weight or force acting
  upon a unit area.
• Fresh water exerts a pressure of 62.4 pounds over
  an area of one square foot (salt water is 64
  pounds). Stated as pounds per square inch (psi)
• At sea level humans live in an atmosphere of air,
  or a mixture of gases, and they exert a pressure
  of 14.7 psi.

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Gas Laws

• Boyles Law
• For any gas at a constant temperature, the
  volume of the gas will vary inversely with the
  pressure, and the density of the gas will very
  directly with the pressure.
• If T constant, then V ? 1/P and Density ?P
• (Never hold your breath!)

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• Charless Law
• For any gas at a constant pressure, the volume of
  the gas will very directly with the absolute
  temperature.
• If P constant, then V ? T
• Or
• For any gas at a constant volume, the pressure
  of the gas will vary with the absolute
  temperature.
• If V constant, then P ? T
• (keep tanks cool and dont fill them too fast.)

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• Henrys Law
• The amount of any given gas will dissolve in a
  liquid at a given temperature is proportional to
  the partial pressure of that gas in equilibrium
  with the liquid and the solubility coefficient of
  the gas in the particular liquid.
• An increase in pressure will increase absorption
• (Oxygen in your blood dissolves at a given
  pressure.)

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Henry's Law

• The amount of any given gas that will dissolve in
  a liquid at a given temperature is a function of
  the partial pressure of that gas in contact with
  the liquid...
• Gas molecules will dissolve into the blood in
  proportion to the partial pressure of that gas in
  the lungs.
•  

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Henrys Law

• At sea level, the dissolved gases
• in the blood and tissues are in
• proportion to the partial pressures
• of the gases in the person's lungs
• at the surface.
• As the diver descends,the
• ambient pressure increases, and
• therefore the pressure of the gas
• inside the lungs increases.

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Injuries During Descent

• Barotrauma, commonly called the squeeze becomes
  a concern during the descent.
• Unable to equilibrate the pressure between the
  nasopharynx and the middle ear through the
  eustachian tube can result in middle ear pain,
• Ringing in the ears, dizziness, hearing loss.
• In severe cases, rupture of the ear drum can
  occur.

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Injuries During Descent

• Similar lack of equilibration
• can occur in the sinuses,
• producing severe frontal
• headaches or pain beneath
• the eye in the maxillary sinuses.

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Injuries at the Bottom

• Nitrogen narcosis.
• Due to nitrogens effect on cerebral function.
• Diver may appear to be intoxicated and may take
  unnecessary risks.

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Nitrogen Narcosis

• Rapture of the deep, the martini effect.
• Direct toxic effect of high nitrogen pressure on
  nerve conduction.
• Variable sensation but always depth-related.
• Some divers experience no narcotic effect at
  depths up to 40 m. whereas others feel some
  effect at around 25 m.
• The diver may feel and act totally drunk.
• Takes the regulator out of their mouth and hands
  it to a fish !

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Injuries During Ascent

• Serious and life-threatening emergencies occur
  during the ascent.
• Most serious barotrauma during ascent is injury
  to the lung. (from 1m. of water to a deep dive).
• Injury results from divers holding their breath
  during ascent.

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Injuries During Ascent

• During the ascent the air in the lung begins to
  expand.
• If not exhaled the alveoli may rupture.
  Resulting in an air embolism.
• May also include mediastinal and subcutaneous
  emphysema due to diffusion of the gas through the
  lung into the mediastinum and neck.
• Pneumothorax is possible if the alveoli rupture
  into the pleural cavity.

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General Assessment of Diving Emergencies

• Early assessment and treatment.
• Must develop the diving history or profile.
  This includes
• Time at which the signs and symptoms occurred
• Type of breathing apparatus utilized
• Type of hypothermia protective garment worn

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Diving History

• Parameters of the dive
• Depth of dive
• Number of dives
• Duration of dive
• Aircraft travel following a dive
• Rate of ascent
• Associated panic forcing rapid ascent
• Experience of the diver
• Properly functioning depth gauge

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Diving History

• Previous medical diseases
• Old injuries
• Previous episodes of decompression illness
• Use of medication
• Use of alcohol
• This history will assist in determining if the
  diver has incurred a pressure disorder

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Pressure DisordersDecompression Sickness (Bends)

• Condition that develops in divers subjected to
  rapid reduction of air pressure after ascending
  to the surface following exposure to compressed
  air.

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General factors relating to development

• Cold water dives
• Diving in rough water
• Overstaying time at given dive depth
• Dive at 25 m. or greater
• Rapid ascent panic, inexperience, unfamiliarity
  with equipment.
• Flying after diving 24 hour wait is
  recommended.
• Driving to high altitude.

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Individual factors relating to development

• Age older individuals.
• Obesity.
• Fatigue lack of sleep prior to dive
• Alcohol consumption prior or after dive
• History of other medical problems.

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Pathophysiology

• Results as nitrogen bubbles enter the tissue
  spaces and small blood vessels.
• Symptoms present when a diver rapidly ascends
  after being exposed to a depth of 10 m. or more
  for a time sufficient enough to allow the bodys
  tissues to be saturated with nitrogen.
• Effects on the body can be direct or indirect

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Direct Effects

• Intravascular blood flow will be decreased,
  leading to ischemia or infarct.
• Extravascular tissues will be displaced, which
  further results in pressure on neutral tissue
• Audiovestibular air can diffuse into the
  audiovestibular system, causing vertigo

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Indirect Effects

• Surface of air emboli may initiate platelet
  aggregation and intravascular coagulation
• Extravascular plasma loss may lead to edema
• Electrolyte imbalances may occur
• Lipid emboli are released

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Presentation

• Decompression sickness divided into two types
  based on the presenting signs and symptoms.

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Type I

• Usually referred to as the bends.
• Patient experiences pain (joints)
• Caused by expansion of gases present in the joint
  space.
• Skin manifestations usually consist only of
  pruritus (itch).
• Rash, spotted pallor, cyanosis, or pitting edema
  may occur.

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Type I

• Treatment mainly consists of oxygen inhalation
  but could require recompression.
• Prognosis is usually good.

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Type II

• Broad spectrum of complaints and could include
  symptoms of Type I
• Paresthesias Paralysis
• Dizziness or vertigo Headache
• Nausea Dyspnea
• Auditory disturbances Chest Pain
• Vestibular disturbances Loss of consciousness
• Hemoptysis

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Type IIIDecompression Sickness

• Pulmonary complications of decompression
  sickness, referred to as the chokes are
  extremely serious.
• Combination of AGE and DCS with neurologic
  symptoms.

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General Symptoms of Decompression Sickness

• Extreme fatigue
• Joint pain
• Headache
• Lower abdominal pain
• Chest pain
• Urinary dysfunction
• Vertigo and ataxia
• Pruritus

• Back pain
• Priapism
• Paresthesias
• Paralysis
• Dysarthria
• Frothy, reddish sputum
• Dyspnea

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Prehospital Management

• Patients usually seek medical attention within 12
  hours of ascent from a dive.
• SS developing more than 36 hours after a dive
  cannot reasonably be attributed to decompression
  sickness.
• Oxygen therapy and possible recompression.

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Prehospital Management

• Assess ABCs
• CPR if required
• Oxygen (NRM or intubate if necessary)
• Left lateral Trendelenburg position if possible
• Protect from excessive heat, cold, wetness, or
  noxious fumes
• Fruit juices or balanced salt solutions if
  conscious
• IVs (crystalloid of choice)
• CNS involvement administer decadron, heparin,
  valium
• If flown, lowest altitude possible and take
  diving equipment with you for analysis
• Early recompression treatment for all forms.

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Pulmonary Overpressure Accidents

• Lung overinflation due to rapid ascent is common
  cause of diving emergencies.
• Air expansion on ascent can rupture the alveolar
  membranes.
• Resulting in hemorrhage, reduced oxygen and
  carbon dioxide transport, and capillary and
  alveolar inflammation.
• Air can escape and cause pneumothorax and tension
  pneumothorax, subcutaneous emphysema, or
  pneumomediastinum

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Air Embolism

• Any person using SCUBA equipment presenting with
  neurologic deficits during or immediately after
  ascent, should be suspected of air embolism
• Form of barotrauma of ascent.
• Very serious condition in which air bubbles enter
  the circulatory system through rupture of small
  pulmonary vessels.
• Air can also be trapped in blebs, air pockets,
  within the pulmonary tissue

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Air Embolism

• Bubbles can be transported to the heart and the
  brain, where they may lodge and obstruct blood
  flow, causing ischemia and possibly infarct.
• Rapid and dramatic onset.
• Sharp, tearing pain.
• Paralysis (frequently hemiplegia).
• Cardiac and pulmonary collapse.
• Unequal pupils.
• Wide pulse pressure

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Air EmbolismPrehospital Management

• Assess ABCs.
• Administer oxygen by NRM.
• Place patient in left lateral Trendelenburg
  position.
• Monitor vital signs frequently.
• Administer IV fluids.
• Corticosteroid.
• Transport to recompression chamber ASAP.

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Pneumomediastinum

• Release of gas through the visceral pleura into
  the mediastinum and pericardial sac.
• Substernal chest pain.
• Irregular pulse.
• Abnormal heart sounds.
• Reduced blood pressure/narrowing pulse pressure.
• Change in voice.
• May or may not be evidence of cyanosis

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PneumomediastinumPrehospital Management

• Administration of high-concentration oxygen via
  nonrebreathing face mask
• Start IV
• Transport
• Treatment generally ranges from observation to
  recompression

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What is Hyperbaric Oxygen Therapy?

• Entirely enclosed chamber
• Breathing oxygen,
• greater than one atmosphere

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What is Hyperbaric Oxygen Therapy?

• Mechanical effect of increased pressure
• - Any free gas trapped in the body will decrease
  in volume as the pressure on it increases
• - Successfully applied to air embolism
• and decompression sickness

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Final Words

• Emergencies can occur on the surface, one meter
  of water, or at any depth.
• More serious emergencies usually follow a dive.
• Be sure you know the Hyperbaric Oxygen Therapy
  facilities in your community.