3. What Does it Mean? History?
SCUBA – Self Contained Underwater
Breathing Aparatus
Long history dating back from 332
BC
Modern fins, mask and snorkel
tubes were developed by fishermen
from America, Russia, France and
England in the 1920s and 1930s
4. History continued
Recreational SCUBA Diving began
between 1942 - 1943, after Emile
Gagnan and Captain Hacques –Yves
Cousteau developed the self-
contained “Aqua-Lung” and new
regulator that was automatic.
Cousteau took many successful,
experimental dives with his friends,
wife and two sons, making this an
experimental family trip and
experience.
5. Introduction
SCUBA diving accidents are fairly
uncommon.
In experienced 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.
6. Introduction
Behavior of gases and pressure
changes during descent and
ascent.
Clinical manifestations seen during
diving or up to 24 h after it.
7. Equipment
Mask- Device covering eyes
and nose, allowing you to
see underwater
Fins – Device put on the
feet to extend the kicking
motion underwater.
8. Equipment continued
BCD or BC – (Buoyancy
compensator device)
Device/jacket that controls
buoyancy up or down
Regulator – Device that
delivers air to you on
demand at reduced
pressure
9. Equipment continued
Pressure gauge – (SPG-
Submersible Pressure
Gauge) Device that tells
diver how much air they
have left
Weights – Lead weights
used to weigh down divers
for depth decent
10. Equipment continued
• Snorkel – Device used to
breath air close to or on the
surface of the water
Body suit – Warm
temperature suit that
protects the body against
abrasions and stings
11. Equipment continued
Wet suit – Insulated suit
used to keep the body
temperature in
Dry suit – Used to keep the
diver dry and warm in
colder temperatures
12.
13.
14. 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.)
15. 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.
17. Gas Laws
Boyle’s 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!)
18. Charles’s 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
19. Henry’s 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.)
20. Henry's Law
Gas molecules will dissolve into the blood in
proportion to the partial pressure of that gas in the
lungs.
21. Henry’s 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.
22. Main Pathologies
Barotrauma – Ear, Sinus,
Pulmonary & Air Embolism
Decompression sickness
Pulmonary edema
Pharmacological and toxic
effects of increased partial
pressures of gases
23. Ear Barotrauma
Most common disorder among
divers (Middle ear involvement).
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.
24. Sinus Barotrauma
Second most common disorder
among divers.
During descent, increase in ambient
environmental pressure can lead to
mucosal engorgement, edema and
inflammation producing blockage of
the sinus ostia.
Frontal sinus – most commonly
affected.
Headache, epistaxis.
Pneumocephalus.
25. 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
26. Air Embolism- Pathophysiology
Arterial gas embolism is the most serious potential
sequel of pulmonary barotrauma.
Arterial gas emboli can result from any of three
processes:
1. Passage of gas bubbles into the pulmonary veins
and from there into the systemic circulation
2. Development of venous gas emboli (either from
barotrauma or decompression sickness), which
overwhelm the filtering capacity of the pulmonary
capillaries to appear in the systemic arterial
circulation.
27. 3. Development of venous gas emboli that reach the
arterial circulation "paradoxically" via a functional
right-to-left shunt, such as a patent foramen ovale.
Reach the systemic arterial circulation.
Gas emboli typically break up as they reach vascular
branch points.
Lodge in vessels with diameters ranging from 30 to
60 µm.
They produce distal ischemia and local activation of
inflammatory cascades.
Air Embolism-Pathophysiology
28. Air Embolism-Clinical features
Cardiac-: Dysrhythmias, myocardial
infarction, and/or cardiac arrest (0.5ml
air can cause)
CNS-: focal motor, sensory, or visual
deficits to seizures, loss of
consciousness, apnea, and death.
Skin-: cyanotic marbling of the skin, focal
pallor of the tongue.
Renal-: hematuria, proteinuria, and renal
failure.
Uterine & GI bleeds
29. Air Embolism- Treatment
Immediate administration of 100 percent
oxygen.
Shift to hyperbaric oxygen facility as soon
as possible.
Widen the pressure gradient for nitrogen
between the bubble and the circulation.
Accelerate re-absorption of gas bubbles,
and hydration to decrease vascular
obstruction and augment collateral flow.
Divers Alert Network at (919) 684-9111.
30. Air Embolism-Treatment
1. Assess ABCs.
2. Administer oxygen.
3. Place patient in left lateral
Trendelenburg position/Supine
position
4. Monitor vital signs frequently.
5. Administer IV fluids.
6. Corticosteroid.
7. Lidocaine.
8. combination of prostacyclin,
indomethacin, and heparin h
31. Pneumomediastinum
Alveolar rupture- gas can dissect along the
perivascular sheath into the mediastinum.
Clinical Features:
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.
Crepitation in the neck
Hamman’s sign
32. Pneumomediastinum - Treatment
Administration of high-concentration oxygen via
non-rebreathing face mask
Treatment generally ranges from observation to
recompression
33. Pneumothorax
Relatively uncommon
Developing in only approximately 10 percent
of episodes of pulmonary barotrauma
Patients with a history of spontaneous
pneumothorax, bullae, or cystic lung disease
are at increased risk.
34. Injuries at the Bottom
• Nitrogen narcosis.
Caused by raised partial pressure of
nitrogen in nervous system tissue.
Usually occurs at depths greater than
100 feet.
Rapture of the deep, the martini effect.
Direct toxic effect of high nitrogen
pressure on nerve conduction.
Variable sensation but always depth-
related.
35. Nitrogen Narcosis
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 !
36. Pressure Disorders
Decompression Sickness (Bends)
Condition that develops in
divers subjected to rapid
reduction of air pressure after
ascending to the surface
following exposure to
compressed air.
37. Decompression Sickness (Bends)
"caisson disease“
First recognized in 1843 among tunnel
workers following return from the
compressed environment of the
caisson to atmospheric pressure.
Term "the bends" is frequently applied
to this illness.
Laborers with decompression sickness
sometimes walked with a slight stoop.
A posture affected by female socialites
around the time of construction of the
Brooklyn Bridge in the late 19th
century.
38. Diver descends -: breathes air under increased
pressure.
Tissues become loaded with increased quantities
of oxygen and nitrogen as predicted by Henry's
law.
Diver ascends-: the sum of the gas tensions in the
tissue may exceed the ambient pressure.
Leads to the liberation of free gas from the tissues
in the form of bubbles.
Pathophysiology
39. The liberated gas bubbles can alter organ
function by blocking vessels, rupturing or
compressing tissue, or activating clotting and
inflammatory cascades.
The volume and location of these bubbles
determine if symptoms occur or not.
Effects on the body can be direct or indirect.
Pathophysiology
40. 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
41. 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.
42. 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.
43. 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 .Rt to lft shunt
COPD, Asthma, prior pneumothorax, thoracic
surgery, IHD, pregnancy, Inguinal hernia,
Panic disorders
45. Type I
Usually referred to as the “bends”.
Musculoskeletal-: Patient experiences pain (joints).
Caused by expansion of gases present in the joint
space. (Elbow & shoulder)
Skin manifestations -: pruritus (itch), localized
erythema.
Lymphatic-: lymphadenopathy and localized edema.
46. Neurologic
60% of divers
Damage to spinal cord.
Paresthesias and weakness
Paraplegia
Loss of bladder control
Memory loss
Ataxia
Visual and speech
disturbances.
Pulmonary
Venous gas embolism (5%)
Gas bubbles – occlude
portions of Pulmonary
circulation.
Chest pain, dyspnea
Right ventricular outflow
obstruction
Circulatory collapse
Type II
Broad spectrum of complaints and could include symptoms of
Type I
49. Treatment
Hydration
Administration of 100 percent oxygen
Positioning the patient in the left lateral decubitus
(Durant's maneuver).
Mild Trendelenburg (bed angled downward toward
head) position in an effort to restore forward blood
flow by placing the right ventricular outflow tract
inferior to the right ventricular cavity, permitting air
to migrate superiorly to a non obstructing position
50. Hyperbaric oxygen therapy – definitive
treatment
In a recompression chamber initiated as
quickly as possible.
Time to initiation of treatment is one of
the main determinants of outcome .
Hyperbaric oxygen therapy decreases
the volume of air bubbles according to
Boyle's law.
Provides oxygenation to hypoxic tissue
by increasing the dissolved oxygen
content of arterial blood.
Treatment
51. Plasma nitrogen concentration
decreases, increasing the gradient
of nitrogen from bubble to plasma,
thus accelerating the absorption of
bubbles.
Hyperbaric therapy should be
undertaken for at least four hours.
Bubble elimination may be poor in
areas of reduced flow where
edema and sludging are present.
HYPERBARIC OXYGEN CHAMBER
53. POTENTIAL COMPLICATIONS
HYPERCAPNIA
ABSORPTIN ATELECTASIS
DRYING & CRUSTING OF SECRETIONS
PULMONARY OXYGEN TOXICITY
-Decreased hypoxemic drive and increased VD in
COPD.
-Mucosal damage due to lack of humidity
RETROLENTAL FIBROPLASIA
CEREBRAL O2 TOXICITY Seizures (hyperbaric)
FIRE (airway fires)
IGNITION HAZARD.
RISK OF RESPIRATORY DEPRESSION IN SOME PATIENTS
WITH COPD IF HIGH CONCENTRATIONS OF OXYGEN
ADMINISTERED (CO2 RETAINERS).
54. Complete resolution of
symptoms in Type II
decompression sickness 75% of
cases
16% - residual symptoms for up
to three months
Adjunctive therapies-: NSAID,
anticoagulants, and
glucocorticoids.
Treatment
55. General Assessment of Diving
Emergencies
• Early assessment and treatment.
• Must develop the diving history or
profile. This includes:
1. Time at which the signs and
symptoms occurred
2. Type of breathing apparatus utilized
3. Type of hypothermia protective
garment worn
56. Diving History
4. Parameters of the dive:
* Depth of dive
* Number of dives
* Duration of dive
5. Aircraft travel following a dive
6. Rate of ascent
7. Associated panic forcing rapid
ascent
8. Experience of the diver
9. Properly functioning depth gauge
57. Diving History
10. Previous medical diseases
11. Old injuries
12. Previous episodes of decompression
illness
13. Use of medication
14. Use of alcohol
• This history will assist in determining if
the diver has incurred a pressure
disorder
58. Conclusion
Recreational SCUBA diving continues to
increase in popularity, and diving-related
injuries have increased proportionally.
Barotrauma is the most common form of
diving-related injury.
Decompression sickness occurs when a
diver returns to the surface and gas
tensions in the tissue exceed the ambient
pressure, leading to the liberation of free
gas from the tissues in the form of
bubbles.
59. The liberated gas bubbles can alter
organ function by blocking blood
vessels, rupturing or compressing
tissue, or activating clotting and
inflammatory cascades.
Treatment of significant
decompression sickness includes
hydration, administration of 100
percent oxygen, positioning the patient
to improve forward blood flow, and
hyperbaric oxygen therapy.
Conclusion