Joint Service
Sub Aqua Diving Centre
DIVING
ILLNESS’ & TREATMENT
REVIEW
Diving Illness
and Treatment
Review
Objectives
Revise Basic Life Support (BLS) skills
For diving incidents:
• understand the conditions
• recognise signs and symptoms
• understand how oxygen administration
benefits these conditions
Understand appropriate equipment and
the practicalities of its use
Revise oxygen administration skills
• breathing casualties
• non-breathing casualties
Diving Illness
and Treatment
Review
Outline
BLS
Medical conditions
Casualty Assessment
Oxygen administration equipment
Oxygen administration in practice
Basic Life Support
(BLS)
Diving Illness
and Treatment
Review
Lesson Outline
BLS skills:
• Essential rescue skills
• Deteriorate quickly if not frequently exercised
• Advice/techniques evolve
Diving Illness
and Treatment
Review
Assessing the Need
Indicators of the need for BLS:
• no response
• no chest movement
• no feel of air movement
Diving Illness
and Treatment
Review
Priorities
D r A
B C
Danger – to casualty and rescuer
Response (AVPU)
Airway
Breathing
Circulation
Diving Illness
and Treatment
Review
Clear airway
Foreign objects
Tongue
Airway blocked by
tongue
Head tilt/chin lift
clears airway
Diving Illness
and Treatment
Review
Priorities
Danger – to casualty and rescuer
Response
•
•
•
•
A – Alert
V – Responds to Voice
P – Responds to Pain
U – Unresponsive
Airway – clear of obstructions
Breathing – check for normal breathing (10 secs.)
Circulation – Cardiac Compressions
Diving Illness
and Treatment
Review
BLS: Decision Process
No
Unresponsive
Leave casualty and get help
Yes
Shout for help,
open up airway
No
Breathing normally?
Yes
Recovery position
Leave casualty and get help, return
and give 30CCs
Stop to recheck only if breathing
resumes, else continue until:
•Qualified help arrives
•Normal breathing
•You are exhausted
Diving Illness
and Treatment
Review
Basic Life Support (BLS)
Monitor effectiveness:
• Sequence:
30 compressions : 2 breaths
• Rate of 100 compressions/minute
• 4–5cm compression
• Stop if normal breathing
resumes/medical assistance
arrives
Diving Illness
and Treatment
Review
Rescue breaths (RB)
Monitor effectiveness:
•
•
•
•
Sight
Feel
Sound
Appearance
Don’t over
ventilate
Medical Conditions
Diving Illness
and Treatment
Review
Oxygen Exposure
Oxygen Partial Pressure Scale (bar)
Hypoxic
Abilities
impaired
.08 .10
Unconsciousness
.16
Long term toxicity risk
.21
AIR
.5 .7
1.0
Low
Hyperoxic
1.3 1.4 1.6
High
Short term
toxicity risk
Inspiration
default set points
At high concentrations oxygen is toxic
PO2<0.16 bar does not support life
Need to remain within accepted oxygen exposure limits
Diving Illness
and Treatment
Review
Hypoxia
Abilities impaired
Hypoxic
.08 .10
Unconsciousness
What is it:
• Lack of oxygen
• PO2< 0.16 bar
.16
.21
AIR
Diving Illness
and Treatment
Review
Hypoxia
Abilities impaired
Hypoxic
.08 .10
Unconsciousness
.16
.21
AIR
Symptoms:
•
•
•
•
•
Inability to think clearly, confusion, sense of losing it
Loss of co-ordination
Unconsciousness, death
Primary danger is symptoms may be vague or absent
It can occur suddenly and without warning!
Diving Illness
and Treatment
Review
Hyperoxia
Long term toxicity risk
Hyperoxic
.21
AIR
.5
1.0
1.4 1.6
Short term
toxicity risk
What is it:
•
•
Too much oxygen
Oxygen becomes toxic at elevated partial pressures
There are two different effects of Hyperoxia:
•
•
Whole Body Oxygen Toxicity when PO2>0.5 bar for long
periods
Central Nervous System (CNS) toxicity when PO2>1.4 bar
for even short periods
Diving Illness
and Treatment
Review
Whole Body Toxicity
Cause: long exposures to PO2>0.5 bar
Monitored to allow for recompression treatment
Physiological reactions including:
• Inflammation in the lungs
• Reduction in vital capacity
• Congestion, oedema, bronchitis, swelling of alveolar walls,
thickening of pulmonary arteries
• Visual impairment
Symptoms:
• Dry cough, discomfort in breathing cycle, increased breathing
resistance, shortness of breath,
• Severe pain, sub-sternal pain or burning
• Temporary short sightedness (Hyperoxic Myopia)
Diving Illness
and Treatment
Review
CNS Toxicity
Also known as Acute Oxygen Toxicity
Reaction to PO2 generally > 1.4 bar
Symptoms:
CON
V
E
N
T
I
D
- Convulsions
- Vision
- Ears, hearing disturbances
- Nausea
- Twitching
- Irritability
- Dizziness
Until convulsions begin, minor symptoms:
• Can occur in ANY order or combination
• Increase in severity
Diving Illness
and Treatment
Review
CNS Toxicity
Convulsions
• Tonic phase – do not assist
o Muscles become tense
o Casualty becomes rigid and holds breath
• Clonic phase – do not assist
o May occur seconds or minutes after the tonic phase
o Casualty jerks violently (convulsion)
• Depressive phase - assist
o Casualty relaxes and is unconscious
o Potential loss of mouthpiece
– Loop flood – loss of buoyancy
– Need for Basic Life Support?
Diving Illness
and Treatment
Review
CNS Toxicity
Convulsions
Phases can occur on surface or after PO2 is reduced
(‘Off effect’)
Progressive damage to nervous system with each
successive convulsion
Diving Illness
and Treatment
Review
Hyperoxia
Long term toxicity risk
Hyperoxic
.21
AIR
.5
1.0
1.4 1.6
Short term
toxicity risk
Causes:
• Inaccurate dive planning
• Failure to analyse gas
• Incorrect marking or fitting of cylinders
Diving Illness
and Treatment
Review
Hyperoxia
Long term toxicity risk
Hyperoxic
.21
.5
1.0
AIR
Aggravating factors
•
•
•
•
Actual PO2
Duration of exposure
Level of exertion
Cumulative O2 exposure
1.4 1.6
Short term
toxicity risk
Diving Illness
and Treatment
Review
Hyperoxia
Long term toxicity risk
Hyperoxic
.21
AIR
.5
1.0
1.4 1.6
Short term
toxicity risk
Avoidance:
• High PCO2 predisposes to oxygen toxicity
• Accurately track your oxygen exposure
Diving Illness
and Treatment
Review
Monitoring Oxygen Exposure
CNS and Whole Body Toxicity need
to be monitored separately
• Data for both provided in BSAC Oxygen
Toxicity Table
• Dive planning software
• Nitrox & mixed gas decompression
computers
Diving Illness
and Treatment
Review
Hypercapnia
What is it:
• Excess CO2 in the blood
Cause:
• High inspired PCO2
o Poor ventilation of diver’s lungs at depth due
to increased gas density
o Absorbent material exhausted in rebreathers
o Channelling in absorbent material rebrerathers
Diving Illness
and Treatment
Review
Hypercapnia
Symptoms
• 0.03 bar PCO2 doubles breathing rate
(dyspnea)
• 0.06 bar PCO2 distress, confusion, lack of
coordination
• 0.10 bar PCO2 severe mental impairment
• 0.12 bar PCO2 loss of consciousness, death
Diving Illness
and Treatment
Review
Hypercapnia
Further impact
• Increases oxygen toxicity potential
• Increases potential for DCI and narcosis
Avoidance
• Meticulous preparation & monitoring of
absorbent life - rebreathers
• Avoiding over exertion
Resolution
• Stop, slow down breathing rate, relax
• Bail out to open circuit - rebreathers
Diving Illness
and Treatment
Review
Decompression illness (1)
Causes
• inadequate elimination of nitrogen from the body during
ascent
• Physical damage to the alveoli due to overpressure
introduces bubbles of air (emboli) into the blood
Bubbles blocking
blood flow
Bubbles in tissues
compress blood
vessels
Patent foramen ovale (PFO) allows bubbles to
pass from venous to arterial circulation
Diving Illness
and Treatment
Review
Decompression Illness (2)
Signs and symptoms
• Denial!
• Itches, rashes
• Numbness, tingling, joint pains
• Vision disturbances
• Dizziness, nausea, headaches, confusion
• Weakness, paralysis, loss of bladder/bowel
control
• Shortness of breath
• Shock, unconsciousness
• Any abnormality after a dive
Signs and symptoms appear from
seconds to many hours after surfacing
Diving Illness
and Treatment
Review
Decompression Illness (3)
On-site first aid
• Lie casualty down flat
• Keep casualty quiet
• Administer 100% oxygen
o Increased nitrogen pressure gradient assists in
nitrogen elimination from bubbles in blood and
tissue
o The higher the percentage of oxygen the more
effective – whenever possible administer 100%
o Improved oxygen supply to tissues where blood
flow is reduced due to bubble blockage
• Treat for shock
Evacuate to a recompression facility as soon as possible
Diving Illness
and Treatment
Review
Burst lung (1)
Cause
• physical damage to lung tissue from over-extension due
to over-pressurisation
Types
Bubbles between
organs and tissues
(emphysema)
Collapsed lung
(pneumothorax)
• Both types can occur in isolation but are
usually accompanied by air embolism
Diving Illness
and Treatment
Review
Burst lung (2)
Signs and symptoms include
•
•
•
•
•
chest discomfort/pain, bloody froth
shortness of breath
changes to vocal tone, crepitation
shock
unconsciousness, death
Signs and symptoms of burst lung are frequently
accompanied by those for decompression illness
Diving Illness
and Treatment
Review
Burst Lung (3)
On-site first aid
• Lie casualty down
• Keep casualty quiet
• Administer 100% oxygen
o Assists in re-absorption of the nitrogen
content of air in pneumothorax or emphysema
o Offsets reduced effective lung surface area for
gas transfer due to collapsed lung
• Treat for shock
• Evacuate to a recompression facility as
soon as possible
Diving Illness
and Treatment
Review
Near Drowning (1)
Cause
• Respiratory interruption due to fluid inhalation
Signs and symptoms
•
•
•
•
Circumstances
No breathing
Cyanosis – ashen grey / blue appearance
Weak or absent pulse
Diving Illness
and Treatment
Review
Near Drowning (2)
On-site first aid
• Rescue Breathing
o Oxygen-enriched if possible
o Concentration of oxygen reaching the
casualty’s lungs during RBs is increased
• Chest compressions if required
• Recovery position
• Evacuate to medical attention
o Even if apparently fully recovered
o Complications of secondary drowning
Diving Illness
and Treatment
Review
Shock (1)
Definition
• inadequate circulation leading to tissue damage due to
inadequate oxygenation and waste removal
Present to a greater or lesser degree in all injuries
Mechanisms
•
•
•
•
•
reduced blood volume (bleeding, burns, oedema)
massive dilation of blood vessels (e.g. fainting)
inadequate cardiac output (e.g. heart attack)
allergic reaction to drugs, food or stings
removal from the water after prolonged immersion
Diving Illness
and Treatment
Review
Shock (2)
Signs and symptoms
•
•
•
•
•
weakness, dizziness
pallor, sweating
rapid pulse rate
rapid breathing, feeling breathless
unconsciousness
Diving Illness
and Treatment
Review
Shock (3)
On-site first aid
•
•
•
•
Treat prime cause
Reassure casualty (TLC)
Keep casualty quiet
Lay casualty down with legs raised
(not in the case of DCI or burst lung)
• Keep warm and comfortable
• Administer oxygen
o Increased oxygen dissolved in the
blood offsets effects of inadequate
circulation
• Monitor condition
• Nothing by mouth (except for DCI)
• Evacuate to medical attention
Diving Illness
and Treatment
Review
Shock (4)
Immersion shock
• Extreme form of blood vessel
dilation due to prolonged
immersion
• Muscles relax due to water
supporting body weight
• If removed from water upright,
blood can pool in lower limbs –
potentially fatal
• Keep casualty horizontal at all
times
• Discourage any movement or
activity by the casualty
Diving Illness
and Treatment
Review
Carbon monoxide poisoning (1)
Cause
• breathing gas contaminated with carbon monoxide
Effect
• carbon monoxide combines about 200 times more readily
with haemoglobin than does oxygen
• interferes with the blood's ability to transport oxygen
• may act as a cellular poison
Diving Illness
and Treatment
Review
Carbon monoxide poisoning (2)
Signs and symptoms
•
•
•
•
•
•
•
•
•
•
headache
pale or greyish appearance
weakness
dizziness, nausea
tunnel vision
vomiting
rapid pulse
rapid breathing
coma
convulsions
Diving Illness
and Treatment
Review
Carbon monoxide poisoning (3)
On-site first aid
• remove casualty from contaminated breathing supply
• lie casualty down with legs raised
• administer 100% oxygen, or oxygen enriched Rescue
Breaths, as appropriate
Benefits of 100% oxygen
• more oxygen is transported in solution in the plasma
• some assistance in breaking down carboxyhaemoglobin
• helps restore normal cellular function
Diving Illness
and Treatment
Review
Summary of diving illnesses
Administration of oxygen is beneficial to
the major diving disorders
100% oxygen will provide the maximum
benefit
Administer oxygen as early as possible
Oxygen is a supplement to other first aid
procedures to increase their effectiveness
Casualty must always be evacuated to
appropriate medical aid:
• As soon as possible
• Irrespective of any apparent resolution of
their condition
Casualty
Assessment
Diving Illness
and Treatment
Review
Incident Procedure - Front
Diving Illness
and Treatment
Review
Incident Procedure – Back
OXYGEN ADMINISTRATION
EQUIPMENT
Diving Illness
and Treatment
Review
Lesson Outline
Configuration of oxygen
administration equipment most
suitable for sport diver use
Oxygen administration
equipment comprises
• Gas cylinder Colour coding – (BS EN
1089-3)
• Regulator Pillar valve connections (BS
EN 850)
two pin index, female outlet, no ‘O’ ring
• Demand valve and mask At least one
demand valve (100 to 160 litres / min. flow
rate), 10 litres/min. (minimum) constant
flow
Diving Illness
and Treatment
Review
Oxygen
Characteristics
• A colourless, odourless, tasteless gas
• Comprises approximately 21% of the atmosphere
(by volume)
• An essential component of metabolism
• Carried in the blood stream
o Primary means - combined with the haemoglobin
o Secondary means - dissolved in the blood plasma
• Plasma’s capacity to transport additional oxygen
utilised in oxygen administration
Will not burn but supports the combustion of
other materials
Diving Illness
and Treatment
Review
Precautions in Use
Fire risk - absolute cleanliness
a necessity
Keep equipment regularly
maintained
Do-it-yourself equipment or
modifications are dangerous
Do not use non-standard
equipment – risk of confusion
OXYGEN ADMINISTRATION IN
PRACTICE
Diving Illness
and Treatment
Review
Casualties
Incident statistics show that the
majority of casualties will be
• Breathing
• Conscious
• Suffering from decompression illness
Will need the use of a demand valve
and oro-nasal mask for maximum
oxygen concentration
Incidence of casualties requiring
Rescue Breaths is much lower
Diving Illness
and Treatment
Review
Administering Oxygen (1)
Start at the earliest opportunity
• Greater nitrogen pressure gradient
• Earliest reduction in tissue hypoxia
Don’t ration oxygen
Tender loving care (TLC)
For a second casualty
• Use second demand valve and
oro-nasal mask, if available
• Otherwise use a pocket mask
• Accept faster consumption of oxygen
Diving Illness
and Treatment
Review
Administering Oxygen (2)
Be prepared for a possible transient worsening
of casualty’s condition
• Initial reaction of brain to increased oxygen
• Oxygen diffusing into bubbles
Oxygen toxicity
• Not a problem at surface pressure / durations involved
• Casualties of underwater O2 toxicity? – administer O2 on
surface once any signs or symptoms have disappeared
No pain killers
Diving Illness
and Treatment
Review
Administering Fluids
Counter dehydration with fluids
• Still isotonic drinks best, or water/squash
• Do not administer caffeinated or fizzy drinks
• Small amounts, at a rate of approx 1 litre/hour
Do not allow to interfere with or delay
• Administration of oxygen
• Evacuation to a recompression facility
Do not administer fluids if
• Casualty is likely to vomit
• Casualty is likely to inhale fluid
• A general anaesthetic may be required
If no oxygen, fluids alone are beneficial
Diving Illness
and Treatment
Review
Evacuation
Don’t delay call to emergency services
Coastguard: VHF Channel 16
DDMO / BHA DCI Helplines:
• England, Wales & N. Ireland: 07 831 151 523
• Scotland: 0845 408 6007
On Land (other)
Ambulance/Police/Coastguard
• Telephone: 999 or 112
DCI
• Irrespective of any apparent improvement, casualty must get medical
attention
• Casualty’s buddy?
All relevant information must accompany any casualty
Diving Illness
and Treatment
Review
Oxygen Supply Exhausted?
Closed Circuit Rebreather
• Can be set to deliver 100% oxygen
Nitrox
• Open Circuit or Semi Closed Circuit
Rebreather
• Reduces the amount of inspired nitrogen
• Not as effective as 100% oxygen but better
than breathing air
Common considerations
• Mouthpiece may not be tolerated
• Oxygen % reduced by air inspired via nose
Diving Illness
and Treatment
Review
Missed Decompression
If a diver misses decompression stops for any
reason, or is subject to a rapid ascent such that it is
considered that they may suffer decompression
illness as a result:
•
•
•
•
Do not wait for signs/symptoms to appear
Lay casualty down and keep quiet
Administer oxygen/fluids
Seek specialist medical advice on further action from
the DDMO/ BHA Help lines
Diving Illness
and Treatment
Review
Entonox
Mixture of oxygen and nitrous oxide
Nitrous oxide is very soluble in blood
• Large quantity of nitrous oxide passes into
nitrogen bubbles to re-establish equilibrium
• Causes size of bubbles to increase
Never administer to a casualty suffering
from a diving accident
Do not administer to a casualty of a
non-diving accident if this follows diving
Ensure emergency personnel fully
understand - Do this tactfully!
Diving Illness
and Treatment
Review
DDMO Contact
If you suspect a diver may have a diving related
problem, even if just a headache after a dive:
• Call Defence Diving Medical Offr (DDMO)
• 24/7 manned number
• 07831151523
• 02392768020
Diving Illness
and Treatment
Review
Diving illness & treatments
Summary:
• Signs & symptoms can be similar for different
conditions
• Knowledge of pre –incident history helps
• Oxygen administration & TLC are beneficial to all
diving illnesses & incidents