Transcript The British Sub
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
D anger – to casualty and rescuer R esponse (AVPU) A irway B reathing C irculation
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
D anger – to casualty and rescuer R esponse
• • • •
A – A lert V – Responds to V oice P – Responds to P ain U – U nresponsive A irway – clear of obstructions B reathing – check for normal breathing (10 secs.) C irculation – Cardiac Compressions
Diving Illness and Treatment Review
BLS: Decision Process
No Unresponsive Yes Shout for help, open up airway Leave casualty and get help Breathing normally?
Yes Recovery position No 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
Hypoxic Oxygen Partial Pressure Scale (bar) Abilities impaired Long term toxicity risk Hyperoxic .08
.10
Unconsciousness .16
.21
AIR .5
.7
1.0
1.3
Low High Inspiration default set points 1.4
1.6
Short term toxicity risk At high concentrations oxygen is toxic PO 2 <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
•
PO 2 < 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 periods when PO 2 >0.5 bar for long
•
Central Nervous System (CNS) for even short periods toxicity when PO 2 >1.4 bar
Diving Illness and Treatment Review
Whole Body Toxicity
Cause: long exposures to PO 2 >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 PO 2 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 PO 2 (‘Off effect’) is reduced Progressive damage to nervous system with each successive convulsion
Diving Illness and Treatment Review
Hyperoxia
Long term toxicity risk .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 Hyperoxic
Diving Illness and Treatment Review
Hyperoxia
.21
.5
Long term toxicity risk 1.0
AIR Aggravating factors
• •
Actual PO 2 Duration of exposure
•
Level of exertion
•
Cumulative O 2 exposure 1.4
1.6
Short term toxicity risk Hyperoxic
Diving Illness and Treatment Review
Hyperoxia
Long term toxicity risk .21
AIR .5
1.0
1.4
1.6
Short term toxicity risk Avoidance:
•
High PCO 2 predisposes to oxygen toxicity
•
Accurately track your oxygen exposure Hyperoxic
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 CO 2 in the blood Cause:
•
High inspired PCO 2
o o o
Poor ventilation of diver’s lungs at depth due to increased gas density Absorbent material exhausted in rebreathers Channelling in absorbent material rebrerathers
Diving Illness and Treatment Review
Hypercapnia
Symptoms
• • •
0.03 bar PCO 2
•
0.06 bar PCO 2 0.10 bar PCO 0.12 bar PCO 2 2 doubles breathing rate (dyspnea) distress, confusion, lack of coordination severe mental impairment 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 O 2 toxicity? – administer O 2 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