joint service sub aqua diving diving illness’ & treatment reviewdiving review

JOINT SERVICE SUB AQUA DIVINGJOINT SERVICE SUB AQUA DIVING

DIVING DIVING

ILLNESS’ & TREATMENTILLNESS’ & TREATMENT

REVIEWREVIEW

DIVING DIVING

ILLNESS’ & TREATMENTILLNESS’ & TREATMENT

REVIEWREVIEW

Diving Illness’ & Treatment

Review


Review

206/2011

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


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Review

306/2011

Outline

BLS

In-Water Rescue

Medical conditions

Casualty Assessment

Oxygen administration equipment

Oxygen administration in practice


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Review

406/2011

BASIC LIFE SUPPORT (BLS)BASIC LIFE SUPPORT (BLS)


Review


Review

DT2.608/02

Lesson Outline

BLS skills:• Essential rescue skills

• Deteriorate quickly if not frequently exercised

• Advice/techniques evolve

Basis on which to build oxygen-enriched RB:• Will inevitably be needed while

equipment is readied

• Will form basis of oxygen-enriched basic life support


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Review

706/2011

Assessing the Need

Indicators of the need for BLS:• no response

• no chest movement

• no feel of air movement


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Review

DT2.808/02

Assessing the Need

Indicators of the need for BLS:

No response No chest movement No feel of air movement


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906/2011

Priorities

D r A B CDanger – to casualty and rescuer

Response (AVPU)

Airway

Breathing

Compressions


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1006/2011

Clear Airway

Foreign objects

Tongue

Airway blocked by tongue

Head tilt/chin lift clears airway


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Review

1106/2011

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.)

Compressions – Cardiac Compressions


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1206/2011

BLS: Decision Process

Unresponsive

Recovery position

Leave casualty and get help

Shout for help, open up airway

Breathing normally? Leave casualty and get help, return & give 30CCs

No

No

Yes

Yes

Stop to recheck only if breathing resumes, else continue until:

•Qualified help arrives•Normal breathing•You are exhausted


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1306/2011

Basic Life Support

• Sequence of 30 compressions: 2 breaths by one rescuer

• Two rescuers: change role every 1-2 minutes

• Monitor effectiveness

• Stop if normal breathing resumes/medical assistance arrives


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1406/2011

Basic Life Support - CC

Place heel of hand in centre of chest

Place heel of other hand on top of first hand

Straight arms – press down on sternum 5-6 cm

Repeat at 100-120 times/min


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1506/2011

Basic Life Support - RB

Expired air can sustain life

Monitor effectiveness

Continue until qualified help comes, the casualty is breathing normally or you are exhausted

• Sight

• Feel

• Sound

• Appearance

Don’t over ventilate



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1606/2011



Breaths are to be• No more than 1 second each

• 2 breaths to take no more than 5 seconds

• Don’t attempt more than 2 breaths each cycle

Regurgitation• Not always normal vomiting

• Monitor exhalation sounds

Basic Life Support - RB


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1706/2011

Recovery Position

If casualty breathing place in recovery position

The ‘how’ position More stable position


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1806/2011

IN-WATER RESCUEIN-WATER RESCUE


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Review

2006/2011

In Water Life Support Sequence

Make Buoyant

Extend Airway

RB for 1 minute

Standing depth/Boat 1 min. RB

De-Kit & Land

Tow, RB - 2 every 15 secs.


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2106/2011

Rescue - to the surface

Diver out of gas• AS Ascent

Incapable/unconscious diver• CBL

Rescue ascents - Urgent• Ascend directly to surface

• May mean ignoring decompression stops

• Divers safer at surface

• DCI can be treated

• Actions to take in case of oxygen convulsions

ControlledBuoyant Lift

AS ascent


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2206/2011

Surface Tows to Shore

Summon help• Ensure casualty buoyant at surface

• Fully inflate BC - face clear of water Consider removing weights

• Summon assistance

Conscious casualty • Reassure

• Unconscious casualty

• Remove mask, mouthpiece and extend airway

Non Breathing casualty• Remove mask, mouthpiece and give RB for 1

minute i.e. 10RBs


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2306/2011

Landing Casualty - Shore

Standing depth• Continue RB for a further 1 minute

• De-kit and land as quickly as possible WITHOUT further rescue breathing

Lift from water• Contact emergency services

• Continue BLS


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2406/2011

Landing Casualty - Boat

Assistance available• At boat prior to landing Continue RB for a further 1 minute

• De-Kit and remove from water as quickly as possible WITHOUT further RB

• Contact emergency services

• Continue BLS


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2506/2011

Effective Rescues

Typical indications• Nervous or reluctant

• Excuses or repeated questions

• Stress indicators

• Slow kit up or constant fiddling

Concerns need to be resolved• Adapt the dive plan

• More suitable dive site

• Peer pressure


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2606/2011

Pre-Dive Buddy Awareness

Buddy reactions• Stopping for no reason• Preoccupation with kit• Slow response to signals• Rapid breathing• Wide staring eyes

Resolve quickly• Stop or move to buddy• OK? Problem?• Not OK, gentle but firm contact• Abort dive


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2706/2011

MEDICAL CONDITIONSMEDICAL CONDITIONS


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2906/2011

Oxygen Exposure

At high concentrations oxygen is toxic

PO2<0.16 bar does not support life

Need to remain within accepted oxygen exposure limits

Hyperoxic

Oxygen Partial Pressure Scale (bar)

1.0.5.21 1.6.16.10.08 1.4

Short term toxicity risk

Long term toxicity riskHypoxic

Unconsciousness

Abilities impaired

AIR


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Review

3006/2011

Hypoxia

What is it:• Lack of oxygen

• PO2< 0.16 bar

.21.16.10.08

Hypoxic

Unconsciousness

Abilities impaired

AIR


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3106/2011

Hypoxia

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!

.21.16.10.08

Hypoxic

Unconsciousness

Abilities impaired

AIR


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Review

3206/2011

Hyperoxic

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

Hyperoxic

1.0.5.21 1.61.4


Long term toxicity risk

AIR


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3306/2011

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)


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3406/2011

CNS Toxicity

Also known as Acute Oxygen Toxicity

Reaction to PO2 generally > 1.4 bar

Symptoms: CON - Convulsions

V - Vision E - Ears, hearing disturbances N - Nausea T - Twitching I - Irritability D - Dizziness

Until convulsions begin, minor symptoms:• Can occur in ANY order or combination• Increase in severity


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3506/2011

CNS Toxicity

Convulsions• Tonic phase – do not assist

• Muscles become tense• Casualty becomes rigid and holds breath

• Clonic phase – do not assist• May occur seconds or minutes after the tonic

phase• Casualty jerks violently (convulsion)

• Depressive phase - assist• Casualty relaxes and is unconscious• Potential loss of mouthpiece

• Loop flood – loss of buoyancy• Need for Basic Life Support?


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3606/2011

CNS Toxicity

Convulsions

• Phases can occur on surface or after PO2 is reduced (‘Off effect’)

• Progressive damage to nervous system with each successive convulsion


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3706/2011

Hyperoxia

Causes:• Inaccurate dive planning

• Failure to analyse gas

• Incorrect marking or fitting of cylinders

Hyperoxic

1.0.5.21 1.61.4



AIR


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Review

3806/2011

Hyperoxia

Aggravating factors:• Actual PO2

• Duration of exposure

• Level of exertion

• Cumulative O2 exposure

Hyperoxic

1.0.5.21 1.61.4



AIR


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3906/2011

Hyperoxia

Avoidance:• High PCO2 predisposes to oxygen toxicity

• Accurately track your oxygen exposure

Hyperoxic

1.0.5.21 1.61.4



AIR


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4006/2011

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


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4106/2011

Hypercapnia

What is it:

• Excess CO2 in the blood

Cause:

• High inspired PCO2

• Poor ventilation of diver’s lungs at depth due to increased gas density

• Absorbent material exhausted in rebreathers

• Channelling in absorbent material rebreathers

CO2CO2


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4206/2011

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

CO2CO2


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4306/2011

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

CO2CO2


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4406/2011

Decompression illness

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

• Patent foramen ovale (PFO) allows bubbles to pass from venous to arterial circulation

Bubbles blocking blood flow

Bubbles in tissues compress blood vessels


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4506/2011


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


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4606/2011


On-site first aid

• Lie casualty down flat

• Keep casualty quiet

• Administer 100% oxygen• Increased nitrogen pressure gradient

assists in nitrogen elimination from bubbles in blood and tissue

• The higher the percentage of oxygen the more effective – whenever possible administer 100%

• 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


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4706/2011

Burst Lung

Cause• Physical damage to lung tissue from over-extension due to

over-pressurisation

Types

Both types can occur in isolation but are usually accompanied by air embolism

Collapsed lung(pneumothorax)

Bubbles between organs and tissues (emphysema)


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4806/2011

Burst Lung

Signs and symptoms• 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


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4906/2011

Burst Lung

On-site first aid• Lie casualty down


• Administer 100% oxygen

• Assists in re-absorption of the nitrogen content of air in pneumothorax or emphysema

• 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


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5006/2011

Near Drowning

Cause• Respiratory interruption due to fluid inhalation

Signs and symptoms• Circumstances

• No breathing

• Cyanosis – ashen grey / blue appearance

• Weak or absent pulse


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5106/2011

Near Drowning

On-site first aid• Rescue Breathing

• Oxygen-enriched if possible

• Concentration of oxygen reaching the casualty’s lungs during RBs is increased

• Chest compressions if required

• Recovery position

• Evacuate to medical attention

• Even if apparently fully recovered

• Complications of secondary drowning


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5206/2011

Shock

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


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5306/2011

Shock

Signs and symptoms• weakness, dizziness

• pallor, sweating

• rapid pulse rate

• rapid breathing, feeling breathless

• unconsciousness


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5406/2011

Shock

On-site first aid• Treat prime cause

• Reassure casualty (TLC)


• Lay casualty down with legs raised (not in the case of DCI or burst lung)

• Keep warm and comfortable

• Administer oxygen• Increased oxygen dissolved in the blood offsets effects of

inadequate circulation

• Monitor condition

• Nothing by mouth (except for DCI)

• Evacuate to medical attention


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5506/2011

Shock

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


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5606/2011

Carbon Monoxide Poisoning

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


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5706/2011

Carbon Monoxide Poisoning

Signs and symptoms• headache

• pale or greyish appearance

• weakness

• dizziness, nausea

• tunnel vision

• vomiting

• rapid pulse

• rapid breathing

• coma

• convulsions


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5806/2011

CASUALTY ASSESSMENTCASUALTY ASSESSMENT


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6006/2011

Incident Procedure - Front


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6106/2011

Incident Procedure - Back


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6206/2011

DT5.6308/02

Oxygen Administration Equipment


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Review

DT5.6412/2008

Gas Cylinders

‘D’ size most convenient

370 to 540 litres (136 to 210 bar)

Larger cylinders available but often more convenient to carry more smaller ones

Colour coding – (BS EN 1089-3)• White shoulder

• Body any non-allocated colour but usually black

Pillar valve connections (BS EN 850)• Two pin index holes

• Female outlet, no ‘O’ ring


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DT5.6512/2008

Regulators

Outlet pressure• Approximately 4 bar (some higher)

• Constant outlet pressure

Inlet• Two index pins

• Male inlet with sealing washer

Simple pressure gauge

Outlets capable of supporting:• At least one demand valve (100 to

160 litres / min. flow rate)

• 10 litres/min. (minimum) constant flow


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DT5.6612/2008

Demand Valves

Provide oxygen on demand

Can be capable of flow rates of up to 160 litres / min.

Fitted with oro-nasal mask• Transparent material

• Inflated or double face seal

• Large/adult and small/child sizes


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DT5.6712/2008

Demand / Resuscitation Valves

Available types• Automatic• Manually controlled

Configuration suitable for sport diver use:• Manually controlled• 100 – 160 litres min. flowrate on

demand• Resuscitation control limited to a

maximum flow rate of 40 litres /min• Over pressure relief valves (set to a

pressure of approx 45cm of water)


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DT5.6812/2008

‘Pocket’ Masks

Central ventilation orifice May be fitted with a porous splash guard May be supplied with an optional non-

return / exhalation valve

Transparent material

Generally have inflated face seal

Connection (with non-return valve) for constant flow oxygen tubing


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DT5.6912/2008

Reservoir mask

aka Hudson/non-rebreathing

For second DCI casualty

Gives oxygen concentration• Higher than pocket mask• Not as high as demand mask

Parts• Oxygen tubing• Reservoir • Mask• Exhaust valves

Flow 10-15 l/min

Fill bag before use


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DT5.7012/2008

Storage Cases

Storage cases should be:• Robust

• Waterproof

• Ideally store equipment in fully assembled state

• Case must have a pressure release valve if used to store cylinder


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DT5.7112/2008

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


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DT5.7212/2008

OXYGEN ADMINISTRATION IN PRACTICE


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7406/2011

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


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Review

DT6.7508/02

Posture

For decompression illness or burst lung, lay casualty flat on back

If decompression illness or burst lung is not involved• Legs may be raised to counter shock

• Monitor for signs of adverse impact on casualty’s breathing


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7606/2011

Administering Oxygen

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


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7706/2011

Administering Oxygen

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


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7806/2011

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


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7906/2011

Evacuation

Don’t delay call to emergency services

Coastguard: VHF Channel 16

DDMO / BHA DCI Helplines:• England, Wales & N. Ireland: 07827 821980• 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


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8006/2011

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


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8106/2011

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


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8206/2011

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!


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Review

DT3.8308/02

Summary

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


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Review

8406/2011

Final 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


Review


Review

8506/2011

joint service sub aqua diving diving illness’ & treatment reviewdiving review

Documents

diving incidents

airway slide

practice slide

exhausted slide

timesmin slide

basic life support bls

feel of air movement

basic life support bls