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

Joint Service Sub Aqua Diving Centre

DIVING DIVING

ILLNESS’ & TREATMENTILLNESS’ & TREATMENT

REVIEWREVIEW

DIVING DIVING

ILLNESS’ & TREATMENTILLNESS’ & TREATMENT

REVIEWREVIEW

Diving Illness and Treatment

Review


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


Review


Review Outline

BLS

Medical conditions

Casualty Assessment

Oxygen administration equipment

Oxygen administration in practice

Basic Life SupportBasic Life Support

(BLS)(BLS)Basic Life SupportBasic Life Support

(BLS)(BLS)


Review


Review Lesson Outline

BLS skills:• Essential rescue skills

• Deteriorate quickly if not frequently exercised

• Advice/techniques evolve


Review


Review Assessing the Need

Indicators of the need for BLS:

• no response• no chest movement• no feel of air movement


Review


Review Priorities

D r A B CDanger – to casualty and rescuer

Response (AVPU)

Airway

Breathing

Circulation


Review


Review Clear airway

Foreign objects

Tongue

Airway blocked by tongue

Head tilt/chin lift clears airway


Review


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


Review


Review 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 and give 30CCs

No

No

Yes

YesStop to recheck only if breathing resumes, else continue until:•Qualified help arrives•Normal breathing•You are exhausted


Review


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


Review


Review Rescue breaths (RB)

Monitor effectiveness:

Don’t over ventilate

• Sight• Feel• Sound• Appearance

Medical ConditionsMedical ConditionsMedical ConditionsMedical Conditions


Review


Review 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

1.3.7

Inspiration default set points

Low High


Review


Review Hypoxia

What is it:• Lack of oxygen • PO2< 0.16 bar

.21.16.10.08

Hypoxic

Unconsciousness

Abilities impaired

AIR


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Review 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


Review


Review Hyperoxia

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


Review


ReviewWhole 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)


Review


Review 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


Review


Review CNS Toxicity

Convulsions• Tonic phase – do not assisto Muscles become tense

o Casualty becomes rigid and holds breath

• Clonic phase – do not assisto May occur seconds or minutes after the tonic phaseo Casualty jerks violently (convulsion)

• Depressive phase - assisto Casualty relaxes and is unconsciouso Potential loss of mouthpiece

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


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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


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Review Hyperoxia

Causes:• Inaccurate dive planning

• Failure to analyse gas

• Incorrect marking or fitting of cylinders

Hyperoxic

1.0.5.21 1.61.4



AIR


Review


Review Hyperoxia

Aggravating factors• Actual PO2

• Duration of exposure

• Level of exertion

• Cumulative O2 exposure

Hyperoxic

1.0.5.21 1.61.4



AIR


Review


Review Hyperoxia

Avoidance:• High PCO2 predisposes to oxygen toxicity

• Accurately track your oxygen exposure

Hyperoxic

1.0.5.21 1.61.4



AIR


Review


Review Monitoring Oxygen Exposure

CNS and Whole Body Toxicity need to be monitored separately• Data for both provided in BSAC Oxygen

Toxicity Table

• Nitrox & mixed gas decompression computers

• Dive planning software


Review


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


Review


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


Review


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


Review


Review

Bubbles blocking blood flow

Bubbles in tissues compress blood vessels

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

Decompression illness (1)

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


Review


Review Decompression Illness (2)

• Denial!

• Itches, rashes

Signs and symptoms

• 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

• Numbness, tingling, joint pains


Review


Review Decompression Illness (3)

• Lie casualty down flat

• Keep casualty quiet

• Administer 100% oxygeno 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

On-site first aid

Evacuate to a recompression facility as soon as possible


Review


Review Burst lung (1)

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

to over-pressurisation

Types

Collapsed lung(pneumothorax)

Bubbles between organs and tissues (emphysema)

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


Review


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


Review


Review Burst Lung (3)

• Lie casualty down


• Administer 100% oxygeno Assists in re-absorption of the nitrogen

content of air in pneumothorax or emphysemao 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

On-site first aid


Review


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


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Review Near Drowning (2)

• Rescue Breathingo Oxygen-enriched if possibleo Concentration of oxygen reaching the

casualty’s lungs during RBs is increased

• Chest compressions if required

• Recovery position

• Evacuate to medical attentiono Even if apparently fully recoveredo Complications of secondary drowning

On-site first aid


Review


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


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Review Shock (2)

Signs and symptoms• weakness, dizziness

• pallor, sweating

• rapid pulse rate

• rapid breathing, feeling breathless

• unconsciousness


Review


Review Shock (3)

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 oxygeno Increased oxygen dissolved in the

blood offsets effects of inadequate circulation

• Monitor condition

• Nothing by mouth (except for DCI)

• Evacuate to medical attention


Review


Review Shock (4)

• 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

Immersion shock


Review


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


Review



Signs and symptoms• headache

• pale or greyish appearance

• weakness

• dizziness, nausea

• tunnel vision

• vomiting

• rapid pulse

• rapid breathing

• coma

• convulsions


Review



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


Review


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

CasualtyCasualty

AssessmentAssessment

CasualtyCasualty

AssessmentAssessment


Review


ReviewIncident Procedure - Front


Review


Review Incident Procedure – Back

OXYGEN ADMINISTRATION OXYGEN ADMINISTRATION EQUIPMENTEQUIPMENT

OXYGEN ADMINISTRATION OXYGEN ADMINISTRATION EQUIPMENTEQUIPMENT


Review


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


Review


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 streamo 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


Review


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 OXYGEN ADMINISTRATION IN PRACTICEIN PRACTICE

OXYGEN ADMINISTRATION OXYGEN ADMINISTRATION IN PRACTICEIN PRACTICE


Review


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


Review


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


Review


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


Review


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


Review


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


Review


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


Review


Review Missed Decompression

• 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

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:


Review


Review Entonox

Do not administer to a casualty of a non-diving accident if this follows diving

Ensure emergency personnel fully understand

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 this tactfully!


Review


ReviewDDMO 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


Review


ReviewDiving 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

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

Documents

treatment review bls

airway slide

treatment review hyperoxia

treatment review objectives

oxygen oxygen

practice slide

exhausted slide

diving incidents