1
Q
O2 deficiency (Hypoxia) causes
MDFA Handbook
A
- Insufficient PO2 in breathing gas
- ppO2 less than 0.2 Bar absolute
- poorly prepared equipment or incorrect drills
- uncommon when diving on air using open circuit sets unless diver runs out of breathing gas
2
Q
O2 deficiency (Hypoxia) signs/ symptoms
MDFA Handbook
A
- Impared judgement and cognitions
- muscular weakness
- poor coordination
- impaired vision
- impaired hearing
- depressed levels of consciousness
- unconsciousness
- death
3
Q
O2 deficiency (Hypoxia) therapeutic treatment
MDFA Handbook
A
- Switch to alternate supply containing sufficient O2
- Follow SOPs
- Administer 100% O2 on the surface
- isolate diving gear for technical assessment
4
Q
O2 Toxicity Causes
MDFA Handbook
A
If O2 is breathed at higher than normal pressure it becomes toxic.
- wet divers ppO2 > 1.4
- RCC divers ppO2 > 2.8
5
Q
VENTID-C
O2 Toxicity signs/symptoms
MDFA Handbook
A
Vision (tunnel)
Ears/ tinnitus
Nausea
Twitching
Irritability/ apprehension
Dizziness
Convulsions
6
Q
O2 Toxicity treatment (therapeutic)
MDFA Handbook
A
- Take off O2, will normally resolve rapidly and spontaneously
- wait 15 mins and try again (x2)
- consider alternative treatment if unable to go back on O2 (discuss with DDMO)
7
Q
O2 Toxicity treatment (Diving)
MDFA Handbook
A
- If convulsion occurs underwater - keep diver at constant depth until after tonic phase then return to surface
- diver surfaces due to convulsion/ must surface to prevent drowning (Risk of pulmonary barotrauma/ AGE/ DCI)
- Remove breathing apparatus and put on fresh air and/ or O2
- Perform DR ABC if req, and carry out neuro.
8
Q
CO2 Poisoning (Hypercapnea) Causes
MDFA Handbook
A
- Insufficient ventilation of a diver in surface supplied equipment (build up of CO2 in helmet)
- Inadequate CO2 scrubbing in closed circuit
- shallow breathing/ skip breathing
- CO2 in the gas mix
9
Q
CO2 poisoning (Hypercapnea) prevention/ signs and symptoms
MDFA Handbook
A
Prevention
- ensure CO2 absorbent fresh and dry and correctly packed
- do not exceed endurance of cannister
- ventilate surface supply regularly
10
Q
CO2 poisoning (Hypercapnea) signs and symptoms
MDFA Handbook
A
Signs/ Symptoms
- Breathlessness, dizziness, nausea, headache, general distress
- Loss of consciousness
- anxiety and confusion
- flushing
11
Q
CO2 poisoning (Hypercapnea) treatment
MDFA Handbook
A
-If at depth stop and relax
- If using counter lung flush through and breathe deeply
- once on surface encourage to relax
- Recovery should be rapid on surface
12
Q
Nitrogen Narcosis causes/ prevention
MDFA Handbook
A
Nitrogen breathed under pressure is similar to anaesthetic
- dependant on depth of dive
Prevention
- limit depth of dive based on experience/ workup
deep dive below 40m should use helium mix
13
Q
Nitrogen narcosis signs/ symptoms
MDFA Handbook
A
30-60m - poor judgement, light headedness, euphoria
60-90m -slowed reflexes, overconfidence
90-120m - progressive depression of consciousness, hallucinations, altered personality
>120m - loss of consciousness
14
Q
nitrogen narcosis treatment
MDFA Handbook
A
- decrease depth of dive
- in rare cases surface the diver
15
Q
Carbon monoxide poisoning
MDFA Handbook
A
- Shouldn’t be present in diving gas mixtures
- Breathing compressed air contaminated by exhaust fumes or other sources
16
Q
Carbon monoxide poisoning prevention
MDFA Handbook
A
ensure air intakes of compressors are upwind and well away from any fumes
- avoid air intakes drawing air from inside compartments
- breathing gas must be obtained from authorised reputable sources
17
Q
Carbon monoxide poisoning signs and symptoms
MDFA Handbook
A
- similar to hypoxia
- pallor
- severe headache
- dizziness
- nausea and vomiting
- dimness of vision
eventually loss of consciousness
18
Q
Carbon monoxide treatment
MDFA Handbook
A
- breathe 100% O2 on the surface for mild exposures
- Hyperbaric O2 in the recompression chamber is required for severe cases
19
Q
Caustic Cocktail cause
MDFA Handbook
A
- water enters a closed or semi closed breathing apparatus
- this eventually mixes with CO2 absorbent
- This may then lead to chemical burns to the face mouth oesophagus, airway and lungs
20
Q
Caustic cocktail prevention
MDFA Handbook
A
- ensure the equipment has no leaks before diving
- if leaks apparent during dive surface as soon as possible
- folllow SOPs
21
Q
Caustic cocktail treatment
MDFA Handbook
A
- remove diver from water, and remove set ASAP
- If diver has swallowed solution then give copious drinks of fresh water
- wash all contaminated surfaces with fresh or salt water
- caustic burns to eyes should be washed with large amounts of water for 20 minutes holding eyelids open.
- this can cause panic, so make sure they haven’t also had a rapid ascent/ breathe holding
22
Q
Decompression Illness Henry’s Law
MDFA Handbook
A
- the amount of gas dissolved in a liquid at a constant temperature is proportional to the partial pressure of the gas over the liquid
- Given enough time all body tissues will saturate with gas
23
Q
Cutaneous DCI
MDFA Handbook
A
- DCI symptoms in the skin
- itching sensation
-common with air diving - Short lasting
- This without swelling or a rash is not considered a DCI
24
Q
Musculoskeletal DCI
MDFA Handbook
A
- AKA joint or limb pain only bends
- joint pain after diving must be taken seriously
- Dull achy pain in character
- local pressure may improve symptoms
-usually unaffected by movement - treat with recompression
25
Lymphatic DCI
| MDFA Handbook
- Localised tissue swelling/ Oedema
- Pigskin appearance
- possibly due to lymphatic vessels draining a specific group of lymph nodes (trunk/head/neck)
26
Cardiopulmonary DCI
| MDFA Handbook
- "the chokes"
- Massive venous gas embolism to pulmonary artery
- Tachypneoa (rapid breathing), shallow breathing
- Dyspneoa (shortness of breath) coughing
- Pulmonary Oedema (fluid on lungs)
- Cardio-respiratory failure
27
Neurological DCI causes
| MDFA Handbook
- Caused by bubbles affecting the brain, spinal chord or nerves
28
# S-M-R-I-M-C
Neurological DCI Signs and symptoms
| MDFA Handbook
Sensory
- tingling/ pins and needles
- altered sensation
- saddle anaesthesia
- Girdle pain
Motor
- Weakness
- Paralysis
- Bowel/ bladder dysfunction
Reflex abnormalities
In-coordination
- antaxia (the staggers)
- Gait distance
- Positive romberg test
- Finger to nose/ heel to shin
Mental status
- cognition
-behaviour
- memory
- orientation
- Alertness
- calculation
- recognition
Cranial nerves
- visual acuity loss
- visual field abnormalities
- eye movement asymmetry
- double vision
- facial sensation loss
- hearing loss
- shoulder weakness
- tongue or Uvula asymmetry
29
Audiovestibular DCI
| MDFA Handbook
Inner ear DCI which may involve the VIII cranial nerve
- severe vertigo
- hearing loss/ tinnitus
- nausea
- associated with helium diving & gas switches
- poor prognosis unless rapidly treated
- difficult to distinguish from inner ear barotrauma
30
constitutional DCI
| MDFA Handbook
- Common
- variety of non-specific symptoms
- malaise
- fatigue
- nausea
- headache
- chills
-
31
# What increases risk?
DCI Risk factors
| MDFA Handbook
Dive profiles
- short/ deeper dives
- saw-tooth patterns
- shallow to deep dives
- rapid ascent
- multiple daily dives
- omitted D
- New dive
- Altitude exposure after diving
- Cold/ hot water during dive / during decompression
- exercise at depth/ during or afrer decompression
- age of diver
- aerobic fitness
- Obesity
- Dehydration
- CO2 retention
32
DCI Classifications
(Traditional)
(M-T-E)
| MDFA Handbook
Traditional
- Type 1 (mild) Cutaneous, Lymphatic, Musculoskeletal
- Type 2 (Serious) all the rest
Descriptive:
Manifestations
- Neurological
- Pain
- pulmonary
- cutaneous
- lymphatic
- constitutional
Time of onset of manifestation
- acute
- delayed
Evolution
- Progressive
- relapsing
- static
- spontaneously impriving ]
- resolved
33
Above all remember DCI
- DCI may have varied and bizzare manifestaions
- may occur after apparently conservative dives
- most common manifestations are Neuro/ limb pain/ consitutional
- if in doubt TREAT
- Call DDMO for advice
34
Barotrauma general/ locations
| MDFA Handbook
- most common injury suffered by divers
- Caused by pressure related changes to gases in air filled body compartements
- pain is usually symptom occuring in the affected area
Locations
- Ear
- sinuses
- teeth
- abdomen
- lungs
- equipment areas (mask/goggles/drysuit)
35
Middle ear barotrauma causes
| MDFA Handbook
- due to dysfunction of eustachian tube
- infection
- allergies
- Polyps
- Smoking
- Gas unable to flow into or out of middle ear
36
Middle ear barotrauma signs/ symptoms
| MDFA Handbook
- upon descent may experience fullness/ pressure in one or both ears
- gradually becoming painful
- if descent not halted deafness, vertigo, nausea and tinnitus may occur
-
37
Middle ear barotrauma treatment
| MDFA Handbook
- rest
- decongestants
- anti inflammatory
- Do not use ear drops if perforated
- use TEED scale to grade severity
38
Inner ear barotrauma Causes
| MDFA Handbook
- rupture and leak or perilymph from round or oval window
- associated with middle ear barptrauma/ excessive equalisation effort
39
Inner ear barotrauma signs and symptoms
| MDFA Handbook
- sensation of blockage
- tinnitus
- high frequency hearing loss followed by complete hearing loss
- nausea, vomiting, vertigo, disorientation, imbalance
- middle ear barotrauma
40
inner ear barotrauma Treatment
| MDFA Handbook
- No diving or pressure exposure
- avoid straining/ valsalva
- bed rest with head elevated
- ENT surgeon referral
- May require surgery
- probably never return to diving
41
Sinus barotrauma Causes and treatment
| MDFA Handbook
-May occur on descent or ascent
- blockage of sinuses
- Nasal obstruction
- Mucosa stretched
- Treatment similar to middle ear barotrauma
- 1/2 weeks before return to diving
42
Dental Barotrauma
| MDFA Handbook
- Predisposed with dental disese
- failed dental restorations
- recent dental work
- can occur on descent or ascent
Signs/ symptoms
- tooth pain
- Maxillary sinus pain
- exploding teeth
Treatment
- Pain relief
- Dental referral
43
Abdominal barotrauma
| MDFA Handbook
- Effervescent antacids before diving
- swallowing air at depth
- intestinal obstruction
signs and symptoms
- abdominal pain
- Pneumoperitineum - air in abdominal cavity
44
Equipment Barotrauma
| MDFA Handbook
- diving with goggles
- not exhaling air into facemask through nose on descent
signs and symptoms
- pain
- Periorbital or conjunctival haemorrhage
45
Pulmonary barotrauma causes
| MDFA Handbook
- caused by excessiv pressure due to over expansion of gas in the lungs
- in diving - results from the failure of expanding lung gases to exit the lungs on ascent
- does not occur in breath hold diving
Causes
- breath holding during ascent
- inhaling while pressing purge button
- uncontrolled ascent
- unconcious ascent
- air trapping in lung
- cysts and blebs
46
Pulmonary Barotrauma effects
| MDFA Handbook
Can cause
- Arterial Gas Embolism (escaped gas migrates to pulmonary circulation)
- Pneumothorax (escaped gas migrates to pleural space between lungs and chest wall)
- interstitial emphysema ( escpaed gas migrates into the Thoracic Cavity along internal structures)
47
Arterial Gas Embolism characteristics and Signgs/ symptoms
| MDFA Handbook
- Onset of symptoms usually occurs within 10 minutes
- most serious of all diving accidents
- brain and heart most susceptible to injury
Signs/ symptoms
- slurred or altered speech
- loss of coordination
- paralysis
- loss of sensation
- visual field deficits
- respiratory problems
- amesia
- altered consciousness
- vertigo
- staggers
- nausea and vomiting
- Nystamus (uncontrolled eye movements)
- diplopia (double vision)
- blurred vision
Treatment
RECOMPRESSION THERAPY ASAP
48
Pneumothorax causes
| MDFA Handbook
- Caused by an accumulation of air or gas in the pleural cavity
- similar to pulmonary barotrauma
- rapid ascent
- breath holding on ascent
- Other barotrauma to lungs
- spontaneous (most common in tall, slim, young males)
49
RISE 'N' FALL
| MDFA Handbook
**Rate**
- breathing altered?
- Tachypnoea (rapid)
**Injury **
- Possibly
**Symmetry**
- affected side moves less
**Effort **
- Respiratory Distress (working hard to breathe)
**'N'eck Signs** (TWELVE)
- Trachea (may be deviated towards non injured side)
- wounds (may be present)
- Emphysema (air trapped around neck/ rice krispies look)
- Larynx (probably intact)
- Veins (visibly distended)
- Expose (Ensure neck and chest are exposed)
**Feel **
-May find damaged ribs
**Assess **
- percussion will show hyper resonance on affected side
**Listen **
- reduced or absent breath sounds on the affected side
**Look **
- May find injuries on the back of chest, not initially seen
50
Conditions to carry out needle decompression
| MDFA Handbook
1. must be acting as a MOD military diver or diving supervisor with the responsibility for the provision or resuscitation and life support measures at a military dive site emergency or accident
2. must be in date for MDFA
3. must have diagnosed a causlaty with a tension Pneumothorax and determined that needle decompression is required to relieve increasing pressure inside pleural cavity identified by RISE'N'FALL
4. must have access to appropriate resources from the Medical Equipment Set On-Site Diving Operations (MEDSO)
5. You must have contacted the DDMO and gained agreement to carry out procedure.
51
Drugs in the POT box
| MDFA Handbook
Midazolam 10mg pre filled syringe
- anti-convulsant
- accountable drug
Co-Codomol 30mg/500mg tablets
- moderate to sever pain control
Lignocaine 1% injection
- injection
- Can benefit some cases of AGE
- also used as local anaesthetic
Enoxaparin sodium injection
- subcutaneous injection
- blood thinner to prevent clots
Ibuprofen 400mg tablets
- mild to moderate pain control
- anit inflammatory
Paracetemol 500mg tablets
- mild to moderate pain control
Cinnarizine 15mg tablets
- mild to moderate nausea, vomiting or vertigo
Ondanseton 2mg injection or infusion
- for severe nausea, vomiting or vertigo
Flumazenil 0.1mg ampoules
- used to reverse the effects of a sedative
52
Storage of drugs
| MDFA Handbook
- Drugs should be stored in sealed container within POT box
- Ideally the POT box should be locked when not in use
- Box stored at room temperature (8-25 degrees celcius)
- Prior to diving ops, packaging checked for damage
- check their expiry dates
- Drugs not used unless authorised by DDMO
- Any drugs used must be annotated on the diver causlaty first aid form
53
MCDO course
flashcards
Decks in class (6)
# Cards
