1. Diving Medicine
LCdr Peter Hatfield

2. Objectives Barotrauma Decompression Illness Gas Problems Putting it together

3. 1. pre-existing medical condition eg myocardial
infarction
2. trauma/drowning/hypothermia
3. Barotrauma
4. Decompression Illness
5. Gas Problems

4. Barotrauma
Boyles Law
Volume inversely proportional to pressure

6. Gas attempts to contract or expand IAW Boyle’s Law
In closed spaces, gas cannot enter or escape
Therefore, a pressure differential will develop
Squeese or reverse squeese

7. 1. Non pulmonary barotrauma
suit/mask squeeze
sinuses
ears
teeth
bowel
2. Pulmonary barotrauma
arterial gas embolism
mediastinal emphysema
pneumothorax
subcutaneous emphysema

8. Suit/mask squeeze

9. Ears/Sinuses

10. Ears Barotrauma Teeds 0-5 Alternobaric vertigo Draeger Ear
Perilymphatic fistula
Facial Baroparesis

11. Barotrauma Treatment Middle Ear
Restrict diving until resolved;
Mild (0-1) 24 to 72 hours
Moderate (2-3) 1 to 8 days
Severe (4-5) may take up to six weeks
decongestant , +/- antibiotic
Perilymphatic fistula ENT referral – may need surgery
Facial Baroparesis need to reverse due to ischemia
-myringotomy

12. Dental- fractured tooth/abcess
Bowel- possible surgical consult
On ascent or descent

13. Pulmonary Barotrauma
Potential alveolar rupture from 1 msw (3 fsw) water depth

14. Pulmonary Barotrauma 1. Arterial Gas Embolism 2. Pneumothorax
3. Mediastinal Emphysema
4. Subcutaneous Emphysema

16. Local air trapping in lungs
Breath-hold on ascent
Panic, buddy breathing, laryngospasm
Local air trapping in lungs
Obstructive lung disease, scarring/fibrosis
Frequent Change in Pressure

17. Symptoms Can co-exist Rapid onset (less than 5 min) Likely on ascent
Conscious/LOC
Any neurological symptom/sign (internal carotid most likely)
Hemoptysis
Shortness of breath
High pitched cry
Pleuritic type Chest pain
Subcutaneous emphysema
Can co-exist
with pneumothorax or mediastinal/subcutaneous emphysema

18. Treatment ABC s Lie down, on side if unconscious
Head down only for short time if at all
Catheterization if unconscious
100% oxygen
Transport to nearest RCC
Maintain 1 ATA ambient pressure if possible

19. Treatment Table 6 4 Hours 46 Minutes 30 09 m (30 ft) 5 20 5 20 5 20 530
09 m
(30 ft) 5 20 5 20 5 20 5 20 5 20 5 20 30
ASCENT RATE:
0.3 m/min (1 ft/min)
18 m
(60 ft) 20 5 20 5 20 5
DESCENT RATE:
18 m/min (60 ft/min)
O2 periods
3 at 18 msw (60 fsw)
6 at 09 msw (30 fsw)

20. Time to Tx of A.G.E. and Response

21. Decompression Illness
Compressed air
79% nitrogen
20% oxygen

22. Venous bubbles unlike AGE
Left/right shunt could become arterial eg patent foramen ovale
1929 Clark infused 2,000 ml air at 50ml/hour into a dog with no signs of DCI
Asymptomatic Military divers can be shown to have bubbles (on doppler) after experimental dives

23. Deeper/longer dives
Inadequate decompression
Age
Fatigue before diving
Cold during decompression
Heavy exercise before during or after diving
Dehydration (alcohol consumption)
Infection, medication
Flying after diving
Rapid decompression at altitude

24. Bubbles cause Blood / bubble interface activates blood components
Body treats the bubble as a foreign object and coats it in protein
RBC agglutination, platelet consumption, vascular permeability, leukocyte activation, etc.
Endothelial injury. Bubbles activate complement system in some individuals.

26. Decompression sickness/stress Continuum
No dive
No stress
Death
Severe DCS
Type II
Mild DCS
Type I
Decompression
stress with
symptoms
stress without

27. Mild Symptoms Severe Symptoms Fatigue
Fleeting joint discomfort (niggles)
Skin itch and erythema
Joint pain
Lymphatic
Skin (cutis marmorata)
Severe Symptoms
CNS/ Spinal
Labyrinthine (staggers)
Pulmonary (chokes)

28. Time to symptoms During decompression Rare 0-30 min 50% 30-60 min 75%
1-6 hours 90%
6-12 hours 95%
12-24 hours 99%

29. Treatment 100 % oxygen delivers oxygen to tissues
nitrogen gradient (elimination)
IV Ringers/normal saline
RCC even if symptoms have resolved

30. Gas Problems SYMPTOMS AT DEPTH Nitrogen Oxygen Carbon Dioxide
Impurities
O CO
Partial pressure at 1ATA = %
At 30m 4ATA =
At 60m 7ATA =

31. Oxygen Toxicity CON – Convulsion V – Visual aberrations
Pulmonary
CNS occurs at partial pressure 1.6 ATA O2 70m on air
6m on 100% O2
CON – Convulsion
V – Visual aberrations
E – Ears, ringing, bells, etc.
N – Nausea
T – Twitching of facial muscles
I – Irritability, behavior changes
D – Dizziness

32. Nitrogen narcosis Carbon dioxide
Martini’s law - 1 martini per every 10 m after 20m depth
Carbon dioxide
1-10 % symptoms
Headache, nausea, fatigue, sweating, tachycardia
SOB, confusion

33. Putting it Together History - most important
dive buddy
Where did the symptoms start and When
descent
bottom
surface ) immediately
2) delayed
Type of dive
Prexisiting conditions

34. Physical exam- ABC s neuro exam Signs- resolving, static, progressing
AGE or DCS treatment is the same “4 min neuro”

35. examples
Case 1 Vertigo
21 year old diver with cold symptoms, pain in ear on descent.
Forced valsalva- sudden ( in water) onset of vertigo, tinnitus, hearing loss
Barotrauma to ear alternobaric vertigo
perilymphatic fistula
Did he get better on the surface
Compare
Diver on air 30m for 25 minutes -no decompression stops. Develops vertigo tinnitus hearing loss 30 mins after surface
Diver on air 10m for 120 minutes

37. Case 2
Diver on air 15m after 10 mins at depth feels dizzy, headache, nausea
Surfaces feels fine after 5 mins O2
CO2,CO, anxiety, non diving medical condition

38. Case 3
24 yr old diver feels unwell at 30m after 20 mins. On surface anxious tingling in the face and arms feels fatigued, rapid breathing
Physical normal
Unsure – trial of pressure?

39. Trial of Pressure/Treatment Table 5
2 Hours 16 Minutes 30
09 m
(30 ft) 5 20 30
ASCENT RATE:
0.3 m/min (1 ft/min)
18 m
(60 ft) 20 5 20 5
DESCENT RATE:
18 m/min (60 ft/min)
O2 periods
2 at 18 msw (60 fsw)
1 at 09 msw (30 fsw)

40. Case 4
Diver on vacation several consecutive days diving. Flying home develops pain in shoulder.
Can calculate “repat” group or wait 24 hours. Do not dive on a travel day

41. Case 5
Diver 40m for 30 mins returns to surface within 5 mins develops weakness in left arm, CN VI palsy and ataxia
?AGE or DCI