1. Decompression Illness: Recognition and Initial Treatment
Michelle Arnesen, PA-C

2. Decompression Illness
Arterial gas embolism (AGE)
Decompression sickness (DCS or “the bends”)

3. What is the first rule of SCUBA diving?
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4. What is the first rule of SCUBA diving?
Always breathe and never hold your breath!

5. Boyle’s Law
PV = k OR P1V1 = P2V2

6. Boyle’s Law

7. How does SCUBA work?
Pressurized air in the tank is delivered to the diver at ambient pressure through the use of a regulator.
Air freely communicates in the diver’s lungs, sinuses, Eustachian tubes and in the artificial air space inside the diver’s mask.

8. How does SCUBA work?
The diver must perform a Valsalva maneuver every few feet during descent to equalize the air pressure in all of these spaces.
A slow ascent with continuous breathing generally ensures that the air spaces will be able to equalize naturally.

9. What is the second rule of SCUBA diving?

10. What is the second rule of SCUBA diving?
Ascend slowly and with control!

11. Breathing compressed air at depth
21% O2, 79% N2
N2 not used on a cellular level.
N2 is absorbed into body tissues in proportion to the surrounding pressure.
N2 dissolves back into the bloodstream during ascent.

12. Breathing compressed air at depth
N2 is off-gassed during ascent and at the surface until it returns to normal levels.
Repetitive diving (more than 1 dive in 24 hours) causes more and more nitrogen to be absorbed in the tissues.

13. Breathing compressed air at depth
Tissue Nitrogen Saturation

14. Failure to always breathe and never hold your breath!
Arterial Gas Embolism
Failure to always breathe and never hold your breath!

15. Arterial Gas Embolism Pathophysiology
Air expands in the lungs, causing alveolar rupture
Gas escapes into the pulmonary veins
Gas becomes lodged in small vessels
Can lead to cerebral arterial gas embolism (CAGE)

16. Arterial Gas Embolism Risk Factors
Uncontrolled ascent (panic)
Obstructive lung disease
Other lung conditions
Can also occur in healthy patients following a “safe” dive profile

17. Arterial Gas Embolism Signs & Symptoms
Dizziness Blurred vision Areas of decreased sensation Chest pain Disorientation Bloody froth from mouth/nose Paralysis Weakness Convulsions Unconsciousness Not breathing Death
Usually within minutes of surfacing, but may take hours for symptoms to appear!

18. Decompression Sickness
Failure to ascend slowly and with control!

19. Decompression Sickness Pathophysiology
Nitrogen is absorbed in tissues at depth proportional to the ambient pressure.
If diver ascends too quickly, N2 gas bubbles come out of solution and become lodged in tissues and vessels.
Tissue damage
CNS reactions
CV/Pulmonary reactions
Bubbles in/near joints  pain, spinal flexion  “bends”

20. Decompression Sickness Risk Factors
Repetitive diving
Alcohol consumption
Dehydration
Exercise after diving
Cold water diving/strenuous conditions
Flying immediately after diving
Pushing the limits
Can also occur in a healthy diver following a “safe” dive profile

21. Decompression Sickness Signs & Symptoms
Fatigue Itchy skin Pain – joints, muscles Dizziness Ringing in ears Numbness/tingling Paralysis SOB Rash Paralysis/weakness Difficulty urinating AMS Amnesia Tremors Staggering Bloody, frothy sputum Collapse Unconsciousness
May take hours for symptoms to appear!

22. DCI History Onset/progression of symptoms Patient Dive computer
Dive buddy/divemaster

23. DCI Rescue Care
Oxygen
CPR
Transport

24. DCI Exam
Head-to-toe
Focus on neuro
Serial neuro checks

25. DCI Differential Diagnosis
R/O other causes
Bloodwork
CXR
Head CT
DCS is a true clinical diagnosis

26. DCI Treatment 100% O2, IVF/OF Assess urgency
Early & severe S/Sx >> Delayed & mild S/Sx
Call DAN Emergency Medical line for assistance
Symptoms may improve quickly with O2, but may reappear with cessation of O2  don’t delay!

27. DCI Treatment Hyperbaric/Recompression Chamber
ASAP, definitely within 24 hours
Patient is re-pressurized while breathing supplemental oxygen and de-pressurized slowly

28. DCI Prognosis Complete resolution Significant neurological dysfunction
Bladder dysfunction
Sexual dysfunction
Paralysis/weakness
Osteonecrosis (DCS)
Return to diving/flying in several days to months, maybe never

29. Summary AGE Failure to always breathe and never hold your breath.
Uncontrolled ascent
Alveolar rupture causing arterial gas embolism
Can be cerebral (CAGE)

30. Summary DCS Failure to ascend slowly and with control.
Quick ascent, pushing the limits
Nitrogen bubbles in tissues/vessels
Joint pain, tissue damage, CNS reactions

31. Summary DCI History/Exam
Onset/progression of symptoms
Get the dive computer
Perform serial neuro checks
R/O other causes

32. Summary DCI Treatment 100% O2, IVF/OF Call DAN
Transfer to hyperbaric chamber as soon as patient is stable  don’t delay!

33. What is the first rule of SCUBA diving?
Always breathe and never hold your breath!

34. What is the second rule of SCUBA diving?
Ascend slowly and with control!

35. What are the three rules of emergency DCI care?
Image courtesy of openclipart.org

36. What are the three rules of emergency DCI care?
Call DAN O2
Transport to hyperbaric chamber without delay!
Image courtesy of openclipart.org

37. References Divers Alert Network (DAN)
Emergency Medical
Non-Emergency Medical
Professional Association of Diving Instructors
SCUBA Diving International
Powell, Mark. Deco for Divers. Essex: AquaPress Ltd and Mark Powell, Print.

38. Michelle Arnesen, PA-C michelle.arnesen@gmail.com 847-334-3208
Thanks for listening!
Michelle Arnesen, PA-C