This document summarizes a lecture on decompression illness given by Dr. James Holm. It begins with an overview of decompression sickness (DCS) and arterial gas embolism (AGE), which are collectively referred to as decompression illness (DCI). It then discusses a case of DCI in a diver and reviews the mechanisms of bubble-related injury. It covers the diagnosis, emergency treatment, and recompression treatment of DCI using hyperbaric oxygen therapy according to US Navy treatment tables.

1. Decompression Illness: Bubble Trouble
James R. Holm, MD, FACP, FACEP, FUHM
Medical Director, Center for Hyperbaric Medicine
Virginia Mason Medical Center, Seattle, WA
Resident Noon Lecture Series
Virginia Mason Medical Center
October 1st, 2018

3. Background
 Education
 Georgetown University
Medical School, 1985
 Northwestern University
Residency in EM/IM, 1989
 Board Certified
 Internal Medicine
 Emergency Medicine
 Undersea & Hyperbaric
Medicine
 Medical Practice
 Emergency Medicine since 1989
 Hyperbaric Medicine since 1997
 VMMC since June 2009
 Diving Experience
 1969 NAUI SCUBA Certified
 1978 NAUI/PADI Instructor

5. Outline
 Case
 Diving Injuries Related to Pressure
 Definition of DCI = DCS and AGE
 Mechanism of Bubble Related Injury
 Diagnosis of DCI
 Emergency Treatment for DCI
 Recompression Treatment for DCI
 Chambers, Treatment Tables, Protocols

6. Case
 48 yo male geoduck diving on surface
supplied air in the Puget Sound
 >20 years of diving without history of DCS
 PMH: HTN, depression, hx of substance
abuse
 Meds: Suboxone, Lexapro, Lisinopril
 Diving Profile
 86 fsw for 21 minutes Bottom Time
 35 minute Surface Interval
 90 fsw for 84 minutes Bottom Time

7.  Surface supplied air without rapid ascent
 Computer set on 44% nitrox (44% O2 54% N2)
 Used one computer for each dive
 After surfacing
 10 minutes later had numbness from umbilicus down and
paraplegia and unable to walk
 Rash (cutis marmorata)
 Given surface O2 and helicoptered to HMC
 Hypotensive and given IV fluid boluses
 Transferred to VMMC
 Numbness and weakness resolved with O2
 Hct 63 WBC 25.4
 Given IV fluids (7 L in 8 hours) HBO2 (Table 6) and pressers and
admitted to ICU
 Treated in ICU with supportive care for ARF and hypotension

8. 86 fsw for 21 minutes Bottom Time (BT)
35 minute Surface Interval (SI)
90 fsw for 84 minutes Bottom Time (BT)

9. 86 fsw for 21 minutes Bottom Time (BT)
35 minute Surface Interval (SI)
90 fsw for 84 minutes Bottom Time (BT)

10. 86 fsw for 21 minutes Bottom Time (BT)
35 minute Surface Interval (SI)
90 fsw for 84 minutes Bottom Time (BT)

11. Diving Injuries Related to Pressure
 Common barotrauma (squeeze)
 Middle ear
 Sinus/tooth/mask
 Uncommon barotrauma
 Inner ear
 Pneumothorax
 Subcutaneous/mediastinal emphysema
 Arterial gas embolism (AGE)
 Decompression sickness (DCS or bends)
 Incidence is estimated at 2-5 cases per 10,000 dives
 VMMC CHM treats about 40 cases a year
 Most cases are mild to moderate severity
 Most are treated through the ED and not admitted

12. Bubble Trouble
 Decompression Sickness (DCS)
 SCUBA divers, pilots, and astronauts
 Staff in multiplace chambers
 Arterial Gas Embolism (AGE)
 SCUBA divers: breath holding upon
ascent
 Iatrogenic: with some medical
procedures

14. Decompression Illness (DCI)
 DCI (Decompression Illness) includes:
 AGE (Arterial Gas Embolism… “Air Embolism”)
 DCS (Decompression Sickness)
 Type I : Pain Only
 Type II: Neurologic or Severe
 Sport divers tend to have more type II
 May have multiple symptoms
 Treatment is essentially the same

15. Bubble Disease
Dissolved gas Pulmonary barotrauma
Venous blood Arterial bloodTissues
DCS AGE
Type I and Type II

16. Mechanism of Bubble Related Injury
Muth CM. N Engl J Med, 2000

17. Massive AGE for Positive Pressure Ventilation
Weaver LK. Chest 1998
Cylindrical, blood occluding gas emboli in the middle meningeal artery
at postmortem exam

18. Mechanism of Bubble Related Injury
Gas bubbles and hemorrhagic infarcts in spinal tissue of animals with
severe decompression sickness at postmortem exam

19. Helps SC. Stroke 1990
Mechanisms of Injury in Gas Embolism

20. Courtesy of Steve Helps and Des Gorman from the University of Adelaide
Video

21. Helps SC. Stroke 1990

22. Non-mechanical Effects of Bubbles

23.  Endothelial damage leads to:
 WBC adherence/activation
 Microvascular leak
 Edema
 Hemorrhage
 Infarction
 Neutrophil mediated process
Levin LL. J Appl Physiol 1981
Non-mechanical Effects of Bubbles

25. Arterial Gas Embolism
 Divers holding their breath upon ascent
or with obstructive airway disease
 Gas moves from the alveoli and into the
left sided circulation to the brain and
heart
 This can occur:
 In as little as 10 ft of water
 Independent of the nitrogen load a
diver has
 Symptoms are severe and immediate
Vann RD. Lancet 2011

26. Causes of Gas Embolism
 Barotrauma
 Scuba diver holding their breath upon ascent
 Patient on positive pressure ventilation
 Surgery or medical procedures
 Faulty contrast injector
 Lung biopsy
 Laparoscopy
 Multiple other procedures

27. Pulmonary Anatomy & Blood-Gas Barrier
West JB. Lancet 1992
“The surprising thing is not that the [pulmonary] capillaries fail,
but that they don’t do so more often”

28. Arterial Gas Embolism in a Diver
 A 24 year old healthy marine in the Royal
Netherlands Navy
 Free ascent training in pool
 He held his breath during from 30 fsw to 15 fsw
 Developed right sided hemiplegia and loss of eyesight
 Course and treatment
 Administration of 100% oxygen led to improvement
 Complete resolution after a USN table 6
 Work up failed to reveal any other risk factors
Courtesy of Lieutenant T.T. (Thijs) Wingelaar, MD

29. Courtesy of Lieutenant T.T. (Thijs) Wingelaar, MD
Video

30. Diagnosis of AGE
 Clinical Diagnosis
 Symptoms occur within seconds or minutes
 Altered LOC
 Seizure
 Neurologic findings
 Cardiovascular collapse
 Lab and X-Ray Findings are Often Negative
 It is rare to see arterial gas on CT

31. Decompression Sickness (DCS)

32. Eads Bridge, MO, 1871
Brooklyn Bridge, NY, 1872 Hudson River Tunnel, NY/NJ, 1902

33. Brooklyn Bridge
 Dr. Andrew Smith
 Coined the term “caisson’s disease” & “bends”
 110 severe cases requiring treatment
 Treatments included:
 Atropine
 Mercury chloride
 Ergot
 Whiskey
 Ginger
 He considered recompression “heroic” but never used it
 Washington Roebling: permanently paralyzed

34. Hudson River Tunnel
 E.W. Moir
 British engineer brought in for the project
 Was the first to use recompression as a treatment
 Reduced the death rate from 25% of the work force per
year to 1.7% of the work force per year
 Moir tables
 Recompress to ½ the working pressure
 Later recompress to ¾ of the working pressure

35. Decompression Sickness
 Inert gas is absorbed/eliminated from different body
“compartments” at different rates (time & depth)
 Even with computers and tables… divers can get
decompression sickness even if “within their limits”!
 Most computers and tables do not account for:
 Dehydration
 Poor fitness
 Advanced age
 Amount of work the diver did
 Other medical problems

36. Assessment of the DCS Patient
 History
 Exam
 Diagnostic tests
 Differential diagnosis
 Tips:
 Presentation may be delayed and vague
 Response to treatment may assist in diagnosis
 Have a low threshold for treatment

37. History and Physical
 History
 Past medical history including medications
 Past diving history including past history of DCI
 Detailed dive history as well as pre- and post-dive history
 Exact onset of each symptoms (especially the first one)
 Physical Examination
 Signs of otic or pulmonary barotrauma
 A quick but careful neurologic exam
 Check for gait, bowel, bladder function
 Check for balance and brain function
 Get them out of the gurney or off the ground if possible
 Findings may be subtle and variable (not “one lesion”)

38. Vann RD, et al. Lancet 2011
By Frequency (Initial & All Symptoms)

40. Cutis Marmorata

41. Diagnostic Tests
 Not too helpful in management
 Chest x-ray changes due to near- drowning,
barotrauma, etc.
 CT and MRI may be negative early but may find
other causes of symptoms
 Blood testing may reveal
 Hemoconcentration
 Elevated CPK (* for AGE)
 Intoxications
*Smith RM. N Engl J Med, 1994

42. AGE or DCS?
Factors AGE DCS
Diving profile rapid ascent time/depth profile
Symptom onset seconds to minutes
(after surfacing)
minutes to hours
(after surfacing)
Type of symptoms cerebral
seizure/LOC
hemiplegia
spinal /peripheral
paraplegia/weakness
numbness/tingling
joint pain

43. Treatment of DCI

44. Treatment of DCI
 Airway
 Breathing
 Circulation
 Body position: “Supine is Fine”
 Oxygen administration (100%)
 Don’t attempt in-water recompression
 Call DAN: 919-684-9111 (emergencies only)
 Usually transport to the closest ED
 Recompress in hyperbaric chamber

45. Recompression

46. Goals of Recompression
 Shrink and dissolve bubbles
 By pressure and counter diffusion mechanisms
 Do not create new bubbles on decompression
 Expedite inert gas elimination
 Oxygenate ischemic tissue
 Reduce “injury/reperfusion” damage
 Don’t hurt your patient or inside attendant

47.  Pressure
 Shrink bubbles (Boyle’s Law)
 Gas Gradient
 Diffuse inert gas out of bubbles
P1V1=P2V2
pN2
100%
O2 100%
HBO2 Effect on Gas Bubbles
pN2 0%

49. HBO2 Effect on Neutrophil Adhesion
Thom SR. Am J Physiol Cell Physiol 1997

50. Hyperbaric Chambers and Treatment Tables

51. US Navy Oxygen Treatment Tables

52. US Navy Table 6 Management

53. Repeat Treatments
 Serious DCI
 Retreat with USN TT6 immediately
 Moderate DCI
 Retreat with USN TT6 4-12 hours
 Mild DCI residuals
 Retreat with USN TT5
 Retreat with USN TT9 (qd or BID)
 Give NSAIDs (1 less HBO2 with tenoxicam *)
 Do nothing, will get better regardless
 Treat until complete resolution or no change on 2
successive treatments
Bennett MB. Undersea Hyperb Med, 2003

54. Questions?
James R. Holm, MD
james.holm@vmmc.org
hbodoctor@yahoo.com