Hyperbaric oxygen therapy

1. Hyperbaric Oxygen Therapy
Dr Deepak Kumar
LADY HARDINGE MEDICAL COLLEGE

2. INTRODUCTION
• Hyperbaric oxygen therapy is defined as
administration of 100% oxygen to a patient
placed inside a chamber pressurized to greater
than 1 atmosphere.

3. Not Hyperbaric Therapy!!!
• Local application of pressurized oxygen to a part of the body
without completely enclosing the patient is not hyper baric
oxygen therapy

4. History
• Initial discovery
– 1662  Henshaw built first hyperbaric chamber
• English physician and clergyman Called the chamber
the “Domicilum”

5. Background
• Elemental Oxygen
– 1775  Discovered by Priestly (English)
• Surgical use
– 1870’s Fontaine & Bert (France)
• Prolong anesthesia
• Improved surgical outcomes
– Wound healing
• Decompression sickness
– 1910-30’s Drager, then Behnke & Shaw
• Reduced morbidity of decompression
• Studies of cardiopulmonary effects initiated

6. Physiology
• Cardiopulmonary
– Increase in PaO2
• Saturation of available hemoglobin molecules
– Hb 97% saturated at atmospheric pressure
– Maximization does NOT significantly increase O2 delivery
• Increase in dissolved O2
– PAO2 is 100mm Hg at atmospheric pressure
– Using 100% FiO2 at 3 atm  up to 2000mm Hg
» Increase O2 from 3ml/L blood to to 60ml/L
» 20 times more O2 circulating in plasma

7. Mechanisms of Action
Increased Oxygen Tension
Vasoconstriction
Increased Fibroblast Replication
Increased Collagen Response
Angiogenesis
Enhanced Leukocyte Function
Attenuation of Reperfusion Injury

8. Mechanism of Action
• Three main effects of HBO2:
1) Delivery of O2 to hypoperfused tissues
• Limit ischemic damage, cell death, and inflammation
• Promotes collagen synthesis and angiogenesis
• Decreases lactate production and tissue acidosis
2) Generation of oxygen free radicals
• Aids in oxygen-dependent killing of bacteria
• Facilitates oxygen dependent transport of antibiotics
3) Vasoconstriction
• Limits leukocyte adhesion and degrannulation
• Decreases tissue edema

9. Dosing and Delivery
• Parameters
– All regimens use
100% O2
– Pressure more
variable
• Most use 2.4 atm
• Maximum
tolerated is 3 atm
• 4 atm induces
seizures
Monoplace Hyperbaric Chamber.

10. Dosing and Delivery

11. Dosing and Delivery
• Common regimens
– Dives between 30 and
120 minutes
• May be daily or BID
• Total number varies by
indication
– Most treatments
around 30 dives
– Optional addition of 10
or more dives
– Monoplace &
Multiplace chambers Multiplace Hyperbaric Chamber.

12. Advantages of a Monoplace Chamber
1. Patients are cared for individually thereby maintaining
patient privacy.
2. Isolation of patients insures that there is no
amplification or spread of disease or infection from other
patients.
3. Patient can enjoy a more comfortable and relaxing
treatment.
4. Multiplace chambers require an awkward and
restraining facemask, Monoplace Chambers do not.
6. Technicians can easily monitor patients.
7. Ideal for patients confined to bed in acute stages of
illness or injury.

14. INDICATIONS
Investigational
Autism
Auto-immune Disorders
Cancer Treatment
Cerebral Palsy
Chemical Toxicity
Chronic Fatigue Syndrome
Crohn’s Disease
Fibromyalgia
Headache Syndromes
Lyme Disease
Macular Degeneration
Pre And Post Surgical Healing (Cosmetic Surgery)
Multiple Sclerosis
Near Drowning
Respiratory distress syndrome
Seizure Disorder
Spinal Cord Injury
Sports Injuries
Stem Cell Recovery Treatment
Stroke
Tinnitus
Traumatic Brain Injury
•

15. Applications
Today’s review
1. Osteoradionecrosis
2. Enhancement of graft & flap viability
3. Malignant otitis externa
4. Sudden SNHL
5. Radiation sensitization

16. Osteoradionecrosis
• Pathophysiology
– Reduction in caliber & number of feeding vessels
– Periosteal & mucosal damage  bone necrosis
– Body of the mandible most affected
ORN Histology – MandibleORN X-ray – Mandible

17. Chronic Non-healing Wounds
• Generalising from other fields
– Diabetic foot ulcers
• Significant reduction in morbidity
• Significant improvement in functional outcomes
• Significant cost savings

18. Clinical Uses and Therapeutic Effects of
Hyperbaric Oxygen
– Rationale for Hyperbaric Oxygen in
Problem Wounds:
• Enhances fibroblast replication
•  collagen synthesis
•  neovascularization
•  leukocyte bacteriocidal activity

19. Skin Grafts & Free Flaps
• Pathophysiology
– Grafted or transplanted tissue may be healthy
– But… implantation site may be hypoxic
• Due to vasospasm, edema, infection
• Oxygen & nutrient supply compromised
• Must establish vascular connection for survival
• HBOT:
– Improves tissue PO2
– Promotes angiogenesis
– Augments immune response & limits inflammation
(oedema)

20. Indication of HBO
Compromised Grafts And Flaps
• Initial treatments should be twice daily
• Once it is more viable and stable then
daily treatment
• 2-2.5 ATM 90-120 minutes

21. Malignant Otitis Externa
• Improved efficacy of immune
response
• Enhancement of bacteriacidal
antibiotic effects
Need RCTs to further
evaluate this indication

22. Radiation Sensitization
• Among first studied uses of HBO2 (1960’s)
– Areas of hypoxia in tumors are resistant to therapy
– Increasing oxygen pressure in the tumor can aid
tumoricidal therapies
• Administration of radiation sensitizing agents (oxygen donors)

23. Radiation Sensitization
• Systematic review (Bennett, et al. 2008)
– Found 19 randomized trials of HBO2 with XRT
• H&N, cervix, bladder, rectum, esophagus, brain
– H&N
• Significant mortality reduction
• Significant decrease in recurrence

24. HBOT in Sudden Sensorineural
Hearing Loss (SSNHL)

25. • Idiopathic sudden sensorineural hearing loss
(ISSNHL) is an otologic emergency with an
incidence of about 5–20 per 100,000
population per year
• It is a sudden,
usually unilateral and greater than 30 dB
hearing loss (HL) over at least 3 contiguous
frequencies, occurring over a period of 72 hr

26. Management
• Controversial: The use of more than one
agent in treatment is exceedingly common
• Choice of agents used varies substantially
among clinicians

27. SSNHL
• A Cochrane Review
(first published in The Cochrane Library in Issue
1, 2005 and previously updated in 2007)
•Comparing the effect on ISSHL and tinnitus of
HBOT and alternative therapies

28. Selection criteria
• Randomized controlled trials that compared
the effect of treatment for either acute or
chronic idiopathic sensorineural hearing loss
and/or tinnitus where hyperbaric oxygen
administration is included

29. • FolLwing trials were included in the review
– Cavallazzi 1996
– Fattori 2001
– Hoffmann 1995a; Hoffmann 1995b;
– Pilgramm 1985
– Schwab 1998
– Topuz 2004

30. R E S U L T S
• 1. Acute ISSHL: pure tone audiometric
change in hearing
• There was a 22% greater chance of
improvement with HBOT
• There was a statistically significant
improvement in those with severe hearing
loss and moderate hearing loss

31. 2. Chronic ISSHL:
• Difference was not statistically significant
• There were no significant improvements in
hearing reported for chronic presentation (6
months) of ISSHL

32. 3. Acute tinnitus:
• The significance of any improvement in
tinnitus could not be assessed
4. Chronic tinnitus: relief of tinnitus
• The difference was not statistically significant

33. Adverse events
– No trials reported any data on adverse events
in a systematic way
– 3 participants suffered middle ear
barotrauma(Pilgramm 1985)

34. Barotrauma

35. Barotrauma
• Barotrauma refers to injury sustained from
failure to equalize the pressure of an air-
containing space with that of the surrounding
environment
• Affects several different areas of the body,
including the ear, face and lungs.

36. Introduction
• Diving
• Aviators (after rapid ascent to altitude)
• Astronauts
• Rarely HBOT

37. Symptoms
• Symptoms of barotrauma include ear pain,
hearing loss, dizziness, tinnitus and
hemorrhage from the ear.

38. Differential diagnosis of
decompression
illness
• Middle-ear or maxillary sinus overinflation
• Gas expansion during ascent and an
obstructed eustachian tube or sinus ostium
• Contaminated diving gas and oxygen toxic
effects

39. Treatment
• Recompression is usually advised even if
manifestations resolve with first aid
(Since untreated decompression sickness can
recur days after the initial onset)
• Complete relief of symptoms in 50-98% of
individuals

40. Outcome
• Depending on the severity of illness
• Period of time that has elapsed between
development of DCI and recompression

41. Contraindications
• One absolute contraindication
– Pneumothorax
• Pressure converts to tension
pneumothorax
– All patients get screening CXR
• Relative contraindications
– History of spontaneous
pneumothorax
– History of throacic surgery
– Concurrent URI
– Emphysema and COPD
– Seizure disorders

42. Complications
• Barotrauma
– Lung parenchyma
• Elevated pressures
may damage alveoli
– Alveolar hemorrhage
– Hemoptysis
– Pneumonitis
– Alveolar rupture
• Pneumothorax
• Pulmonary interstitial
emphysema
Pneumothorax

43. Complications..
• Lens deformation causes temporary myopia
• Exacerbation of other processes
– Dental abscess, sinusitis, laryngocele, etc.
• Claustrophobia, anxiety, etc.
• Oxygen toxicity
– Very rare, but may cause seizures
• Potential effects on tumor growth
– Controversial

44. Fire Risk
• Especially monoplace
– 100% oxygen
– Highly pressurized
– Enclosed space
• Rare… but not rare enough
– 50 deaths due to HBO2-related fires since 1980
– Must remove all flammable materials
– Fire safety protocol is essential
• Risk reduced in multiplace chambers
– Chamber pressurized
– O2 delivered individually via tight-fitting masks
– Attendants may enter in an emergency

45. Contraindications
• Absolute Contraindications
– Untreated Pneumothorax
– Bleomycin –cardiotoxicity
– Cisplatin- delayed wound healing
– Disulfiram- blocks superoxide dimutase
(SOD)

46. Absolute HBO Contraindications
Recent Bleomycin Use – recent is not established although a one year period
may be sufficient.
Current Doxorubicin (Adriamycin) – wait 2-3 days prior to starting HBO.
Undersea and Hyperbaric Medicine board Review Course for Physicians
Penn Medicine. August 2010.

47. Absolute HBO Contraindications
Disulfiram (Antabuse) – blocks superoxide
dismutase which decreases the body’s ability to
neutralize oxygen free radicals; inhibits
hyperoxic induction of cytochrome P450.
Potential for pulmonary toxicity.

48. Contraindications
Relative Contraindications
• URI
• COPD with bullous emphysema or CO2 retention
• Claustrophobia
• Seizures
• Ear or sinus surgery or recent thoracic surgery
• Optic neuritis
• Pacemakers (verify for pressure tolerance)
• Pregnancy
• Congenital Spherocytosis

49. Costs
• HBO2 is relatively expensive…
– Monoplace chamber < Multiplace chambers
– Most facilities have multiplace chamberss, etc.
– But…
• Medicare reimburses for most accepted indications

50. Summary
• HBO2 derives its clinical benefit via
– Increase in the oxygen delivery to hypoxic tissue
– Promoting native mechanisms of healing
– Decreasing tissue edema & reperfusion injury
• Dosing
– Most commonly 30-40 dives of 90 min at 2.4atm but
less than 3 atm
• Costs
– Significant, yet analyses support cost savings in proven
indications

51. Summary
• Supported ORL-HNS indications
– ORN & CRN, radiation soft tissue injury
– Flap & graft survival
• Unsupported ORL-HNS indications
– Sudden SNHL, tinnitus, Bell’s palsy
• Areas of uncertainty
– Likely effect: MOE & skull base osteo, fistulas
– Poor side effect profile: radiation sensitization

52. Summary
• Further research
– Molecular mechanism incompletely understood
• Animal studies
• Human tissue studies
– Need ethical randomized control trials
• Variety of indications
– More combination regimens for cancer treatment
& post-XRT reconstruction salvage
• What are the optimal dose & delivery shemes?