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American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
Lectures References Link
www.baromedical.com/clarkefiles.asp
Hyperbaric Medicine 2013
Best Evidence and Practice Standards
American Osteopathic College ofOccupational and Preventive Medicine
Las Vegas, Nevada
‘Approved’ Indications for Hyperbaric Oxygen Therapy
FDA…’on label’ standard
UHMS…leading scientific resource
Published evidence…EBM hierarchy
CMS/Medicare…leading health care purchaser
Commercial insurers…largely guided by CMS
Cerebral Arterial Gas Embolism
Pathophysiology
I/R injury clarifies earlier relapse issues
Essential elimination of USN TT 6A
Hyperbaric dosing: USNTT 6; Comex Cx 30
Differential diagnosis ‘CAGE vs. DCS’ unnecessary
Iatrogenic prevalence
The monoplace chamber
Cerebral Arterial Gas Embolism
Pathophysiology
I/R injury clarifies earlier relapse issues
Essential elimination of USN TT 6A
Hyperbaric dosing: USNTT 6; Comex Cx 30
Differential diagnosis ‘CAGE vs. DCS’ unnecessary
Iatrogenic prevalence
The monoplace chamber
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American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
National Board of Diving & Hyperbaric Medical Technology
Position Statement (2009-04)
Intermittent Air BreathingIt is the position of the National Board of Diving & Hyperbaric Medical Technologythat every recompression treatment facility and every clinical hyperbaric oxygenchamber, regardless of type or class, be equipped to provide intermittent airbreathing. Intermittent airbreathing, commonly referred to as an ‘air break’,serves to prophylax against and lower the incidence of central nervous systemoxygen toxicity. Intermittent air breathing also serves to treat premonitory signsand symptoms of oxygen toxicity, thereby reducing the potential for symptomprogression to overt seizure.
The application and sequencing of intermittent air breathing will be at thediscretion of the hyperbaric physician. However, intermittent air breathing shouldbe immediately instituted (by either multiplace chamber tender or monoplacechamber operator) whenever an acute change in patient status occurs and isconsistent with, or suggestive of, CNS oxygen toxicity.
www.nbdhmt.org
Decompression Sickness
Cochrane: recompression universally accepted standard
US Navy Diving Manual Rev. 6; 2005 TT6 (Comex Cx 30)
Serial dosing protocol
Basic science advances
Effects of treatment delay; current controversy
Monoplace aspects
Clinical Outcome as a Function of Treatment Delay
Delay(h) N CR IR Effectiveness
1 – 6 2,559 2,401 (94%) 135 (5%) 2,536 (99%)
6 – 12 1,802 1,579 (88%) 216 (12%) 1,795 (97%)
12 – 24 555 473 (85%) 80 (14%) 553 (100%)
24 – 36 234 189 (81%) 43 (18%) 232 (99%)
> 36 119 90 (76%) 29 (24%) 119 (99%)
~ 5,278 consecutive cases
Xu W, et al. PLoS One 2012;7(11):e 50079
Decompression Sickness
Cochrane: recompression universally accepted standard
US Navy Diving Manual Rev. 6; 2005 TT6 (Comex Cx 30)
Serial dosing protocol
Basic science advances
Effects of treatment delay; current controversy
Monoplace aspects
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American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
Carbon Monoxide Poisoning
Oxygen is the antidote…
Cochrane: ‘Existing RCT’s do not establish whether HBO reduces
incidence of adverse neurologic outcomes’
RCT trial design & interpretation issues: O2 dosing; serious vs.
mild cases; blinding/shams; f/u periods and screening tools
Raphael, et al. 1989 Ducasse, et al. 1995 Thom, et al. 1995
Scheinkestel, et al. 1999 Weaver, et al. 2002
Annane, et al. 2011 Garrabou, et al. 2011
Carbon Monoxide Poisoning
1. Lab studies uniformly (less 1) support HBOdemonstrate HBO mechanisms; superiority of HBO
at 3 ATA oxygen
2. Pregnant pts. not studiedlab, retrospective and prospective (Elkharrat, et al. 1991)
data produce an essential ‘hyperbaric’ consensus; nocontrarian views
trans-placental physiology ‘fetus as a sponge’
Annane group treat pregnant pts.
3. Pediatric pts. not studiedsofter consensus; no published debates pro and con
4. Severe* cases, preponderance of evidence supports HBO
* arguably: significant CNS manifestations: LOC: coma:
profound cognitive, visual or auditory changes
5. Less severe* cases, no compelling data HBO vs. NBO
* arguably: headache; nausea; vomiting; dizziness; fatigue;
malaise; syncope; confusion; subtle cognitive, visual orauditory changes; tachycardia; tachypnea
6. Data argues for high (3 ATA) initial tx. pressureprecise dosing course not reconciled
7. HBO ‘harms’; good patient safety profile
8. HBO economics arguably favorable
Problem Wound Healing: Diabetic Foot Ulcers
Basic science advances
Controlled trials
Cochrane
Meta-analysis update
Efficacy vs. effectiveness
Tissue oximetry case management
Modern dosing
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American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
HBO Cell Signaling Mechanisms in Wound Repair
Enhanced VEGF expression, Feng J, et al. 1998
HBO induced VEGF per c-Jun/AP-1 activation, Lee C-C, et al. 2006
Simultaneous activation of ERK and JNK pathways, Lee C-C, et al. 2006
Enhanced SPC mobilization via NO elevation, Thom SR, et al. 2006
NO mediated inhibition of neutrophil adhesion, Thom SR, 2004
NO mediated reversal of impaired EPC mobilization, Gallagher KA, 2007
NO mediated enhancement of Ang2 gene expression, Lin S, et al. 2002
0
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∆ N
O (
nM
)
0 5 10 15 20
200
400
600
800
1000
HBO
SNP
4mg/kg
Time (min)
A
Thom SR, et al. 2006Am J Physiol. Heart Circ;290C
Problem Wounds Healing: Diabetic Foot Ulcers
Basic science advances
Controlled trials
Cochrane
Meta-analysis update
Efficacy vs. effectiveness
Tissue oximetry case management
Modern dosing
HBO seems to improve chances of healing in pts. withDFU’s and may reduce the number of major amputations
Cochrane (2012)
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American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
Problem Wounds Healing: Diabetic Foot Ulcers
Basic science advances
Controlled trials
Cochrane
Meta-analysis update
Efficacy vs. effectiveness
Tissue oximetry case management
Modern dosing
Problem Wounds Healing: Diabetic Foot Ulcers
Basic science advances
Controlled trials
Cochrane
Meta-analysis updates
Efficacy vs. effectiveness
Tissue oximetry case management
Modern dosing
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American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
Crush Injury, Compartment Syndrome, Acute TraumaticPeripheral Ischemia
Basic science
Dosing protocol
Controlled clinical trial
Evidence-based appraisal
Hyperbaric Mechanisms
Immediate support of hypoxic tissues
Edema reduction
Mitigation of reperfusion injury
Generation of oxygen free radical scavengers
Dosing protocol
Complete vs. partial perfusion compromise
Pre-op in intermediate compartment pressures
‘Well spaced’ BID post-op
C. Perfringens Infections/Gas Gangrene
Basic mechanisms
Clinical evidence
Timing of HBO re surgery
Confusion; gas gangrene vs. nec. fasciitis
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American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
Basic Mechanisms
Inhibition alpha toxin production: Van Unnik AJM, 1965
Bactericidal (stops clostridia) at 1,400 mmHg O2:Kaye D, 1967
Bacteriostasis (stops a toxin production) at 250 mmHg
Other Benefits
Reduced mortality (when combined with surgery & antibiotics)
Vasoconstriction; edema reduction & improved perfusion
Tighter demarcation for ablation
Advantages of Early HBO
It is life-saving because less heroic surgery needs to be performed
in very ill pts. and cessation of alpha-toxin production is rapid
It is limb and tissue sparing because no major amputations or
excisions are done in advance and until demarcation becomes clear
It clarifies demarcation, so that there is a clear distinction between
obviously lost and still viable tissue
Bakker DJ, 1988
C. Perfringens Infections/Gas Gangrene
Basic mechanisms
Clinical evidence
Timing of HBO re surgery
Confusion; gas gangrene vs. nec. fasciitis
Late Radiation Tissue Injury
Mandibular osteoradionecrosis
Soft tissues; pelvic, larynx, colon, skin, etc~ little evidence supporting radiation myelitis
Radiation tissue injury prophylaxis
Mandibular Osteoradionecrosis
‘Marx Protocol’; treatment pressure issues
Annane et al. RCT issues
XRT portal issues; IMRT and IGRT
Decreasing ORN incidence-conformal XRT
F-8
American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
Mandibular Osteoradionecrosis
Annane et al. RCT issues
‘Marx Protocol’; treatment pressure issues
XRT portal issues; IMRT and IGRT
Decreasing ORN incidence-conformal XRT
10-20 mmHg
5 5 10 15 20 35 40 55
5 15 25 40 55
Mandibular Osteoradionecrosis
Annane et al. RCT issues
‘Marx Protocol’; treatment pressure issues
XRT portal issues; IMRT and IGRT
Decreasing ORN incidence-conformal XRT
Soft Tissue Radiation Injury
XRT late effects ‘not anatomic specific’ assumption
Radiation proctitis XRT results: Level 1 evidence
Disease modifying vs. supportive care alternative
Dosing issues; chamber pressure vs. oxygen pressure
F-9
American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
Soft Tissue Radiation Injury
XRT late effects not anatomic specific assumption
Radiation proctitis XRT results: Level 1 evidence
Disease modifying vs. supportive care alternative
Dosing issues; chamber pressure vs. oxygen pressure
National Cancer Institute Consensus; 1990
High risk-lifetime risk definitions
Small vintage 1985 RCT as the basis
Dosing protocol; 20/10 vs. 30/10 confusion
Radiation Tissue Injury Prophylaxis
National Cancer Institute Consensus; 1990
High risk-lifetime risk definitions
Small 1985 RCT as the basis
Dosing protocol; 20/10 vs. 30/10 confusionpre and post-op timing issues
Radiation Tissue Injury Prophylaxis Skin Flaps-Skin Grafts
Compromised Skin Flaps
Surgical exploration vs. immediate hyperbaric referral
Tissue oxygen tension screening
Dosing protocol
Evidence-based appraisal
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American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
Skin Flaps-Skin Grafts
Compromised Skin Grafts
Preparation vs. preservation
Tissue oxygen tension screening
Autologous vs. bioengineered
‘Preparation/preservation of Compromised SkinGrafts …’excludes artificial skin’
Medicare Hyperbaric LCD’s:Clearly meeting the intent of this policy limitation…
Autografts (autologous, patient’s skin)
Allografts (allogenic, genetically non-identical; cadaver sourced)
Isografts (genetically identical; patient’s twin)
Arguably meeting intent…
Alloderm…donated human skin *
Graftjacket… donated human skin *
Epicel…epidermal autograft cultivated from the patient
Laserskin… epidermal autograft cultivated from the patient
* FDA approved as banked human tissue
Products arguably not meeting intent…no human elements
Biobrane…silicone, collagen, nylon mesh
EZ-derm…porcine-derived xenograft
Integra…fully artificial product
Oasis…porcine-derived extracellular matrix
Permacol…porcine-derived collagen based
Strattice… porcine-derived dermal graft
Suprathel…fully synthetic monolayer dressing
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American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
Exceptional Blood Loss Anemia
Challenging cases’ multidisciplinary management
HBO best guided by pt’s calculated accumulating O2 debt
HBO tapered with increasing RBC mass
Dosing protocol
Necrotizing Soft Tissue Infections
Softer evidence support than gas gangrene
Confusion re mixing this condition with gas gangrene
Dosing issues
Basis for HBO Therapy
Improve leukocyte function in hypoxic tissues
Bacteriostatic for some organisms
Reduces amount/number of debridements
Earlier opportunities for skin grafting
Gibson 1986 41 46 9/29 (31) 7/12 (58) <0.05
Riseman 1990 29 41 4/17 (23) 8/12 (67) <0.02
Brown (1994) 54 35 9/30 (30) 10/24 (42) 0.40
Shupak (1995) 37 32 9/25 (36) 3/12 (25) 0.71
Holllabaugh (1998) 26 23 1/14 (7) 5/12 (42) 0.5
Wilkinson (2004) 44 14 2/33 (6) 4/11 (36) 0.03
Mindrup (2005) 42 21 2/16 (13) 7/26 (27) 0.44
George (2009) 78 10 4/48 (8) 4/30 (13) 0.48
Hassan (2010) 67 22 5/29 (17) 10/38 (26) 0.37
TOTALS 418 27 45/241 (19) 58/177 (33) 0.001
Study N Overall Rate HBORate Non-HBOMortality (%) Mortality (%) Mortality (%) P Value
Necrotizing Soft Tissue Infections
Softer evidence support than gas gangrene
Confusion re mixing this condition with gas gangrene
Dosing issues
F-12
American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
Refractory Osteomyelitis
Scientific and laboratory basis
Limited and poorly clinical data
Abuse issues
Basis for HBO Therapy
Bone pO2 (mmHg)
Healthy bone…~ 45 mmHg
Infected bone… ~ 20-22 mmHg
Infected bone & HBO… ~ 109mmHg
Stimulates osteoclasts, fibroblasts and angiogeneis
Bacteriostatic (anaerobes); Enhances PMNL function
Enhances aminoglycoside transport across cell wall
Refractory Osteomyelitis
Scientific and laboratory basis
Limited and poorly clinical data
Abuse issues
Acute Thermal Burn Injury
Hyperbaric medicine’s basis
Cochrane position re clinical data
Clinical practice; dosing protocol
Basis for HBO Therapy
Reduced edema
Enhanced collagen synthesis
Improved dermal element preservation
Better preservation of ATP levels
Improved infection control
Improved microcirculation
Cochrane 2005)
Insufficient evidence to support-refute HBO effectiveness
Evidence from two RCT’s don’t produce clear guidelines
F-13
American Osteopathic College of Occupational and Preventive MedicineOMED 2013, Mandalay Bay Convention Center, Las Vegas
Tuesday, October 1, 2013, Aerospace Medicine Day
Clinical Practice and Hyperbaric Dosing
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