Best Evidence and Practice Standards ... · National Board of Diving & Hyperbaric Medical...

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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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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


Effects of treatment delay; current controversy

Monoplace aspects

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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


Controlled trials

Cochrane

Meta-analysis update

Efficacy vs. effectiveness

Tissue oximetry case management

Modern dosing

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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

-5

∆ 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


Controlled trials

Cochrane




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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Controlled trials

Cochrane




Modern dosing



Controlled trials

Cochrane

Meta-analysis updates



Modern dosing

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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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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

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10-20 mmHg

5 5 10 15 20 35 40 55

5 15 25 40 55






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

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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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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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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

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Refractory Osteomyelitis

Scientific and laboratory basis

Limited and poorly clinical data

Abuse issues


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


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

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Clinical Practice and Hyperbaric Dosing

Best Evidence and Practice Standards ... · National Board of Diving & Hyperbaric Medical...

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