Davis Hyperbaric Laboratory USAF HYPERBARIC NEWSLETTER January 1998

nated Coccidiodes immites infection”) with the manu- ***TABLE OF CONTENTS*** script to follow in the first quarter of 1998. Hyperbaric has long been recognized as a limb saving treatment for non-healing foot wounds in Research & Development 1 the diabetic. Why do antibiotics fail in these patients and why is HBO so effective? If the bacteria isolated Clinical Hyperbarics 3 from these wounds are sensitive to the antibiotics given then why do the wounds persist? Could it be that or- Operational Hyperbarics 10 ganisms that cannot be cultured in vitro are the cause of some of the problems? In collaboration with researchers Hyperbaric Training & Education 10 at the University of Scranton (PA) and the AF Epidemi- ology lab at Brooks, we identified bacterial species in a wound using standard clinical microbiology and mo- Parallel Universes 13 lecular biology techniques that do not require in vitro culture isolation. Both techniques found a problem Personals 16 bacteria: Bacteroides fragilis. However, the molecular biology approach also found Proteobacterium, an un- usual pathogenic organism that is difficult to grow in RESEARCH & DEVELOPMENT vitro. This finding tends to support the idea that previ- ously unidentified bacteria may play a role in diabetic wounds and that appropriate treatments (including HBO) must be used to defeat them. This ground BASIC SCIENCE RESEARCH breaking work is being submitted to the journal Diabe- tes Care (“Bacterial species identification in a non- This past year has been a busy one for cellular healing diabetic foot wound: identification by 16s ribo- hyperbaric research at Brooks AFB. In the area of in- somal DNA sequence”). We plan to use this prelimi- fectious disease we are exploring the feasibility of using nary work as a springboard to funding a more extensive hyperbaric oxygen as a means of treating problem lung study in the coming year. infections. The scientific basis for this study is the well Hyperbaric oxygen has been known to lessen known phenomenon that prolonged exposure to pure the damage produced during ischemia-reperfusion, oxygen can cause severe inflammation in the lungs and mainly through reduced sequestration of neutrophils that short exposures to hyperbaric oxygen have systemic (the cells that cause the most tissue damage during a immune effects. Taken together this suggests that hy- stroke or heart attack). Neutrophils do their damage by perbaric oxygen may increase the immune response in producing small highly reactive molecules that damage susceptible individuals giving them an edge in defeating essential components of the living cell, especially DNA difficult infections. We are studying this question in and membranes. One of the most important of these mice that are susceptible to a nasty, incurable fungal dangerous molecules, peroxynitrite, has been the subject infection caused by the organism Coccidiodes immites of our investigations. We have found that in activated which is found in soil in the southwestern US. While immune cells that have plenty of oxygen available, ex- the study is not yet complete, preliminary indications posure to HBO reduces production of peroxynitrite by are that HBO does produce changes in infected lungs about 40%. Activated immune cells maintained under that are consistent with an improved response. The hypoxic conditions produce only about 25% as much preliminary results of the study, in collaboration with peroxynitrite as cells grown under normal oxygen con- scientists at the Texas Center for Infectious Disease, are ditions. HBO exposure does not have any effect on per- to be reported at the AsMA annual meeting in Seattle oxynitrite production in hypoxic cells. Taken together (“Hyperbaric oxygen treatment of mice with dissemi- these observations suggest that HBO serves to attenuate an active immune response in normal tissues thereby preventing unwanted damage, while having little effect locations, and modular steel section (panels) chambers in hypoxic tissues. that can be transported for far forward deployment or This investigation along with another related contingency hospital placement. For monoplace paper are being submitted to the Journal of Cellular emergency transport/evacuation use we entered into a Physiology for publication. In collaboration with Dr. collaborative evaluation of existing technologies with Bowden at the Brooke Army Medical Center, Clinical the US Navy. We are convinced these technologies Investigations Branch, we are developing some new will bring clinical hyperbaric treatment to the combat- studies to examine the role of hyperbarics in limiting ant in-theater, meeting CONOPS requirements for cellular adhesion. Much needed in vitro dose response low-cost, cube, modularity and flexibility for deploy- studies (i.e., -time relationships) of HBO’s ef- ment of far forward support of the warfighter. fect on adhesion are planned, as well as, a clinical trial Pursuant to that goal of developing an alternate to examine in detail the effects of HBO on various adhe- material multiplace chamber, the USAF constructed a sion molecules. prototype concrete contingency hospital room (CCHR) What effect does hyperbaric oxygen have on using post-tensioned concrete construction materials. tumor growth? Based on epidemiology the an- The project demonstrated several advantages includ- swer is none at all. Could hyperbarics be used as an ing: 1) large, rectangular, floor-flush doors facilitating adjuvant to cancer chemotherapy or radiation treat- rapid and easy causality ingress/egress, 2) significant ment? We have examined this issue in one of the most cost reduction over steel vessels -- approximately 30%, problematic of all human cancers: advanced prostate 3) variable room size and configurations (square, rec- cancer. In a manuscript accepted for publication in the tangular or irregular) offering flexibility to accommo- journal Anticancer Research (“The effect of hyperbaric date existing building designs, 4) sliding doors that do oxygen on growth and chemosensitivity of metastatic not encroach floor space, and with vertical walls sig- prostate cancer”) we showed that there was a slight nificantly improving space efficiency, and 5) modular benefit when hyperbarics was given along with doxoru- support systems for easy transport and installation. A bicin and taxol, two front-line anticancer drugs. In a significant advantage of this technology is that the follow-up paper we examined in detail the pressure de- CCHR can be constructed by military or contractor pendent effect of HBO on tumor growth (“Exposure to civil engineers instead of mechanical engineer pres- hyperbaric oxygen induces cell cycle perturbation in sure vessel specialists. Furthermore, the CCHR can be prostrate cancer cells”, submitted to the journal Pros- rapidly constructed, in-theater, in a minimum of 36 tate and presented at 1997 UHMS annual meeting) and days (steel vessels average more than a year). The found that of 3 ATA and greater can synchro- prototype chamber completed pressure cycling tests nize a tumor cell population, setting the tumor up for with over 25,000 cycles (simulating a service life of greater damage during chemotherapy and slowing more than 25 years) and peak pressure successfully growth. tested to 85 psig (> 6 ATA), far surpassing the de- John Kalns, PhD signed pressure level of 29.4 psig (3 ATA). The code Research Scientist case to certify the technology is before the American Society of Mechanical Engineers (ASME) Committee CHAMBERS: THE NEXT GENERATION! for Pressure Vessels for Human Occupancy (PVHO). Once this approval cycle is completed, the technology Most of us in (HBO) are will be available for implementation. aware that up to now an operational limitation of our An alternative to the CCHR is a modular, ex- discipline has been the lack of in-theater/field support pandable hyperbaric chamber system (MEHCS). Al- for the requirement of combat casualty care and man- though this chamber is composed of traditional steel agement. The size, cost and fabrication time of steel materials, the MECHS has many advantages over pressure vessels made forward deployment prohibitive. welded steel chamber technology including: 1) modu- We acknowledge that the efficacy of hyperbaric oxy- lar design for optimizing deployability configuration-- gen is significantly enhanced if treatment is initiated meeting the requirements for reduced medical assem- quickly (within 4 - 6 hours) following injury. There- blage, 2) large doors facilitating rapid and easy cau- fore, to get HBO as close to the point of wounding as sality ingress/egress, 3) flexibility to extend treatment tactically possible, thus advancing our wartime readi- room size depending upon patient load requirements, ness mission, and addressing the Joint Health Service 4) sliding doors that do not encroach floor space, 5) Support Plan: Vision 2010, we are pursing alternate optimized interior illumination, and 6) vertical walls chamber materials technologies. These technologies maximizing interior space efficiency. This chamber is include, for multiplace chambers: concrete/resin com- designed as a 3 ATA system and has the nominal posite materials for placement at contingency hospital configuration of approximately 8 feet by almost 11

2 feet, and weighs about 14,000 pounds. This chamber Finally, I mentioned we are pursuing technol- meets all safety codes prescribed by ASME-PVHO. ogy to combine forward deployed chambers, perhaps Cost of the MECHS is less than $500,000, for a six- CONUS chambers as well, with a system to generate place chamber. This innovative modular system can greater than 99% pure oxygen. This system has been be warehoused, completely palletized (in sections) under development in a sister function at Brooks AFB ready for rapid forward deployment, thus attending to for several years. It is now reaching maturity and factors required by air transportable medical facilities. ready for implementation. The system is small and Modularity of the design allows bolted parts to be has the ability to generate 30 liters of “pure” oxygen readily moved into medical treatment facilities per minute. The current configuration can also liq- through existing doors or passageways before assem- uefy and store large quantities of oxygen for later use. blage, thus requiring little or no structural modifica- It is quite rugged and has a 500 hour service (filter tions. Furthermore, the system allows rapid configu- change) interval. More about this technology in a ration changes to adapt to increased causality loads, or subsequent newsletter as we get closer to our objective. alternative relocation of the system with minor down- Historically, during contingency operations time. MECHS is available, but will require integra- Hyperbaric Medicine relied upon CONUS, or at best tion into the inventory before it is deployable. host, hospital facilities for administration of this im- Operational hyperbarics recognized a need for portant modality. This will no longer be the case, as a portable chamber to support deployed operations, we bring these technologies to maturity. Since we will providing safe aeromedical evacuation of theater casu- be able to initiate treatment for the combatant, in- alties to a definitive medical hyperbaric treatment fa- theater, we will preserve the combatant's optimal cility. A joint service (USN/USAF) collaborative ef- mission capability by reducing the magnitude of the fort was funded by the Department of Defense, For- injury, and shortening the duration of recovery from eign Comparative Testing Program, to evaluate two battlefield injuries. candidate systems. The emergency hyperbaric treat- Larry Krock, PhD ment/evacuation system (EHTES) is a collapsible Director, Applied Research chamber constructed of composite materials, and is approximately 30 inches in diameter, and about seven CLINICAL HYPERBARICS feet long, when inflated. The chamber weighs less than 150 pounds and is self-contained, easily trans- portable, and capable of withstanding at least 3 ATA. CRUSH INJURY, HBO AND YOU Current chamber pressurization employs available air sources (compressed gas cylinders), but we are pursu- This clinical article is geared at improving our ing reduced logistic requirements through use of a understanding of the application of Hyperbaric Oxygen support cart with molecular sieve oxygen generating (HBO) to the Acute Traumatic Peripheral Ischemias capabilities. EHTES is easily pressurized in minutes (ATPIs) and how the various mechanisms of injury and with minimal training and has a built-in injury prevention may be better understood. system for oxygen administration with overboard dumping capability during air transport. Stabilized Reperfusion patients can be transported safely, while pressurized, Primary & Edema Gradient Injury by gurney, ambulance, or aircraft. As I mentioned Ischemia above, the USAF entered into a collaborative venture Crush with the US Navy on this project. The Navy will evaluate chamber compliance to ASME-PVHO stan- Injury 4+ 4+ 3+ 2+ dards, and test operational requirements on two can- Compart- didate systems—one from the UK and another from ment Italy. The AF component of this joint endeavor is to Syndrome 4+ 4+ 4+ 3+ evaluate the aeromedical worthiness of the candidate system. Tests conducted will extend the evaluation to determine compatibility with the airborne environ- Micro- Compro ment for system use with patients during aeromedical Second Circulation Contracture Infec- -mised evacuation flights. Currently, we are working with -ary Stasis Formation tion Wound the aeromedical research engineers to define test re- Healing quirements for this system. Evaluation will com- Crush mence later this year. Injury 4+ 1+ 1+ 3+

Compart- ment Syndrome 4+ 3+ 1+ 1+ 3 Crush injuries and compartment syndrome are microvascular circulation, appears to be effective in commonly recognized as belonging to the family of in- limiting this reperfusion scenario. jury known as ATPIs, along with such notable others as: As alluded to above, the edema and hypoxia burns; frostbite; threatened flaps; and replantations. The processes exacerbate each other, since as one worsens, it common pathway in all of these conditions is traumatic feeds the other. As the edema increases, the extravas- hypoxia! Some of the primary characteristics of the AT- cular compartment pressures increase which squeezes PIs include Hypoxia, Ischemia, Edema, Gradient Injury, off the microvascular circulation (stasis), preventing the and Reperfusion Injury. Secondary characteristics delivery of oxygen and nutrients. As this progresses, include Microcirculation Stasis, Contracture Formation, cellular damage worsens, permitting additional fluid Infection, and Compromised Wound Healing. leakage, and worsening the edema. This vicious circle The concept of Gradient Injury can be visual- continues, eventually resulting in cell death. Edema also ized in the following graph, where there is a spectrum exacerbates hypoxia by increasing the distance between of tissue viability in and around the immediately dam- capillaries, thus increasing the distance through which aged area. This spectrum ranges from minimal injury the delivered oxygen must diffuse before reaching the to total tissue non-viability, with all of the possibilities affected cells. The following diagram illustrates how the between. It is the tissues in the middle of the spectrum that are of great interest to us, because those are the ones that are at greatest risk, and will derive the most Distance benefit from hyperbarics. In the end, being able to sal- vage a sufficient quantity of otherwise marginal tissue Volume = may be the difference between saving and losing a limb! P*R2

This is the If R doubles, volume into Volume increases which the fixed by 22 = 4 load of oxygen is distributed Thus, the Diffusion Distance, “R” is related to the

square root of the delivered oxygen load (PaO2) of oxygen available for cellular use is related to the square of the diffusion distance. Thus, if the intercapil- lary distance doubles, the oxygen load available at the tissue level will decrease by a factor of four, exacerbat- So just what is this reperfusion injury brough- ing the existent hypoxic conditions. haa-haa all about? It seems that these little leukocytes A scale for evaluating traumatic injury has can sense that there’s trouble in “River City”, but don’t been advanced as the “Mangled Extremity Severity have enough oxygen to do anything about it. So they Scale”, or MESS. The MESS score is calculated as just stick themselves to the blood vessel walls, waiting shown below. for some oxygen to come along so they can unleash their peroxidases and other “disolvazymes.” Unfortu- Skeletal Soft Tissue Points Limb Ischemia Points nately, in these circumstances, the fairly indiscriminate Low Energy 1 Pulse decreased/absent 1 nature of these oxidative materials, and the quantities in Stab, Simple Fx present/WNL which they are released, seems to add to the damage, Medium Energy 2 Pulseless, Paresthesias 2 rather than help. In this hypoxic milieu, just a little ad- Open & Mult Fx Diminished Cap Refill ditional cell wall damage from peroxidases becomes Hi Energy/Crush 3 Cool, Insensate 3 irreparable due to the lack of oxygen; intracellular fluids Shotgun, Hi-V GSW Numb, Paralyzed leak out and cannot be recovered as there is no oxygen Crush + Contam *Double Score > 6 Hr * to power the osmotic pumps. This extra fluid contributes 4 to the local edema, which, in turn, worsens the existent hypoxia. Hyperbaric oxygen, applied early in the injury Shock Score Points Age Factor Points scenario, seems to prevent the WBCs from becoming BP > 90 0 < 30 YO 1 “sticky”, so that once perfusion is restored (re- Transient Hypotension 1 30 - 50 YO perfusion) this cascade of oxidative enzyme release is 2 Persistent Hypotension greatly reduced. Just a single HBO treatment delivered 2 > 50 YO 3 before, or within one hour of, re-establishment of the

4 Since a MESS of 7 or more is a 100% predictor of appreciation of how HBO can help in the treatment of eventual amputation in an untreated individual, the ap- this disorder. Compartment syndrome may develop plication of HBO in such cases provides a valuable following any traumatic injury to a tissue compartment therapeutic treatment option in reducing limb loss. which is surrounded by relatively inelastic fascia. As Therefore, HBO is recommended with a MESS score of fluid extravasates into the injured tissue. The pressure 6 - 7 in all individuals, and should be considered in the builds up within the fascial compartment until the cap- compromised host (i.e., diabetes, PVD, collagen vascu- illary bed perfusion pressures are exceeded. At this lar disease) if the MESS score reaches 5 - 6; and at a point, the microcirculation shuts down creating an MESS of 3 - 4 in severely compromised patients. ischemic, hypoxic environment, and the process is now Application of HBO decreases the effects of the self-sustaining. As with crush injury, surgery is the various mechanisms that lead to cell damage by several primary treatment modality to decompress the tissue paths. First, HBO can increase the oxygen concentra- compartment. HBO plays an important role as adjunc- tion 15 - 20 fold, providing a four-fold increase in the tive therapy for all of the reasons previously discussed. diffusion distance prior to the re-emergence of hypoxic Factors seen in compartment syndrome in- conditions. In addition, hyperbaric conditions permit the clude: blood plasma to carry 5 - 6 volume percent of oxygen over and above the 20 volume percent carried by hemo- u Clinical Findings globin. This level of oxygen, if present in the plasma, is – Severe pain in muscle compartment capable of sustaining the basal metabolic functions of – Marked increase in pain with passive muscle cells at risk---thus, the cells may be able to re-establish stretch their intracellular environment and prevent the critical – Marked swelling in muscle compartment loss of additional fluids. Understanding this provides – Marked tenseness in muscle compartment the explanation for why topical oxygen simply cannot – Neuropathy, myelopathy, and/or encephalopathy work: the oxygen must be dissolved in the plasma to u Skeletal Muscle Compartment Pressures reach the affected cells at the cellular level. Topically – > 40 mmHg in uncompromised host applied oxygen simply cannot diffuse past the surface – Serial pressures rising toward 35 mmHg layers of the tissue, providing inadequate PO2 inter- – 30 - 40 mmHg in mildly compromised host (DM, nally! HBO is also known to produce a 15 - 20% vaso- PVD, CVD) constriction, decreasing the amount of fluid entering the – 20 - 30 mmHg in hypotensive patients with BP area, and, thus, limiting additional edema formation. 33 - 50% below normal HBO also is capable of increasing the PO2 above the 30 mmHg threshold essential for fibroblast function, The diagnosis of compartment syndrome may be made collagen synthesis, and other healing functions. In- when any three of the clinical findings are present, or creased oxygen tensions also serve to facilitate “fast any ONE of the pressure findings exists! Primary surgi- mode” oxidative bacterial killing mechanisms in those cal treatment should be initiated as quickly as possible; leukocytes which are present, as well as, inhibiting the however, if surgical delays are unavoidable, an initial growth of any anaerobic pathogens which may have HBO treatment should be considered. Once surgery has been introduced. Recommendations for HBO treatment been completed, follow-up HBO may help salvage mar- following a crush injury are: ginal tissue, or even a limb! u Initiate Primary Interventions (Surgery, etc) Benton P. Zwart, MD, MPH – If unavoidable delay, consider HBO early! Fellow, Hyperbaric Medicine u Begin HBO ASAP Following Definitive Treatment – HBO TID for 1 (2-3) day(s) after the injury CHRONIC REFRACTORY OSTEOMYELITIS – BID/TID & duration are controversial (CRO) – If improved, decrease HBO to BID over next 4 - 6 days Introduction – If threatened flaps, continue HBO BID for up to Non-hematogenous osteomyelitis is a surgical 14 days disease which customarily responds to aggressive – If osteomyelitis, continue HBO for up to 60 debridements of sequestered (dead) bone and appropri- treatments ate intravenous antibiotics. Only after antibiotics fail or the disease process is complicated by local factors such With the basics under our belts, we may now as crushed tissue or systemic host factors such as severe examine compartment syndrome in order to gain an peripheral vascular disease, does Hyperbaric Oxygen

5 (HBO) become an adjunctive therapeutic modality. fixation she developed osteomyelitis. Repeated admis- Coupled with attentive daily wound care, HBO achieves sions for bone debridements, bone grafts, musculocuta- lasting healing rates of 80 - 90 % in chronic refractory neous flaps, and IV antibiotics, accrued > $250,000 cases. (direct medical costs, 1978-85 dollars). A distal This article will highlight the cost impact of pretibial wound continued to drain from exposed bone conventional chronic osteomyelitis treatment and de- and she still could not work. An HBO consult was ob- finitive treatment of refractory cases including HBO. A tained and she was hospitalized for definitive care in- brief review of applicable bone physiology provides a volving a repeat bone debridement, IV antibiotics and a framework for describing the epidemiological and course of HBO. If this failed she would have a below pathophysiological basis of this disease. Consideration the knee amputation and go on to prosthetic rehabilita- will also be given regarding the microorganisms in- tion. Her HBO therapy was begun as an inpatient then volved in the etiology and clinical presentation and continued as an outpatient; wherein, she made slow, but management of CRO. The Cierny-Mader classification continued, progress ultimately receiving 77 exposures. will be introduced identifying the impact of local and HBO and associated daily wound care added $18,000 to systemic host factors. The adjunctive use of HBO treatment costs. Loss of income over the 7 year period treatment regimen is described and the desired treat- was at least $238,000. HBO led to a shortened hospital ment outcome is identified. A case presentation is given stay, reduced morbidity (a healed wound, no amputa- which highlights several important decision points in tion) and a return to productive life. Review of several the management of this disease that can favorably de- studies of chronic osteomyelitis in patients treated with termine outcome. either HBO or amputation revealed an average cost of HBO and wound care of $20-30,000 versus the cost of Healthcare Impact amputation and rehabilitation of $50-70,000.

A triad of overlapping clinical, economic and Normal Bone Structure and Physiology social costs must be accounted for to arrive at the total healthcare dollar impact of CRO. The highest clinical Bone is cellular and well vascularized; ap- costs are found among these three settings: diabetes proximately 300 cc of blood passes through the skeletal mellitus, work-related injuries and motor vehicle acci- system per minute. Osteoblasts dents (MVA), where the severity of the disease or the actively lay down collagen and trauma coupled with a setting of a compromised envi- secrete bone concentrically ronment (host or ambient) is the common denominator. around themselves, becoming Given a crush injury from a fall at a remote construc- resident osteocytes. Osteoclasts tion site or as a result of an MVA, in a person who is are bone-eaters, phagocytosing delayed in receiving definitive surgical attention or bone and placing calcium ions happens to be a diabetic, sets the stage for osteomyelitis. back into circulation in the These infections often result in multiple treatment fail- blood in response to calcitonin. ures, ending in amputation. A quarter of the 11 million Bone is the site of the body diabetics in the US will develop a foot infection, repre- store of calcium and phosphate. senting 15% of all hospital admissions. In 1988 dol- This Ca-P homeostasis also lars, foot infections cost > $200 million and limb am- involves a complex interplay of putations cost > $350 million. The economic costs of enzyme systems which are repeated hospitalizations, retraining for new job or ex- modulated by circulating hor- pense of accommodation, disability compensation, and mones processed in various years of productive life lost adds up to a sizeable burden metabolic centers in the endo- on the taxpayers. In 1989, 200,000 US work injuries crine glands, lungs, gut, and accounted for $17 billion. The cost to society for the kidneys. Bone is of two types: suffering of those so afflicted is difficult to quantify, but Figure A trabecular/spongy (T) bone and involves the loss of independence, chronic pain, mal- compact ( C ) bone with a mar- adjustment disorders, (e.g., depression, divorce, alco- row cavity (Fig A). The differences in morphology holism, drug dependency, and suicide). dictate differences in mobilization of substances from A sample case illustrates many of the cost as- the blood to the cells and back. T-bone is fed via the pects of chronic osteomyelitis. During the seven years extracellular fluid (plasma) portion of the blood in a low prior to HBO therapy, a 36 year old female began with pressure diffusional method in the peripheral marrow open fractures of the distal tibia and fibula stemming portions and ends of long bones. An important portal of from an MVA. Following open reduction, internal entry into a bone is the nutrient artery. C-bone is nutri-

6 Pathophysiology

F Infected bone is hypoxic with PO2 in the range i of 15 - 23 mm Hg. Oxygen consumption is elevated by the activity of the bacterial burden and inflammatory g cells. Ischemia from crush injuries, for example, com- u pounds hypoxia due to traumatic disruption of vessels and associated increased immune response activation. r Hypoxia contributes to the favorable environment for bacteria by reducing leukocyte killing capacity (loss of e “oxidative burst”). Additionally, hypoxia lowers fibro- blast and osteoblast/osteoclast activity, retarding heal- ing. Chronic osteomyelitis originates as non- B hematogenous spread from a contiguous focus of infec- tion due to a traumatic break in the skin. Clinically, it may first appear as a cellulitis with bullae on the skin fied by collagen lined Haversian canals which have little overlying the bone infection. It becomes a persistently canals (canaliculi) which imply two way diffusional open, draining, painful wound, often with exposed dead gradients. These canals lead to individual cells which bone. Infected bone is non-healing in the case of frac- have interdigitating tight junctions which require a tures and leads to non-union. This disease is often greater expenditure of ATP for active carriers/protein complicated by host factors (e.g., diabetes mellitus). co-factors to pass substances back and forth between Chronic refractory osteomyelitis (CRO) is characterized cells and blood (Fig B). The whole process depends by duration longer than 6 months, unresponsive to anti- upon aerobic (oxygen) for maximum effi- biotics and surgery, with or without compromising host ciency. factors. Normal bone has a PO2 of > 40 mmHg and > 300 mmHg with HBO; there is no change in blood Cierny-Mader Classification flow during hyperbaric oxygen administration (Fig C). Perfusion in infected bone is lessened due to local This clinical classification was devised to in- edema and resultant increased intramedullary pressures; corporate anatomical and physiological aspects of the however, perfusion is not changed by HBO therapy disease process. This classification is further divided acutely. among systemic and local compromising factors. These are found in the groupings below. 350 300 Anatomical Stage 250 200 Osteo ä 150 bone Stage 1: Medullary Osteomyelitis 100 Normal ä 50 bone Stage 2: Superficial Osteomyelitis 0 ä 20% 100% Stage 3: Localized Osteomyelitis O2 O2 ä 1ATA 2ATA Stage 4: Diffuse Osteomyelitis Epidemiology Physiologic Stage Closed fractures have a < 1% incidence of os- teomyelitis, rising to 5% with open fractures and > 30% ä with crush injuries. Less than 1% of elective orthopedic äA Host: Normal surgery cases become infected. This climbs to > 30% B Host: for emergent cases. Sites of predilection are the lower ä extremity followed by the mandible. äSystemic Compromise(Bs) ä Local Compromise (Bl) C Host: Definitive Treatment Worse Than Present Disease 7 Effects of Adjunctive HBO Localä Compromise äVenous Stasis HBO is considered as an adjunctive therapy in Vessel Compromise CRO to reverse the effects of hypoxia in the wound tis- ä sue environment. It aids in the elimination of the mi- äArteritis crobial burden by restoring the “oxidative burst” of the Radiation killing leukocyte. Fibroblasts become more migratory ä and efficient at laying down more mature collagen äLymphedema cross-linkages which provide a better foundation for Scarring angiogenic buds to invade. Osteoblast and osteoclast ä activity normalizes to restructure the healing bone. Ac- Loss of Sensation tivity of some antibiotics is augmented by HBO, as noted above. äSystemic Compromise HBO Treatment Regimen Malnutrition ä Pure oxygen at 2.4 ATA for 90 minutes is Renal, Liver Failure ä given daily Monday through Friday. Each treatment äImmune Deficiency session involves three oxygen periods (30 minutes each) Diabetes interspersed with 10 minute air breaks. A total of 30 ä treatments are scheduled, followed by reassessment. äMalignancy Wound care includes daily debridement of accessible Tobacco & ETOH dead tissue and sequestra. Twice daily (BID) dressing ä changes consist of packing wounds with 2% boric acid äAge Extremes soaked gauze until no clinical indications of infection Chronic Hypoxia are present. Treatment goal is to achieve total coverage of all exposed bone with granulation tissue, without Clinical Management drainage, erythema, swelling, or pain. This wound will then be aerobically stable enough to support a graft or The pillars of clinical management is surgical flap and allow the patient to return to productive life. debridement of devitalized tissue and appropriate sys- Clinical case reports and animal studies have shown temic antibiotics. Irrigation and suction arrays can be 60 - 90% healing rates in CRO treated adjunctively with used to quiet a wound in preparation for more definitive HBO. treatment. Various methods of obliteration (to fill surgical defects) involve fasciocutaneous or mus- Robert N Bertoldo, DO, MPH cle flaps, autogenous bone grafts, and skin grafts. It is Fellow, Hyperbaric Medicine preferable to have as little foreign inert material in the wound area as possible; therefore, in the case of frac- CASE REPORTS ture, external fixation is desired. Staphylococcus aureus accounts for 40 - 60% A 25 year old gentleman ignited his heater of cases of osteomyelitis, however, other aerobic gram when the evenings became cold. At approximately positive (e.g., Staph. epidermidis) and gram negative 0100-0200 hours he awakened. He felt very “dry” with (e.g., E. coli) bacteria, as well as anaerobic gram posi- an accompanying headache, nausea, vomiting, and mild tive (e.g., Clostridia) and gram negative (e.g., Pseudo- shortness of breath. In addition, he felt mentally monas) organisms can be the triggers for osteomyelitis. “slowed.” At the Emergency Room his COHgb was In fact, mixed infections are found in 10 - 20% of cases. 31%. After 3 hours of 100% oxygen the COHgb was 6. Some antibiotics used in an anaerobic There was no significant past medical history (hypoxic) environment are noted to have far less effi- and review of systems proved unremarkable. Physical cacy, namely, aminoglycosides, quinolones, exam showed subtle neurological abnormalities. Coor- trimethoprim/sulfamethoxisole (TMP/SMX), and van- dination showed mild impairment of heel-shin test, comycin. Conversely, high oxygen tensions have shown mild impairment of tandem/heel/toe walking, and a in vitro and vivo augmentation of the action of several “wobbly” Rhomberg. Mental status revealed difficulty antimicrobials, e.g. tobramycin, TMP/SMX and nitrofu- with serial 7’s and a feeling of only 80% mental func- rantoin. tion.

8 He was treated with a standard USAF CO cebo (session of 21% oxygen at 1.1 ATA for 90 min- Treatment Table. At depth, his wits were noted to be utes, twice daily, over 6 days). All the patients received sharper and he seemed to have more energy. Upon the same standard therapies (anticoagulant, antibiotics, completion of the treatment table, there were no abnor- wound dressings). Transcutaneous oxygen pressure malities on physical exam. In fact, he felt his mental measurements (PtCO2) were done before (patient function to have returned to 100%. Follow-up over the breathing normal air) and during treatment (HBO or ensuing 48 hours revealed no residua. placebo) at the first, fourth, eighth, and twelfth sessions. This case demonstrates the value of quickly The two groups (HBO group, n=18; placebo group, removing the toxin, carbon monoxide, from the biologic n=18) were similar in terms of age; risk factors; num- system. His scenario, his COHgb, and his symptoms all ber, type or location of vascular injuries, neurologic suggest a serious exposure. Natural history for this sort injuries, or fractures; and type, location, or timing of of exposure suggests that Delayed Neurologic Sequelae surgical procedures. Complete healing was obtained for (DNS) must be anticipated. Its published incidence is 17 patients in the HBO group vs. 10 patients in the pla- between 10 - 25%. This problem can range from mild cebo group (p < 0.01). New surgical procedures (such IQ decrements to loss of bowel/bladder control. And, as skin flaps and grafts, vascular surgery, or even am- there is a significant potential for permanent residua. putation) were performed on one patient in the HBO Recent literature suggests DNS may well be a group vs. six patients in the placebo group (p < 0.05). form of the ischemia-reperfusion injury. Here, an Analysis of groups of patients matched for age and se- ischemic period causes local injury (i.e., endothelium). verity of injury showed that in the subgroup of patients This is followed by oxygenated reperfusion. Because of older than 40 with grade III soft-tissue injury, wound the injury leukocytes arrive, attach, and activate. In healing was obtained for seven patients (87.5%) in the essence, the leukocytes now become factories of oxygen HBO group vs. three patients (30%) in the placebo radicals causing significant local damage. This injury group (p < 0.05). No significant differences were found with its accompanying edema results in neurologic in the length of hospital stay and number of wound dysfunction. HBO seems to mitigate this process by dressings between groups. For the patients with com- inhibiting the leukocyte attachment, thus short- plete healing, the PtCO2 values of the traumatized limb, circuiting the attack and minimizing the damage. In measured in normal air, rose significantly between the fact, Steve Thom’s work at the University of Pennsylva- first and twelfth sessions (p < 0.001). No significant nia would suggest the mechanism is an inhibition of the change in PtCO2 value was found for the patients whose leukocyte beta-2 integrin. As future investigations fur- healing failed. The Bilateral Perfusion Index (BPI = 2 ther clarify this mechanism, I think we can be fairly PtCO of the injured limb/PtCO2 of the uninjured limb) at certain there will be an expansion of HBO indications. the first session increased significantly from 1 ATA air to 2.5 ATA oxygen (p < 0.05). In patients with com- WPB plete healing, the BPI was constantly greater than 0.9 at 2.5 ATA oxygen during the following sessions, whereas LITERATURE REVIEW the BPI in air progressively rose between the first and the twelfth sessions (p < 0.05), reaching normal values Hyperbaric in the Management of at the end of the treatment. In conclusion, this study Crush Injuries: A Randomized Double-Blind Placebo- shows the effectiveness of HBO in Improving wound Controlled Clinical Trial. G. Bouachour, P. Cronier, healing and reducing repetitive surgery. We believe J.P. Gouello, et al. that HBO is a useful adjunct in the management of se- Journal of Trauma: Injury, Infection, and vere (grade III) crush injuries of the limbs in patients Critical Care 41(2): 333-339, 1996. more than 40 years old. Commentary: This is the first controlled and random- Abstract: HBO is advocated for the treatment of severe ized clinical trial looking at HBO treatment of major trauma of the limbs in association with surgery because crush injuries. These injuries were grade III (from of its effects on peripheral oxygen transport, muscular Gustillo)---extensive soft-tissue injury with or without ischemic necrosis, compartment syndrome, and infec- bony involvement, with or without adequate soft-tissue tion prevention. However, no controlled human trial coverage. The damage originated from blunt trauma. had been performed until now to specify the role of No penetrating trauma was included. HBO in the management of crush injuries. Thirty-six There was no difference between HBO and patients with crush injuries were assigned in a blinded non-HBO groups under 40 years of age. However, for randomized fashion, within 24 hours after surgery, to patients greater than 40 years old there was a sig- treatment with HBO (session of 100% oxygen at 2.5 nificant benefit using HBO. The HBO group dis- ATA for 90 minutes, twice daily, over 6 days) or pla- played markedly better healing, not to mention less sec-

9 ondary surgical procedures. And, transcutaneous oxy- dropped in price to between $350 and $400. Gentex is gen measurements (PtCO2) proved to be an excellent open to all suggestions that improve the mask’s per- marker for healing. In fact, treatment successes showed formance. I for one am glad to see the mask and over- an average change from the first day to the twelfth day board hoses are now available up to 120 inches. An of 21 mmHg to 90 mmHg oxygen tension. adapter with longer hoses could be one option. The In the military, blunt trauma is certainly mask comes in four sizes; Small Narrow, Medium nar- prevalent; however, equally important is high energy row, Medium Wide, Large Wide. Mr. Robert McKay is penetrating trauma. As yet, there are no similar trials. the point of contact for Gentex (909) 481-7667 or sug- There are only retrospective anecdotal series in which gestions can be sent directly to me. HBO is used regularly, but mentioned only in passing The new hyperbaric mask requires less pres- (i.e., Bosnian conflict). It would be very interesting to sure than the old MBU 5/P mask. If using the A-14 look at this data more closely and compare it to data regulator, set the pressure dial to the letter “S” in the obtained in those regions of the conflict without HBO word SAFETY. The “S” setting delivers approximately facilities. 1 in H2O. If using a different oxygen delivery system, WPB calibrate your delivery system to deliver 1 in H2O. Gentex has developed a compatible oxygen regulator OPERATIONAL HYPERBARICS that can replace the A-14 regulator inside the hyper- baric chamber. Gentex is also looking at developing a compatible overboard dump system. AN UPDATE ON THE NEW MASK NOTE: The HyperMed Patient Mask can- In the January 1997 issue of the USAF Hyper- not be used with the current overboard baric newsletter, SSgt Massa, discussed his work on the dump system on Air 99/S hyperbaric new hyperbaric mask. To refresh your memory, the chambers. Modifications to the overboard modified MBU-5/P aviators breathing mask had been in dump system and a Venturi system is re- use since the 1970’s. The mask is still a depot item, but quired. the modified adapter is not available. The expense to re-mill the adapter was not cost effective. Recent tech- The new HyperMed mask and the older modi- nological developments in oxygen masks has greatly fied MBU 5/P mask are both available inside our cham- increased wearing comfort and reduced USAF mainte- ber. The HyperMed mask is preferred and used exclu- nance costs. sively by all of our personnel. The fit and comfort is The Davis Hyperbaric laboratory in conjunc- considerably better. tion with the Gentex Corporation finished testing a Many thanks to all the volunteer divers who modified aviator’s MBU-20/P derivative oxygen mask. assisted with the test and evaluation of this mask. The mask was tested with the assistance of TSgt Rogelio Cano, SSgt Dave R. Case and Mr. Ron Holden of the John Kettinger, SMSgt USAF Research Chamber Operations Section. The mask was Superintendent, Operations and Development tested at 3.0, 2.5, 2.0 ATA and ground level using a pressure demand regulator (A-14) and pressure trans- We at the Davis Hyperbaric Laboratory are also proud to ducers. A mass spectrometer was used to analyze oxy- announce the promotion of SSgt Tom Massa to Second gen levels, carbon dioxide, and other exhaled gases. Lieutenant Tom Massa. Tests confirmed that the mask could physiologically maintain levels of inspired oxygen while also exhaust- HYPERBARIC TRAINING AND EDUCATION ing expired carbon dioxide and other exhaled gases to a lesser . The mask has been approved and is available LECTURES from the Gentex Corporation. Gentex has made a few additional changes that have improved the performance The Staff/Fellow Conferences at Davis Hyper- and durability of the mask. The hardshell’s diameter baric Laboratory are alive and extremely well. We have has been increased to reinforce against cracks. The had the pleasure and privilege to host numerous formal strap assembly has been changed slightly. The new lectures/discussions. All of them have been CME ac- mask now comes in a blue transparent color . The credited by the Office of the USAF Surgeon General. transparent color is essential for monitoring patients Each has been videotaped to facilitate continuing profi- inside the chamber. Best of all, Gentex has made sig- ciency training in Hyperbaric Medicine. nificant cost reductions. The mask has reportedly WPB

10 HBO LECTURE/SAFETY VIDEOS HYPERBARIC COURSE

The Davis Hyperbaric Laboratory Video Li- The Hyperbaric Nursing Course has been re- brary, has had a growth spurt! The monthly vised. The course is 7 weeks long, it requires the 1 Staff/Fellow Lecture Series held at Brooks AFB, is now week HTHCO course as pre-requisite, and four weeks being videotaped. OJT on the job site. The focus of the course changed Lectures by scientists, foreign visitors, nurses, from book learning and demonstrations, to hands on in technical experts and physicians are available, and can the chamber. A total of eleven scheduled dives are now be borrowed. All you have to do is ask! Plans are in the in the course plan; more emphasis has been placed on works to have these filmed lectures accredited for CHT, the specialized nursing skills needed in the hyperbaric CME, and nursing. environment. The nurses’ critical care backgrounds are put to the test during the training dives with drips, ven- To borrow a film--- tilators and critical management. The course continues as before, listed in the Call: DSN: 240-3281 AFCAT 36-2223, as a TDY to school at BAFB, enroute COM: (210) 535-3281 to the new base. The number of nursing contact hours Write: DET 1, HSC/AOH has not yet been determined. Questions? Call, Capt Bar- 2509 Kennedy Circle, Suite 309 bara Susen COM: (210) 536-3281, DSN: 240-3281 or Brooks AFB, TX 78235-5304 E-mail: [email protected]. E-mail: [email protected]. Capt Barbara Susen Capt Barbara Susen Chief, Clinical Education & Equipment Development Chief, Clinical Education & Equipment Development ENLISTED HYPERBARICS A Partial Listing Long Term Health Effects of Diving There is a Clinical Hyperbaric Training Aircraft Mishap Investigation---Australian Style Course for Technicians (B3AZY4X0X1-005) tentatively Fire Review/Operational Safety (2 hours) scheduled for April 1998. This three-week course is Pharmacology of HBO & Biochemistry of Healing mandatory for 4NOX1s and 4MOX1s who are stationed Monoplace Protocols at or have an assignment to a clinical hyperbaric treat- Crush Injury/Compartment Syndrome ment facility. Let us know ASAP if you have individu- The Historical Basis and Use of TcPO2 (2 hours) als who require training. Our POC for the course is Basic Science and HBO TSgt Robert Johnston; he can be contacted at DSN: 240- Cardiopulmonary Effects of Pressure 3281. Osteomyelitis and HBO Clinical Hyperbaric Medicine is losing physi- HBO---Delivery and Extraction in Human Tissues cians, nurses and technicians from all three clinical Diabetes Mellitus and ABI treatment facilities within the next year due to separa- Wound Healing and Oral-Maxillofacial Surgery tions, retirements and PCS. We are looking for a few Croatia Experience with HBO (4 hours) folks who are interested in broadening their horizons Nicaraguan Indigenous Diving Experiences (2 hours) and would like a challenging job in the exciting field of Brown Recluse Spider Bites Clinical Hyperbaric Medicine. If you're up to the chal- Carbon Monoxide Poisoning lenge, contact one of the POC’s listed: HBO and Frostbite Brooks AFB, Texas: MSgt Dave Pridgen or SMS John Altitude DCS---Current Concepts Kettinger at DSN: 240-3281. Women’s Health in Hyperbaric/Hypobaric Arenas Environmental Medicine---The Russian Experience Wright-Patterson AFB, Ohio: MSgt Hector Chavez at Forensic Aspects of Diving Accidents DSN: 787-8603

WPB Travis AFB, California: MSgt John Gorum at DSN: 799-3988

MSgt David Pridgen Manager, Hyperbaric Medicine (DHL)

11 FELLOWSHIP TRAINING FOR PHYSICIANS City, Missouri, followed by a flexible internship at the Rocky Mountain Hospital in Denver, Colorado. After The USAF School of Aerospace Medicine Aerospace Medicine Primary Course, he became a trains two physicians annually in a Clinical Hyperbaric squadron medical element leader for the 428th Tactical Medicine Fellowship at the Davis Hyperbaric Labora- Fighter Squadron (F-16B) at Nellis AFB. Next, he flew tory. The primary emphasis of the program is clinical with the 390th Electronic Tactical Squadron (EF-111A) (i.e., wound care and adjunctive use of hyperbaric oxy- at Mountain Home AFB. From there he entered and gen for wound healing). However, fellows also treat successfully completed a Family Practice Residency at sickness (DCS) cases that are referred Creighton University. Elmendorf AFB was the next from the mid-south and are consultants for USAF op- stop. He next matriculated to the twin residencies of erational DCS cases occurring worldwide. The USAF Aerospace and Occupational Medicine at the School of has been treating aviator's DCS in hyperbaric chambers Aerospace Medicine on Brooks AFB. He completed his since 1959. MPH degree at the University of Texas in San Antonio. In 1974 the Surgeon General established a hy- As commander of the 9th Aerospace Medicine perbaric center (later named the Davis Hyperbaric Labo- Squadron at Beale AFB (supporting high-altitude U-2 ratory) at Brooks AFB to direct the development of op- operations based in Cyprus, Saudi Arabia, France, erational and clinical hyperbaric medicine throughout England, and Korea) he logged both diving and flying the Air Force. Davis Hyperbaric Laboratory is the lead time. In fact, he accumulated over 500 hours of flying agent for all DoD Clinical Hyperbaric Medicine pro- in more than 30 different US and Allied military air- grams. craft. In addition, he served as medical group com- The physician fellowship was established in mander during Operation Southern Watch. 1978. It was the first Clinical Hyperbaric Medicine Dr Bertoldo is currently certified by the Ameri- Fellowship in the United States, and remains the only can Board of Family Practice and the American Board military hyperbaric fellowship. of Preventive Medicine. In the year of training, fellows learn the latest He and his wife, Barbara, are the parents of techniques in the management of chronic nonhealing two children, Nathan and Emily. wounds. In addition, they learn the nuances of the other thirteen accepted indications for hyperbaric oxygen Dr. Benton P. Zwart completes our Hyper- therapy. Included in that list is the operationally rele- baric Medicine Fellowship team. Dr. Zwart came to the vant altitude-induced DCS. Fellows become singularly USAF after receiving his Bachelor’s Degree (summa qualified in dealing with this malady. The current pro- cum laude) and Master’s Degree in Electrical Engi- gram achieves an exceptionally broad-based experience neering at Lehigh University. During his first tour of with multiple outside rotations (i.e., , duty he made major contributions to the development of monoplace chamber operations, international confer- a satellite navigation program known today as the ence attendance). Global Positioning System. Fellows actively participate in hyperbaric Col (S) Zwart then obtained his medical degree medicine education by teaching classes to physicians, at the University of Connecticut School of Medicine in nurses, and technicians at the School of Aerospace Farmington, CT, and underwent Family Practice train- Medicine. Opportunities for basic science and clinical ing at Oakwood Hospital in Dearborn, Michigan. Sub- research are available and encouraged. sequently, he was chosen to be the OIC of Flight Medi- Fellowship training incurs a two-year pay-back cine at Scott AFB, followed by an assignment as Chief, commitment. At the completion of training, fellowship Aerospace Medicine at Zweibrucken AB, Germany. trained physicians are assigned to one of the USAF's During those years he flew in aircraft such as the UH-1 clinical hyperbaric medicine facilities located at Brooks Huey, C-9 Nightingale, F-4 Phantom, and the C-23 AFB, Travis AFB, or Wright-Patterson AFB. Sherpa and has now logged over 950 career flight Physicians interested in fellowship training hours. should contact Lt Col William P. Butler, Director, He then entered the Residency in Aerospace Hyperbaric Medicine Fellowship, Davis Hyperbaric Medicine, earning his MPH from the Harvard School of Laboratory, Brooks AFB at DSN 240-3281. Public Health. After completing his RAM program, he WPB earned board certification in Aerospace Medicine and recently passed his Occupational Medicine Boards. Dr. Fellow Profiles Zwart spent a year traveling worldwide as a member of the Inspector General team. Subsequently, his Dr Robert N. Bertoldo attended medical aeromedical expertise was acknowledged when he was school at the University of Health Sciences, Kansas selected Chief, Flight Medicine Branch, Aeromedical

12 Consultation Service here on Brooks AFB. Just prior to Diving Medicine Training for Uniformed Physicians, beginning his Fellowship, he was the Director, Base Physician Assistants, and Physiologists Medical Services at San Vito Air Station, Italy, sup- porting the Bosnian peacekeeping efforts. He was di- The Naval Diving and Salvage Training Center rectly involved in the humanitarian efforts of Joint Task (NDSTC), Panama City, Florida offers five graduate Force Silver Wake during the evacuation of Albania. level diving medicine courses for interested DoD physi- He and his wife, Kay, are the parents of three cians, PA’s, and physiologists. Quotas for training slots daughters, Lauren, Kara, and Rebecca. are offered based on operational need and order of ap- plication. This training is required for Navy Undersea We welcome both of these highly qualified Medical Officers and Navy residents in Aerospace physicians to the realm of Hyperbaric Medicine. They Medicine and highly encouraged for all Flight Sur- are certain to make many contributions to the field geons, Army Special Operations Medical Officers, and during the upcoming years. Aviation Physiologists. The Recognition and Treatment of Diving WPB Casualties courses (R & T) are 10 days long. Graduates receive 63 hours of CME credit and are certified to ini- MEDICAL SUPPLEMENTAL TEAM MEMBERS tiate hyperbaric treatment of dysbaric illnesses, to re- view diving duty physical exams, and to serve as inside There have been a lot of Supplemental Dive tenders during recompression therapy. This course pro- team members, both MC and NC trained. We always vides training necessary to safely and effectively per- need more!!! The HTHCO course has now been re- form as a medical advisor for diving operations. Stu- duced to 4 days, being offered only four times a year. dents learn each job as part of the chamber team during Class slots need to be requested from your MAJCOM by diving accident scenarios and do several chamber dives, your training action officer. The AFCAT has full pre- the deepest being 165 FSW. Applicants must have a requisite information. Plan now for the future. current diving physical exam. There are no extra physi- The function and services our supplemental cal fitness requirements. divers perform for their specific clinical HBO units are The Diving Medical Officer courses (DMO), a so important. They enhance our staff by knowledge, pipeline course for Navy Undersea Medical Officers, are energy and numbers. I know you join me in thanking 9 weeks in length. The course consists of one week of them for their willingness to volunteer their time to our diving physics, 2 weeks of diving medicine which is units. almost identical to the R & T course, 5 weeks of dive training, and a final week of advanced diving medicine Capt Barbara Susen topics. Unlike the R & T students, DMO students must Chief, Clinical Education & Equipment Development complete the rigors of Navy which in- clude daily strenuous physical training, one stressful week of SCUBA confidence training and certification PARALLEL UNIVERSES dives to 190 FSW. DMO’s become bona fide Navy di- vers qualified in open-circuit SCUBA and all Navy surface supplied rigs. They get a closed-circuit SCUBA US NAVY familiarization which culminates in pool dives with the Draeger LAR-V. In addition to a current diving physi- Clinical Hyperbaric Medicine cal, applicants must pass a diver physical readiness test and a 1000 yard timed surface swim with fins. Gradu- James Chimiak, who is the Head of the Navy ates receive 95 hours of CME credits. Operational Medicine Institute’s Hyperbaric Medicine NDSTC, a tenant command on the Naval Division, was recently selected to co-chair a joint papers Coastal Systems Station, is considered to be one of the session on the cross-over day of the AsMA and UHMS best diver training facilities in the world. These courses annual meetings. He will represent the Aerospace provide uniformed medical providers excellent con- Medical Association. Dr. Chimiak is a Fellowship tinuing medical education opportunities and current, trained Hyperbaricist (Duke University), in addition to professional instruction in diving medicine. The are no being an active Flight Surgeon. course costs. Government messing and berthing are available. For more information and the 1998 course dates, contact LT Jackson, at DSN 436-5216/5 or COMM (904) 235-5216/5. WPB

13 US ARMY A Draeger mask with a demand regulator has been used for the past 25 years without serious accident. The Army has decided to close the chamber Pressurized oxygen is used, rather than LOX. Although complex at Ft. Rucker, Alabama. However, this was not the overboard dump system was characterized as the end of Army Hyperbaric Medicine. LTC Daniel “ancient,” it obviously functions well. A re- Fitzpatrick, one of the Army’s few fellowship trained search/experimental chamber was shown that was cre- hyperbaricists, moved to Eisenhower Regional Hospital ated from a cut-out British torpedo tube. The chemistry on Ft. Gordon, Georgia. There, he began a Hyperbaric lab shown appeared rudimentary; but, it apparently Medicine program. To accomplish this task, Davis Hy- functioned without major difficulties. perbaric Laboratory loaned their Sechrist monoplace Treatment of diving accidents did not include unit to the Army. Presently, there is talk of establishing the use of USN TT5 or USN TT6A. The Catalina Table a multiplace chamber there. or the USN TT6 was the treatment of choice. In addi- The Army’s Institute of Surgical Research (ISR tion, clinical treatments were almost uniformly per- a.k.a. Burn Unit) has shown a new interest in Hyper- formed at 2.2 bar for 60 minutes of oxygen. Gas gan- baric Medicine. Colonel Cleon Goodwin, Commander, grene was treated at 3 ATA. Several patient examples has been discussing the possible use of HBO for his pa- were given. A patient with macular degeneration had tients with the staff of Davis Hyperbaric Laboratory. his progressive blindness halted. A University mathe- Needless to say, this is an exciting future. WPB matics professor suffering a bilateral amputation from a grenade blast was successfully treated to halt an infec- CROATIAN PHYSICIANS VISIT tion. War casualties were regularly treated. These From 27 - 31 October 1997, DHL was pleased included “Croatian soldiers, Muslim deserters, Serbian and privileged to host a delegation of five Croatian phy- prisoners, and Croatian civilians.” During this sicians. During the visit they were exposed to a wide “passionate war,” only two physicians manned the unit. variety of USAF missions both medical and the line. In There were 200 casualties treated. Many of these pa- addition, they were able to see the civilian multiplace tients had external fixators. One patient exceeded 300 and monoplace units in the San Antonio area. Each pounds. Generally, only three casualties were treated tour was noted to be an excellent experience and many simultaneously. In order to enter and remove the pa- in-depth discussions ensued. Needless to say, a number tients, “slides” had to be used. The chamber room was of friendships were forged. frequently very hot (no air conditioning) with little in During the lecture series, much information the way of breezes. was exchanged. Certainly, the clinical material was Of the 200 casualties, 172 (86%) were secon- interesting; however, it was the data regarding the war dary to explosives or projectiles. Primarily injured were that was riveting. lower extremities. There were 103 explosive injuries, Hyperbaric Medicine has been alive in Croatia 51 rifle injuries, and 18 major lacerations. In addition, for over 30 years. The unit at Split, Croatia (the sole there were 28 (14%) other injuries. These included Hyperbaric Medicine unit in the country) is a part of the acoustic injuries (i.e., blast-related hearing loss---10), Navy Medical Institute which provides Undersea & Hy- frostbite (“7 Muslim deserters and 6 Croatian soldiers”-- perbaric Medicine, Occupational Medicine, Medical -13), Sudeck’s reflex dystrophy (2), osteomyelitis (2), Selection Process, Epidemiology & Tropical Medicine, anaerobic hand infection (1). No burns were treated; Microbiology & Medical , and Sanitary the critical nature of the injury was cited as the main Chemistry & Toxicology. The Undersea & Hyperbaric mitigating factor. Average number of treatments was 7; Medicine division supports Navy diving and submarine average hospitalization was 20 days. No comparison to activities (1 submarine), in addition to clinical Hyper- non-HBO treated casualties has yet to be accomplished. baric Medicine. These data were provided in hard copy; however, it is in Two 2-lock walk-in hyperbaric chambers that Croatian. can treat eight patients plus two inside observers make The biggest problem facing the casualties was up the unit’s hardware. Also, there is a “wetpot” dive transportation/evacuation. A distance that could be simulator sphere that has a 15 ATA capability. Current “overflown in less than 4 hours” frequently required “up staffing include 3 specialists in Occupational Medicine to 17 days” to traverse. The average transport time was (one with Undersea training specialty), 4 Hyperbaric 4 days. nurses (2 RN’s and 2 corpsmen) 1 engineer of Chemis- This prompted the placement of “small teams try, 1 Chemistry lab technician, and 4 chamber opera- of surgeons to the front lines to prepare the casualties tors. Up to 250 patients are treated annually. for transport.” Preventive fasciotomies were the rule, often preventing compartment syndrome. Although

14 osteomyelitis was seldom treated during the war, much Here, the primary industry of the indigenous Miskito of the present patient population suffers osteomyelitis. Indians is sea-harvesting. These Indians scuba dive for Its pathogenesis is felt secondary to this front line sur- the spiny lobster. There are about 150,000 Miskito In- gery. However, it was pointed out that many extremities dians. They form the largest ethnic group in a country and lives were saved by this practice. with only 4.3 million population. With an unemploy- Hyperbaric oxygen therapy (HBO) was used to ment rate of 65% and a poverty rate of 85%, any con- reverse “hypoxia/ischemia.” Only 8% of the total casu- sistent income in Nicaragua is rigorously sought. alties generated received HBO. Although this was felt Prior to 1958, there was no . De- to be “too little,” it was recognized that “more spite its introduction, only about 120 Miskito Indians (casualties) probably could not have been handled.” used scuba to collect the lobsters. The depths were usu- Treatments continued seven days a week without ally 40 fsw or less and lobster traps seemed more effi- breaks. cient. Another wartime triumph of the Navy Medical During the 11 year civil war, most industry was Institute was its Preventive Medicine program. With shut down including the lobster fishery. In 1990, it re- over 300,000 soldiers in the field, there was less than a opened and scuba became the preferred collection 1% mortality. Of considerable concern was tetanus. method. Now, over 2,500 Miskito divers are actively Although 90% of the population is felt to be immu- diving for lobster. The depth of harvest has deepened to nized, about 15 tetanus cases are encountered annually. 90 - 120 fsw. And, many daily dives are made. An These cases are primarily seen in older peasants and average of 7.5 tanks per day are used for 4.7 consecutive newborn gypsies (questionable umbilical cord cutting days (range is 1 - 12 days). As a result, there has been a practices). Grenade, shrapnel, and gun shot wounds are surge of . Over 100 cases are seen high risk injuries. Preventive measures were felt neces- annually. sary. During several months bridging 1990-1991 over When these divers present, it is almost invaria- 2,000,000 citizens were vaccinated. No cases of tetanus bly for a significant neurological “hit.” The divers do occurred in soldiers and the overall populace incident not seek help for “minor” symptoms (i.e., limb pain, rate fell. With over 20,000 severe injuries and over rash, paresthesias, etc.). Among the more serious pres- 20,000 less severe injuries, this was a remarkable ac- entations are motor deficits (78%), urinary problems complishment. (52%), dizziness and/or vertigo (39%), loss of con- In late 1992, there were thousands of refugees. sciousness (17%), cranial nerve deficits (7%), blindness Fifteen cases of Typhus abdominalis were encountered. and other visual abnormalities (2%), and aphasia (2%). This was the only “imported epidemic.” Hemorrhagic Treatments included HBO (75%), steroids (72%), vita- fever with renal involvement (from animals) was found mins (22%), aspirin (20%), heparin (17%), and in just over 50 soldiers. Only 3 perished. Water and NSAIDs (11%). USN TT6 (74%) and USN TT5 (92%) food supplies were well controlled---there were “no true were the primary HBO treatment regimens. Multiple outbreaks” of food/water borne illness. HBO treatments were not infrequent as hospitalization Needless to say, this sort of informational in- averaged 11 days (range was 0 - 120 days). terchange not only forged collegial respect, but also Of interest, Dr. Olayo performs the HBO demonstrated the need for future such exchanges. The treatments in a 2-person multiplace chamber that is data obtained (not yet published, and, perhaps, never to outside under an awning. He performs all the manual be published) is uniquely valuable to military medicine. valve-turning that is necessary for pressurization, de- pressurization, and venting. Communication is by WPB hand-signals and tapping on the chamber itself. There are no “inside observers.” Needless to say, Dr. Olayo is NICARAGUAN VISITOR PLEADS FOR HELP often overtasked and overly tired. He is looking for some help. Dr. Humberto Olayo, Chief Physician at the The USAF was approached because of its long Regional Hospital Knave Amanecer on the eastern coast interest in DCS research. It was felt by Drs. Barratt and of Nicaragua, visited DHL on 5 December 1997. He Van Meter that we would be interested in prospective, was accompanied by Drs. Diana Barratt and Keith Van randomized studies using steroids in conjunction with Meter from the Jo Ellen Smith Medical Center Hyper- HBO for these unfortunate victims. baric Medicine Department. These two physicians have Another, more important, reason the USAF been working with Dr. Olayo intermittently in Nicara- should be interested in supporting Dr. Olayo with in- gua for some time now. termittent personnel is operational readiness. It is my Dr. Olayo runs the sole Nicaraguan hyperbaric contention that this setting is analogous to being opera- chamber along the Central American Miskito Coast. tionally deployed. It is remote with only a modicum of

15 resources available. Teams would, of necessity, have to Major Monica Skarban, chief nurse at Travis bring much of their own equipment including the trans- AFB, will leave in March 1998 for Grand Forks, North portable hyperbaric chamber. In addition, they would Dakota. probably need to bring much of their own habitat. This Captain Allison Bowden will be leaving would be a grand environment to train the teams for Wright-Patterson AFB this summer. As yet, her new forward HBO placement and operation. Such a team- assignment is unknown. training would directly support the UTC concept that Colonel E. George Wolf, DoD Lead Agent for Clinical Although it is tough for us to lose such quality people, Hyperbaric Medicine, has presented to the USAF Sur- we wish them great luck in their new endeavors and geon General for approval. These teams would not just look forward to their return to Hyperbaric Medicine. be limited to Brooks AFB. I would envision each clini- cal center with at least two teams. Each team would And, speaking of folks in Hyperbarics: deploy for 1 - 2 weeks annually for training. As a result, some incredible clinical DCS Captain Sue Ann Bradbury is now stationed studies could be accomplished. In addition, Dr. Olayo at Travis AFB following her successful completion of would obtain some much needed assistance. Observing the Hyperbaric Nursing Course. and treating severe neurological DCS (both spinal and Captain Charlene Sylvestre will be taking the cerebral) would be a tremendous asset for both Staff Hyperbaric Nursing Course in March/April to fill Major Hyperbaricists and Fellows. The experience would indi- Skarban’s position at Travis AFB. She is currently a rectly benefit our “customers.” Indeed, these supplemental diver at Wright-Patterson AFB. “customers” are active duty line soldiers. This would Captain Perry Carlson has settled into the also be an incredibly positive humanitarian project in a Wright-Patterson AFB routine along with his family. country where we have not always been viewed as a Incidentally, he is a Navy-trained diver. positive influence. And, finally, this would be a won- Captain Jack Smith has just returned from derful test ground for the UTC concept and training to Germany successfully completing the Hyperbaric Nurs- implement this concept. ing Course. He formally joined the Brooks AFB team in Needless to say, Dr. Olayo is pursing this vig- June. orously through his Ministry of Health and the US Em- bassy and the State Department. With a little luck and USAF Hyperbaric Medicine is also suffering through USAF/SG support, this could well become a reality. the upheavals of retirement.

WPB Colonel John Bishop, who heads Hyperbaric Medicine at Wright-Patterson AFB, will retire in Janu- PERSONALS ary 1998. Colonel Ben Slade, who lead Hyperbaric USAF Hyperbaric Medicine is losing a number of valu- Medicine at Travis AFB, retired this past summer. He able individuals: is now in civilian Hyperbaric Medicine practice with Dr. Paul Cianci in California. Senior Airman Kelly Byrd, who was a medi- TSgt Geno Sekinger, who is an operations cal technician at Davis Hyperbaric Laboratory, married physiology technician at Davis Hyperbaric Laboratory, Dr. (Lt Commander—Canada) Aaron Kahn, separated is planning to retire this upcoming summer. from the USAF, and is now working for DCIEM in To- TSgt Rich Welch, who is an operations physi- ronto. ology technician at Davis Hyperbaric Laboratory, is SSgt Jennifer Middendorf, who was a medi- planning to retire this upcoming summer. cal technician at Davis Hyperbaric Laboratory, recently completed cross-training into Occupational Therapy at Congratulations to these friends on their retirements. Wilford Hall Medical Center. She is now stationed at We wish them the best in their civilian pursuits. We WHMC. look forward to future visits at any variety of confer- SSgt Jerry Querido, who was a medical tech- ences. nician at Davis Hyperbaric Laboratory, is now in train- WPB ing to become a military Physician’s Assistant. 2 Lt Tom Massa, who was an operations physiology technician, was accepted to OTS and is now a physiologist at Columbus AFB, Mississippi.

16 EDITOR’S NOTES

This newsletter is a bunch of work; however, it is a load of fun! I am sincerely grateful to all who contributed to its final face. Comments and suggestions are wel- come! Articles, case reports, informational letters, etc. are welcome! Please send it all to:

USAF Hyperbaric Newsletter DET 1, HSC/AOH 2509 Kennedy Drive, Suite 309 Brooks AFB, Texas 78235-5119

Lt Col William P. Butler, Editor

***The content of this newsletter represents the views of the authors and is not to be con- strued as official policy or position of the US government, the Department of Defense, or the Department of the Air Force.***

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