Adjunct HBO 2 Therapy: March 16, 2016 William Tettelbach, MD, FACP, FIDSA System Medical Director of Wound & Hyperbaric Medicine Services An Essential Tool For The Care DFUs Fedorko, L., et al., Hyperbaric Oxygen Therapy Does Not Reduce Indications for Amputation in Patients With Diabetes With Nonhealing Ulcers of the Lower Limb: A Prospective, Double-Blind, Randomized Controlled Clinical Trial. Diabetes Care, 2016. Margolis, D.J., et al., Lack of effectiveness of hyperbaric oxygen therapy for the treatment of diabetic foot ulcer and the prevention of amputation: a cohort study. Diabetes Both these studies have significant shortcomings: Inclusion of Wagner grade 2 DFUs in 46 out of 103 (45%) subjects available for end point adjudication. 1 Margolis cohort study 2 included Wagner 2 DFUs in 54.3% of the HBO 2 group that also showed no benefit of HBO 2. Including a substantial cohort of patients with Wagner grade 2 DFUs that do not even meet the indications set by the Undersea & Hyperbaric Medical Society unavoidably biases the study s conclusion toward the absence of benefit from HBO 2 therapy. Both these studies have significant shortcomings: Inclusion of Wagner grade 2 DFUs in 46 out of 103 (45%) subjects available for end point adjudication. 1 Margolis cohort study 2 included Wagner 2 DFUs in 54.3% of the HBO 2 group that also showed no benefit of HBO 2. Including a substantial cohort of patients with Wagner grade 2 DFUs that do not even meet the indications set by the Undersea & Hyperbaric Medical Society unavoidably biases the study s conclusion toward the absence of benefit from HBO 2 therapy. 1
Other significant shortcomings: Study s use of photographic adjudication whether a limb met the criteria for amputation rather than the use of actual amputation rates as an outcome measure. 1 The fact that there may be patients who met the criteria for major amputation but who went on to heal undermines the conclusions of this study. Elements of GRADE Clear separation between quality of evidence and strength of recommendations Explicit evaluation of the importance of outcomes Explicit and comprehensive criteria for downgrading and upgrading the quality of evidence rating Transparent system of moving from evidence to recommendations 2
Diabetic Foot Infections: Treatment Algorithm for the use of HBO 2 1 2 Wagner Grading System: A. Grade 1: Superficial Diabetic Ulcer B. Grade 2: Ulcer with deep structures involved: ligament, tendon, joint capsule or fascia no active infection (abscess or osteomyelitis) C. Grade 3: Ulcer with deep structures involved: ligament, tendon, joint capsule or fascia + evidence of infection (abscess or osteomyelitis) D. Grade 4: Gangrene to portion of forefoot E. Grade 5: Extensive gangrene of foot 1. Huang ET et al; UHMS CPG Oversight Committee. A clinical practice guideline for the use of hyperbaric oxygen therapy in the treatment of diabetic foot ulcers. Undersea Hyperb Med. 2015 May-Jun;42(3):205-47. 2. Wagner FW, The diabetic foot. Orthopedics. 1987 Jan;10(1):163-72. 3
Osteomyelitis Infected bone is hypoxic * Normal Oxygen Tension (21% O 2 at sea level) - Healthy Bone = 45 mmhg - Infected Bone = 21 mmhg Hyperbaic Oxygen Tension (100% O 2 at 2 ATA) - Healthy Bone = 321 mmhg - Infected Bone = 104 mmhg * Rabbit animal model HBO 2 & Antibiotics with Osteomyelitis in Rats 10 7 Limb Preservation Treatment Network CFU x g -1 of Tibial Bone 10 6 10 5 10 4 Control HBO Cefazolin Cefazolin + HBO Hyperbaric 10 3 2 wk 4 wk TeleHealth Mendel et al Undersea Hyperb Med 26:169, 1999 4
Benefits of HBO 2 Tissue oxygen tension restored to > 30 mmhg - required by Neutrophils to destroy bacteria by oxidative killing mechanisms (1,2) Direct suppressive effect on anaerobic pathogens (3,4) Augments transport of certain antibiotics across bacterial cell walls - active transport of antibiotics (e.g. gentamicin, tobramycin, amikacin) across bacterial cell walls does not occur if tissue oxygen tensions are below 20 to 30 mmhg (5) Enhances osteogenesis (6) Reduces tissue edema (7) Promotes capillary angiogenesis (8) Prevents polymorphonuclear leukocytes from adhering to damaged blood vessel linings - decreases the degree of inflammation which may accompany the surgical treatment of refractory osteomyelitis Can reduce treatment costs of complicated refractory osteomyelitis by approximately 5x - 1987 estimated per case costs reduced from $115,000 to $20,000 (9) Adjunct HBO2 Therapy: An Essential Tool For The Care DFUs! Adjunct HBO2 Therapy: An Essential Tool For The Care DFUs! Benefits of HBO 2 : References 1. Hohn DC. Oxygen and leukocyte microbial killing. Davis JC, Hunt TL (eds.), Hyperbaric Oxygen Therapy, Bethesda, Undersea Med. Soc. 1977:101-110. 2. Kindwall EP. Uses of hyperbaric oxygen therapy in the 1990s. Cleve Clin J Med 1992;59: 517-28. 3. Slack WK, Thomas DA, Perrins D. Hyperbaric oxygenation in chronic osteomyelitis. Lancet. 1965;1:1093-1094. 4. Park MK, Myers RAM, Marzella L. Oxygen tensions and infections: Modulation of microbial growth, activity of antimicrobial agents, and immunologic responses. Clin Infect Dis 1992; 14: 720-740. 5. Verklin RM, Jr, Mandell GL. Alteration of effectiveness of antibiotics by anaerobiosis. J Lab Clin Med. 1977 Jan;89(1):65-71. 6. Steed DL. Enhancement of osteogenesis with hyperbaric oxygen therapy. A clinical study. J Dent Res 1982;6IA:288. 7. SkyharMJetal.:Hyperbaric oxygen reduces edema and necrosis of skeletal muscle in compartment syndromes associated with hemorrhagic hypotension. Journal of Bone andjoint Surgery 1986;68A:1218-1224. 8. Hunt, T.k., Halliday, and D.R. Knighton, Impairment of microbicidal function in wounds: Correction with oxygenation, In Soft and Hard Tissue Repair, T.K Hunt, R.B. Heppenstall, and E. Pines, Editors. 1984, Praeger: New York. p. 455-68. 9. Strauss M.B., Refractory osteomyelitis. Journal of Hyperbaric Medicine 2: 147-159;1987. 5