Physics of Hyperbaric Medicine
Adapted from - https://emedicine.medscape.com/article/1464149-overview#a2
- The application of Boyle’s law (p1 v1 = p2 v2) is seen in many aspects of HBOT. This can be useful with embolic phenomena such as decompression sickness (DCS) or arterial gas emboli (AGE). As the pressure is increased, the volume of the concerning bubble decreases. This also becomes important with chamber decompression; if a patient holds her breath, the volume of the gas trapped in the lungs overexpands and causes a pneumothorax.
- Charles’ law ([p1 v1]/T1 = [p2 v2]/T2) explains the temperature increase when the vessel is pressurized and the decrease in temperature with depressurization. This is important to remember when treating children or patients who are very sick or are intubated.
- Henry’s law states that the amount of gas dissolved in a liquid is equal to the partial pressure of the gas exerted on the surface of the liquid. By increasing the atmospheric pressure in the chamber, more oxygen can be dissolved into the plasma than would be seen at surface pressure.
The clinician must be able to calculate how much oxygen a patient is receiving. In order to standardize this amount, atmospheres absolute (ATA) are used. This can be calculated from the percentage of oxygen in the gas mixture (usually 100% in HBOT; 21% if using air) and multiplied by the pressure. The pressure is expressed in feet of seawater (fsw), which is the pressure experienced if one were descending to that depth while in seawater. Depth and pressure can be measured in many ways; some common conversions are 1 atmosphere (atm) = 33 feet of seawater (fsw) = 10 meters of sea water (msw) = 14.7 pounds per square inch (psi) = 1.01 bar.
What is the physiology of hyperbaric oxygen therapy (HBOT)?
Hyperbaric Physiology Table 1 below summarizes the physiologic mechanisms of HBOT. Each of these is discussed in the context of the indications for HBOT.What is the physiology of hyperbaric oxygen therapy (HBOT)?
Decrease gas bubble size
Air or gas embolism
Fibroblast proliferation/collagen synthesis
Leukocyte oxidative killing ‡
Necrotizing soft tissue infections
Reduces intravascular leukocyte adherence
Crush injury/compartment syndrome
Reduces lipid peroxidation
Van Unnik A
Necrotizing soft tissue infections
*Most oxygen carried in the blood is
bound to hemoglobin, which is 97%
saturated at standard pressure. Some
oxygen, however, is carried in solution,
and this portion is increased under
hyperbaric conditions due to Henry's
law. Tissues at rest extract 5-6 mL of
oxygen per deciliter of blood, assuming
normal perfusion. Administering 100%
oxygen at normobaric pressure increases
the amount of oxygen dissolved in the
blood to 1.5 mL/dL; at 3 atmospheres,
the dissolved-oxygen content is
approximately 6 mL/dL, which is more
than enough to meet resting cellular
requirements without any contribution
from hemoglobin. Because the oxygen is
in solution, it can reach areas where
red blood cells may not be able to pass
and can also provide tissue oxygenation
in the setting of impaired hemoglobin
concentration or function.
Additionally, evidence is growing that HBOT alters the levels of proinflammatory mediators and may blunt the inflammatory cascade. More studies are needed to further elucidate this complex interaction.
As HBOT is known to decrease heart rate while maintaining stroke volume, it has the potential to decrease cardiac output. At the same time, through systemic vasoconstriction, HBOT increases afterload. This combined effect can exacerbate congestive heart failure in patients with severe disease; however, clinically significant worsening of congestive heart failure is rare.
- Henshaw IN, Simpson A. Compressed Air as a Therapeutic Agent in the Treatment of Consumption, Asthma, Chronic Bronchitis and Other Diseases. Edinburgh: Sutherland and Knox; 1857.
- Kindwall E, Whelan H. Hyperbaric Medicine Practice. 2nd ed. Flagstaff, AZ: Best Publishing Company; 2004:chap 1, 18, 19, 20, 25, 29, 30.
- Feldmeier J. Hyperbaric Oxygen 2003: Indications and Results- The Hyperbaric Oxygen Therapy Committee Report. Kensington, Maryland: Undersea and Hyperbaric Medical Society, Inc.; 2003:chap 1, 2, 4, 5, 7, 8.
- Leslie CA, Sapico FL, Ginunas VJ, Adkins RH. Randomized controlled trial of topical hyperbaric oxygen for treatment of diabetic foot ulcers. Diabetes Care. Feb 1988;11(2):111-5. [Medline].
- Boerema I, et al. Life without blood. A study of the influence of high atmospheric pressure and hypothermia on dilution of the blood. J Cardiovascular Surg. 1960;1:133-146.
- Bassett BE, Bennett PB. Introduction to the physical and physiological bases of hyperbaric therapy. In: Hunt TK, Davis JC. Hyperbaric Oxygen Therapy. Bethesda, MD: Undersea Medical Society; 1977:11-24.
- Bird AD, Telfer AB. Effect of Hyperbaric Oxygen on Limb Circulation. Lancet. Feb 13 1965;1(7381):355-6. [Medline].
- Nylander G, Lewis D, Nordström H, et al. Reduction of postischemic edema with hyperbaric oxygen. Plast Reconstr Surg. Oct 1985;76(4):596-603. [Medline].
- Sukoff MH, Ragatz RE. Hyperbaric oxygenation for the treatment of acute cerebral edema. Neurosurgery. Jan 1982;10(1):29-38. [Medline].
- Knighton DR, Silver IA, Hunt TK. Regulation of wound-healing angiogenesis-effect of oxygen gradients and inspired oxygen concentration. Surgery. Aug 1981;90(2):262-70. [Medline].
- Hunt TK, Pai MP. The effect of varying ambient oxygen tensions on wound metabolism and collagen synthesis. Surg Gynecol Obstet. Oct 1972;135(4):561-7. [Medline].
- Mader JT, Brown GL, Guckian JC, et al. A mechanism for the amelioration by hyperbaric oxygen of experimental staphylococcal osteomyelitis in rabbits. J Infect Dis. Dec 1980;142(6):915-22. [Medline].
- Park MK, Myers RA, Marzella L. Oxygen tensions and infections: modulation of microbial growth, activity of antimicrobial agents, and immunologic responses. Clin Infect Dis. Mar 1992;14(3):720-40. [Medline].
- Mandell GL. Bactericidal activity of aerobic and anaerobic polymorphonuclear neutrophils. Infect Immun. Feb 1974;9(2):337-41. [Medline].
- Zamboni WA, Roth AC, Russell RC, et al. The effect of acute hyperbaric oxygen therapy on axial pattern skin flap survival when administered during and after total ischemia. J Reconstr Microsurg. Oct 1989;5(4):343-7; discussion 349-50. [Medline].
- Thom SR. Effects of hyperoxia on neutrophil adhesion. Undersea Hyperb Med. Spring 2004;31(1):123-31. [Medline].
- Thom SR. Functional inhibition of leukocyte B2 integrins by hyperbaric oxygen in carbon monoxide-mediated brain injury in rats. Toxicol Appl Pharmacol. Dec 1993;123(2):248-56. [Medline].
- Thom SR. Antagonism of carbon monoxide-mediated brain lipid peroxidation by hyperbaric oxygen. Toxicol Appl Pharmacol. Sep 1 1990;105(2):340-4. [Medline].
- Van Unnika. Inhibition of toxin Production in Clostridium Perfringens in Vitro by Hyperbaric Oxygen. Antonie Van Leeuwenhoek. 1965;31:181-6. [Medline].
- Mirhij NJ, Roberts RJ, Myers MG. Effects of hypoxemia upon aminoglycoside serum pharmacokinetics in animals. Antimicrob Agents Chemother. Sep 1978;14(3):344-7. [Medline].
- Keck PE, Gottlieb SF, Conley J. Interaction of increased pressures of oxygen and sulfonamides on the in vitro and in vivo growth of pathogenic bacteria. Undersea Biomed Res. Jun 1980;7(2):95-106. [Medline].
- Mendel V, Reichert B, Simanowski HJ, et al. Therapy with hyperbaric oxygen and cefazolin for experimental osteomyelitis due to Staphylococcus aureus in rats. Undersea Hyperb Med. Fall 1999;26(3):169-74. [Medline].
- Muhvich KH, Anderson LH, Criswell DW, et al. Hyperbaric hyperoxia enhances the lethal effects of amphotericin B in Leishmania braziliensis panamensis. Undersea Hyperb Med. Dec 1993;20(4):321-8. [Medline].
- Harvey EN. Decompression sickness and bubble formation in blood and tissues. Bull NY Acad Med. 1945;21:505-36.
- Brubakk A, Neuman T. Bennett and Elliott's Physiology and Medicine of Diving. 5th ed. Great Britain: Elsevier Science Limited; 2003:chap 10.
- Bove A. Bove and Davis' Diving Medicine. 4th ed. Elsevier Inc.; 2004:chap 8, 10.
- Neuman TS. Arterial gas embolism and decompression sickness. News Physiol Sci. Apr 2002;17:77-81. [Medline].
- Navy Department. Diving Medicine and Recompression Chamber Operations. In: US Navy Diving Manual. 5. Rev 4. Washington DC: 1999.
- Spencer MP. Decompression limits for compressed air determined by ultrasonically detected blood bubbles. J Appl Physiol. Feb 1976;40(2):229-35. [Medline].
- Butler BD, Hills BA. Transpulmonary passage of venous air emboli. J Appl Physiol. Aug 1985;59(2):543-7. [Medline].
- Abernathy CM, Dickinson TC. Massive air emboli from intravenous infusion pump: etiology and prevention. Am J Surg. Feb 1979;137(2):274-5. [Medline].
- Khan M, Schmidt DH, Bajwa T, Shalev Y. Coronary air embolism: incidence, severity, and suggested approaches to treatment. Cathet Cardiovasc Diagn. Dec 1995;36(4):313-8. [Medline].
- Michenfelder JD, Martin JT, Altenburg BM, et al. Air embolism during neurosurgery. An evaluation of right-atrial catheters for diagnosis and treatment. JAMA. May 26 1969;208(8):1353-8. [Medline].
- Fong J, Gadalla F, Gimbel AA. Precordial Doppler diagnosis of haemodynamically compromising air embolism during caesarean section. Can J Anaesth. Mar 1990;37(2):262-4. [Medline].
- Davies JM, Campbell LA. Fatal air embolism during dental implant surgery: a report of three cases. Can J Anaesth. Jan 1990;37(1):112-21. [Medline].
- Brown SD, Piantadosi CA. Recovery of energy metabolism in rat brain after carbon monoxide hypoxia. J Clin Invest. Feb 1992;89(2):666-72. [Medline].
- Thom SR, Taber RL, Mendiguren II, et al. Delayed neuropsychologic sequelae after carbon monoxide poisoning: prevention by treatment with hyperbaric oxygen. Ann Emerg Med. Apr 1995;25(4):474-80. [Medline].
- Goulon MA, Barios M, Rapin M, Mouilhat F, Grobuis S, Labrousse J. Intoxicationoxy carbonee at anoxie aique par inhalation de gay de charbon et d'hydrocarbures. (English Translation). J Hyperbaric Med. 1986;1:23-41.
- Weaver LK, Hopkins RO, Chan KJ, et al. Hyperbaric oxygen for acute carbon monoxide poisoning. N Engl J Med. Oct 3 2002;347(14):1057-67. [Medline].
- Raphael JC, Elkharrat D, Jars-Guincestre MC, et al. Trial of normobaric and hyperbaric oxygen for acute carbon monoxide intoxication. Lancet. Aug 19 1989;2(8660):414-9. [Medline].
- Scheinkestel CD, Bailey M, Myles PS, et al. Hyperbaric or normobaric oxygen for acute carbon monoxide poisoning: a randomised controlled clinical trial. Med J Aust. Mar 1 1999;170(5):203-10. [Medline].
- Ducassé JL, Celsis P, Marc-Vergnes JP. Non-comatose patients with acute carbon monoxide poisoning: hyperbaric or normobaric oxygenation?. Undersea Hyperb Med. Mar 1995;22(1):9-15. [Medline].
- Grace TW, Platt FW. Subacute carbon monoxide poisoning. Another great imitator. JAMA. Oct 9 1981;246(15):1698-700. [Medline].
- Barret L, Danel V, Faure J. Carbon monoxide poisoning, a diagnosis frequently overlooked. J Toxicol Clin Toxicol. 1985;23(4-6):309-13. [Medline].
- Garland H, Pearce J. Neurological complications of carbon monoxide poisoning. Q J Med. Oct 1967;36(144):445-55. [Medline].
- Winter PM, Miller JN. Carbon monoxide poisoning. JAMA. Sep 27 1976;236(13):1502. [Medline].
- Hunt TK, Twomey P, Zederfeldt B, et al. Respiratory gas tensions and pH in healing wounds. Am J Surg. Aug 1967;114(2):302-7. [Medline].
- Sheikh AY, Gibson JJ, Rollins MD, et al. Effect of hyperoxia on vascular endothelial growth factor levels in a wound model. Arch Surg. Nov 2000;135(11):1293-7. [Medline].
- Faglia E, Favales F, Aldeghi A, et al. Adjunctive systemic hyperbaric oxygen therapy in treatment of severe prevalently ischemic diabetic foot ulcer. A randomized study. Diabetes Care. Dec 1996;19(12):1338-43. [Medline].
- Doctor N, Pandya S, Supe A. Hyperbaric oxygen therapy in diabetic foot. J Postgrad Med. Jul-Sep 1992;38(3):112-4, 111. [Medline].
- Abidia A, Laden G, Kuhan G, et al. The role of hyperbaric oxygen therapy in ischaemic diabetic lower extremity ulcers: a double-blind randomised-controlled trial. Eur J Vasc Endovasc Surg. Jun 2003;25(6):513-8. [Medline].
- Kalani M, Jorneskog G, Naderi N, et al. Hyperbaric oxygen (HBO) therapy in treatment of diabetic foot ulcers. Long-term follow-up. J Diabetes Complications. Mar-Apr 2002;16(2):153-8. [Medline].
- Perrins DJ. Influence of hyperbaric oxygen on the survival of split skin grafts. Lancet. Apr 22 1967;1(7495):868-71. [Medline].
- Monies-Chass I, Hashmonai M, Hoere D, et al. Hyperbaric oxygen treatment as an adjuvant to reconstructive vascular surgery in trauma. Injury. May 1977;8(4):274-7. [Medline].
- Greenwood TW, Gilchrist AG. Hyperbaric oxygen and wound healing in post-irradiation head and neck surgery. Br J Surg. May 1973;60(5):394-7. [Medline].
- Reinisch JF. The pathophysiology of skin flap circulation. The delay phenomenon. Plast Reconstr Surg. Nov 1974;54(5):585-98. [Medline].
- Gustilo RB, Mendoza RM, Williams DN. Problems in the management of type III (severe) open fractures: a new classification of type III open fractures. J Trauma. Aug 1984;24(8):742-6. [Medline].
- Skyhar MJ, Hargens AR, Strauss MB, et al. Hyperbaric oxygen reduces edema and necrosis of skeletal muscle in compartment syndromes associated with hemorrhagic hypotension. J Bone Joint Surg Am. Oct 1986;68(8):1218-24. [Medline].
- Schraibman IG, Ledingham IM. Hyperbaric oxygen and local vasodilatation in peripheral vascular disease. Br J Surg. Apr 1969;56(4):295-9. [Medline].
- Illingworth CFW, Smith G, Lawson DD, et al. Surgical and physiological observations in an experimental pressure chamber. Br J Surg. 1961;49:222-227.
- Bartlett RL. Stroman RT, Nickels M, et al. Rabbit model of the use of fasciotomy and hyperbaric oxygenation in the treatment of compartment syndrome. UHMS (Suppl.). 1998;25:1095-1100.
- Strauss MB, Hargens AR, Gershuni DH, Hart GB, Akeson WH. Delayed use of hyperbaric oxygen for treatment of a model anterior compartment syndrome. J Orthop Res. 1996;4:108-111.
- Sonoda A, Maekawa Y, Arao T, et al. Spontaneous gangrene of the scrotum and penis (Fournier's gangrene). J Dermatol. Oct 1980;7(5):371-5. [Medline].
- Stevens DL, Tweten RK, Awad MM, et al. Clostridial gas gangrene: evidence that alpha and theta toxins differentially modulate the immune response and induce acute tissue necrosis. J Infect Dis. Jul 1997;176(1):189-95. [Medline].
- Knighton DR, Halliday B, Hunt TK. Oxygen as an antibiotic. The effect of inspired oxygen on infection. Arch Surg. Feb 1984;119(2):199-204. [Medline].
- Knighton DR, Fiegel VD, Halverson T, et al. Oxygen as an antibiotic. The effect of inspired oxygen on bacterial clearance. Arch Surg. Jan 1990;125(1):97-100. [Medline].
- Kaye D. Effect of hyperbaric oxygen on Clostridia in vitro and in vivo. Proc Soc Exp Biol Med. Feb 1967;124(2):360-6. [Medline].
- Escobar SJ, Slade JB Jr, Hunt TK, et al. Adjuvant hyperbaric oxygen therapy (HBO2)for treatment of necrotizing fasciitis reduces mortality and amputation rate. Undersea Hyperb Med. Nov-Dec 2005;32(6):437-43. [Medline].
- Gozal D, Ziser A, Shupak A, et al. Necrotizing fasciitis. Arch Surg. Feb 1986;121(2):233-5. [Medline].
- Riseman JA, Zamboni WA, Curtis A, et al. Hyperbaric oxygen therapy for necrotizing fasciitis reduces mortality and the need for debridements. Surgery. Nov 1990;108(5):847-50. [Medline].
- Palmer JD. Neurosurgery 96. New York: Churchill Livingstone; 1996:875-79.
- Alderson D, Strong AJ, Ingham HR, et al. Fifteen-year review of the mortality of brain abscess. Neurosurgery. Jan 1981;8(1):1-6. [Medline].
- Brook I. Bacteriology of intracranial abscess in children. J Neurosurg. Apr 1981;54(4):484-8. [Medline].
- Yang SY. Brain abscess: a review of 400 cases. J Neurosurg. Nov 1981;55(5):794-9. [Medline].
- Dohrmann PJ, Elrick WL. Observations on brain abscess. Review of 28 cases. Med J Aust. Jul 24 1982;2(2):81-3. [Medline].
- Miller JD, Fitch W, Ledingham IM, et al. The effect of hyperbaric oxygen on experimentally increased intracranial pressure. J Neurosurg. Sep 1970;33(3):287-96. [Medline].
- Moody RA, Mead CO, Ruamsuke S, et al. Therapeutic value of oxygen at normal and hyperbaric pressure in experimental head injury. J Neurosurg. Jan 1970;32(1):51-4. [Medline].
- Lampl L, Frey G, Bock KH. Hyperbaric oxygen in intracranial abscesses - update of a series of 13 patients. Undersea Biomed Res (Suppl.). 1992;19:83.
- Rubin P. The Franz Buschke lecture: late effects of chemotherapy and radiation therapy: a new hypothesis. Int J Radiat Oncol Biol Phys. Jan 1984;10(1):5-34. [Medline].
- Marx RE. Osteoradionecrosis: a new concept of its pathophysiology. J Oral Maxillofac Surg. May 1983;41(5):283-8. [Medline].
- Marx RE. A new concept in the treatment of osteoradionecrosis. J Oral Maxillofac Surg. Jun 1983;41(6):351-7. [Medline].
- Feldmeier JJ, Hampson NB. A systematic review of the literature reporting the application of hyperbaric oxygen prevention and treatment of delayed radiation injuries: an evidence based approach. Undersea Hyperb Med. Spring 2002;29(1):4-30. [Medline].
- Bevers RF, Bakker DJ, Kurth KH. Hyperbaric oxygen treatment for haemorrhagic radiation cystitis. Lancet. Sep 23 1995;346(8978):803-5. [Medline].
- Chong KT, Hampson NB, Corman JM. Early hyperbaric oxygen therapy improves outcome for radiation-induced hemorrhagic cystitis. Urology. Apr 2005;65(4):649-53. [Medline].
- Feldmeier J, Carl U, Hartmann K, et al. Hyperbaric oxygen: does it promote growth or recurrence of malignancy?. Undersea Hyperb Med. Spring 2003;30(1):1-18. [Medline].
- Niinikoski J, Hunt TK. Oxygen tensions in healing bone. Surg Gynecol Obstet. May 1972;134(5):746-50. [Medline].
- Strauss MB, Malluche HH, Faugere MC. Effect of hyperbaric oxygen on bone resorption in rabbits. Seventh Annual Conference on Clinical Application of HBO. June 1982;Anaheim, California:8-18.
- Davis JC, Gates GA, Lerner C, et al. Adjuvant hyperbaric oxygen in malignant external otitis. Arch Otolaryngol Head Neck Surg. Jan 1992;118(1):89-93. [Medline].
- Hart GB, O'Reilly RR, Broussard ND, et al. Treatment of burns with hyperbaric oxygen. Surg Gynecol Obstet. Nov 1974;139(5):693-6. [Medline].
- Niezgoda JA, Cianci P, Folden BW, et al. The effect of hyperbaric oxygen therapy on a burn wound model in human volunteers. Plast Reconstr Surg. May 1997;99(6):1620-5. [Medline].
- Cianci P, Lueders HW, Lee H, et al. Adjunctive hyperbaric oxygen therapy reduces length of hospitalization in thermal burns. J Burn Care Rehabil. Sep-Oct 1989;10(5):432-5. [Medline].
- Cianci P, Williams C, Lueders H, et al. Adjunctive hyperbaric oxygen in the treatment of thermal burns. An economic analysis. J Burn Care Rehabil. Mar-Apr 1990;11(2):140-3. [Medline].
- Ketty SS, Schmidt CF. The effects of altered arterial tensions of carbon dioxide and oxygen on cerebral blood flow and cerebral oxygen consumption of normal young men. J Clin Investigation. 1978;27:484-492.
- Lambertsen CJ, Kough RH, Cooper DY, et al. Oxygen toxicity; effects in man of oxygen inhalation at 1 and 3.5 atmospheres upon blood gas transport, cerebral circulation and cerebral metabolism. J Appl Physiol. Mar 1953;5(9):471-86. [Medline].
- Brozak J, Grande F. Body composition and basal metabolism in man correlation analysis versus physiologic approach. Human Biol. 1955;27:22-31.
- Murphy-Lavoie H, Butler FK, Hagan CE. Hyperbaric oxygen therapy in the management of central retinal artery occlusion. 12. Durham: Undersea and Hyperbaric Medicine Society; 2008. 57-66.
- Rumelt S, Brown GC. Update on treatment of retinal arterial occlusions. Curr Opin Ophthalmol. Jun 2003;14(3):139-41. [Medline].
- Hayreh SS, Zimmerman MB. Central retinal artery occlusion: visual outcome. Am J Ophthalmol. Sep 2005;140(3):376-91. [Medline
- Hertzog LM, Meyer GW, Carson S, et al. Central retinal artery occlusion treated with hyperbaric oxygen. J Hyperbaric Medicine. 1992;7:33-42.
- Beiran I, Goldenberg I, Adir Y, Tamir A, Shupak A, Miller B. Early hyperbaric oxygen therapy for retinal artery occlusion. Eur J Ophthalmol. Oct-Dec 2001;11(4):345-50. [Medline].
- Weiss JN. Hyperbaric oxygen treatment of nonacute central retinal artery occlusion. Undersea Hyperb Med. Nov-Dec 2009;36(6):401-5. [Medline].
Medical Oxygen Hyperbaric Clinic
4660 South Biltmore La.
Madison, WI 53718