Oxygen use

The ultimate consumption of the oxygen is realized within the mitochondrion which is the intracellular organelle responsible for oxidation of end-products of energy substrates (Figure 1.2-1). Figure 1.2-1. The mitochondrial respiratory chain and pathways of intermediary metabolism Figure 1.2-1. The mitochondrial respiratory chain and pathways of intermediary metabolism Indeed, 90 of the oxygen is consumed in the mitochondrion. End-products of energetical substances originating from lipids,...

Risk Factors

A variety of risk factors have been identified over the past century in an effort to explain the variations in susceptibility to DI 2-4,14,21-24,108-123. These Altitude Exposure either diving at altitude or subsequent exposure Exercise before, after or during the bottom phase of a dive Injury previous DI or other acute injuries Omitted decompression missed stops errors of depth monitoring Personal traits (gender physiognomy level of fitness) Profiles (variables of depth, multiple ascents,...

Effect of hyperoxia on VO2 of the healthy subject at exercise

(Condition of physiological oxygen-supply dependence) Webster23 did not find an ergogenic effect on subsequent incremental exercise performance or maximal oxygen consumption after a 1-hr exposure to HBO at 202.6kPa (2.0ata). Controversial observations and interpretations have been made about the quantity of oxygen uptake in the exercising subject some authors have found an increase of VO2 max with increased DO2 in human24 and animal25 studies, which has not been observed by others26'27....

Susceptibility of bacteria to oxygen

Bacteria can be sorted into the following groups depending on their tolerance to oxygen3-7 1. strictly aerobic bacteria those absolutely requiring molecular oxygen to develop since oxygen is the final obligatory electron acceptor, 2. microaerophiles those able to use oxygen but developing best in concentrations of oxygen lower than in air, 3. aero-anaerobes or facultative anaerobes those developing with or without oxygen since their metabolisms are based either on respiration or fermenting...

Anaerobic necrotizing fasciitis

Although the term necrotizing fasciitis was coined by Meleney in 1924 to designate gangrene related to haemolytic Streptococci29, since Wilson (1952)30 it is now used for a sub-cutaneous infection spreading along the deep fascia, causing secondary skin lesions and sparing muscles until late stages of infection. Many terms have been coined necrotizing fasciitis31-34 clostridial cellulitis35,36 non-clostridial crepitant cellulitis37 synergistic necrotizing cellulitis , and for penis and scrotum...

Literature review

The rationale for using HBO in acute traumatic ischemia is to increases tissue oxygen tensions in hypoxic tissues to levels which make it possible for the host responses to become functional. With HB0 at 240 kPa the haemoglobin-borne oxygen content is increased only from 19,8 ml of oxygen per dl blood to 20,4 ml O2, whereas plasma and tissue oxygen tensions increase tenfold. The resulting effect is that oxygen diffusion distance from capillaries is increased by a threefold factor (Krogh19)....

References

Rudolph, R., Ballantyne, D., Skin Grafts. In Plastic Surgery, Mac Carthy, (edr), W.B.Saunders, Philadelphia, pp. 226-274, 1990. 2. Daniel, R., Kerrigan, C., Principles and Physiology of Skin Flap Surgery. In Plastic Surgery, Mac Carthy, (edr), W.B.Saunders, Philadelphia, pp. 275-328, 1990. 3. Revis, D., Seagel, M.et al ,(November 5, 2003) Skin Grafts http www.emedicin.com. 4. Jansen,D., McGee, J. et al, (January 30, 2005) Flaps, muscle-musculocutaneous flaps, http www. Emedicine.com. 5....

Effects of HBO on the host defence mechanisms

Hamblen47 carried out the first experimental study of the effects of HBO on osteomyelitis in rats. In 1980, in a rabbit model for osteomyelitis, Mader showed how HBO (100 O2 at 2 ata) improved the bactericidal activity of the PMN's against Staphylococci and how intramedullary PO2 increased from 20 mmHg in normoxia to 104 mmHg at 2 ata48. In an in vitro study carried out at the same time, after increasing pressure of oxygen from 45 to 150 mmHg for two hours, the bactericidal activity of PMN's...

Features of diffusion

At the microvascular level the delivery of oxygen to the tissues is achieved by diffusion. The driving force determining the amount of diffusion is the difference in partial pressures of the blood between the capillary and the mitochondria in adjacent cells. The quantity of diffusing agent per unit time (J) is proportional to the surface of diffusion (F), the absolute temperature (T) and the ideal gas constant (R) and inversely proportional to the viscosity of the solvents and the radius (r) of...

Hyperbaric oxygen therapy

Several authors have studied the use of hyperbaric oxygen in patients with radiation cystitis174'178'206-221 (Table 2.2.8-3). Bevers206 reported a prospective study of 40 patients most of them required transfusion. Patients had received unsuccessful treatments clot evacuation, electrocoagulation, alum, tranexamic acid. They received 20 sessions of 100 oxygen at 3 bar pressure for 90 minutes, 5 or 6 times a week. In 4 patients, 40 sessions were given because of persistence of symptoms. Hematuria...

Clinical studies

Although animal studies considering the reported evidences on compromised grafts and flaps confer a high degree of validity, relevant human studies for HBO as adjunct therapy are essential to enroll it in the therapeutic armamentarium. In 1966 Perrins reported the use of HBO to enhance flap survival reducing the failure rate in a series cases and next year he presented a controlled study106 of HBO effect on skin split grafts. The protocol included 48 patients randomly assigned to a control and...

History Of Hyperbaric Medicine

Service d'Urgence Respiratoire, de R animation M dicale et de M decine Hyperbare, H pital Calmette, Centre Hospitalier et Universitaire, Lille, France Hyperbaric Medicine goes back a long way, since its history derives from the history of diving which dates back to ancient times. The history of Hyperbaric Medicine has been closely linked with the development of technology for underwater activities and the advance in knowledge about the physical laws and physiological mechanisms of breathing...

Crush injury

Crush injuries occur when a part of the body is subjected to a high degree of energy or pressure. It happens usually after being hit by a heavy object or being squeezed between two objects. The greater the energy involved the more severe the tissue damage. Two or more tissues muscle, bone, skin, nerve involved Injury severe enough that tissue survival is questionable If tissue recovers, functional deficits are likely Gradient of injury from minimal to irreversible with a partial viable grey...

Contents

Physical and Pathophysiological Bases of Hyperbaric B. Ratzenhofer-Komenda, J. Niinikoski, M. Hamilton-Farell 1.1. Physics of Hyperbaric Pressure 15 W. Welslau 1.2. Biochemistry of Oxygen 25 1.3. Physiologic Effects of Increased Barometric Pressure 31 W. Welslau 1.4. Physiologic Effects of Hyperbaric Oxygen on Oxygen Transport and Tissue Oxygen Pressure 49 B. Ratzenhofer-Komenda, R. Favory, W. Welslau, F.M. Smolle-J ttner, D. Mathieu 1.5. Physiologic Effects of Hyperbaric Oxygen on Hemodynamics...

Mechanisms of hyperoxic vasoconstriction

Hyperoxic vasoconstriction does not seem to be of reflexive in origin. Differences in regional distribution, the vascular site of action88 and the decrease in sympathetic activity during hyperoxia11-13,89 argue against this theory. All authors agree that hyperoxic vasoconstriction is linked to regulatory mechanisms acting at the level of the microcirculation units. Whalen amp Nair81,82, were the first to show that cellular PO2 in muscles underwent no change in hyperoxia and that this was due to...