notes by dr. Claudio Italiano
In 1991 the Hyperbaric Therapy Study Group in the SIAARTI published a list of
indications about the use of the hyperbaric chamber. But what is a hyperbaric
chamber and what is it for?
A hyperbaric chamber is a cylindrical metal apparatus, invented in 1916 by Alberto Gianni, a diver, which is, seen from the outside, a kind of water autoclave, able to withstand the pressure of air inside.
In it air or oxygen are pumped in order to treat people who are housed inside it. The writer has a hyperbaric chamber patent (cf. curriculum) and has been inside a hyperbaric chamber during exercises carried out by the Italian Navy.
When you "go down in altitude", when the air is pumped inside, the atmosphere becomes heavy and you can breathe compressed air, which becomes "heavy" so that it seems to pick it up with your hand. Meanwhile, the lips seem to get numb and the word becomes strange, for "Donald effect", that is, we talk like Donald Duck! Inside the hyperbaric chamber people are hosted essentially for two types of treatment:
- The hyperbaric decompression is a treatment in the case of divers with gaseous embolism; in fact the divers who do not respect the decompression tables when they rise to the surface, as nitrogen is dissolved in their blood when pressure rises, the gas starts to "effervescere", just like a sparkling drink, causing dangerous gaseous embolisms, with stacking of platelets and severe ischemic disorders of cerebral species.
- The hyperbaric oxygen therapy is indicated in the case of patients suffering from various diseases, as specified below, who still need oxygen at an adequate pressure.
In general the pathologies that are treated are:
- Disease due to batteric anaerobic infection, which is known to fear oxygen; in this case the high concentration of oxygen that reaches the infected tissues is exploited, especially in the myocarditis, in the osteomyelitis, in the necrosis of the tissues by anaerobic bacteria.
- In carbon monoxide poisoning, for example smoke poisoning in fires, for improper use of wood and gas stoves, etc.
- Barotraumi, ie divers who emerge quickly without implementing decompression maneuvers and use the tables provided for divers
- Acute anemia where the blood transfusion is not indicated or possible
- Radiodermatitis, radionecrosis and osteoradionecrosis
- Peripheral vascular insufficiency, vascular ulcers, decubitus and cutaneous ulcers
- Osteomyelitis and osteonecrosis, infected prostheses, surgical interventions, reconstructive plastic
acute cerebral and medullary edema
- Hypoxic-asphyxiated syndromes
- burns and frostbites
- Acinomycetes infections (see mycosis)
- Multiple sclerosis
- Chronic vasculopathies, motor re-education of pareto-spastic syndrome
- Ischemic cardiopathies, pulmonary heart, some disturbances of the heart rhythm
- Crushing syndrome
- vascular headache
- Vestibular and acoustic syndromes
- Conservation of transplant organs
In the scientific research phase with favorable results
- thrombosis of the artery and retinal vein, diabetic retinopathy, pigment retinopathy
Indilactable, urgent and primary indications, for which Hyperbaric Therapy must be implemented as quickly as possible and plays a decisive role.
This pathology, in the underwater and hyperbaric, can occur following a
pulmonary overdistension and / or misunderstood patency of the interatrial
septum, while, in the clinical setting, may occur as a result of surgical
interventions (cardiac surgery, neurosurgery, thoracic surgery and general
surgery major), hemodialysis procedures and cannulation of central vessels. The
type of gas that is in the circulatory district is not as important as the
quantity of this gas. Hyperbaric Oxygen Therapy (O.T.I.) has its own rationale
either in the recompressive treatment, and therefore in the reduction of the
volume of the gaseous bubble, or in the use of Oxygen as a metabolic gas for a
better oxygenation of the hypoxic tissue. As far as experimental and clinical
demonstrations are concerned, the extent of those proposed so far is such that
arterial gas embolism is considered mandatory for hyperbaric therapy, when
neurological symptoms are present. (Moon 1989, Dutka 1992, Leitch 1984).
The triggering event of a decompression sickness is the formation of gaseous
bubbles within the tissues and blood. These bubbles form from the inert gas
dissolved in the tissues that become supersaturated when, suddenly, the ambient
pressure is reduced. The gas most usually involved in this are nitrogen, carbon
monoxide, argon and water vapor. Helium or, at most, neon and hydrogen may also
be involved in deep-water diving. The most accredited therapy for these forms is
the therapeutic recompression in the hyperbaric chamber. The reduction in the
volume of the bubble, linked to the Boyle-Mariotte law, is the cardinal element
of the indication. The use of oxygen at high partial pressures, improving the
oxygenation of the tissues rendered ischemic, exploit the pressure element, in
harmony with the oxygen element, have been proposed and are commonly used. The
recompressive treatment in a hyperbaric chamber with Oxygen is to be applied
promptly and in any case no later than 24 hours after the accident (Workman
1968, Fructus 1979, Flyrm 1992).
Mionecrosis and crackling cellulitis are rapidly progressive infections caused
by anaerobic germs, mostly of the Clostridic species. The alterations induced by
Clostridia are directed and mediated by the production of an alpha-exotoxin
capable of determining tissue necrosis, haemolysis, specific neurological
alterations. O.T.I plays a direct antibacterial role, increasing the partial
pressure of tissue and indirect oxygen, stimulating the "killing" function of
polymorphonuclear cells. For this pathology there is an urgent indication for
treatment with O.T.l. in association with antibiotic therapy and local surgery.
(Bakker 1988, Hart 1983, Lamy 1977, Heimbach 1992).
A hypoxic district condition can inhibit the killing function of
polymorphonuclear cells, and therefore, a localized infection can develop and be
generalized. This pathology includes necrotic fasciitis, non-clostridic
mionecrosis, and progressive bacterial gangrene that recognize specific
anatomical locations of localization and germs. The O.T.I. it can be validly
used for the normalization of the partial pressure of the tissue. A therapeutic
triad composed of antibiotic-therapy, local surgical therapy and OTI, is of
fundamental importance for the treatment of this pathology. (Mader 1987, Bakker
1985, Thom 1992).
The diabetic patient is a patient suffering from a complex metabolic pathology, also characterized by a reduced peripheral perfusion. Moreover, a reduced sensitivity for a specific neuropathy is superimposed, and, for these two pathological events, lesions of the extremities that tend to septic evolution are easily determined. Diabetic gangrene is the most important cause of amputation in diabetics and international literature agrees on this aspect. O.T.I., In these years, has established itself as a valid therapeutic method, both for its effect on the mixed bacterial flora, both for its demarcation of the colliquated areas and for the support of the repair of the surrounding tissues.The more timely its application, the greater the possibility of obtaining a positive result. (Baroni, 1985, Wattel 1991, Oriani 1992).
Carbon monoxide poisoning is a severe intoxication that results in direct and distant consequences. The direct damage is conditioned by the binding that is found between the porphyrin groups (Hemoglobin, Myoglobin, Cytochrome a-a3), and carbon monoxide, and therefore the inability to transport Oxygen to the tissues and to the inhibition of cytochrome oxidase. Secondary damage is characterized by a post-interval neurological syndrome of unknown etiology that occurs in a variable time frame up to 40 days from the pathological event. Hyperbaric Oxygen performs a direct mass action (Haldane's law) on hemoglobin and myoglobin, displacing the link created with carbon monoxide, while its effect on cytochrome a-a3 has not yet been demonstrated. share of dissolved oxygen, improves tissue oxygenation. Numerous studies have demonstrated the validity of this treatment in severe CO poisoning on both acute and delayed damage. The World Health Organization has inserted the O.T.l. in the protocol of treatment of CO poisoning and specific protocols have been implemented to be applied according to the severity of the disease. (Wattel 1985, Meyers 1989, Hall 1992).
Post-traumatic acute ischemia occurs when, following a severe trauma, the
district circulation is compromised. The alteration that is determined can lead
to an ischemia of the affected district and, subsequently to bacterial
superinfection. The timely application of the O.T.l. It is aimed, in a situation
of compartmental suffering, to increase the partial pressure of tissue oxygen,
to reduce the vasogenic urge, to demarcate the vital areas from the non-viable
ones, grafting the macrophage mechanism. The O.T.I. it is to be applied promptly,
in association with a correct antibiotic and surgical therapy for the
stabilization of the bone segments.
(Strauss 1988, Mathieu 1991, Strauss 1992).
This pathology is determined following a radiation therapy that determines, locally, a decrease in the vascularization, a tissue hypoxia, a stop of reparative processes (reduced cellular activity). The mechanism of action of 011. in the treatment of this pathology, it foresees the normalization, of the tissue oxygenation, the neoangiogenesis, the activation of the macrophage function, determining an improvement of the tissue reparative processes. Numerous controlled studies have been published which highlight the efficacy of O.T.l. in the treatment of this pathology and also the analysis of the beneficial costs is favorable to this type of treatment (Marx 1987, Van Marckesteun 1990, Marx 1992).
This indication has found its rationale in the improved knowledge of cochlear physiology and in demonstrating the high oxygen demand of this structure. It has been shown that a high intensity noise and / or a high pressure wave (shotgun) are able to determine a severe hypoxia in cochlear level and how this hypoxic crisis, with a self-holding mechanism, can induce a damage ischemic. The indication broadens. I. is recommended on the condition that it can be started early. As the days go by, the prognosis is changed in the negative direction and the O.T.l. it is not able to modify the results (Holbach 1976, Lamm 1990, Cavallazzi 1991).