UNDERWATER APNEA - PRE-SYNCOPAL STATE OR SAMBA AND BLACK-OUT

Risks and dangers associated with excessively prolonged apnea: pre-syncopal state or Samba and Black-out

Samba

Samba: better defined (but not quite properly) prensicopal state, it often precedes the black-out.It is recognized for the conscious but discontrolled motor activation that often traces the movements prior to the injury; Samba it is the reversible result of numerous but small hypoxic necrosis due to prolonged apnea, easily visualized with computed tomography (CT) or brain magnetic resonance (RMC)

Black-out: also commonly associated with syncope (with which it shares respiratory arrest BUT NOT cardiac arrest); it seems to be a brain reaction to plasma oxygen deficiency. Through the black-out, the brain disconnects all functions except those vital (and temporarily also pulmonary ventilation) in an attempt to save oxygen for their nerve cells. The blackout is characterized by the state of total unconsciousness associated with muscle stiffening (which makes insufflation more difficult), and induces relatively extensive necrosis an "area of the cerebral cortex (also visible on CT or MRI); in the black-out the heart continues to beat and to perfuse the little oxygen left in the plasma to the tissues, and for this reason, if treated promptly, it represents an easily reversible condition. Obviously, the presence of water in the lungs can cause drowning, but even considering the possibility that the lungs remain dry, if the subject is not brought back to the surface with the nose and mouth completely emerged and free, he will not be able to reacquire ventilation and the necessary perfusion.

Permanent brain lesions: in the event that the unsafe person is resuscitated to the limit of his possibilities, the cerebral necrosis induced by prolonged hypoxia could be irreparable and cause serious functional compromises comparable to those of cerebral stroke.

Death: in the event of a black-out it is possible to state that the gaseous quantity of blood can guarantee the survival of the injured person for a few minutes; if the rescuers are unable to promptly restore ventilation and / or heart rhythm, it is possible that brain death occurs.

Otolaryngology (ENT) Risks and Dangers

In the "underwater apnea, the risks and related dangers, of the otolaryngological type, are different:

Rhinitis, sinusitis, pharyngitis and laryngitis: these two disorders, generally characterized by etiology unrelated to the marine environment (allergic reactions, viral, bacterial or fungal infections), totally prevent the practice of deep apnea and often also that of dynamic apnea. They make it impossible to compensate for the eardrums (due to swelling of the mucous membranes relating to the mouth of the eustachian tube) and of the sinuses (cavity of the splanchnocranium). The sinuses and tubes are generally air-filled spaces which, if obstructed by the mucus, undergo hydrostatic pressure causing excruciating pangs followed by capillary ruptures and small hemorrhages.

Barotraumatic otitis: represents the bugbear of every freediver. Barotraumatic otitis is a lesion of the eardrum or of the middle and inner ear due to hydrostatic pressure which is NOT adequately compensated. In the event that it is an inflammation or rupture of the tympanic membrane (and also in this case it depends on the site of the lesion), it is usually easily reversible conditions without major consequences for the auditory function (provided that they are adequately treated and not repeated ); on the contrary, if the damage affects or extends to the middle and inner ear, the extent of the lesion is extremely serious. In this case it is essential to go immediately to a hyperbaric center for the relative therapy in a specific room; to the middle and inner ear can lead to total deafness. Usually, both are characterized by severe pain but it may happen that the lesion to the middle and inner ear does not cause a symptomatology proportional to the extent of the damage, compromising the timeliness of the diagnosis, therefore the efficacy of the therapy.

Infectious external otitis: it is the infection of the external auditory canal and / or of the tympanic membrane caused by one or more pathogens (such as bacteria and fungi). It can cause swelling of the lymphatic glands and often turns out to relapse due to the alteration cutaneous (squamous eczematous) of the auricular epithelium. For preventive purposes, it is advisable to take care of the hygiene of the external auditory canal after each dive (especially in the swimming pool, in the lake and in the sea near the ports where pollutants and plankton are abundant), by rinsing with physiological water and possibly 1-2% boric water or 0.5% chlorinated water; for the treatment it is advisable to refrain from wetting the ear until remission (at least 2-3 weeks).

Alternobaric vertigo: it is nothing but a labyrinthine dysfunction (center of the inner ear involved in the regulation of balance) of short duration; it is caused above all by strong changes in temperature and by the malfunctioning of the middle ear and / or of the inner ear, which in particular conditions negatively undergo sudden changes in hydrostatic pressure (change in depth).