As with all medical treatments, hyperbaric oxygen therapy includes
medical risks and possible side-effects. Most are related to the
unique aspects of HBO such as significant and relatively rapid
changes in pressure inside the chamber and the high levels of oxygen
used. Most are relatively mild and self-limited, but some can be
severe and even life-threatening.
Side Effects of Hyperbaric Oxygen Therapy
Hyperbaric oxygen is usually well tolerated with few side-effects.
However, there are some side effects that patients may experience.
Visual Refractive Changes
Hyperbaric oxygen therapy treatments can temporarily change the
shape of the lens in the eye. This usually results in worsening
myopia (nearsightedness), but improvement in presbyopia (the
inability to focus on objects near the eye due to age-related
changes in the lens). This change usually reverts back to its
pre-treatment status six-eight weeks after treatments stop. Rarely,
the change will not completely return to its baseline level.
Cataract Maturation
While HBO therapy has not been shown to cause cataracts, there is
some thought it may cause pre-existing cataracts to mature faster
than normal.
Claustrophobia
Due to the confined and enclosed nature of the hyperbaric chamber,
some patients can develop a feeling of claustrophobia, and those who
are already claustrophobic can experience a worsening of their
symptoms. A multi-place chamber (such as we operate) can help
alleviate some of these feelings due to the size of the chamber. If
claustrophobic symptoms become severe enough, pre-treatment sedation
can be considered on a case-by-case basis.
Hypoglycemia
Some patients with diabetes experience a drop in blood sugar during
hyperbaric treatments. In order to prevent this, patients are
encouraged to eat before coming for treatments and blood glucose is
monitored during the dive at appropriate intervals.
Complications of Hyperbaric Oxygen Therapy
While it's generally very safe, as with all medical treatments,
Hyperbaric Oxygen Therapy carries with it the risk of complications
that in rare instances can be life threatening and/or result in
permanent or long-term disability.
The Health Benefits of HyperBaric Oxygen Therapy
Barotrauma of the Ear
Barotrauma is a term that refers to injury due to increased
pressure. Barotrauma of the ear is the most frequent complication of
HBO. The middle-ear is an air-filled cavity behind the ear drum that
connects to the throat through a slit-like passage called the
eustachian tube. During compression, if the air pressure in the
middle-ear cannot be equalized with the external pressure, the
eardrum will bow inward, leading to pain and possibly rupture,
leading to hearing loss.
Round or Oval Window Rupture
Round and/or oval window rupture is a phenomenon related to ear
barotruama. The round and oval windows are membranes separating the
air-filled middle ear from the fluid-filled inner ear. Rarely,
over-vigorous attempts to equalize the pressure in the middle ear
can lead to increased pressure in the inner-ear and can rupture
these membranes. Deafness is the result. So, while rupture of these
windows is not related to pressure change per-se, it is related to
maneuverers used to prevent another complication.
Sinus Squeeze
Similarl to the middle-ear, the sinuses are air-filled spaces in the
skull. Failure to equalize the pressure in the sinuses and the
external environment leads to severe pain and possibly bleeding into
the sinuses.
Tooth Squeeze
Recent dental work can leave air-filled voids in teeth. The
inability to equalize the pressure in these pockets can lead to pain
and even cracking of the teeth.
Pneumothorax or Pulmonary Barotrauma
Pulmonary barotruama refers to damage to the lung tissue as a result
of pressure change, resulting in air leaking from the lungs into the
chest cavity causing a dropped lung, or pneumothroax. This generally
occurs in patients with air trapping lesions in the lungs, such as
can occur in emphysema or asthma. During decompression, these
air-filled pockets will begin to expand, and, if the pressure is not
relieved by the airways in the lungs, these pockets can rupture.
This released air can cause excess pressure in the chest cavity
leading to difficulty breathing and decreased blood pressure that
can result in death if untreated. Treatment consists of emergency
evacuation of air from the chest cavity by inserting a needle
through the chest wall, and, subsequently, placing a chest tube to
re-expand the lung.
Oxygen Toxicity Seizures
The high level of oxygen in the blood that occurs during HBO
treatments can be toxic to the central nervous system and can result
in seizure activity. While this is rare during clinical hyperbaric
treatments, it does occur and may be more likely in those with
pre-existing seizure disorders or hypoglycemia (low blood sugar).
Treatment consists of simply removing the supplemental oxygen from
the patient, which will terminate the seizure.
Pulmonary Oxygen Toxicity
Elevated oxygen concentrations can be detrimental to the lungs.
Prolonged exposure to high levels of oxygen can eventually lead to
chest pain, difficulty breathing, and eventually, respiratory
failure. In the early stages of the condition, the lungs rapidly
return to baseline once the oxygen concentration is decreased. Thus,
due to the intermittent nature of HBO treatments, pulmonary oxygen
toxicity is rarely seen in clinical practice. On the other hand,
this can become a concern in critically ill patients who must be
maintained on supplemental oxygen between treatments or those
patients who require unusually frequent or prolonged treatment
courses.
Decompression Sickness
Decompression sickness, or the bends, is a result of the uptake of
nitrogen into the blood when air (which is about 80 percent
nitrogen) is breathed at increased ambient pressure. This is
generally more of a concern for the inside attendants, who breathe
air during a treatment, rather than patients, who are breathing 100%
oxygen. This can become a concern if a patient must be removed from
oxygen for prolonged periods of time during the dive. Decompression
sickness can result in pain, neurological injury, cardiopulmonary
collapse, and possibly death.
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