Hyperbaric Oxygen Therapy - Hyperbaric Chamber Information ...

Results of assessment
Is it safe?
Adverse events
Potential risks for patients undergoing therapy with HBO are listed in Table 9. Most
available data on adverse events are retrospective case series; properly designed and
conducted studies are lacking. This suggests that estimates of incidence are uncertain,
although the nature of the event might be recognised.
Table 9 Adverse events associated with exposure to hyperbaric oxygen.
Myopia Claustrophobia
Barotrauma
Oxygen toxicity
Decompression illness
The most common adverse events associated with the procedure include middle ear
barotrauma and reversible myopia. 1,2,4 The first occurs in about 2% of subjects.
Measures to prevent or treat this condition have been studied with some
recommendations currently available. 33,34
Progressive myopia is associated with prolonged, daily exposure to HBO 35-37 and is more
common in higher pressures. Spontaneous reversal usually occurs within a few days to
several weeks after therapy is discontinued. There is some evidence that extending the
number of exposures to more than 100 increases the risk of irreversible changes to the
refractive media of the lens or to the development of new cataracts. 1,2 In an
observational study published in Sweden, 24 of 25 patients (mean age of about 65 years)
undergoing at least 150 hourly sessions of HBOT for persistent leg ulcers developed
myopia of one diopter or more. The mean change in refraction was 3.0 diopters. Of 15
subjects with clear lens nuclei before treatment, seven developed cataracts with definite
increases in the turbidity of the lens nucleus. More than half developed these changes
within six months of exposure to HBOT. Termination of therapy did not lead to a
reversal of changes to the lens. 37 While some patients may require extended exposure to
HBOT, which is dependent on several factors, it is uncommon for the number of
sessions to exceed 60 treatment sessions (usually 90 minutes at 2.4 ATA) in Australian
clinical practice.
Claustrophobia may induce anxiety when patients are placed in the confines of the
treatment chamber. Mild sedatives may assist in the continuation of therapy.
Oxygen toxicity may be manifested as pulmonary or neurologic changes and are often a
major cause for concern. Seizures have been estimated to occur at a rate of about 0.01
percent 1 but do not seem to produce residual effects.
Operational safety guidelines and recommendations
Hyperbaric Oxygen Therapy Facilities Industry Guidelines (HOTFIG)
Guidelines published under the auspices of the Hyperbaric Technicians and Nurses
Association (HTNA) were released in August 1998, although preliminary work started as
14 Hyperbaric oxygen therapy