TREATMENT OF DECOMPRESSION SICKNESS
Effective first aid will greatly increase the chances of subsequent recovery, especially if there is likely to be any delay in decompression. In the first instance, 100% oxygen should be administered and the prompt attention of a diving specialist doctor is essential.
THE PRINCILPALS OF THERAPEUTIC RECOMPRESSION
While first aid measures will assist the casualty, the definitive treatment for the dysbaric disorders is recompression.
Therapeutic recompression is designed to accomplish three objectives:
a. Reduce the volume of gas bubbles and thereby relieve local tissue pressure, restore tissue architecture and restart blood flow.
b. Promote the resorption of inert gas bubbles.
c. Increase blood O2 content and thereby improve O2 delivery to injured tissue.
GENERAL TREATMENT PROTOCOL IN A TWO COMPARTMENT COMPRESSION CHAMBER
Following an examination by a specialist diving doctor at the A&E dept, the casualty will be transported by ambulance to the Hyperbaric Treatment Centre. Upon arrival the casualty will be met by the team supervisor or attendant who will explain how and what treatment will be given (based on the advice of the diving doctor). The Casualty and the attendant will then enter the chamber. If the casualty is incapacitated to the point mobility is affected, a stretcher can be used. Once inside the casualty is made comfortable and the treatment will commence as soon as possible.
TREATMENT OF TYPE 1 DECOMPRESSION SICKNESS
The conditions for which this treatment is appropriate are mild coetaneous symptoms, lymphatic involvement and pain-only bends in which there is no evidence of neurological signs after a FULL EXAMINATION.
a. Proceed as follows:
1. The patient starts breathing 02 at the surface.
2. Descend to 18m over one or two minutes stopping only if the patient or attendant has difficulty clearing his or her ears.
3. The timing of the treatment starts on reaching 18m.
b. If symptoms are completely relieved within 10 minutes AND a repeat examination by the attendant or Medical Officer has revealed no neurological signs, decompression may proceed in accordance with Table 61. Otherwise use Table 62.
c. If Table 62 is used and symptoms are not completely relieved at 18m, the table may be extended by up to two further 02 breathing periods at both 18m and 9m on the advice of a Diving Medicine Specialist.
NOTES: If oxygen is not available, the patient should be transferred to a chamber which is equipped with oxygen.
If transfer is not possible, Table 64 may be used without oxygen following consultation with a Diving Medicine Specialist.
THE TREATMENT OF TYPE 2 DECOMPRESSION SICKNESS
The condition for which this treatment is appropriate are all cases of decompression sickness other than those in type 1. If necessary, consult a Diving Medicine Specialist and proceed as follows:
a. The patient starts breathing O2 on the surface.
b. Descend to 18m over one or two minutes stopping only if the patient or attendant has difficulty clearing his or her ears.
c. If the symptoms and signs are completely relieved at 18m, decompress according to Table 62.
d. Very occasionally, patients who are recompressed shortly after the onset of symptoms may continue to deteriorate at 18m. If the patient's condition has not stabilised within 20 minutes of reaching 18m, compress to 50m on air or breathing 32/67% 02/N2 by BIBS, and decompress using Table 64. In rare instances, continued deterioration may require a transfer to Table 65.
e. If the symptoms have remained static or improved incompletely after three 20 minute periods on 100% 02 at 18m, Table 62 may be extended. If it is considered that further time at 18m is needed, or if the patient has been recompressed to 18m following deterioration during decompression to 9m, Table 64 and 65 may be used following an extended stay at 18m. These tables should only be used on the advice of a Diving Medicine Specialist.
f. If 02 is not available, compress to 50m and decompress on Table 64 omitting the 02 periods.
THE TREATMENT OF ARTERIAL GAS EMBOLISM
(less than one hour after the onset of symptoms)
a. In cases of definite arterial gas embolism where less than 1 hour has elapsed from the onset of symptoms, the chamber is to be pressurised without delay, with air, or
32% 02 if available, to 50m at the fastest rate that can be tolerated by the patient and attendant.
b. If the patient is free of symptoms and signs after 25 minutes, and 02 is available, then decompression may be commenced using Table 63. If 02 is not available Table 64 should be used.
c. If there are persisting symptoms and signs after 30 minutes at 50m, no matter how minor, Table 64 should be used. If 02 is not available then Table 64 may be used without it.
d. If the patient is deteriorating at 50m, contact a Diving Medicine Specialist as a matter of urgency. It may be necessary to compress the patient further and continue treatment of Table 65. This should not be contemplated however, unless:
1. A Diving Medicine Specialist is on site.
2. The chamber is capable of supporting a prolonged treatment.
THE TREATMENT OF ARTERIAL GAS EMBOLISM
(more than one hour has elapsed from the onset of symptoms)
Where there has been a delay of more than 1 hour between the onset of symptoms and recompression, treatment should be commenced on Table 62 and managed as of decompression sickness with neurological symptoms.
RECURRENCE OF SYMPTOMS
Further treatments may be necessary over the period of a several days depending on symptoms.