Tenders on Tables 5, 6, 6A, 1A, 2A, or 3 should have a minimum of a 12-hour
surface interval before no-decompression diving and a minimum of a 24-hour
surface interval before dives requiring decompression stops. Tenders on Tables 4,
7, and 8 should have a minimum of a 48-hour surface interval prior to diving.
Post-Treatment Observation Period. After a treatment, patients treated on a
Treatment Table 5 should remain at the recompression chamber facility for 2
hours. Patients who have been treated for Type II decompression sickness or who
required a Treatment Table 6 for Type I symptoms and have had complete relief
should remain at the recompression chamber facility for 6 hours. These times may
be shortened upon the recommendation of a Diving Medical Officer, provided the
patient will be with personnel who are experienced at recognizing recurrence of
symptoms and can return to the recompression facility within 30 minutes. All
patients should remain within 60 minutes of a recompression facility for 24 hours
and should not be left alone during that period.
Post-Treatment Transfer. Patients with residual symptoms should be transferred
to appropriate medical facilities as directed by qualified medical personnel. If
ambulatory patients are sent home, they should always be accompanied by
someone familiar with their condition who can return them to the recompression
facility should the need arise. Patients completing treatment do not have to remain
in the vicinity of the chamber if the Diving Medical Officer feels that transferring
them to a medical facility immediately is in their best interest.
Inside Tenders. Treatment table profiles place the inside tender(s) at risk for
decompression sickness. After completing treatments, inside tenders should
remain in the vicinity of the recompression chamber for 1 hour. If they were
tending for Treatment Table 4, 7, or 8, inside tenders should also remain within 60
minutes of a recompression facility for 24 hours.
21-6.4 Flying After Treatments. Patients with residual symptoms should fly only with
the concurrence of a Diving Medical Officer. Patients who have been treated for
decompression sickness or arterial gas embolism and have complete relief should
not fly for 72 hours after treatment, at a minimum.
Emergency Air Evacuation. Some patients will require air evacuation to another
treatment or medical facility immediately after surfacing from a treatment. They
will not meet surface interval requirements as described above. Such evacuation is
done only on the recommendation of a Diving Medical Officer. Aircraft pressurized
to one ata should be used if possible, or unpressurized aircraft flown as low as
safely possible (no more than 1,000 feet is preferable). Have the patient breathe
100 percent oxygen during transport, if available.
Tender Surface Interval. Tenders on Tables 5, 6, 6A, 1A, 2A, or 3 should have a
24-hour surface interval before flying. Tenders on tables 4, 7, and 8 should not fly
for 72 hours.
Treatment of Residual Symptoms. After completion of the initial recompression
treatment and after a surface interval sufficient to allow complete medical evaluation,
additional recompression treatments may be instituted. For persistent Type II
symptoms, daily treatment on Table 6 may be used, but twice-daily treatments on
Treatment Tables 5 or 9 may also be used. The treatment table chosen for re-treatments
must be based upon the patient’s medical condition and the potential for
pulmonary oxygen toxicity. Patients surfacing from Treatment Table 6A with
extensions, 4, 7, or 8 may have severe pulmonary oxygen toxicity and may find
breathing 100 percent oxygen at 45 or 60 feet to be uncomfortable. In these cases,
daily treatments at 33 feet may also be used. As many oxygen breathing periods
(30 minutes on oxygen followed by 5 minutes on air) should be administered as
can be tolerated by the patient. Ascent to the surface is at 20 feet per minute. A
minimum oxygen breathing time is 90 minutes. A practical maximum bottom time
is 3 to 4 hours at 33 feet. Treatments should not be administered on a daily basis
for more than 5 days without a break of at least 1 day. These guidelines may have
to be modified by the Diving Medical Officer to suit individual patient circumstances
and tolerance to oxygen as measured by decrements in the patient’s vital
capacity.
Additional Recompression Treatments. Additional recompression treatments are
indicated as long as they are prescribed by a Diving Medical Officer. In treating
residual symptoms, no response to recompression may occur on the first one or
two treatments. In these cases, the Diving Medical Officer is the best judge as to
the number of treatments. Consultation with NEDU or NDSTC may be appropriate
(phone numbers are listed in paragraph 21-1.4). As the delay time between
completion of initial treatment and the beginning of follow-up hyperbaric treatments
increases, the probability of benefit from additional treatments decreases.
However, improvement has been noted in patients who have had delay times of up
to 1 week. Therefore, a long delay is not necessarily a reason to preclude followup
treatments. Once residual symptoms respond to additional recompression treatments,
such treatments should be continued until no further benefit is noted. In
general, treatment may be discontinued if there is no further sustained improvement
on two consecutive treatments.
Returning to Diving after Treatment Table 5. Divers who meet all of the criteria
for treatment using Treatment Table 5, as outlined in paragraph 21-5.4.1 and who
have had complete relief, may return to normal diving activity 7 days after
surfacing from the Treatment Table 5. If there is any doubt about the presence or
absence of Type II symptoms, the diver should be examined by a Diving Medical
Officer before resumption of diving.
21-6.6.1 Returning to Diving After Treatment Table 6. Divers who had symptoms of arterial
gas embolism, Type II DCS, or Type I DCS requiring a Treatment Table 6
should not dive for at least 4 weks and should resume diving only upon the
recommendation of a Diving Medical Officer.
Returning to Diving After Treatment Table 4 or 7. A diver having cardiorespiratory
and/or CNS symptoms severe enough to warrant Treatment Table 4 or 7 should not dive for a minimum of 3 months, and not until a thorough review of his
case by a Diving Medical Officer has established that return to normal diving
activity can be accomplished safely.
