CHAPTER 21 — Recompression Therapy
Change A 21-27
symptoms in the affected diver, then stop decompression. When oxygen is
restored, continue treatment from where it was stopped.
21-5.7.2
Switching to Air Treatment Table. If O2 breathing cannot be restored in 2 hours
switch to comparable air Treatment Table at current depth for decompression if 60
fsw or shallower. Rate of ascent must not exceed 1 fpm between stops. If an
increase in treatment depth deeper than 60 feet is needed, use Treatment Table 4.
21-5.8
Use of High Oxygen Mixes. High oxygen N2O2/HeO2 mixtures may be adminis-
tered during treatment when 100 percent oxygen cannot be tolerated. The
premixed gases shown in Table 21-5 may be used over the depth range of 0-225
fsw.
High-oxygen mixtures can be used for treating patients at depth when no signifi-
cant improvement was made at 60 fsw. High-oxygen mixtures may also be used
for patients experiencing pulmonary oxygen toxicity at 60 fsw and shallower.
Ideally, the ppO2 of the treatment gas used should be 1.5 to 3.0 ata. Using nitrogen
as the background gas is an acceptable practice for treating DCS/AGE. Recent
studies suggest that using helium as the background gas may be more beneficial.
Using HeO2 reduces the amount of nitrogen dissolved in the patient’s tissue and
facilitates the off-gassing of nitrogen.
21-5.9
Treatment at Altitude - Tender Considerations. Divers serving as inside tenders
during hyperbaric treatments at altitude are performing a dive at altitude and there-
fore require more decompression than at sea level. Tenders locking into the
chamber for brief periods should be managed according to the Diving At Altitude
procedures (paragraph 9-12). Tenders remaining in the chamber for the full treat-
ment table must breathe oxygen during the terminal portion of the treatment to
satisfy their decompression requirement.
The additional oxygen breathing required at altitude on TT5, TT6, and TT6A is
given in Table 21-6. The requirement pertains both to tenders equilibrated at alti-
tude and to tenders flown directly from sea level to the chamber location.
Table 21-5. High Oxygen Treatment Gas Mixtures.
Depth (fsw)
Mix (HeO2 or N2O2)
ppO2
0–60
100%
1.00–2.82
61–165
50/50
1.42–3.0
166–225
64/36 (HeO
2)
2.17–2.8
