21-42 Change A U.S. Navy Diving Manual—Volume 5 Treatment Table 6A 1. Descent rate - 20 ft/min. 2. Ascent rate - 165 fsw to 60 fsw not to exceed 3 ft/min, 60 fsw and shallower, not to exceed 1 ft/min. Do not compensate for slower ascent rates. Compensate for faster rates by halting the ascent. 3. Time at treatment depth does not include compression time. 4. Table begins with initial compression to depth of 60 fsw. If initial treatment was at 60 feet, up to 20 minutes may be spent at 60 feet before compression to 165 fsw. Contact a Diving Medical Officer. 5. If a chamber is equipped with a high-O₂ treatment gas, it may be administered at 165 fsw and shallower, not to exceed 3.O ata O₂ in accordance with paragraph 21-5.7. Treatment gas is administered for 25 minutes interrupted by 5 minutes of air. Treatment gas is breathed during ascent from the treatment depth to 60 fsw. 6. Deeper than 60 feet, if treatment gas must be interrupted because of CNS oxygen toxicity, allow 15 minutes after the reaction has entirely subsided before resuming treatment gas. The time off treatment gas is counted as part of the time at treatment depth. If at 60 feet or shallower and oxygen breathing must be interrupted because of CNS oxygen toxicity, allow 15 minutes after the reaction has entirely subsided and resume schedule at point of interruption (see paragraph 21-5.5.6.1.1). 7. Table 6A can be lengthened up to 2 additional 25-minute periods at 60 feet (20 minutes on oxygen and 5 minutes on air), or up to 2 additional 75-minute periods at 30 feet (60-minutes on oxygen and 15 minutes on air), or both. 8. Tenders breathes 100 percent O₂ during the last 60 minutes at 30 fsw and during ascent to the surface for an unmodified table or where there has been only a single extension at 30 or 60 fsw. If there has been more than one extension, the O₂ breathing at 30 fsw is increased to 90 minutes. If the tender had a hyperbaric exposure within the past 12 hours, an additional 60 minute O₂ breathing period is taken at 30 fsw. 9. If significant improvement is not obtained within 30 minutes at 165 feet, consult with a Diving Medical Officer before switching to Treatment Table 4. Figure 21-9.  Treatment Table 6A.   Treatment Table 6A Depth/Time Profile Time at Depth (minutes) Total Elapsed Time: 350 Minutes 5 Hours 50 Minutes (Not Including Descent Time) 165 25 5 20 35 20 20 30 60 60 30 5 5 5 15 15 60 30 0 Depth (fsw) Descent Rate 20 Ft/Min. Ascent Rate 3 Ft/Min. Ascent Rate 1 Ft/Min. Ascent Rate 1 Ft/Min.