Us Navy Dive Manual Chapter 14 Rev 6 Change A

Front 1

The normal operational limit for surface-supplied mixed gas diving is ______ fsw for _____ minutes.

Back 1

300 fsw, 30 minutes

Front 2

Exceptional exposures should be undertaken only at the ______________________ discretion in an emergency. Planned exceptional exposure dives require prior __________________ approval.

Back 2

Commanding Officer’s discretion, CNO approval

Front 3

Repetitive diving is not allowed in surface-supplied helium-oxygen diving, except when?

Back 3

Another dive may be performed following a dive aborted 100 fsw and shallower. Add the bottom time of all the dives to the bottom time of the new dive and use the deepest depth when calculating a table and schedule for the new dive.

Front 4

What is the required surface interval in-between no-decompression mixed gas dives?

Back 4

The diver must wait 12 hours before making a second dive.

Front 5

What is the required surface interval in-between decompression mixed gas dives?

Back 5

The diver must wait 18 hours.

Front 6

To minimize pulmonary oxygen toxicity effects, a diver should take a one day break after _______ consecutive days of mixed gas diving.

Back 6

Four days

Front 7

How do you figure how long you must wait to fly or ascend to altitude following a mixed gas dive?

Back 7

No-decompression dive, the diver must wait 12 hours
Decompression dive, the diver must wait 24 hours

Front 8

Four gas mixtures are required to dive the surface-supplied mixed gas tables over their full range. What are they?

Back 8

1. Bottom Mixture - The bottom mixture may vary from 90% helium 10% oxygen to 60% helium 40% oxygen depending on the diver’s depth. The allowable range of bottom mixtures for each depth is shown in the mixed gas dive tables.
2. 50% Helium 50% Oxygen - This mixture is used from 90 fsw to 40 fsw during decompression. Oxygen concentration in the mixture may range from 49 to 51 percent.
3. 100% Oxygen - Oxygen is used at the 30- and 20-fsw water stops during in-water decompression and at 50, 40 and 30 fsw in the chamber during surface decompression.
4. Air - Air is used as an emergency backup gas throughout the dive and to provide air breaks during oxygen breathing.

Front 9

Helium-oxygen mixtures must be analyzed for oxygen content with an instrument having an accuracy of _______ percent.

Back 9

±0.5 percent

Front 10

What gas mixture is in the EGS gas for a mixed gas dive?

Back 10

Mixture shall be the same as the bottom mixture unless the bottom mixture contains less than 16 percent oxygen, in which case the EGS gas mixture may range from 15 to 17 percent oxygen.

Front 11

Where can you find the maximum and minimum concentrations of oxygen allowable in the helium-oxygen mixture at depth?

Back 11

The Surface-Supplied Helium-Oxygen Decompression Table

Front 12

The maximum oxygen concentration in the mix for a mixed gas dive has been selected so that the diver never exceeds an oxygen partial pressure of ______ ata while on the bottom.

Back 12

1.3 ATA

Front 13

The minimum oxygen percentage allowed in the mixture is _____ percent for depths to 200 fsw and _____ percent for depths in excess of 200 fsw.

Back 13

14 % for depths to 200 fsw, 10 % for depths in excess 200 fsw

Front 14

To offer a decompression advantage to the diver, is it encouraged to dive with a mixture "near maximum" or "near minimum" oxygen percentage?

Back 14

Maximum oxygen percentage

Front 15

During mixed gas diving operations, in what circumstances does the divers bottom time not started when the diver leaves the surface?

Back 15

When the bottom mixture contains less than 16% oxygen, you must descend to 20’ on air then shift to bottom mix then shift to bottom mix. Ventilate the divers for ::20. Once confirmed on bottom mix and leak check performed, you may commence descent and bottom time is started. If descent to 20’ and shift to bottom mix takes longer than 5 minutes, start the bottom time at the 5 minute mark.

Front 16

For surface decompression, what is the ascent rate from the 40 fsw water stop to the surface?

Back 16

40 fsw/min

Front 17

When does the time at the decompression stop begin and end during mixed gas diving?

Back 17

The first decompression stop time begins when the diver arrives at the stop and ends when he leaves the stop. For all subsequent stops, the stop time begins when the diver leaves the previous stop and ends when he leaves the stop. The single exception is the first oxygen stop at 30 fsw. The 30-fsw oxygen stop begins when the divers are confirmed to be on oxygen at 30 fsw and ends when the divers leave 30 fsw. The ascent time from the 30- to the 20-fsw oxygen stop is included in the 20-fsw oxygen stop time.

Front 18

At what point during the dive do you shift from bottom mix to 50% helium 50% oxygen mixture?

Back 18

Leave bottom and decompress on bottom mixture to 90 fsw, then shift the diver to a 50% helium 50% oxygen mixture. If there is a 'D' stop at 90' ventilate divers for ::20, if the 'D' stop is shallower than 90', ventilate at shallower stop. GAS SHIFT TIME IS INCLUDED IN STOP TIME.

Front 19

At what point during the dive do you shift from 50% helium 50% oxygen mixture to 100% oxygen?

Back 19

Upon arrival at the 30 fsw stop, shift the diver to 100% oxygen

Front 20

For all dives, surface decompression may be used after completing the 40 fsw water stop as during surface decompression, from 40 fsw to the surface, what gas does the diver breath?

Back 20

The diver surfaces while breathing 50% helium 50% oxygen

Front 21

To prevent hypoxia, a special descent procedure is required when the bottom mixture contains less than 16% oxygen. Explain.

Back 21

1. Place the diver on air on the surface.
2. Make the appropriate predive checks.
3. Have the diver descend to 20 fsw.
4. At 20 fsw, shift the diver to the bottom mix and ventilate the diver for 20 seconds.
5. Confirm the diver is on bottom mix, then perform a final leak check. The diver is allowed 5 minutes to descend to 20 fsw, shift to the bottom mixture and perform equipment checks.
6. Have the diver begin descent.
7. Start bottom time.
a. If the diver spends 5 minutes or less performing above procedures, bottom time starts when the diver leaves 20 fsw.
b. If the diver spends more than 5 minutes performing above procedures, bottom time starts at the 5 minute mark.

Front 22

Your bottom mix is less than 16% and you descend on air to shift to bottom mix at 20 fsw. After shifting to bottom mix you must bring the divers back to the surface to correct a leak check problem. What is your procedure for bringing the divers back up to the surface?

Back 22

1. Shift the diver from the bottom mixture back to air.
2. Ventilate the diver.
3. Confirm the diver is on air.
4. Have the diver begin ascent.
5. When the diver reenters the water, the 5 minute grace period begins again. No adjustment of bottom time is required for the previous exposure at 20 fsw.

Front 23

What are the procedures for aborting a mixed gas dive from depths of 100 fsw and shallower?

Back 23

1. Ensure the diver is in a no-decompression status.
2. If the bottom mixture is 16% oxygen or greater, ascend directly to the surface at 30 fsw/min.
3. If the bottom mixture is less than 16% oxygen, ascend to 20 fsw at 30 fsw/min. Shift the diver from the bottom mixture back to air.
4. Ventilate the diver.
5. Confirm the diver is on air.
6. Complete ascent to the surface on air.

Front 24

What are the procedures for aborting a mixed gas dive from deeper than 100 fsw?

Back 24

1. Follow the normal decompression schedule to the surface.
2. Repetitive diving is not allowed following a dive aborted deeper than 100 fsw.

Front 25

What are the rules for repeting after an aborted mixed gas dive?

Back 25

The aborted dive must be 100 fsw and shallower. Add the bottom time of all the dives to the bottom time of the new dive and use the deepest depth when calculating a table and schedule for the new dive.

Front 26

What are the procedures for shifting to 50 % helium/50% oxygen at 90 fsw?

Back 26

1. Shift the console to 50% helium 50% oxygen when the diver reaches 90 fsw.
2. If there is a decompression stop at 90 fsw, ventilate each diver for 20 seconds at 90 fsw.
3. Confirm the divers are on 50% helium 50% oxygen.
4. If there is no decompression stop at 90 fsw, delay ventilation until arrival at the next shallower stop.
5. Gas shift time is included in the stop time.

Front 27

What are the procedures for shifting to 100 % oxygen at the 30-fsw stop?

Back 27

1. Shift the console to 100% oxygen when the diver reaches 30 fsw.
2. Ventilate each diver for 20 seconds.
3. Verify the diver’s voice change.
Time at the 30-fsw stop begins when the divers are confirmed to be on oxygen.

Front 28

What are the rules for air breaks during 100% oxygen breathing at 30 and 20 fsw during in water decompression for a mixed gas dive?

Back 28

At the 30-fsw and 20-fsw water stops, the diver breathes oxygen for 30-minute periods separated by 5-minute air breaks. The air breaks do not count toward required decompression time. When an air break is required, shift the console to air for 5 minutes then back to 100% oxygen. Ventilation of the divers is not required. For purposes of timing air breaks, begin clocking oxygen time when all divers are confirmed on oxygen. If the total oxygen stop time is 35 minutes or less, an air break is not required at 30 minutes. If the final oxygen period is 35 minutes or less, a final air break at the 30-minute mark is not required. In either case, surface the diver on 100% oxygen upon completion of the oxygen time.

Front 29

When is a diver eligible for surface decompression during a mixed gas dive?

Back 29

After completion of the 40 fsw stop

Front 30

What is the ascent rate from 40’ to the surface during a mixed gas surface decompression dive?

Back 30

40 fpm

Front 31

What depth are the divers compressed to for the chamber phase of a mixed gas surface decompression dive?

Back 31

50’

Front 32

What is the descent rate in the chamber during a mixed gas surface decompression dive?

Back 32

Not to exceed 100 fpm

Front 33

When do the divers go on 100% oxygen during the chamber phase of a mixed gas surface decompression dive?

Back 33

Upon arrival at 50’ in the chamber

Front 34

Explain the break down of lengths and depths of O2 periods at 50’ in the chamber during a mixed gas surface decompression dive?

Back 34

The first period consists of 15 minutes on oxygen at 50 fsw followed by 15 minutes on oxygen at 40 fsw. Periods 2, 3, and 4 are spent at 40 fsw. Periods 5, 6, 7 and 8 are spent at 30 fsw. Ascent from 50 to 40 and from 40 to 30 fsw is at 30 fsw/min. Ascent time is included in the oxygen/air time. Ascent from 40 to 30 fsw, if required, should take place during the air break.

Front 35

What breathing medium does the diver surface on in the chamber during a mixed gas surface decompression dive?

Back 35

When the last oxygen breathing period has been completed, return the diver to breathing chamber air.

Front 36

What are the procedures for switching from an in-water decompression to a Sur “D” while at 30’ or 20’ in the water?

Back 36

The diving supervisor can initiate surface decompression at any point during in-water oxygen decompression at 30 or 20 fsw, if desired. Once in the chamber, the diver should receive the full number of chamber oxygen periods prescribed by the tables. Unlike in air diving, no credit is allowed for time already spent on oxygen in the water.

Front 37

What are the procedures if the divers arrive early at the first stop?

Back 37

1. Begin timing the first stop when the required travel time has been completed.
2. If the first stop requires a gas shift, initiate the gas shift and ventilation upon arrival at the stop, but begin the stop time only when the required travel time has been completed.

Front 38

What are the procedures for delays in arrival at the first stop?

Back 38

1. Delay less than 1 minute. Delays in arrival at the first stop of less than 1 minute may be ignored.
2. Delay greater than 1 minute. Round up the delay time to the next whole minute and add it to the bottom time. Recompute the decompression schedule. If no change in schedule is required, continue on the planned decompression. If a change in schedule is required and the new schedule calls for a decompression stop deeper than the diver’s current depth, perform any missed deeper stops at the diver’s current depth. Do not go deeper.

Example: If the delay time to arrival at the first stop is 3 minutes and 25 seconds, round up to the next whole minute and add 4 minutes to the bottom time. Recheck the decompression table to see if the decompression stop depths or times have changed.

Front 39

Delays in leaving/arriving at the next stop.
What is the procedure for delays deeper than 90 fsw during mixed gas diving?

Back 39

1. Delays less than 1 minute may be ignored.
2. Greater than 1 minute. Add the delay to the bottom time and recalculate the required decompression. If a new schedule is required, pick up the new schedule at the present stop or subsequent stop if the delay occurs between stops. Ignore any missed stops or time deeper than the depth at which the delay occurred. If a delay occurs between stops, restart subsequent stop time at completion of the delay.

Front 40

Delays in leaving/arriving at the next stop.
What is the procedure for delays 90 fsw and shallower during mixed gas diving?

Back 40

1. Delays less than 1 minute may be ignored.
2. Delays greater than 1 minute require no special action except as described below under special considerations when decompressing with high oxygen partial pressure. Resume the normal decompression schedule at the completion of the delay. If a delay occurs between stops, restart subsequent stop time at completion of the delay.

Special considerations when decompressing with high oxygen partial pressure:
1. Delays greater than 5 minutes between 90 and 70 fsw. Shift the diver to air to avoid the risk of CNS oxygen toxicity. At the completion of the delay, return the diver to 50% helium 50% oxygen. Add the time on air to the bottom time and recalculate the required decompression. If a new schedule is required, pick up the new schedule at the present stop or subsequent stop if delay occurs between stops. Ignore any missed stops or time deeper than the depth at which the delay occurred.
2. Delays leaving the 30-fsw stop. Delays greater than 1 minute leaving the 30-fsw stop shall be subtracted from the 20-fsw stop time.

Front 41

In the rare instance of diver entrapment or umbilical fouling, bottom times may exceed 120 minutes, the longest value shown in the table. When it is foreseen that bottom time will exceed 120 minutes, who do you contact for advice on which decompression procedure to follow?

Back 41

Navy Experimental Diving Unit

Front 42

In the rare instance of diver entrapment or umbilical fouling, bottom times may exceed 120 minutes, the longest value shown in the table. When it is foreseen that bottom time will exceed 120 minutes, immediately contact the Navy Experimental Diving Unit for advice on which decompression procedure to follow. If advice cannot be obtained in time, what are your procedures?

Back 42

1. Decompress the diver using the 120-minute schedule for the deepest depth attained.
2. Shift to 100 percent oxygen at 40 fsw.
3. Surface the diver after completing 30 minutes on oxygen at 40 fsw. Oxygen time at 40 fsw starts when divers are confirmed on oxygen.
4. Compress the diver to 60 fsw in the chamber as fast as possible not to exceed 100 fsw/min.
5. Treat the diver on an extended Treatment Table 6. Extend Treatment Table 6 for two oxygen breathing periods at 60 fsw (20 minutes on oxygen, then 5 minutes on air, then 20 minutes on oxygen) and two oxygen breathing periods at 30 fsw (60 minutes on oxygen, then 15 minutes on air, then 60 minutes on oxygen).

Front 43

What are your actions if the umbilical helium-oxygen supply is lost on the bottom?

Back 43

1. Shift the diver to the emergency gas system (EGS).
2. Abort the dive.
3. Remain on the EGS until arrival at 90 fsw.
4. At 90 fsw, shift the diver to 50% helium 50% oxygen and complete the decompression as planned.
5. If the EGS becomes exhausted before 90 fsw is reached, shift the diver to air, complete decompression to 90 fsw, shift the diver to 50% helium 50% oxygen, and continue the decompression as planned.

Front 44

If the diver cannot be shifted to 50% helium 50% oxygen at 90 fsw or the 50% helium 50% oxygen supply is lost during decompression, what are your actions?

Back 44

1. Shift the diver to air and continue the decompression as planned while trying to correct the problem.
2. Shift the diver to 50% helium 50% oxygen once the problem is corrected. Time spent on air counts toward decompression.

If the problem cannot be corrected:
1. Continue the planned decompression on air.
2. Shift the diver from air to oxygen upon arrival at the 50-fsw stop.
3. Breathe oxygen at 50 and 40 fsw for the decompression times indicated in the decompression table, but not to exceed 16 minutes at 50 fsw. Oxygen time at 50 fsw starts when divers are confirmed on oxygen. If the 50-fsw stop exceeds 16 minutes, travel divers to 40 fsw and add remaining 50-fsw stop time to the 40-fsw stop time on oxygen.
4. Surface decompress following completion of the 40-fsw stop.

Front 45

What are your actions if the diver cannot be shifted to oxygen at 30 fsw or the oxygen supply is lost during the 30- or 20-fsw water stops?

Back 45

1. Switch back to 50% helium 50% oxygen. If a switch to 50% helium 50% oxygen is not possible, switch the diver to air.
2. If the problem can be quickly remedied, reventilate the diver with oxygen and resume the schedule at the point of interruption. Consider any time on helium-oxygen or air as dead time.
3. If the problem cannot be remedied, initiate surface decompression. Ignore any time already spent on oxygen at 30 or 20 fsw. The five minute surface interval requirement for surface decompression begins upon leaving the 30- or 20-fsw stop.
4. If the problem cannot be remedied and surface decompression is not feasible, complete the decompression on 50% helium 50% oxygen or air. For 50% helium 50% oxygen, double the remaining oxygen time at each water stop. For air, triple the remaining oxygen time.

Example: A diver loses oxygen 15 minutes into the 30-fsw water stop and is switched back to the 50% helium 50% oxygen decompression mixture. The problem cannot be corrected. The divers original schedule called for 32 minutes of oxygen at 30 fsw and 58 minutes of oxygen at 20 fsw.
Seventeen minutes of oxygen time (32 - 15) remain at 30 fsw. Fifty-eight minutes remain at 20 fsw. The diver should spend an additional 34 minutes (17 x 2) at 30 fsw on the 50/50 mixture, followed by 116 minutes (58 x 2) at 20 fsw. Surface the diver upon completion of the 20-fsw stop.

Example: A diver loses oxygen 10 minutes into the 30-fsw water stop and is switched to air. The problem cannot be corrected. The diver’s original schedule called for 28 minutes of oxygen at 30 fsw and 50 minutes of oxygen at 20 fsw.
Eighteen minutes of oxygen time (28 - 10) remain at 30 fsw. Fifty minutes remain at 20 fsw. The diver should spend an additional 54 minutes (18 x 3) at 30 fsw on air followed by 150 minutes (50 x 3) on air at 20 fsw. Surface the diver upon completion of the 20-fsw stop.

Front 46

What are your actions if the oxygen supply in the chamber is temporary lost during surface decompression?

Back 46

Have the diver breathe chamber air, once restored, return the diver to oxygen breathing. Consider any time on air as dead time.

Front 47

What are your actions if the oxygen supply in the chamber is permanently lost during surface decompression? No 50% helium/50% oxygen is available.

Back 47

If no 50% helium/50% oxygen is available, multiply the remaining oxygen time by three to obtain the equivalent chamber decompression time on air.

Front 48

What are your actions if the oxygen supply in the chamber is permanently lost during surface decompression? 50% helium/50% oxygen is available.

Back 48

If 50% helium 50% oxygen is available, multiply the remaining oxygen time by two to obtain the equivalent chamber decompression time on 50/50. If the loss occurred at 50 or 40 fsw, allocate 10% of the equivalent air or helium-oxygen time to the 40-fsw stop, 20% to the 30-fsw stop, and 70% to the 20-fsw stop. If the diver is at 50 fsw, ascend to 40 fsw to begin the stop time. If the loss occurred at 30 fsw, allocate 30% of the equivalent air or helium-oxygen time to the 30-fsw stop and 70% to the 20-fsw stop. Round the stop times to the nearest whole minute. Surface upon completion of the 20-fsw stop.

Example: The oxygen supply to the chamber is lost 10 minutes into the first 30-minute period on oxygen. Helium-oxygen is not available. The original surface decompression schedule called for three 30-min oxygen breathing periods (total of 90 minutes of oxygen). The diver is at 50 fsw.

The remaining oxygen time is 80 minutes (90-10). The equivalent chamber decompression time on air is 240 minutes (3 x 80). The 240 minutes of air stop time should be allocated as follows: Twenty-four minutes at 40 fsw (240 x 0.1), 48 minutes at 30 fsw (240 x 0.2), and 168 minutes at 20 fsw (240 x 0.7). As addressed above, the diver should ascend from 50 to 40 fsw and begin the 24 minute stop time at 40 fsw.

Front 49

What are your actions if the decompression gas supply becomes contaminated with the bottom mixture, 50/50 mix, air, or oxygen?

Back 49

1. Find the source of the contamination and correct the problem. Probable sources include: An improper valve line-up on the console, (This can be verified by checking oxygen percentage on console oxygen analyzer) or an accidental opening of the emergency gas supply (EGS) valve.
2. When the problem is corrected: Ventilate each diver for 20 seconds and confirm divers are on decompression gas. Continue decompression as planned. Do not lengthen stop times to compensate for the time spent correcting the problem.

Front 50

CNS oxygen toxicity symptoms are unlikely but possible while the diver is breathing 50% helium 50% oxygen in the water at depths 60 fsw and deeper. If symptoms of oxygen toxicity do appear between 90-60 fsw, what are your actions?

Back 50

1. Bring the divers up 10 feet and shift to air to reduce the partial pressure of oxygen. Shift the console as the divers are traveling.
2. Ventilate both divers upon arrival at the shallower stop. Ventilate the stricken diver first.
3. Remain at the shallower stop until the missed time at the previous stop is made up.
4. Resume the planned decompression breathing air.
5. Upon arrival at the next shallower stop, return the divers to the 50% helium 50% oxygen mixture. Ignore any missed time on the 50/50 mixture. A recurrence of symptoms is highly unlikely because of the reduced oxygen partial pressure at the shallower depth.

Example: Red Diver has an oxygen toxicity symptom 5 minutes into his scheduled 9-minute 80-fsw stop. The stage with both divers travels to 70 fsw and the console is shifted to air. Upon arrival at 70 fsw, Red diver is ventilated for 20 seconds followed by Green diver. The divers remain at 70 fsw for the remaining 4 minutes left from their 80-fsw stop and then start their 10 minute scheduled 70-fsw stop time at the completion of the 4 minutes. Upon reaching 60 fsw, the console is shifted back to their 50/50 mixture and both divers are ventilated. The normal decompression schedule is resumed at 60 fsw.

Front 51

If symptoms of oxygen toxicity progress to an oxygen convulsion at 90-60 fsw despite the measures taken to treat for oxygen symptoms, what are your actions?

Back 51

1. Shift both divers to air if this action has not already been taken.
2. Have the unaffected diver ventilate himself and then ventilate the stricken diver.
3. If only one diver is in the water, launch the standby diver immediately and have him ventilate the stricken diver.
4. Hold the divers at depth until the tonic-clonic phase of the convulsion has subsided. The tonic-clonic phase of a convulsion generally lasts 1 to 2 minutes.
5. At the end of the tonic-clonic phase, have the dive partner or standby diver ascertain whether the diver is breathing. The presence or absence of breath sounds will also be audible over the intercom.
6. If the diver appears not to be breathing, have the dive partner or standby diver attempt to reposition the head to open the airway. Airway obstruction will be the most common reason why an unconscious diver fails to breathe.
7. If the affected diver is breathing, have the dive partner or standby diver tend the stricken diver and decompress both divers on air following the original schedule. Shift the divers to 50% helium 50% oxygen upon arrival at 50 fsw. Surface decompress upon completion of the 40-fsw water stop.
8. If it is not possible to verify that the affected diver is breathing, leave the unaffected diver at the stop to complete decompression, and surface the affected diver and the standby diver at 30 fsw/min. Shift the unaffected diver back to his 50/50 mixture for completion of decompression. The standby diver should maintain an open airway on the stricken diver during ascent. On the surface the affected diver should receive any necessary airway support and be immediately recompressed and treated for arterial gas embolism and missed decompression.

Front 52

It is very unlikely that a diver will develop symptoms of CNS oxygen toxicity while breathing 50% helium 50% oxygen at the 50- and 40-fsw water stops. If the diver does experience symptoms of CNS oxygen toxicity at 50 or 40 fsw while breathing either 50% helium 50% oxygen or 100% oxygen, what are your actions? Chamber is available.

Back 52

1. Bring the divers up 10 feet and shift to air to reduce the partial pressure of oxygen. Shift the console as the divers are traveling to the shallower stop.
2. Ventilate both divers upon arrival at the shallower stop. Ventilate the stricken diver first.
3. Remain on air at the shallower depth for double the missed time from 50- and 40-fsw water stops, then surface decompress the diver. If the diver was on 100% oxygen due to loss of 50/50, triple the missed time from the 50- and 40-fsw water stops, then surface decompress.

Example: A diver on 50% helium 50% oxygen experiences an oxygen symptom five minutes into his 10 min stop at 50 fsw. He immediately ascends to 40 fsw and begins breathing air. The decompression schedule calls for a 10 min stop at 40 fsw. The diver missed 5 min of helium-oxygen at 50 fsw and will miss 10 min more at 40 fsw by virtue of the fact that he is on air. The total missed helium-oxygen time is 15 min. The diver should remain at 40 fsw for 30 min, then surface decompress.

Example: A diver on 100% oxygen experiences an oxygen symptom five minutes into his 10 min stop at 40 fsw. He immediately ascends to 30 fsw and begins breathing air. The missed oxygen time at 40 fsw is 5 min. The diver should remain on air at 30 fsw for 15 min, then surface decompress.

Front 53

It is very unlikely that a diver will develop symptoms of CNS oxygen toxicity while breathing 50% helium 50% oxygen at the 50- and 40-fsw water stops. If the diver does experience symptoms of CNS oxygen toxicity at 50 or 40 fsw while breathing either 50% helium 50% oxygen or 100% oxygen, what are your actions? No chamber is available.

Back 53

1. Bring the divers up 10 feet and shift to air to reduce the partial pressure of oxygen. Shift the console as the divers are traveling to the shallower stop.
2. Ventilate both divers upon arrival at the shallower stop. Ventilate the stricken diver first.
3. Remain on air at the shallower depth for double the missed time from 50- and 40-fsw water stops. If the diver was on 100% oxygen due to loss of 50/50, triple the missed time from the 50- and 40-fsw water stops, then surface decompress.
4. If surface decompression is not feasible, continue decompression in the water on either air or oxygen depending on the diver’s condition:
To continue on oxygen, ascend to 30 fsw (or remain at 30 fsw if already there). Take a 10 min period on air (Time on air does not count toward decompression). Then shift the diver to oxygen and complete decompression in the water according to the schedule.
To continue on air, ascend to 30 fsw (or remain at 30 fsw if already there). Compute the remaining 30- and 20-fsw air stop times by tripling the oxygen time given in the original schedule. Surface upon completion of the 20-fsw stop.
Alternatively, the diver may complete the 30-fsw stop on air by tripling the oxygen stop time, then switch to oxygen upon arrival at 20 fsw. Remain at 20 fsw for the oxygen time indicated in the original schedule. Surface upon completion of the 20-fsw stop.

Front 54

If oxygen symptoms progress to an oxygen convulsion despite the measures taken to treat oxygen symptoms or if a convulsion occurs suddenly without warning at 50 or 40 fsw, what are your actions?

Back 54

1. Shift both divers to air if this action has not already been taken. Have the unaffected diver ventilate himself then ventilate the stricken diver.
2. If only one diver is in the water, launch the standby diver immediately and have him ventilate the stricken diver.
3. Hold the divers at depth until the tonic-clonic phase of the convulsion has subsided. The tonic-clonic phase of a convulsion generally lasts 1 to 2 minutes.
4. At the end of the tonic-clonic phase, have the dive partner or standby diver ascertain whether the diver is breathing. The presence or absence of breath sounds will also be audible over the intercom.
5. If the diver appears not to be breathing, have the dive partner or standby diver attempt to reposition the head to open the airway. Airway obstruction will be the most common reason why an unconscious diver fails to breathe.
6. If the diver is breathing, hold him at his current depth until he is stable, then take one of the following actions:
a. If the diver missed helium-oxygen or oxygen decompression time at 50 fsw, hold the diver at depth until the total elapsed time on air is at least double the missed time on helium-oxygen, then surface decompress. If the diver was on 100% oxygen in accordance due to loss of 50/50 mix, remain at depth until the total elapsed time on air is at least triple the missed time on oxygen, then surface decompress. In either case, add the 40-fsw water stop time to the 50-fsw chamber oxygen stop time.
a. If the diver did not miss any helium-oxygen or oxygen decompression time at 50 fsw, surface decompress. Add any missed oxygen or helium-oxygen time at 40 fsw to the 50-fsw chamber oxygen stop time.
7. If surface decompression is not feasible, complete decompression in the water on air. Compute the remaining stop times on air by doubling the remaining helium-oxygen time, or tripling the remaining oxygen time at each stop.
4. If the diver is not breathing, surface the diver at 30 fsw/min while maintaining an open airway. Treat the diver for arterial gas embolism.

Front 55

If the diver develops symptoms of CNS toxicity at the 30- or 20-fsw water stops, what are your actions? Chamber is available.

Back 55

If a recompression chamber is available on the dive station, initiate surface decompression. Shift the console to air during travel to the surface. Once in the chamber, take the full number of chamber oxygen periods prescribed by the tables. Unlike in air diving, no credit is allowed for time already spent on oxygen in the water.

Front 56

If the diver develops symptoms of CNS toxicity at the 30- or 20-fsw water stops, what are your actions? Chamber not is available.

Back 56

1. If a recompression chamber is not available on the dive station and the event occurs at 30 fsw, bring the divers up 10 fsw and shift to air to reduce the partial pressure of oxygen. Shift the console as the divers are traveling to 20 fsw. Ventilate both divers with air upon arrival at 20 fsw. Ventilate the affected diver first. Complete the decompression on air in the water at 20 fsw. Compute the required air time at 20 fsw by tripling the sum of the missed oxygen time at 30 and 20 fsw.
2. If a recompression chamber is not available on the dive station and the event occurs at 20 fsw, shift the console to air, ventilate both divers, affected diver first, and complete the decompression in the water at 20 fsw on air. Compute the required air time at 20 fsw by tripling the missed oxygen time at 20 fsw.

Front 57

If symptoms progress to an oxygen convulsion despite the actions taken to treat oxygen symptoms or if a convulsion occurs suddenly without warning at the 30- or 20-fsw water stops, a serious emergency has developed. What are your actions?

Back 57

1. Shift both divers to air.
2. Have the unaffected diver ventilate himself and then ventilate the stricken diver.
3. If only one diver is in the water, launch the standby diver immediately and have him ventilate the stricken diver.
4. Hold the divers at depth until the tonic-clonic phase of the convulsion has subsided. The tonic-clonic phase of a convulsion generally lasts 1 to 2 minutes.
5. At the end of the tonic-clonic phase, have the dive partner or standby diver ascertain whether the diver is breathing. The presence or absence of breath sounds will also be audible over the intercom.
6. If the diver appears not to be breathing, have the dive partner or standby diver attempt to reposition the head to open the airway. Airway obstruction will be the most common reason why an unconscious diver fails to breathe.
7. If the diver is breathing, hold him at depth until he is stable, then surface decompress.
8. If surface decompression is not feasible, ventilate both divers with air and complete decompression in the water on air. Compute the remaining stop times on air by tripling the remaining oxygen time at each stop.

Example: A diver goes off oxygen 10 minutes into the 30-fsw water stop and is switched to air. The diver’s original schedule called for 28 minutes of oxygen at 30 fsw and 50 minutes of oxygen at 20 fsw.
Eighteen minutes of oxygen time (28 - 10) remain at 30 fsw. Fifty minutes remain at 20 fsw. The diver should spend an additional 54 minutes (18 x 3) at 30 fsw on air followed by 150 minutes (50 x 3) on air at 20 fsw. Surface the diver upon completion of the 20-fsw stop.

9. If the diver is not breathing, surface the diver at 30 fsw/min while maintaining an open airway and treat the diver for arterial gas embolism.

Front 58

What are your actions for oxygen toxicity symptoms in the chamber during a mixed gas surface decompression dive?

Back 58

At the first sign of CNS oxygen toxicity, the patient should be removed from oxygen and allowed to breathe chamber air. Fifteen minutes after all symptoms have completely subsided, resume oxygen breathing at the point of interruption.

If symptoms of CNS oxygen toxicity develop again or if the first symptom is a convulsion, take the following action:
1. Remove the mask.
2. After all symptoms have completely subsided, decompress 10 feet at a rate of 1 fsw/min. For a convulsion, begin travel when the patient is fully relaxed and breathing normally.
3. Resume oxygen breathing at the shallower depth at the point of interruption.

If another oxygen symptom occurs, complete decompression on chamber air. Follow the guidance given for permanent loss of chamber oxygen supply to compute the air decompression schedule.

Multiply the remaining oxygen time by three to obtain the equivalent chamber decompression time on air. If 50% helium 50% oxygen is available, multiply the remaining oxygen time by two to obtain the equivalent chamber decompression time on 50/50. If the loss occurred at 50 or 40 fsw, allocate 10% of the equivalent air or helium-oxygen time to the 40-fsw stop, 20% to the 30-fsw stop, and 70% to the 20-fsw stop. If the diver is at 50 fsw, ascend to 40 fsw to begin the stop time. If the loss occurred at 30 fsw, allocate 30% of the equivalent air or helium-oxygen time to the 30-fsw stop and 70% to the 20-fsw stop. Round the stop times to the nearest whole minute. Surface upon completion of the 20-fsw stop.

Example: The oxygen supply to the chamber is lost 10 minutes into the first 30-minute period on oxygen. Helium-oxygen is not available. The original surface decompression schedule called for three 30-min oxygen breathing periods (total of 90 minutes of oxygen). The diver is at 50 fsw. The remaining oxygen time is 80 minutes (90-10). The equivalent chamber decompression time on air is 240 minutes (3 x 80). The 240 minutes of air stop time should be allocated as follows: Twenty-four minutes at 40 fsw (240 x 0.1), 48 minutes at 30 fsw (240 x 0.2), and 168 minutes at 20 fsw (240 x 0.7). As addressed above, the diver should ascend from 50 to 40 fsw and begin the 24 minute stop time at 40 fsw.

Front 59

If the time from leaving 40 fsw in the water to the time of arrival at 50 fsw in the chamber during surface decompression exceeds 5 minutes but less than 7 minutes, what are your actions?

Back 59

If the surface interval is less than or equal to 7 minutes, add one-half oxygen period to the total number of chamber periods required by increasing the time on oxygen at 50 fsw from 15 to 30 minutes. Ascend to 40 fsw during the subsequent air break. The 15-min penalty is considered a part of the normal surface decompression procedure, not an emergency procedure.

Front 60

If the time from leaving 40 fsw in the water to the time of arrival at 50 fsw in the chamber during surface decompression exceeds 7 minutes, what are your actions?

Back 60

If the surface interval is greater than 7 minutes, continue compression to a depth of 60 fsw. Treat the divers on Treatment Table 5 if the original schedule required 2 or fewer oxygen periods in the chamber. Treat the divers on Treatment Table 6 if the original schedule required 3 or more oxygen periods in the chamber.

On rare occasions a diver may not be able to reach 50 fsw in the chamber because of difficulty equalizing middle ear pressure during a surface decompression dive. In this situation, what are your actions?

Compress the diver to the deepest depth he can attain initially. This will usually be less than 20 fsw. Begin oxygen breathing at that depth. Once oxygen breathing has begun, attempt to gradually compress the diver to 30 fsw. If surface decompression was initiated while the diver was decompressing on oxygen in the water at 20 fsw, attempt to gradually compress the diver to 20 fsw. In either case, double the number of chamber oxygen periods indicated in the table and have the diver take these periods at whatever depth he is able to attain. Oxygen time starts when the diver initially goes on oxygen. Interrupt oxygen breathing every 60 minutes with a 15-min air break. The air break does not count toward the total oxygen time. Upon completion of the oxygen breathing periods, surface the diver at 30 fsw/min. Carefully observe the diver post-dive for the onset of decompression sickness. This “safe way out” procedure is not intended to be used in place of normal surface decompression procedures. Repetitive diving is not allowed following a dive in which the “safe way out” procedure is used.

Front 61

An omitted decompression stop deeper than 50 fsw when more than 60 minutes of decompression are missed is an extreme emergency. What are your actions?

Back 61

The diver shall be returned as rapidly as possible to the full depth of the dive or the deepest depth of which the chamber is capable, whichever is shallower. For nonsaturation systems, the diver shall be rapidly compressed on air to the depth of the dive or to 225 feet, whichever is shallower. For compressions deeper than 165 feet, remain at depth for 30 minutes. For compressions to 165 feet and shallower, remain at depth for a minimum of two hours. Decompress on USN Treatment Table 8. While deeper than 165 feet, a helium-oxygen mixture with 16 percent to 21 percent oxygen, if available, may be breathed by mask to reduce narcosis.

Front 62

What are your actions for lightheaded or dizzy diver on the bottom?

Back 62

1. Have the diver stop work and ventilate the rig.
2. Check the oxygen content of the supply gas.
These actions should eliminate hypoxia and hypercapnia as a cause.

If ventilation does not improve symptoms, the cause may be a contaminated gas supply.
1. Shift banks to the standby helium-oxygen supply and continue ventilation. Also ventilate standbys rig.
If the condition clears, isolate the contaminated bank for future analysis and abort the dive on the standby gas supply.

If the entire gas supply is suspect, place the diver on the EGS and abort the dive. Follow the procedures for loss of bottom mix.
1. Shift the diver to the emergency gas system (EGS).
2. Abort the dive.
3. Remain on the EGS until arrival at 90 fsw.
4. At 90 fsw, shift the diver to 50% helium 50% oxygen and complete the decompression as planned.
5. If the EGS becomes exhausted before 90 fsw is reached, shift the diver to air, complete decompression to 90 fsw, shift the diver to 50% helium 50% oxygen, and continue the decompression as planned.

Front 63

How will vertigo due to inner ear problems respond to ventilation?

Back 63

It will not respond and in fact may worsen. The vertigo will be accompanied by an intense sensation of spinning and marked nausea. Also, it is usually accompanied by a history of difficult clearing during the descent. One form of vertigo, however, alternobaric vertigo, may be so short lived that it will disappear during ventilation.

Front 64

When will Alternobaric vertigo usually occur?

Back 64

Just as the diver arrives on the bottom and often can be related to a difficult clearing of the ear. It would be unusual for alternobaric vertigo to occur after the diver has been on the bottom for more than a few minutes.

Front 65

If symptoms of dizziness are not cleared by ventilation and/or shifting to alternate gas supplies, what are your actions?

Back 65

Have the dive partner or standby diver assist the diver(s) and abort the dive.

Front 66

What are your actions if the diver becomes unconscious on the bottom?

Back 66

Contact a DMO!
1. Make sure that the breathing medium is adequate and that the diver is breathing. Verify manifold pressure and oxygen percentage.
2. Check the status of any other divers.
3. Have the dive partner or standby diver ventilate the afflicted diver to remove any accumulated carbon dioxide in the helmet and ensure the correct oxygen concentration.
4. If there is any reason to suspect gas contamination, shift to the standby helium-oxygen supply and ventilate both divers, ventilating the non-affected diver first.
5. When ventilation is complete, have the dive partner or standby diver ascertain whether the diver is breathing. The presence or absence of breath sounds will be audible over the intercom.
6. If the diver appears not to be breathing, the dive partner/standby diver should attempt to reposition the diver’s head to open the airway.
7. Check afflicted diver for signs of consciousness:
-If the diver has regained consciousness, allow a short period for stabilization and then abort the dive.
-If the diver remains unresponsive but is breathing, have the dive partner or standby diver move the afflicted diver to the stage. This action need not be rushed.
-If the diver appears not to be breathing, maintain an open airway while moving the diver rapidly to the stage.
8. Once the diver is on the stage, observe again briefly for the return of consciousness.
-If consciousness returns, allow a period for stabilization, then begin decompression.
-If consciousness does not return, bring the diver to the first decompression stop at a rate of 30 fsw/min (or to the surface if the diver is in a no-decompression status).
9. At the first decompression stop:
-If consciousness returns, decompress the diver on the standard decompression schedule using surface decompression.
-If the diver remains unconscious but is breathing, decompress on the standard decompression schedule using surface decompression.
-If the diver remains unconscious and breathing cannot be detected in spite of repeated attempts to position the head and open the airway, an extreme emergency exists. One must weigh the risk of catastrophic, even fatal, decompression sickness if the diver is brought to the surface, versus the risk of asphyxiation if the diver remains in the water. As a general rule, if there is any doubt about the diver’s breathing status, assume he is breathing and continue normal decompression in the water. If it is absolutely certain that the diver is not breathing, leave the unaffected diver at his first decompression stop to complete decompression and surface the affected diver at 30 fsw/minute, deploying the standby diver as required. Recompress the diver immediately and treat for omitted decompression accordingly.

Front 67

If symptoms of decompression sickness occur deeper than 30 fsw, what are your actions?

Back 67

1. Recompress the diver 10 fsw.
2. The diver may remain on 50% helium 50% oxygen during recompression from 90 to 100 fsw.
3. Remain at the deeper stop for 1.5 times the stop time called for in the decompression table. If no stop time is indicated in the table, use the next shallower stop time to make the calculation.
4. If symptoms resolve or stabilize at an acceptable level, decompress the diver to the 40-fsw water stop by multiplying each intervening stop time by 1.5 or more as needed to control the symptoms.
5. Shift to 50% helium 50% oxygen at 90 fsw if the diver is not already on this mixture.
6. Shift to 100 percent oxygen at 40 fsw and complete a 30 minute stop, then surface decompress and treat on Treatment Table 6.
7. If during this scenario, symptoms worsen to the point that it is no longer practical for the diver to remain in the water, surface the diver and follow the guidelines for treatment of decompression sickness outlined in Chapter 20.

Front 68

If symptoms of decompression sickness occur at 30 fsw or shallower, what are your actions?

Back 68

1. Remain on oxygen and recompress the diver 10 fsw.
2. Remain at the deeper stop for 30 minutes.
3. If symptoms resolve, surface decompress the diver at the end of the 30 minute period and treat on Treatment Table 6.
4. If symptoms do not resolve, but stabilize at an acceptable level, decompress the diver to the surface on oxygen by multiplying each intervening stop time by 1.5 or more as needed to control symptoms.
5. Treat on Treatment Table 6 upon reaching the surface.
6. If during this scenario symptoms worsen to the point that it is no longer practical for the diver to remain in the water, surface the diver and follow guidelines for treatment of decompression sickness outlined in Chapter 20.

Front 69

If symptoms of Type I decompression sickness occur during travel from 40 fsw to the surface during surface decompression or during the surface undress phase, what are your actions?

Back 69

1. Compress the diver to 50 fsw following normal surface decompression procedures.
2. Delay neurological exam until the diver reaches the 50-fsw stop and is on oxygen.
3. If Type I symptoms resolve during the 15-minute 50-fsw stop, the surface interval was 5 minutes or less, and no neurological signs are found, increase the oxygen time at 50 fsw from 15 to 30 minutes, then continue normal decompression for the schedule of the dive. Ascend from 50 to 40 fsw during the subsequent air break.
4. If Type I symptoms do not resolve during the 15-minute 50-fsw stop or symptoms resolve but the surface interval was greater than 5 minutes, compress the diver to 60 fsw on oxygen. Treat the diver on Treatment Table 5 if the original schedule required 2 or fewer oxygen periods in the chamber. Treat the diver on Treatment Table 6 if the original schedule required 3 or more oxygen periods in the chamber. Treatment table time starts upon arrival at 60 fsw.
5. If the neurological examination at 50 fsw is abnormal, compress the diver to 60 fsw on oxygen. Treat the diver on Treatment Table 6. Treatment table time starts upon arrival at 60 fsw.

Front 70

If symptoms of Type II decompression sickness occur during travel from 40 fsw to the surface during surface decompression or during the surface undress phase, what are your actions?

Back 70

Compress the diver to 60 fsw on oxygen. Treat the diver on Treatment Table 6. Treatment table time starts upon arrival at 60 fsw.

Front 71

True or False: Surface-supplied helium-oxygen dives can be performed at altitude.

Back 71

True

Front 72

What are the procedures for measuring water depth, obtaining the Sea Level Equivalent Depth and correcting in-water decompression stop depths for surface-supplied helium-oxygen dives while diving at altitude?

Back 72

Identical to the procedures for air diving

Front 73

Table 9-5 (Repetitive Groups Associated with Initial Ascent to Altitude) and Figure 9-15 (Diving altitude worksheet) cannot be used to correct the bottom time of a diver who is not fully equilibrated at altitude. How long must a diver wait after arrival at altitude before making the first dive.

Back 73

12 hours

Front 74

Repetitive diving is not allowed during surface-supplied helium-oxygen diving at altitude. Following a no-decompression dive, the diver must wait _____ hours before making a another dive. Following a decompression dive, the diver must wait _____ hours before making another dive.

Back 74

Following a no-decompression dive - 12 hours, Following a decompression dive - 18 hours

Front 75

What is a useful indicator of proper hydration?

Back 75

A clear colorless urine

Front 76

What is the purpose for ventilating the chamber?

Back 76

A means of controlling oxygen level, carbon dioxide level, and temperature.

Front 77

When may non-diving medical personnel be used as inside tenders?

Back 77

Non-diving medical personnel may be qualified as Inside Tenders (examples would include U.S. Naval Reserve Corpsmen, and nursing personnel). Qualifications may be achieved through Navy Diver Inside Tender PQS. Prerequisites: Current diving physical exam, conformance to Navy physical standards, and diver candidate pressure test.

Front 78

What prerequisites are required to use specialized medical care providers such as a surgeon, respiratory therapist, IDC, etc., inside the chamber during recompression therapy?

Back 78

Since these are emergency exposures, no special medical or physical prerequisites exist. A qualified Inside Tender is required inside the chamber to handle any system related requirements.

Front 79

During treatments, at what depth may all chamber occupants may breathe 100 percent oxygen without locking in additional personnel?

Back 79

45 feet or shallower

Front 80

Treatment gas is designed to keep the ppO2 between _______ and _______ ata at the treatment depth.

Back 80

1.5 and 3.0 ata

Front 81

What treatment gas should be used between 61-165 fsw treatment depth?

Back 81

50/50

Front 82

What treatment gas should be used between 166-225 fsw treatment depth?

Back 82

64/36 (HeO2 only)

Front 83

What are the symptoms of CNS oxygen toxicity?

Back 83

VENTID-C (Vision, Ears, Nausea, Twitching\Tingling, Irritability, Dizziness, Convulsions)

Front 84

What are the procedures for handling CNS oxygen toxicity symptoms in the chamber during a treatment?

Back 84

1st symptom – Off O2, 15 minutes after all symptoms have subsided, resume oxygen breathing.
2nd symptom or if the first symptom is a convulsion – Off O2, after all symptoms have completely subsided, decompress 10 feet at a rate of 1 fsw/min. For a convulsion, begin travel when the patient is fully relaxed and breathing normally. Resume oxygen breathing at the shallower depth at the point of interruption.
3rd symptom - If another oxygen symptom occurs after ascending 10 fsw, contact a Diving Medical Officer to recommend appropriate modifications to the treatment schedule.

Front 85

What are the symptoms of pulmonary oxygen toxicity?

Back 85

On Treatment Tables 4, 7, or 8 or with repeated Treatment Tables 5, 6, or 6A (especially with extensions) prolonged exposure to oxygen may result in end-inspiratory discomfort, progressing to substernal burning and severe pain on inspiration.

Front 86

If a patient who is responding well to treatment complains of substernal burning due to pulmonary oxygen toxicity, what are your actions?

Back 86

Discontinue use of oxygen and consult with a DMO.

Front 87

If a significant neurological deficit remains and improvement is continuing (or if deterioration occurs when oxygen breathing is interrupted) but the patient complains of substernal burning due to pulmonary oxygen toxicity, what are your actions?

Back 87

Oxygen breathing should be continued as long as considered beneficial or until pain limits inspiration. If oxygen breathing must be continued beyond the period of substernal burning, or if the 2-hour air breaks on Treatment Tables 4, 7, or 8 cannot be used because of deterioration upon the discontinuance of oxygen, the oxygen breathing periods should be changed to 20 minutes on oxygen, followed by 10 minutes breathing chamber air or alternative treatment gas mixtures with a lower percentage of oxygen should be considered. The Diving Medical Officer may tailor the above guidelines to suit individual patient response to treatment.

Front 88

What are your actions for a loss of O2 in the chamber during a treatment?

Back 88

If repair can be completed within 15 minutes:
1. Maintain depth until repair is completed.
2. After O2 is restored, resume treatment at point of interruption.

If repair can be completed after 15 minutes but before 2 hours:
3. Maintain depth until repair is completed.
4. After O2 is restored: If original table was Table 5, 6, or 6A, complete treatment with maximum number of O2 extensions.

If O2 breathing cannot be restored in 2 hours switch to the 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 symptoms worsen and an increase in treatment depth deeper than 60 feet is needed, use Treatment Table 4.

Front 89

Tenders on Treatment Tables 5, 6, 6A, 1A, 2A, or 3 should have a minimum of a ______ hour surface interval before no-decompression diving and a minimum of a ______ hour surface interval before dives requiring decompression stops.

Back 89

18 hour before no-decompression diving
24 hour before dives requiring decompression stops

Front 90

Tenders on Treatment Tables 4, 7, and 8 should have a minimum of a _______ hour surface interval prior to diving.

Back 90

48 hour

Front 91

After a treatment, patients treated on a Treatment Table 5 should remain at the recompression chamber facility for ____________. 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 ________. 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 _______________. All patients should remain within _____________ travel time of a recompression facility for 24 hours and should be accompanied throughout that period.

Back 91

2 hours, 6 hours, 30 minutes, 60 minutes

Front 92

After completing treatments, inside tenders should remain in the vicinity of the recompression chamber for __________.

Back 92

1 hour

Front 93

What is the tender O2 breathing requirements for a TT-5?

Back 93

Tender breathes 100 percent O2 during ascent from the 30-foot stop to the surface. If the tender had a yprevious hyperbaric exposure in the previous 18 hours, an additional 20 minutes of oxygen breathing is required prior to ascent.

Front 94

What are the tender O2 breathing requirements for a TT-6?

Back 94

Tender breathes 100 percent O2 during the last 30 min. 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 feet. If there has been more than one extension, the O2 breathing at 30 feet is increased to 60 minutes. If the tender had a hyperbaric exposure within the past 18 hours an additional 60-minute O2 period is taken at 30 feet.

Front 95

What are the tender O2 breathing requirements for a TT-6A?

Back 95

Tender 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 18 hours, an additional 60 minute O2 breathing period is taken at 30 fsw.

Front 96

What are the tender O2 breathing requirements for a TT-9?

Back 96

Tender breathes 100 percent O2 during last 15 minutes at 45 feet and during ascent to the surface regardless of ascent rate used.

Front 97

What are the rules for flying after treatment tables for patients and tenders?

Back 97

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.
Tenders on Treatment Tables 5, 6, 6A, 1A, 2A, or 3 should have a 24-hour surface interval before flying. Tenders on Treatment Tables 4, 7, and 8 should not fly for 72 hours.

Front 98

For persistent Type II symptoms, daily treatment on Table ______ may be used, but twice-daily treatments on Treatment Tables _____ or _____ may also be used.

Back 98

6, 5 or 9

Front 99

Divers diagnosed with AGE or Type II DCS may be medically cleared to return to diving duty ______ days after initial diagnosis and treatment by a DMO, if initial hyperbaric treatment is successful and no neurologic deficits persist.

Back 99

30 days

Front 100

Impending natural disasters or mechanical failures may force the treatment to be aborted. For instance, the ship where the chamber is located may be in imminent danger of sinking or a fire or explosion may have severely damaged the chamber system to such an extent that completing the treatment is impossible. In these cases, the abort procedure for death of a patient could be used for all chamber occupants (including the stricken diver) if time is available. If time is not available, what procedure may be taken?

Back 100

1. If deeper than 60 feet, go immediately to 60 feet.
2. Once the chamber is 60 feet or shallower, put all chamber occupants on continuous 100 percent oxygen. Select the Air/Oxygen schedule in the Air Decompression Table corresponding to the maximum depth attained during treatment and the total elapsed time since treatment began.
3. If at 60 fsw, breathe oxygen for period of time equal to the sum of all the decompression stops 60 fsw and deeper in the Air/Oxygen schedule, then continue decompression on the Air/Oxygen schedule, breathing oxygen continuously. If shallower than 60 fsw, breathe oxygen for a period of time equal to the sum of all the decompression stops deeper than the divers current depth, then continue decompression on the Air/Oxygen schedule, breathing oxygen continuously. Complete as much of the Air/Oxygen schedule as possible.
4. When no more time is available, bring all chamber occupants to the surface (try not to exceed 10 feet per minute) and keep them on 100 percent oxygen during evacuation, if possible.
5. Immediately evacuate all chamber occupants to the nearest recompression facility and treat according to Figure 20?1 (Treatment for AGE or Type II DCS). If no symptoms occurred after the treatment was aborted, follow Treatment Table 6.

Front 101

In general, what type of equipment is in the primary medical kit?

Back 101

Diagnostic and therapeutic equipment that is available immediately when required. This kit shall be inside the chamber during all treatments.

Front 102

In general, what type of equipment is in the secondary medical kit?

Back 102

The secondary emergency kit contains equipment and medicine that does not need to be available immediately, but can be locked-in when required. This kit shall be stored in the vicinity of the chamber.

Front 103

Which commands shall maintain those drugs recommended by the American Heart Association for ACLS?

Back 103

All commands with chambers that participate in area bends watch

Front 104

How often are the primary and secondary medical kits inventoried?

Back 104

Each time the kit is opened, it shall be inventoried and each item checked for proper working order and then re-sterilized or replaced as necessary. Unopened kits are inventoried quarterly.

Front 105

How many times may a Treatment Table 5 be extended?

Back 105

Treatment Table 5 may be extended two oxygen-breathing periods at 30 fsw.

Front 106

How many times may a Treatment Table 6 be extended?

Back 106

Treatment Table 6 may be extended up to four additional oxygen-breathing periods, two at 30 feet and/or two at 60 feet.

Front 107

How many times may a Treatment Table 6A be extended?

Back 107

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.

Front 108

You have a patient who has a reoccurrence of symptoms upon arrival at 30 fsw on a TT-5. What are your actions?

Back 108

Recompress to 60 fsw and complete three 20 min. oxygen breathing periods and come out on a TT-6 with extensions if needed

Front 109

You have a patient who has a reoccurrence of symptoms at 60 fsw or deeper in the chamber. What are your actions?

Back 109

If deeper recompression is not needed, continue and/or extend current table. If deeper recompression is needed, compress to depth of relief (165 feet maximum) with patient off O2 and remain at depth :30 min. on air or treatment gas if available. If no more time is needed at depth enter a TT-6A and decompress accordingly