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25 Cards in this Set
- Front
- Back
CNS O2 toxicity is not likely to occur at partial pressures below _____
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1.3 ATA
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What are the causes of CNS O2 Toxicity
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1. Increased ppo2 with depth change
2.Increased exposure time 3.stress from exercise 4.CO2 build up 5.individual susceptablity |
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What is the clearest warning sign of CNS o2 Tox.
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twitching
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What piece of equipment is essential for safe closed circuit diving
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buddy lines
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where should you position yourself when dealing with a convulsing diver
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behind the diver
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when is the diver at the greatest risk of getting hypoxia
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on the surface
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What is the primary cause of hypoxia in the Mk 25
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inadequate/incorrect purge of the breathing bag.
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How are chemical injuries best prevented.
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by prefoming a careful dip test during pre dive set up
preforming a leak check before leaving the surface |
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What is middle ear oxygen absorbtion syndrome?
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negative pressure that develops in the middle ear following a long O2 dive
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Symptoms of middle ear O2 absorbtion syndrome.
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1.sense of pressure or mild discomfort in bolth ears
2.muffled hearing 3.moist crackling sensation in the ears |
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What are the single-depth oxygen exposure limits?
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Normal: 25 fsw for 240 min
30 fsw for 80 min 35 fsw for 25 min 40 fsw for 15 min Max: 50 fsw for 10 min no excursion allowed when using single depth diving limits |
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Operational considerations
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minimum manning 5
chase boat buddy diver required |
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Is heavy work recommended for the Mk 25
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no
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What is the average gas consumption for MK 25
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over bottom= 50 psi(3.4 bar)
gas consumption (normal) 15-17 psi per min |
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Canister duration is dependant on.
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water temp
exercise rate mesh size of absorbent |
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What type of canister is sofnolime 8-12 only approved for use in?
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urethane canister
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What are the limits for downward excursions when using the transit with excursion limits
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21-40 fsw=15 minutes
41-50 fsw= 5 minutes |
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Are downward excursions allowed using single depth limits?
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No
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What is a off oxygen interval
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The time a diver stops breathing O2 on one dive to the time a diver stars breathing O2 on a second dive
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Which direction does the gas breathing loop flow on the re breather
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clockwise
inhalation on the left exhalation on the right |
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What is a sucessive oxygen dive
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one that follows a previous o2 dive after a off o2 interval of less than 2 hours
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when would you not have to adjust for off oxygen exposure limits
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if the off oxygen interval is greater than 2 hours
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What is the maximum o2 time permitted with in 24 hours
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4 hours (240 mins) max o2 time
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The mixed gas to oxygen rule states that if a diver made a previous dive with a breathing gas of ___ ata or greater the previous exposure must be treated as a closed circuit O2 dive
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1.0 ata or greater
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what is the rule for flying after closed circuit o2 diving
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flying is permitted after diving unless it was after a multiple uba profile
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