#3 Deep Diving

Nitrox's effect of nitrogen in body

EANx decreases the residual nitrogen you accumulate, making repetitive dives longer

DCS signs

Favoring an arm or leg, or rubbing a joint Paralysis Unconsciousness Staggering Collapse Coughing spasms Blotchy skin rash

A(n) ______________ allows me to mount two independent regulators on a single cylinder.

H valve

what can elevate CO2 in the body, contributing to narcosis

Hard work overexertion improper breathing

My buddy and I descend to 6 metres/20 feet, where I notice I'm having trouble remembering what we're supposed to do, and also feel anxious. Are these likely the effects of gas narcosis?

No

DCS Symptoms

Pain, often in the limbs and also often (but not necessarily) in the joints. The pain can change location and intensity over time. Numbness, tingling or paralysis Unusual fatigue or weakness Skin itch Shortness of breath Dizziness and vertigo

longer no stop times. (T/F)

True

Just before tying the bowline as described in Question 2, my buddy had to work hard flipping over a 10 kg/25 lb anchor so we could attach the line. Could this have contributed to narcosis?

Yes

on a deep dive to 29 metres/97 feet, I notice my buddy having difficulty tying a bowline, a knot my buddy knows well. Is this likely a sign of narcosis?

Yes

After a dive, I find I accidentally exceeded no stop limits, and my computers say I missed five minutes of emergency decompression. I should

alert my buddy, breathe oxygen and monitor for DCS symptoms.

Which of the following factors are thought to increase the risk of DCS? (Choose all that apply.) Dehydration Poor fitness Injuries/illness Altitude Carbon dioxide increase Gas narcosis

all but gas narcosis

I'm planning a deep dive that I will limit to the recommended optimal depth of 30 meters/100 feet. This is recommended because

allowable dive time deeper is short most divers start to find narcosis noticeable at the depth light and temperature may

My buddy and I are at 33 metres/110 feet. I feel intoxicated and notice I have trouble concentrating when I try to read my computer. To alleviate this, I should

ascend to a shallower depth until symptoms/signs subside

When do most cases of DCS occue

at the surface within one to two hours of the dive, though it can occur underwater at a shallow depth, or can be delayed as long as 48 hours.

The habit that reduces the risk of running out of gas is to...

check my SPG frequently

The primary reason divers get decompression sickness is

diver error

certain drugs can make narcosis occur shallower...

drugs that cause drowsiness including tranquilizers barbiturates sleeping pills some decongestants alcohol

After a dive, a diver has suspected DCS signs and symptoms. The diver is breathing and fully responsive. We should assist the diver by providing emergency oxygen, contacting emergency medical care and having the diver sit comfortably until help arrives. (t/f)

false

I should wear less weight on a deep dive than I would on a shallower dive. (t/f)

false

Whether gear is optimal relates to...

features that give it superior performance at deeper depths

Composition of Nitrox (EANx) and its benefits

increased proportion of oxygen and a decreased proportion of nitrogen can benefit deep dives because you have significantly longer no stop times - the higher the oxygen and the lower the nitrogen, the more no stop time at a given depth

causes of anxiety underwater

low vis cold darkness

Making a safety stop, I want the stop depth to be about ____________ level.

midchest

My buddy and I descend on a deep dive, adjusting our buoyancy as we go. Ideally, we should arrive at the bottom __________ buoyant.

neutrally

Determine your psi per minute surface rate with this formula:

psi used/actual bottom time x conversion factor = surface air consumption rate

Optimal equipment for deep diving refers to which 3 pieces

regulator, alternate air source and cylinder

As PADI Deep Divers, my buddy and I make a dive to 37 metres/120 feet. Looking at my dive computer, I find I'm having trouble understanding everything it's telling me. I should...

signal my buddy and ascend together.

A ____________ extra gas supply has the advantages of being available to multiple buddy teams and the possibility of a higher capacity.

staged

Rather than adequate, you need to consider whether your gear is....

suitable and optimal for deep diving

You can ensure equipment suitability by

taking care of your gear, by inspecting and checking it before diving, and by not diving with anything that isn't or doesn't seem to be working properly. Have all the gear required by the local environment.

Gas narcosis

the narcotic property that results from breathing air or enriched air nitrox under pressure

A head-above-feet descent helps me maintain my orientation on a deep dive. (t/f)

true

An audible ascent rate alarm on my computer can help me monitor my ascent rate without looking at it (t/f)

true

My buddy and I are planning a deep dive and will stay well within limits at all times. This should help reduce our DCS risk. (t/f)

true

One reason I don't put a diver with suspected DCS back in the water for recompression is that recompression takes hours - far longer than a diver can endure, even in reasonably warm water, without special equipment. (t/f)

true

T/F My personal depth limit depends upon conditions, or even how I feel that day.

true

Whether your gear is suitable relates primarily to...

whether it is in good working order and appropriate for the local environment

After a dive, a diver complains of feeling unusually fatigued and weak, and says there's marked pain in the knee. Are these possible DCS symptoms?

yes

Drawback to Nitrox

you have to manage oxygen exposure - the higher the oxygen content, the shallower the maximum useable depth For example, diving with EANx32 (32 percent oxygen), the maximum depth is 33 metres/110 feet. With EANx36 (36 percent oxygen), it's 28 meters/95 feet Enriched air also has special considerations related to equipment, cylinder markings and analyzing your gas.

Factors for personal depth limit

-Environmental conditions (e.g., a cold, low-visibility quarry versus a warm, clear, tropical wall) -Your physical and mental state. You should be healthy and may feel challenged, but should not have undue anxiety or lack confidence in your ability to make the dive safely. -Previous dives. You should have ample no stop time for the planned depth so you don't push your limits. If using enriched air nitrox, you also need to pay attention to oxygen exposure limits (learn about these in the PADI Enriched Air Diver course). -Time/distance to emergency assistance, proper first aid resources and medical treatment. The longer it would take to reach these, the shallower and more conservative you'll want to plan your dive. -Your dive buddy's training and experience. Plan the dive within the limits of the diver with the least training/experience.

Signs (What You See in Another Diver) Include:

-Inappropriate behaviors that are not normal for the diver -Short attention span, slowed thinking, trouble understanding computer or hand signals -Impaired vigilance and a disregard for safety -Stupor and semi-consciousness -Failure to follow the dive plan

Symptoms (What You Feel) of Narcosis Include:

-Rigid, inflexible thinking and difficulty concentrating (being unable to adapt to unexpected conditions) -Loss of good judgment and a false sense of security Short-term memory loss -Lack of concern for a specific task or personal safety -Unjustified elation -Drowsiness or feeling intoxicated -Anxiety

While deep diving to 27 metres/90 feet, and while diving to any depth, I make a point of breathing slowly and deeply from my diaphragm/abdomen because it...

-helps me relax -is the most efficient way to breathe -use less energy

My buddy and I are making a deep dive along a wall. We should stay....

... close to the wall

Descending into deep water without a reference to follow, it helps if my buddy and I descend....

... so we can see each other

While ascending along a line, my buddy needs help to adjust a loose weight system. I need both hands to provide it, and it will take a couple of minutes. Probably the best method for stopping on the line would be to...

... wrap my leg around it

How long should you wait after losing your buddy to surface

1 minute

sing the RDP, follow these procedures if you accidentally exceed no stop limits

1. If you exceed the no stop (no decompression) limit by no more than five minutes, make an eight-minute stop at 5 metres/15 feet. Do not dive again for at least six hours. 2. If you exceed the no stop (no decompression) limit by more than five minutes, make a stop at 5 metres/15 feet for at least 15 minutes (gas supply allowing) and do not dive for at least 24 hours.

High-performance second stages include...

1. balanced adjustable models 2. Venturi-assisted models 3. pilot-valve second stages

I'm leading the buddy team on a deep dive. I should

1. check with my buddy frequently. 2. swim slowly. 3. stay within two seconds of my buddy. 4. use touch contact in poor visibility.

factors thought to predispose a diver to DCS

1. dehydration 2. excess fat and poorfitness 3. age 4. heavy exertion immidiately before, during, or after deep dive 5. Injuries or illness 6. alcogol use 7. cold water 8. hot showers or baths immidiately after a dive 9. CO2 disease 10. exposure to altitude

factors that raise your breathing rate

1. excitement 2. activity 3. cold

Alternate air sources

1. extra second stage 2. H valve 3. pony bottle 4. side mounting 5. dual outlet valves

Decents without a reference practices

1. maintain a head above feet position 2. maintain buddy visual 3. watch your dive computer 4. don't go faster than your computer (60ft/min)

DCI First Aid and Treatment

1. oxygen 2. cpr if needed 3. recovery position left side down 4. contact local EMS

Equipment for deep diving

1. reference line 2. Dive light 3. First Aid and emergency oxygen 4. extra gas supply 5. extra weights

When swimming on a wall remember...

1. watch your depth 2. stay near the wall 3. avoid contact with wall 4. if a current occurs put air in BC and swim away from wall and adjust your bouyancy

A recreational deep dive is defined as a dive deeper than _______ to a maximum of __________.

18m/60ft ; 40m/130ft

Most divers feel narcosis at what depth

30m/100ft

Max for recreational dive depth

40m/130ft though 100ft is recommended