Part 2 Flashcards
Which factor likely increases the cold stress experienced in an individual immersed in cold water?
Low body mass-to-surface area ratio.
❝A person with a low body mass-to-surface area ratio would probably be described as an ectomorph, one with a relatively long and lean form relative to mass. Such a form favors heat loss, as does relatively small total body mass, minimal skinfold thickness and the reduced mass/blood volume associated with relative dehydration.❞
What is the recommended frequency for adult tetanus boosters?
Every 10 years, once the individual has been adequately immunized.
❝However, at the time of an injury, if it has been 5 years or more since receiving the vaccine a booster may be recommended. It is not harmful to have the vaccine administered in less than 10 years and can further reduce the risk of developing tetanus.❞
When Heat flow is mediated by circulation currents in any gas or liquid, what is this known as?
Convection
❝The still liquid or gas surrounding a warm body will not remain still as it is warmed; it will become less dense and begin to rise, creating a convection current bringing cooler liquid or gas in contact with the skin. Convective heat loss is minimized by isolating the microclimate around the skin from surrounding environmental liquid or gas.❞
Is respiratory heat loss increased when breathing from compressed gas sources underwater?
Yes.
❝Gas cools as it expands through the process of being drawn out of a compressed gas cylinder. The increase in heat loss through respiratory warming of breathing gas is small during most recreational diving but increases dramatically in the deep diving range. Inspired gas is typically warmed during deep, commercial diving operations.❞
Can the ciguatera toxin that is found in predatory reef fish be eliminated by thorough cooking?
No.
❝ Ciguatoxin poisoning is one of the few foodborne illnesses that cannot be mitigated by proper handling or thorough cooking. Don’t forget that ciguatera toxin does not affect the texture, taste, or smell of fish, and they are not destroyed by gastric acid, cooking, smoking or freezing.❞
Is an Insect repellent with greater than 50% DEET more effective than those containing lower concentrations.
No.
❝The effectiveness of DEET plateaus at a concentration of 50%. Higher concentrations don’t seem to provide additional protection.❞
The Titan Triggerfish (Balistoides viridescens), from the Indo-Pacific, can inflict severe bite wound. When are they considered most aggressive?
When building and guarding an egg nest.
Where is the tympanic membrane found?
At the inner end of the ear canal, separating the external ear from the middle ear.
❝The tympanic membrane is more commonly known as the eardrum.❞
Is a wetsuit working best when it allows a thin layer of water between the neoprene and the skin surface?
No.
❝It is a common misconception that the insulation layer under a wetsuit is increased by trapping a thin layer of water. If some water is allowed in, continuous circulation usually results in additional thermal stress. The warmest wetsuit would fit snugly enough to eliminate water entrance without significantly restricting superficial blood circulation. A comfortably fitting wetsuit under which dry spots can be found post-dive is probably the best case possible❞
What connects the middle ears to the back of the throat (nasopharynx). And helps to equalize the middle ear?
The Eustachian tubes, one in each ear, connect the middle ear and the back of the throat (nasopharynx).
❝They keep the middle ear “equalized” by keeping the air pressure on both sides of the eardrum the same. Because they are surrounded by cartilaginous tissue they don’t allow for expansion. Therefore a diver must equalize his or her ears by gently “opening” the tubes—that is, by introducing air through them and into the middle ear.❞
If you surface with a feeling of fullness in your ears or hear crackling sounds, you should?
Discontinue diving and seek a medical evaluation.
What is the most common contributor to a reverse block?
Difficulty equalizing on the descent or congestion.
Do dive computers that display water temperature consider the diver’s thermal stress in decompression computation?
No.
❝The water temperature may have very little relation to the thermal stress of the diver. Think about a diver conducting the same dive in a thin wetsuit, a thicker wetsuit or a drysuit with extreme protection undergarments. The gauge measurement of water temperature would have little relation to what would be experienced. There are currently no dive computers that monitor real-time thermal stress or mathematical algorithms to translate such monitoring data into meaningful decompression schedule adjustments.❞
A diver surfaces with these signs and symptoms, shortness of breath or the sensation of not getting enough air while at depth, These symptoms start before ascent, on the surface they start coughing up pink, frothy sputum and have noisy breathing that can be heard without a stethoscope.
The diver has immersion pulmonary edema (IPE), or pulmonary edema of diving.
❝This occurs when a diver or surface swimmer experiences an accumulation of fluid in the lungs❞
Symptoms of vertigo that persist for more than several minutes are most likely a sign of?
Inner-ear barotrauma.
❝Inner-ear barotrauma is a pressure injury to the inner-ear structures, which may or may not involve perforation (perilymph fistula) of the round or oval window. Perforation of these delicate structures is a serious injury and requires medical attention. Divers may experience prolonged severe vertigo, hearing loss and tinnitus. Symptoms of vertigo that last more than several minutes could also be a sign of inner-ear decompression sickness (IEDCS). IEDCS may also present with similar symptoms and requires medical attention.❞
