Aeromed (3-04.93) Flashcards
The four types of hypoxia are (2-64)
Hypoxic
Hypemic
Histotoxic
Stagnant
Hypoxic hypoxia is caused by (2-65)
Low FiO2 (low partial pressure of oxygen)
Hypoxic hypoxia generally occurs at altitudes greater than (2-70)
10000’ MSL
Hypemic hypoxia is caused by (2-66)
Decreased oxygen carrying capacity of blood (anemia, hypovolemia, CO poisoning, nitrites)
Stagnant hypoxia is caused by (2-67)
Inadequate circulation of blood (cardiogenic shock, vasodilation, high G forces)
Histotoxic hypoxia is caused by (2-68)
Inability of cells to utilize oxygen (CN/CO, alcohol, narcotics)
Susceptibility to hypoxia is affected by (2-71)
Diet and nutrition Physical fitness Ascent rate Duration of exposure Ambient Temperature
The system most affected by hypoxia is (2-72)
Nervous system (i.e. brain)
The four stages of hypoxic hypoxia are (2-74)
Indifferent
Compensatory
Disturbance
Critical
The indifferent stage of hypoxia is characterized by (SpO2, altitude, symptoms) (2-74)
> 90%
<10000’
Tachycardia, tachypnea
The compensatory stage of hypoxia is characterized by (SpO2, altitude, symptoms) (2-74)
80-90%
10000-15000’ ASL
Drowsy, impaired fine motor ability, poor judgement
The disturbance stage of hypoxia is characterized by (SpO2, altitude, symptoms) (2-74)
70-80%
15000-20000’ ASL
Impaired speech, vision, gross motor ability, memory; reduced pain sensation
The critical stage of hypoxia is characterized by (SpO2, altitude, symptoms) (2-74)
<70%
20000’
Seizures, unconsciousness, cardiac arrest
Supplemental oxygen is recommended for night flight above what altitude? (2-82)
4000’ ASL
Hyperventilation is defined as (2-85)
Excessive rate and depth of ventilation resulting in reduced PaCO2
Hyperventilation in an aviation setting is usually caused by (2-86)
Hypoxia (Anxiety)
Signs of hyperventilation (reduced PaCO2) include (2-92)
Dizziness
Carpal-pedal spasms and paresthesia
Visual imparement
Trapped gas disorders can cause what symptoms? (2-101)
Toothache
Earache
Abdominal Pain
Sinus pressure
Boyle’s Law is the relationship between
Volume and pressure of a gas; as pressure decreases, volume increases (P = 1/V)
The volume of a gas doubles at approximately what altitude? (2-103)
15000’ ASL
How do you reduce the chance for abdominal pain from a trapped gas disorder? (2-106)
Maintain healthy eating habits
Avoid risky foods prior to flight (onion, apples, cabbage, beans, cucumbers, melons)
Relieving abdominal pain from a trapped gas disorder may include (2-107)
Passing gas
Abdominal percussion
Reducing altitude
Relieving ear pain from a trapped gas disorder may include (2-114)
Yawning, jaw opening/closing Chewing gum (not recommended during flight) Valsalva (do not perform on ascent)
Ear pain from a trapped gas disorder is called ___, and usually occurs when? (2-109)
Barotitis media
Descent
Treatment of sinus pain from a trapped gas disorder may include (2-119)
Forceful valsalva
Slower rate of descent
Ascent to clear sinuses
Tooth pain from a trapped gas disorder is called __, and usually occurs where? (2-120)
Barodontalgia
>5000’ ASL
Henry’s law states (2-122)
The amount of gas dissolved in a liquid is proportional to the pressure of the gas above the liquid.
Decompression sickness (DCS) is attributed to what gas (2-124)
Nitrogen
What factors influence the development of decompression sickness when flying? (2-126)
Rate of ascent
Altitude
Duration of Exposure
Physical exertion
What are the two common names for the different types of decompression sickness? (2-130)
The bends and the chokes
What symptoms are associated with the bends? (Tab 2-130)
Joint pain
Paresthesias
What symptoms are associated with the chokes? (2-130)
Sharp or burning sensation in chest
“Feeling of running a sprint to exhaustion”
Sensation of suffocation
Blurry vision, Headache, Unilateral paresthesia/weakness
The chokes may resemble what two disease processes? (2-130)
Pulmonary Embolism
Stroke
Describe the 4 methods that can limit the development of decompression sickness? (2-131)
Denitrogenation (100% FiO2 for 30 min = 30% loss) Cabin Pressurization (to between 8000-10000') Limit time at altitude Aircrew restrictions (no flight within 24h after SCUBA)
Treatment for decompression sickness includes (2-136)
Immediate landing
High FiO2
Report to MO or transport to definitive care
Hyperbaric chamber (if symptoms persist)
Decompression sickness can be delayed by as many as __ hours (2-137)
48
What is stress? (3-2)
A psychological condition resulting in 1) a change in body chemistry and function, 2) a perceived or actual demand for action
The four types of stressors are (3-3)
Psychosocial (life events)
Environmental
Physiological (self-imposed)
Cognitive (mental)
The acronym for the physiological stressors is (3-17)
D rugs (dehydration) E xhaustion A lcohol T obacco H ypoglycemia
The four types of stress responses are (3-43)
Emotional
Behavioral
Cognitive
Physical
The 24 hour sleep/wake cycle is called the (3-75)
Circadian Rhythm
You should not sleep more than __ hours at a time when recovering from sleep deprivation (3-98)
10
During high tempo work periods, the best way to avoid fatigue is (3-95)
Taking naps
Soldiers should sleep a minimum of __ hours per day for continuous operations (3.84)
5
The two types of photoreceptors in the eyes are (8-6)
Rods and Cones
Rods are used for __ vision, use the chemical __, and are located where on the retina (8-6)
Night or low-intensity light, rhodopsin, peripheray
Cones are used for __ vision, use the chemical __, and are located where on the retina (8-6)
Day or high-intensity light, iodopsin, center
Night vision requires a build-up of the chemical __, which takes approximately __ minutes (8-10)
Rhodopsin, 30-45 minutes
The three types of vision are (8-12)
Photopic
Mesopic
Scotopic
Define photopic vision (8-13)
Occurs in bright light
Uses cones only (rods bleached)
Allows sharp, colorful, high-contrast images
Define mesopic vision (8-14)
Occurs at dawn, dusk, and full moonlight
Uses rods and cones
Reduces color vision and visual acuity
Define scotopic vision (8-15)
Occurs at night with poor illumination
Uses rods only
Decreased visual acuity
Scotopic vision requires the use of peripheral vision because (8-17)
Rods are located less in the center of the retina and more on the peripheray
Explain the five major visual deficiencies (8- 19-23)
Myopia (nearsightedness) Hyperopia (farsightedness) Astigmatism (unequal curvature of lens) Presbyopia (Hardening of the lens, causes cataracts) Cataracts (cloudy lenses)
Any surgery to correct visual deficiencies results in automatic __ (8-27)
Disqualification from flight duty (may be temporary or permanent)
To best see objects at night, you should use __ vision, and look at an object no longer than __ (8-47,49)
Off-center (look 10 deg above/below/side of object)
3 seconds per position
The halo effect, observed around lights, indicates ___ (8-75)
High humidity and possibility of ground fog
One ounce of alcohol (one drink) causes the equivalent physiological effect as an altitude of __ (8-83)
2000’
Resuming crew member duties after consuming alcohol has what two requirements? (8-84)
At least 12 hours since last drink
No residual effects (hangover)
Alcohol causes what type of hypoxia? (8-83)
Histotoxic
Smoking causes what type of hypoxia? Due to? (8-86)
Hypemic, CO
A one pack/day smoker has their night vision reduced by __%, or the equivalent of what altitude? (8-86)
20%, 4000’
The army regulation regarding aeromedical is
3-04.93
