Lecture 4/15 - Extreme Conditions Flashcards

Final (48 cards)

1
Q

Tightening the vocal cords = _____ pitched voice

A

Higher

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2
Q

Loosening the vocal cords = ______ pitched voice

A

Lower

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3
Q

What is the definition of atmospheric pressure?

A

The result of gravity (keeping the atmosphere attached to planet) & weight of the atmosphere between us and outer space

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4
Q

In outer space, the atmospheric pressure is _____ mmHg

A

0 mmHg

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5
Q

The highest altitude on earth is ______ which is on _______. What is the barometric pressure here? Inspired PO2?

A

9000 m (9 Km)

The summit of Mount Everest

PB = 253 mmHg

PIO2 = 43 mmHg

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6
Q

T/F: The concentration of oxygen in the atmosphere doesn’t change when you’re close to outer space.

A

False

ONLY changes when close to outer space

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7
Q

How does decreasing your barometric pressure affect oxygen?

A

Decrease PB → less pressure available to push gas into lungs

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8
Q

What is the inspired partial pressure of O₂ at the summit of Mount Everest?

What is the normal inspired PP of O₂?

What does this mean?

A

PPgas = [gas concentration] x (PB - 47 mmHg)

[0.21] x (253 mmHg - 47 mmHg) = 43.26 mmHg → 43 mmHg

Normal = 150 mmHg

Lower pressure to push O₂ into lungs is causing the low inspired PP O₂ → low arterial PO₂ (also low alveolar PO₂)

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9
Q

How do people generally climb Mount Everest?

A

Can only tolerate low PO₂ of 43 mmHg for a couple of hours

Climbers try to reach Summit ASAP → spend a few minutes there → come back down

They stop at base camps to allow body to adapt to low O₂ while going up the mountain

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10
Q

How does breathing change at high altitudes?

A

You will feel out of breath and hyperventilate to compensate.

The body will accommodate after a few days and ventilation will normalize.

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11
Q

Besides the lungs, what organ is affected by low PO₂ due to going to high altitudes?

What effects does this have on the body?

A

Kidney

Less oxygen is being delivered to the kidney → kidneys O₂ sensors in the deep medulla sense this → increases EPO production → increases Hb/Hct

Increase in Hb/Hct helps w/O₂ delivery through body

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12
Q

How is your respiratory system different if you were born at a high altitude? How is this beneficial?

A

More surface area = more alveoli = increased gas exchange in lungs

People born at high altitudes will have much better/longer endurance because increased ability for gas exchange dt increased surface area in their lungs

Examples: Kenya, Ethiopia

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13
Q

The limiting factor for every day activities, including sports, is the ______.

A

Heart → cardiac output

(not the lungs)

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14
Q

We have _____ more lung area than we need. How is this beneficial?

A

3x

This is a safety factor to help us cope with short term damage. It makes it manageable. (ex. smoking)

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15
Q

The lowest altitude on in North America is ______. The atmospheric pressure is _______.

A

Death Valley

Increased

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16
Q

How does diving underwater affect atmospheric pressure?

A

Water is heavy → greatly increases pressure along with decreased altitude, which increases pressure as well

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17
Q

At 500 ft underwater, barometric pressure is ____ that of sea level. What is this equal to in torr?

A

16x

(16) x (760 torr) = 12,160 torr

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18
Q

At a PB of 5000 mmHg the inspired O₂ partial pressure is ______

A

1044 mmHg → about 10x normal

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19
Q

What are scuba tanks filled with?

Why is this a concern when scuba diving?

A

Filled with atmospheric gas → 79% N₂ & 21% O₂

Increased PB with diving → extremely high inspired nitrogen partial pressure almost 4000 mmHg

Nitrogen is insoluble and at high pressures, N₂ will dissolve in blood

Concerns:
- Mental status
- Air embolism when decompressing/resurfacing too quickly

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20
Q

Why don’t they fill scuba tanks with 100% oxygen? Is 100% oxygen in scuba tanks a standard practice?

A

It’s more expensive.
- Higher risk of explosion/fires
- Oxygen toxicity

This is NOT the standard. Atmospheric air with nitrogen is standard.

21
Q

What is the biggest concern with scuba diving? Explain. What can prevent this?

A

Rapidly resurfacing → sudden changes in nitrogen pressure in the body

relatively insoluble nitrogen that was compressed/dissolved into blood when deep under water → When rapidly resurfacing Nitrogen comes out of solution/blood in the form of gas/airair emboli form in circulatory system

Prevention:
- Gradual ascending
- Hyperbaric chamber
- Don’t include nitrogen in the tank

22
Q

An air embolism in the _____ coronary artery is more fatal. Why?

A

Left

Remember L coronary supplies BB leading to the ventricles. Both can be fatal but L is wayyyy worse. You will probably die.

23
Q

What are some places where an air embolism can be fatal?

A

L (or R) coronary artery (heart)

Carotid artery (brain)

Pulmonary artery (lung)

24
Q

What is the purpose of a hyperbaric chamber?

A

Returns body to a high pressure environment after diving
- allows gradual release of nitrogen to prevent sudden formation of air emboli

25
What is "rapid decompression"? This is also termed as ________
This term is used to describe dissolved (pressurized) nitrogen in the blood coming out of blood in the form of gas/air. This is usually due to coming from a highly pressurized area to a less pressurized area quickly while breathing air that has the same composition as atmospheric air. "Blood boiling"
26
The movie that has a very visual example of "rapid decompression" is called ________. They were on _____. Who was in the movie?
Total Recall Mars Arnold Schwarzenegger (5 syllables)
27
What can help with altitude sickness when climbing Mt Everest?
- Going up gradually - Stopping at camp bases to allow body to adjust - Acetazolamide (Diamox)
28
T/F: Altitude sickness is genetic.
**True**
29
What is the most common camp base people stop at when climbing the summit of Mount Everest to allow their body to adjust to lower barometric pressure? What is the barometric pressure there? Inspired PO₂? What is special about this camp base?
Camp Base 3: PB = 317 mmHg PIO₂ = 56.5 mmHg What special about this camp is that this is where people find out if they are genetically predisposed to altitude sickness.
30
When diving & resurfacing quickly, if an air emboli isn’t immediately fatal, what do we need to worry about?
Smaller air emboli from the nitrogen leaving out of the blood in gas form coming together and forming larger embolus later on.
31
A standard hyperbaric chamber is ____ normal sea level pressure. What does this equal to in mmHg? How are military hyperbaric chambers different?
**3x** **2280 mmHg** **Military: Can go higher than 3x** - More expensive & dangerous (higher pressure = more explosive)
32
Where are places that commonly have hyperbaric places? Descibe them.
**Oil rigs**: Hyperbaric rooms - Active divers live at high pressures because it’s healther so body doesn't have to keep adjusting every dive. - Cons: Expensive; oil/gas are flammable & pressure is explosive — these are combined; high insurance premiums **Large Medical Centers**: academic chamber - Can have single or multi person (container over patient’s head like a fish bowl that enriches that area only) - Cons: expensive; large; high insurance premiums **Military base**: hyperbaric chamber -Can go higher than 3x sea level pressure & larger multi person -Cons: expensive; dangerous **Small/Rural Hospitals**: traveling/mobile hyperbaric chamber that go to multiple places that are needed (not associated with the hospital probably)
33
What are secondary uses of a hyperbaric chamber?
Hyperbaric chamber can also push extra oxygen into the blood If you have a bad circulatory system or immune system → **additional O₂ = oxidative stress** Can be used to kill viruses/bacteria & heal infections/wounds (O₂ is toxic to these)
34
In a hyperbaric chamber, the FiO₂ is ____% and the pressure is ______. This increases oxygen in the blood in the __________.
100% Increased (Usually 3 atm) DISSOLVED STATE!!!!! Dissolved state only.
35
Oxygen is _____ in blood. What is the significance of Hb with O₂?
insoluble Since it is insoluble in blood Hb acts as a carrier for O₂ to avoid being in solution
36
What is the only way to increase the amount of O₂ in the blood beyond what Hb carries? How do you do this?
Increasing PAO₂ (alveolar O₂ tension — they mean the same thing) How to increase PAO₂: - Increase FIO₂ - Increase environmental pressure
37
_______ helps convince highly insoluble O₂ gas to go into blood in the dissolved form.
Higher pressure
38
Why is CO₂ problematic when diving at deep depths?
There is a small amount of CO₂ in atmospheric air (0.3 mmHg) → when diving at deep depths there is increased dissolved CO₂ in the blood **CO₂ is an acid**, higher risk for acidosis
39
The typical FiO₂ needed in a healthy anesthetized pt is ___%. Why is this?
**30%** General Anesthetics **prevents the body from shunting blood by messing with hypoxic pulmonary vasoconstriction (HPV)** GA also **increases the risk for airway reactivity** To compensate for this, we use 30% instead of 21% (RA)
40
ROS =
Reactive oxygen species
41
The dangerous oxygen molecules are called ______. What are they? (4) Describe them. (Go over each one until you hit all major points)
**ROS (reactive oxygen species)** **1. Superoxide (O₂⁻)**: - 1 extra electron → causes reactivity/degrades compounds **2. Nitric Oxide (NO)**: - Excessive amounts = react/create dangerous compounds **3. Peroxynitrite (OONO⁻)**: - Destroys/mutates DNA - Created by **Oxidative stress or (Superoxide + Nitric Oxide)** - Long term → causes cancer **4. Hydrogen Peroxide (H₂O₂)**: - Used as an aseptic for infections - Smaller - Less dangerous
42
Superoxide + Nitric Oxide =
Peroxynitrite (OONO⁻)
43
How does our body use ROS in good ways?
In controlled amounts, used to to degrade unwanted/foreign compounds in the body. Example → Macrophages, Immune killer cells
44
How does the body regulate ROS in the body? List them (4)
They are regulated by the following enzymes - **Superoxide Dismutase**: degrades Superoxide - **Peroxidase**: degrades Hydrogen Peroxide - **Catalase**: forms and degrades Hydrogen Peroxide - **Acetylcysteine**: scavenges and destroys excess ROS
45
What is N-Acetylcysteine? What is it used for?
Enzyme that destroys excess ROS Medication used to reduce liver damage from Acetaminophen OD from disrupted CYP450 metabolism
46
Describe the Iron lung; uses; machine; mechanics
Old way of ventilating someone who doesnt have adequate skeletal muscle support Uses: **Polio** - an infection that destroys the communication between the NS & skeletal muscles → can't properly ventilate Machine: - cylinder shaped w/ cap on end - **pressure seal** between inside of the tank and outside environment Mechanics: - on inside: lower environmental pressure when we need to inspire - Machine pulls on pulley to stimulate the same motion of diaphragm contracting down → pulls air into the patient
47
What are the main differences between ventilation with the iron lung & PPV?
Iron Lung: - Less trauma - Pulling air in = more natural - Air evenly distributed - NOT mobile or portable Positive Pressure Ventilator (PPV): - Pushing air in = abnormal - Uneven distribution of air: Alveoli closest to large airway fill first → pushes on other alveoli (reason why we need pressure to open) - Vent IS mobile or portable
48
What was the name of the last person who was in the iron lung and what degree were they able to obtain?
Paul Alexander He received a Law degree from UT Austin