temperature ppt notes Flashcards by Josh Newby

Heat is a form of what?

energy (kinetic energy)

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Heat can be transfered from a hotter substance to a colder one, but never what?

cold to hot

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what is the measured thermal state of a substance whch quantifies the energy distribution among the molecules in a system?

Temperature

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what properties of a substance change with temperature changes?

physical properties

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what is the standard unit of temperature?

kelvin

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0 K= what C

0 C= what K

0 k = what

how do u convert C to K

-273.15 C

273 K

absolute 0

add 273.15

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what is 1 calorie

the amt of heat needed to raise the temp of 1 g of h20 by 1 degree C

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what occurs to kenetic energy during freezing and thawing

decreases when cools (freezing)

Increases when warms (thawing)

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The majority of the body’s heat is locted where?

core

brain
thorax
abdomen

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since core temp is the gold standard where are some common sites to measure this

pulm artery

esophagus

rectum

bladder

tympanic

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metabolic rate increases by ___ - _____% for each degree C increase in core temp

6-7%

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CO increases by ________ per degree C

3L/min

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the body compensates for excessive heat loss by what 2 ways

decreasing rate of loss
increasing rate of heat production

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Heat is a product of what?

and thus heat can be increased by increasing what?

metabolism

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what is an effective way of increasing metabolism?

shivering

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The down fall of shivering is an increase in O2 consumption by 400-500%, this emphesizes the importance of us doing what?

keeping out pt’s warm to prevent stressful increases in metabolism

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What is non-shivering thermogenesis?

complex mechanism not involving ATP

triggers brown fat metabolism

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what effects does Anesthesia have on thermoregulation

general and regional anesthesia blunt the normal thermoregulatory mechanism
Potent inhaled agents cause vasodilation and disrupt normal hypothalmic shivering regulation
inhalation agents, propofol induction, vasodilating drugs, and regional anesthetics induce vasodilation
regional- heat loss due to loss of sympathetic tone

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The greatest decrease in core body temp occurs when during anesthesia

1st hour of operative time

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4 routes of heat loss

Radiation

Convection

Conduction

Evaporation

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most heat is lost from the body by what route

Radiation

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Burn pt’s lose the highest % of heat by what route

Evaporation

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What route is the transfer of heat energy by emission of infra-red radiation (energy) to the surrounding walls, equip, floor…etc

give ex

radiation

Heat just leaves your body

stop by placing a blanket on pt

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what type of heat loss is the transfer of thermal energy by heating air adjacent to the skin, it increases kinetic energy expands, becoming less dense and rises carrying heat away

give ex

Convection

air currents pass by and remove the heat, we literally blow it away

in pool and water finally gets warm then u move and it is cold again,

WHat type of heat loss is the loss of heat (transfer) by direct contact with a less hot substance give ex

Conduction when u sit in a chair and get up the chair is hot from your ass the good thing is the heat can be maintained by the contact

\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* what type of heat loss is due to loss of latent heat of vaporization of moisture on the skin. Thi is limited by the gradient of skin H2O to atmospheric H2O difference give ex

Evaporation sweating

\*\*\*\*\*\*\*\*\*\*\*\*\* What is the formula for evaporation

H₂0_L+ Heat= H₂O_G

\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* What is Absolute humidity and how is it measured

the mass of water vapor in given volume of air Grams (g)

\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* what is relative humidity? and how is it written?

The RATIO of the mass of water vapor in a giver volume of air to the mass required to saturate that given volume of air at the same temp percent (%) actual H₂O vapor / Max. potential H₂O saturation

why does relative humidity increase a the temperature falls?

b/c the saturate vapor pressure falls

Fully saturated air at 37⁰C cantains how much water

44mg/L

How do we humidify gasses?

Foam noses electrical humidifiers/ nebs Soda lime Moistened circuit low dry gas flows

what are risk factors for perioperative hypothermia

age increased GA regional Anesthesia ASA III or IV trauma Low body fat Endocrin D/O OR temp abd cases OPEN Cold fluids Length High gas flows

what is the #1 risk factor for periop hypothrmia

\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* a temp of this causes what CV effects \*\*33-36^oC \*\*32-33^oC \<30^oC 19-20^oC

\*\*Increased HR BP CO \*\*Decreased HR BP CO bradycardia, v-fib asystole \*\*important

Hypothermia of renal, at temp \< 33^oC can cause what

polyuria

Hypothermia effects of hematological system

HCT rises(from fluid shift interstitial) increased coags (plt's are sequestered in spleen and liver)

Methods of acheiving and maintaining perioperative normothermia

Circulating water matress Heated humidifiers \*low fresh gas flows (decreases evaporation) 0.5-1 L/min Metallic reflective blankets heat and moister exchangers (artificial noses) warm IV fluid Ambient temp (increase room temp) Forced air warming blankets (bair hugger)

The easiest way to prevent heat loss is to stop what?

radiation

More heat = more what?

kinetic energy

Where does heat start at?

cellular level with ATP

Heat is a product of what?

Metabolism

what is a d/o of hypermetabolism (rare)

shivering increases O₂ comsumption by how much

400-500%

Brown fat metabolism occurs in primarimy whom

babies and neonates

what is a great way you can reduce evaporation

use low gas flows

\*\* fully saturated air at 37⁰C contains how much water

44mg/L (i also wrote 1g=ml i don't know why or what it ment)

of the absolute humidity of gas in the lungs at 37⁰C is 44mg/L what should happen if then is 35⁰C

be less than 44

the relative humidity of gas in the lungs is always what

100%

97⁰F is how much K

97-32 x 5/9=K 97-32=65 65 \* 5=325 325/9=36.111111111 36.1+273.15=_309.25 K_