# Anesthesiology - Thermoregulation

drraythe's version from 2015-04-18 23:04

## THERMOREGULATION

Question Answer
**what is the normal temperature range for a dog/cat? (F and C)100.5-102.5*F (or 38.5 to 39.2)
**how do you convert C to F?(*C x 1.8) + 32= *F (The F always goes with 32, which is the normal temp in Buffalo, so thats how I'll remember it's the F with 32)
**how do you convert F to C?(F-*32) / 1.8= *C (The F always goes with 32, which is the normal temp in Buffalo, so thats how I'll remember it's the F with 32)
**what temp is considered to be hypothermia?<37*C (99*F)
what temp is considered mild hypothermia?36.6*C-37*C (98-99*F)
what temp is considered moderate hypothermia?35.5-36.6*C (96-98*F)
what temp is considered severe hypothermia?33.3-35.5*C (92-96*F) (2 and 6 are on severely frigid terms with each other)
what temp is considered critical hypothermia?<33*C (<92*F) (if you're even below 2 the humanitarian, then you are TOO LOW)
where does temp change in the body and where is it constant? where is temperature regulated in the body, and how much change before the body triggers a response to change it?Peripheral temperature might fluctuate, but core temp remains the same. the control center for temp is the hypothalamus which keeps the set core temp. If the core temp varies more than 0.2-0.4* outside of this range, then the hypothalamus sends signals to warm or cool the body
what are some things the body can do in response to being too cold? too hot?too cold: vasoconstrciton, shivering, piloerection, brown fat metabolism, bh (look for warmpth). Too hot: vasodilation, sweating, panting, look for cold place
why are animals more prone to problems with temperature regulation during anesthesia?the only mechanisms the body can utilize under anesthesia to change the temperature is vasoconstriction/dilation. This means it is not as effective as usual which means you need a anesthetist to help monitor temp.
when you are monitoring temperature-- where can you take a CORE temperature? where can you take a peripheral temp? which place is used most often and why?CORE: tympanic membrane, pulmonary aa, distal esophagus, nasopharanx. PERIPHERAL: mouth, axilla, rectum. THE MOST USED is rectum, because the core measurements are kinda invasive, and rectal temp most accurately represents the core temp out of all the peripheral measures
hypothermia might cause postoperative shivering...why wouldn't we want this?shivering increases the metabolic rate which can increase the O2 demand a LOT (she said 400% inc of O2 demand by shivering)
7 reasons you don't want hypothermia(1) postoperative shivering (2) impaired coagulation (3) prolonged drug action (4) delayed recovery (5) inc in wound infections (6) increased mortality (7) reduction in MAC (leaves them at risk of too deep of a plane of anesthesia- recovery will take longer)
what are 4 predisposing factors of hypothermia?**large surface area to mass ratio in smaller animals (g pig > cat dog > horse), also cachexia, neonates, geriatric animals
what are 4 preoperative causes of hypothermia?(1) prolonged preparation time (2) inadequate patient warming (3) general anesthesia (gas, high flow, non-rebreathing systems!) (4) clipping
heat loss during anesthesia mainly induced by (4 things)RADIATION (body heat radiates out of body to colder enviro), conduction, CONVECTION (heat is carried away by air around body), evaporation
what are 4 intraoperative causes of hypothermia?(1) open chest or abdominal procedures (2) room temp IV fluids (cold) (3) temperature of the operating room (4) prolonged duration of the sx
endotherm animals have a constant body temperature. what are the two thermal compartments, which body parts are in the two compartments, and what is the big reason for the diff?CORE COMPARTMENT has the brain and the trunk. PERIPHERAL compartment has the other tissue, skin, and extremities. The difference is that the core is very well perfused, whereas the periphery is used as the buffer compartment
what's the main (general) cause of perioperative hypothermia?when there is a rapid redistribution from core to periphery causing an initial rapid heat loss. This is because of drug-induced vasiodilation, as well as mainly RADIATION(body heat just radiates out to colder environment) and CONVECTION (air around body drawing heat away) (also a little bit by conduction and evaporation)
what are some ways you can prevent hypothermia?PREVENTION>TREATMENT! always take routine temp measurements for this. avoid prolonged preparation times, avoid contact with cold surfaces (use towels and blankets), avoid cold air (AC off), cover pt during waiting periods, use low gas flows where appropriate, warm the IV fluids
what are some methods of acting warming you can use to prevent hypothermia?circulating warm water heating pads, forces air warming blankets (bair hugger, hot dog), warm water bottles/packs (not too hot!), warm peritoneal/pleural lavage, warm fluids (in line fluid warmers)
when the animal is recovering from anesthesia, temperature should be monitored until it reaches...>38*C (100.4*F) (basically normal temp, its the same temp as when you stop actively warming during anesthesia)
how can you help prevent hypothermia while the patient recovers?cover pt while awake,
if the patient is shivering during recovery, what should you do?provide O2 (shivering causes inc in metabolism requires more O2)
At what temperature should you start actively warming a patient during recovery? give some examples of how to actively warm themactively warm if the temp <36*C (97*F) (seven needs to warm up to you) can use warm air heating device or infrared light
HYPERthermia--> at what temperature should you dec heating devices? when should you start active cooling?Dec heating devices at >38*C (100.4*F). active cooling efforts at >41*C (106*F) (Six is dangerous and packing heat)
5 consequences of hyperthermia?(1) inc O2 requirement (2) inc cardiac work (3) inc resp. work (4) inc risk of hypercapnia and resp. acidosis (5) alteration of coagulation and protein functions
which is a bigger deal- hyper or hypothermia?hypothermia
5 big causes of hyperthermia?(1) excessive warming (2) furry, large dogs (3) hot climate (4) excitement during recovery (5) drug related
what are the drugs which can cause hyperthermia in anyone, and why does this happen?telazol and ketamine inc mm activity and inc excitement so they can cause hyperthermia
which drugs can cause hyperthermia in CATS?opioids (hydromorphone, fentanyl) (cats get HOT and bothered when theyre HIGH on dope)
what are two genetic disorders that can cause hyperthermia?HYPP(horses) and malignant hyperthermia
how can hypothermia cause an anesthetic overdose?continued administration of normothermic amounts of anaesthetic to a hypothermic patient can produce a relative anaesthetic overdose (bc it dec the MAC)