mini study guide (LASER to hypothermia) Flashcards
Laser is an acronym for?
light amplification by stimulated emission of radiation
there are two types of lasers what are they?
long wavelength lasers
short wavelength lasers
long wavelength lasers do what?
absorb more water and do not penetrate deep into tissue
short wavelength lasers do what?
absorb less water and penetrate deeper into tissue
when using lasers you should use how much FIO2?
less than 30%
should you use nitrous oxide with lasers? why?
no
because it supports combusion
what must be immediately avaiable when using a laser?why?
water or saline
most ETT are flammable
what ETT are flammable?
made from polyvinyl chloride (PVC) red rubber, and silicone
how should you protect the eyes during a laser case?
tape eyelids closed
avoid petroleum based lubricants
cover eyelids with saline soaked gauze
use protective glasses specific to the laser being used.
what is the most vulnerable component of the ETT?
the cuff
laser resistent ETT do not have laser resistant?
cuffs
name the three components fo the fire triad?
ignition source
oxidizer
fuel
name examples of the ignition source?
electrosurgeical cautery
laser
name examples of the oxidizers?
oxygen
nitrous oxide
name examples of the fuel
ETT
drapes
surgical supplies
according to the ASA operating room fire guidelines, what should you do in order, when a fire is present?
- stop ventilation and remove the ETT
- stop the flow of all airway gases
- remove other flammable material from the airway
- pour water or saline into the airway
- if fire isn’t extinguished on the first attempt, then use a CO2 fire extinguisher
according to the ASA operating room fire guidelines, what should you do in order, after the fire is controlled?
- re-establish ventilation by mask, avoid supplemental O2 or nitrous oxide
- check the ETT for damage, fragments may remain in the patient’s airway
- perform bronchoscopy to inspect for airway injury or retained fragments
why do you not squeeze the reservoir bag as you extubate the patient when an airway fire has been present?
this can create a blow torch effect at the distal end of the ETT and/or push debris into the lower airway
the body regulates core temperature between ___ and ___ degrees celsius.
36.7 - 37.1 celsius
hypothermia is defined as core body temperature less than _____ celsius
36 degrees
who is at the greatest risk of developing perioperative hypothermia?
patients at extremes of age are at the greatest risk of developing perioperative hypothermia
the maintenance of body temperature involves three components which are:
afferent limb
control center
efferent response
what components make up the afferent limb of thermoregulation?
thermoreceptors:
skin
deep tissue
spinal cord
what components make up the control center of thermoregulation?
hypothalamus: preoptic region
brainstem
efferent response to cold produces what?
vasoconstriction
piloerection
shivering
non-shivering themogensis
shivering increases oxygen consumption by up to what percent
400-500%
what are you at increased risk for when you are shivering d/t increased oxygen consumption?
myocardial ischemia and infarction
non-shivering thermogenesis occurs in what population?
babies
what is the efferent response to being hot?
vasodilation and diaphoresis
list the 4 ways to transfer heat in order from greatest to least?
radiation
convection
conduction
evaporation
describe radiation?
heat follows a temperature gradient. if the patient is warmer than the environment, then heat is lost to the environment in the form of infrared radiation
most heat is lost how with radiation?
skin
how can you reduce radiation heat loss?
covering the patient
describe convection?
the transfer of heat by the movement of matter (air)
wind chill is an example of what type of heat loss?
convection
what type of flow increases the amount of heat lost to convection?
laminar flow
the rate of evaporation is based on?
function of the exposed surface area and the relative humidity of the environment
describe how evaporation can happen during surgery?
from respiration, wounds, and exposure of internal organs during surgery
describe conduction?
heat lost when the patient comes into direct contact with a cooler object
what determines the amount of conductive heat loss?
the temperature gradient and the thermal conductivity of the object
give examples of how you can loss heat due to conduction?
cold OR table, IV fluids, and irrigation fluids
how many stages are there in intraoperative heat transfer?
three
what happens in phase 1 of intraoperative heat transfer?
heat distribution from core to periphery
what happens in phase 2 of intraoperative heat transfer?
heat transfer is greater than heat production
what happens in phase 3 of intraoperative heat transfer?
heat transfer is equal to heat production
during what types of procedures does the distribution of heat from core to periphery occur with?
general
spinal
epidural anesthesia
anesthetic agents impair the thermoregulation in three ways which are?
altering hypothalamus response
prevent shivering
cause vasodilation
A _____ amount of heat is lost during phase 1
nominal, heat redistribution is way more important during this phase
how can the anesthesia provider improve the redistribution of heat from the core to periphery in phase 1?
place a warm blanket on the patient before entering the OR, minimizes the central to peripheral temperature gradient.
perioperative hypothermia increases the risk of ?
morbidity and mortality
what 3 medication are used to treat postoperative shivering includes?
meperidine
clonidine
dexmedetomidine
oxygen consumption is reduced by ____ percent for every 1 degree C reduction in body temperature
5-7%
name 7 incidences where induced hypothermia is useful during?
cerebral ischemia (stroke) cerebral aneurysm clipping TBI cardiopulmonary bypass cardiac arrest aortic cross clamping carotid endarterectomy
name three ways to minimize intraoperative heat loss?
HME
warming blanket
Fluid warmers
perioperative hypothermia affects the patient pharmacologically how?
slowed drug metabolism = prolonged effects of anesthetic agents
increased solubility of volatile agents = prolonged emergence
perioperative hypothermia affects the patient cardiovascular status how?
SNS stimulation - myocardial ischemia and dysrhythmias
shifts the oxyhemoglobin curve to the left- decreased o2 available to the tissues
vasoconstriction meaning decreased tissue PO2 = surgical site infection
coagulopathy and plt dysfunction - increased blood loss
sickling of hemoglobin 5- risk of sickle cell crisis
