miscellaneous topics overview Flashcards
maintenance of body temperature: afferent, efferent limb, and efferent responses
sources of heat loss from greatest to least and how to prevent them or how it happens
radiation (60%) > convection > evaporation > conduction
radiation: most heat is lost via skin. covering patient reduces radiant heat loss
convection: “wind chill” or air over body that whisks away heat that has radiated from body.
evaporation: respiration, wounds, exposure of internal organs during surgery
conduction: direct contact with cooler object. ex: cold OR table, irrigation fluids, IV fluids being cold
triphasic curve of heat transfer
phase 1: GA or spinal/epidural anesthesia, heat goes from central to peripheral compartment. anesthetic agents prevent thermoregulatory response in hypothalamus, prevent shivering, cause vasodilation. putting a blanket over this patient helps a ton.
phase 2: heat loss to environment exceeds heat production
phase 3: equilibrium between heat loss and heat development occurs
intraoperative events that contribute to heat loss
recalibration of hypothalamic set point
drug induced vasodilation
impaired shivering
core to peripheral temperature redistribution
cool ambient temperature
cool OR temperature
administration of room temp fluids and cold blood products
which temperature monitoring spot is best for accuracy and safety over a long period of time
esophageal
CV consequences of perioperative hypothermia and clinical relevance
pharmacologic consequences of perioperative hypothermia and clinical relevance
shivering increases O2 consumption by
400-500%
pharmacologic modalities to tx postop shivering include
meperidine
clonidine
dexmedetomidine
O2 consumption is reduced _____ % for every 1 degree c reduction in body temperature
5-7%
induced hypothermia is useful during
CVA
cerebral aneurysm clipping
TBI
CPB
cardiac arrest
aortic cross clamping
CEA
key points of esophageal temperature measurement
key points of nasopharynx temperature measurement
key points of rectal temperature measurement
key points of bladder temperature measurement
key points of p.artery temperature measurement
key points of tympanic membrane temperature measurement
key points of skin temperature measurement
anesthetic considerations for removing vocal cord papilloma with a CO2 laser includes
adding saline to cuff of ett (acts as heat sink for thermal energy produced by laser and if laser breaks balloon, surgeon will see saline in field)
air with O2 to keep O2 below 30%
protect eyes with clear lenses
use laser resistant ett
3 ingredients to create a fire and examples
OSA operating room fire guidelines: steps to take when fire is present
- stop ventilation and remove ett
- stop flow of all aw gases
- remove flammable material from aw
- pour water or saline into aw
- if fire isn’t extinguished on first attempt, use CO2 extinguisher
OSA OR fire guidelines: steps to take after fire is extinguished
- re establish ventilation by mask. avoid supplemental O2 or N2O
- check ett for damage. fragments may be in patients airway still
- performed bronchoscopy for inspect for aw injury or retained fragments
laser light acronym and how it differs
Light Amplification by Stimulated Emission of Radiation
1. monochromatic (light is single wave length)
2. coherent (light oscillates in same phase)
3. collimated (light exists as narrow parallel beam)
long wavelength lasers in relation to water absorption and tissue penetration
absorb more water and do not penetrate deep into tissue