Apex- Misc: Thermoregulation/Airway Fires/Lasers/Burns Flashcards
What is the BEST method of minimizing intraoperative heat loss?
A. Forced air warmer
B. Circulating water mattress
C. Warm blankets
D. Fluid warmer
A. Forced Air warmer
Rank the four mechanisms of heat transfer in order of importance:
Convection, Evaporation, Radiation, Conduction
- Radiation
- Convection
- Evaporation
- Conduction
- You love to radiate in the sun- thats your primary preference of warming
- convection oven would be second warmest compared to the sun
- Evaporation - sweating
- Conduction ….. idk
Hypothermia is defined as a core body temp less than what
who’s at greatest risk of developing perioperative hypothermia?
< 36 degrees celsius
extremes of age
1 source of heat loss
Radiation
-heat follows a temp gradient. If pt is warmer than the enviornment, the heat is lost to the envionrment in the form of infrared radiation
-most heat is lost thru the skin and covering hte patient reduces radiant heat loss
T/F: most of the heat is lost through the skin
True
radiation*
T/F: covering the patient reduces radiant heat loss
true
most heat is lost through skin
What kind of heat loss is the transfer of heat by the movement of matter
Convection - Air
second mort important source of heat loss
What kind of heat loss describes when air movement over the body whisks awary the heat that has radiated from the body
Convection
Does laminar or turbulent flow increase the amount of heat lost to convection
laminar
what kind of heat loss is a function of the exposed surface area and the relative humidity of the envionrment
evaporation
water can be lost by evaporation from respiration, wounds, and exposure of internal organs during surgery
What kind of air loss describes when heat is lost when the patient comes into direct contact with a cooler object
examples?
conduction
cold OR table, IVF, irrigation fluids
Which temp monitoring site offers the BEST combination of accuracy and safety over an extended period of time?
- Rectal
- Esophageal
- Tympanic membrane
- Esophageal
B. Esophageal
Shivering increases O2 consumption by how much?
what does this increase the risk of?
400-500%
myocardial ischemia and infarction
Where should esophageal temp be monitored?
how many cm pas the incisiors?
distal 1/3 - 1/4 of esophagus
38-42 (~40)cm passt incisiors
T/F- skin temp does not correlate with core body temp
true
Temp is (directly/inversely) related to solubility of anesthetic agents
inversely related
-decreased temp = increased solublity (longer wakeup)
O2 comsumption is reduced by what % for every 1 degree C reduction in body temp?
7%
Skin temp is often how many degrees less than core temp?
2-4 degrees celsius
Anesthetic considerations for removal of vocal cord papilloma with a carbon dioxide laser include:
A. reducing the FiO2 by adding nitrous
B. applying reflecting tape to a red rubber ETT
C. using amber goggles
D. adding saline instead of air to the cuff of the ETT
D.
2 benifits:
- acts as a heat sink for the thermal energy produced by the laser
- if the laser breaks the balloon, then the surgeon will see the salline in the surgical field- adding dye to the saline makes it more obvious
When should you add saline to your ett cuff instead of air and why?
airway surgery with a laser
- acts as a heat sink for the thermal energy prodduced by the laser
- if the laser breaks the balloon, then the surgeon will see the saline in the surgical field
When a laser is in use, air should be blended with o2 to maintain an fio2 < what
can nitrous be used?
< 30%
no- nitrous supports combustion
What color glasses for CO2 laser?
clear
Fire triad and 2 examples of each
- ignition source- cuatery, laser
- oxidizer: oxygen, nitrous
- fuel: ETT, drapes, surgical supplies
What color goggles for each laser:
CO2
Nd: YAG
Ruby
Argon
CO2 = Clear
Nd: YAG = Green
Ruby = Red
Argon = Amber
5 key points regarding laser safety
- keep FiO2 < 30%
- No nitrous
- Laser resistant ETT
- Fill cuff with saline
- Protect pt’s eyes by taping eylind closed, covering them with saline-soaked gauze, and using protective glasses specific to the laswer used
T/F: you should squeeze the reservior bag when extubating the patient for an airway fire
false
can create a blow-torch effect at the distal end of hte ETT and push debris in to the lower airway
5 steps for airway fire
3 steps to take after fire is controlled
- stop ventilation and remove ETT –> AKA: Disconnect and pull
- turn off all flows
- remove other flammable materia lfrom the airway -> throw down drapes
- pour water or saline into airway
- if still not extinguished - use a CO2 fire extinguisher
- re-establish ventilation by masking on RA
- check ETT for damage - fragments may still be in airway
- bronch to inspect for airway injury or retained fragments
T/F: short wavelength lasers penetrate DEEPER into tissue
true- bc they absorb LESS water
opposite of what you would think
-long wavelength laswers absorb more water and do NOT penetrate deep into tissue
4 C’s of CO2 lasers
CO2
Clear goggles
Cords (vocal cord surgery)
Cornea at risk for damage
Most lasers pose risk to which eye structure
what’s the exception
Retina
CO2 = CORNEA
Match Laswer with type of surgery:
Nd:Yag, Ruby, Argon, CO2
retinal, tumor debulking/tracheal, oropharyngeal/vocal cords, vascular lesion
CO2 = cords
Nd: YAG = tumor debulking/tracheal
Ruby = Retinal
Argon = Vascular lesion
which of these ETTs are flammable, those madefrom:
-polycinyl chloride, red rubber, or silicone
all of them!
T/f: laser reflective tape is no longer advised
true
better to use a laswer resistant ETT (its not laser proof though)
what is the most vulnerable part of the ETT to laswer
the cuff
T/f: laser resistant tubes have laser resistant cuffs
FALSE- the cuffs are not laswer resistant
ETT for a co2 laser vs Nd:Yag laswer
CO2 = LaserFlex
Nd:Yag = Lasertubus
laser resisant tube - 2 cuffs, distal and proximal - which one do you fill with saline and why
saline goes in proximal cuff - it helps absorb theral energy produced by the laser, making it less likely to ignite
distal cuff = air
hopefully if the proximal cuff perf’s , the distal cuff will remain intact and permit continued PPV
Why is gas embolus a risk with laser surgery?
Bc gas may be used to cool the tip of the laswer probe
highest risk in laparoscopic uterine surgery
T/F: laser resistant ETT also reduce the risk of fire when electrosugical cautery is used
False
How should the patien’ts eyes be protected when laswer are in use (3)
what type of lubricants should be avoided
- type eyelids closed
- cover eyelids with saline-soaked gauze
- appropriate glasses
no petroleum-based lube
37%
I dont understand how this computes but okay
—->full arm =9 + front = 18 + head = 10
Rule of nines:
Head = 10
Trunk = 36%
Arm = 9%
Leg = 18%
Perneum= 1%
4 Classes of burn injury: name and what parts
1- Superficial- Epidermis only
2- Partial-thickness- Extends to dermis
3- Full thickness - Complete destruction of both epidermis and dermis (subq)
4th - Full-thickness- Extends to muscle and bone
At which classification does a burn not hurt because the nerve endings are obliterated?
3rd and 4th
What is the BEST IVF to administer in the intial 24hrs after a major burn:
A. D5W
B. 3% NaCl
C. 5% Albumin
D. LR
what about 24 hours AFTER a major burn
D. LR for first 24hrs
D5W for 2nd 24
*Albumin should be avoided during the first 24 hours bc it’s lost to the intersistal space
How long should albumin be avoided after a major burn and why
first 24 hrs bc it’ll be lost to the intersistial space
Why are burn pts at risk for hypovolemic shock
bc immediately after a burn, microvascular permeability increases –> capillarly leak –> edema, hypovolemia, and shock
T/F- fluid requirements are higher in the 2nd 24 hours following a burn
False -
*fluid shifts and edema are greatest in the first 12 hrs and begin to stabllize by 24 hours
2 most common fluid resusitation formulas for the acutely burned patient
These formulas are used for adults and kids > what
Parkland and Modified Brooke
adults and kids > 20kg
both use LR in the 1st 24hrs and D5W thereafter
What does a rising hemoglobin in the first few days after a major burn suggest?
inadequate fluid volume resuscitation
Burn pts:
consider transfusion if Hct < what in the thealhy patient or < what in the pt with cardiovascular disease
Healthy- HCt < 20
CVD- Hct < 30
Parkland and Modified brooke formula main difference
other aspects that are the same
Parkland = 4ml LR x %TBSA burned x kg
Modified Brooke = 2ml LR x %TBSA burned x kg
in the first 24 hours
both say no to colloids for first 24 hours
2nd 24 hours:
both say D5W maintenance rate
& Colloids at 0.5ml x %TBSA burned x kg
Burn Resusitation:
Urine output:
Adult-
Child (<30kg)
High voltage electrial burn:
Adult > 0.5ml/kg/hr
Child (<30kg) > 1ml/kg/hr
High voltage electrical injury > 1-1.5ml/kg/hr
Burn Resusitation:
Goal BP:
Adult:
Infant:
Child:
Adult- MAP > 60
Infant- SBP > 60
Child- SBP - 70– 90 + (2 x age in years)
gimme a break
Burn Resusitation: HR goal
80-140
age depedent
Burn Resusitation: Base deficit goal
<2
Burn Resusitation: O2 delivery index
600ml 02/min/m2
never gonna use that
Burn Resusitation: mixed venous oxygen tension (PvO2)
35-40mmHg
T/f: electrical burns often leave little visible damage on the skin
True- but can cause great damage to the viscera
Why would an electrical burn necessitate a greater fluid volume resusitation
myoglobinemia
from extensive muscle damage - it’s nephrotoxic and needs to be washed out
What might Abdominal Compartment Syndrome happen in the burn patient?
criteria
treatment (4)
Aggressive fluid resuscitation
IAP > 20mmHg AND evidence of organ dysfunction
Neuomuscular blockade
Sedation
Diuresis
Abdominal decompression via lapartomy
CO binds to hemoglobin with an affinity of _ x that of oxygen
200x
T/F- why is the pulseox inaccurate in the pt with CO poisioning
bc it cant differentiate between oxyhemboglobin and carboxyhemoglobin resulting in a falsely levated result
tx for carboxyhemoglobin
100% FiO2 or hyperbaric o2
What is the first priority in all burn patients
administering a high FiiO2
What is the gold standard for diagnosing hte extent of airway injury
Fiberoptic bronchosocpy
T/F: tracheal intubation should occur early in burn patietns
true
*the fiberoptic approach is prob the safeest method
But at the same time it says a surgical airway increases the risk of pulmonary sespsi and later pulmonary complications and should only be used as a last resort
Discuss the use of Sux and NDMR’s after a burn
After 24 hours, upregulation of receptors:
No sux - massive hyperkalemia
NDMR- increase 2-3 fold (to cover the increased receptors)
Difference in order of importance of heat loss mechanisms in burn pts compared to non-burn patients
Burns : Radiation > Evaporation > Convection > Conduction
Non- Burn: Radiation > Convection > Evaporation > conduction
Abdominal compatement syndrome is defined as an IAP greater than what
20mmHg
+ signs of end organ damage (hd instability, oliguria, ect)
What causes Neuromalignant syndrome?
dopamine depletion in the* basal ganglia *and hypothalamus
Tx: bromocriptine, dantrolene
What is Bromocriptine used for?
To treat neuroletpi malginant syndrome
*dopamine depletion in basal ganglia and hypothalmus
T/F: Dantrolene can be used to treat neuroleptic malignant syndrome
True
dantrolene, bromocriptine, and ECT
T/F: Sux is contrainndicated in NMS
false -it’s safe
Which has muscle rigidity:
Serotonin syndrome, Anticholineregic Syndrome, or NMS?
SS & NMS;
not anticholinergic syndrome
What is chlorpromazine ?
what can it cause
what can it treat?
Thorazine- dopamine antagonist (antiemetic/antipsychotic)
NMS
supportive care for serotonin syndrome (main tx- cypohepatadine)
4 main serotonergic drug classes that can cause serotonin syndrome
6 other drugs that can cause it
- SSRI’s
- SNRI’s
- MAOI’s
- TCA’s
- methylene blue
- mmeperidine
- fentanyl
- tramadol
- sibutramine - appetite suppress (NE + SSRI)
Is serotonin syndrome more likely to cause right or left sided heart failure?
why
right sided
it’s metabolized in the lungs and spares the left heart
