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
short wavelength lasers in relation to water absorption and tissue penetration
absorb less water and do penetrate deep into tissues
eye protection to use for
CO2
Ng:Yag
Ruby
Argon
CO2: Clear lenses:
Ng:YaG: Green lenses
Ruby: Red
Argon: Amber
CO2
wavelength
type of surgeries used
structures damaged
wavelength 10,600 nm
type of surgeries used: oropharyngeal, vocal cord
structures damaged: cornea
Nd:Yag
wavelength
type of surgeries used
structures damaged
wavelength 1,064 nm
type of surgeries used: tumor debunking, tracheal
structures damaged: retina
Ruby
wavelength
type of surgeries used
structures damaged
wavelength: 694nm
type of surgeries used: retinal
structures damaged: retinal
Argon
wavelength
type of surgeries used
structures damaged
wavelength 515nm
type of surgeries used: vascular lesion
structures damaged: retina
flammable ETT’s
most of them. made of polyvinyl chloride, red rubber, silicone
type of ETT to use if lasers are involved
laser resistant ETT (not reflective tape)
best ett for if CO2 laser is going to be used
laserflex tube
best ett for if Nd:Yag is going to be used
lasertubus
rule of nines for burns includes
head 10%
trunk 36%
arm 9%
leg 18%
perineum 1%
estimate TBSA burned
36-38%
classify 1st-4th degree burns, thickness, tx, what it includes
children and burns % on TBSA
childs head is 19% tbsa (9.5 front and 9.5 back)
for every year >1y up to 10y, you can decrease head surface area by 1% and increase each leg by .5%
best fluid for resuscitation in initial 24h and after 24h
initial: LR
after: D5W
why are fluid requirements more in the first 24 hours following a burn
fluid shifts and edema are greatest in the first 12 hours and begin to stabilize by 24h
what to avoid in first 24h (think volume)
albumin, will just get lost in interstitial space
how to monitor adequate resuscitation for burn victim
rising HGB in first few days suggests inadequate fluid resuscitation
consider transfusion if Hct <20 (healthy patient) or <30 (pre existing CAD)
parkland fluid resuscitation guidelines for children and adults >20kg
modified brooke fluid resuscitation guidelines for children and adults >20kg
clinical end points of burn patient resuscitation
UOP (adult, child, high voltage electrical injury)
BP (adult, infant, child)
HR
base deficit
DO2
mixed venous O2 tension (PvO2)
UOP adult >.5mL/kg/h
UOP child >1mL/kg/h
UOP high voltage electrical injury >1-1.5mL/kg/h (myoglobin is nephrotoxic)
BP adult MAP >60
BP infant SBP >60
BP child SBP 70-90 + (2x age in years)
HR 80-140bpm
base deficit <3
DO2 600mL O2/min/m^2
mixed venous O2 tension (PvO2) 35-40mmHg
intraabdominal compartment syndrome and tx
can results from aggressive fluid resuscitation
intra abdominal pressure >20mmHg AND evidence of organ dysfunction (hemodynamic instability, oliguria, increased PIP)
tx: NMB, sedation, diuresis, laparotomy for decompression
carbon monoxide poisoning overview and tx
CO shifts oxyhgb curve to left
oxidative phosphorylation is also impaired
inadequate DO2 and utilization cause metabolic acidosis
blood takes cherry red appearance
tx: 100% FiO2 or hyperbaric O2
dose of non depolarizing NMB’s with burn patients
decrease 2-3x (up regulation of extra junctional receptors begins after 24h)
succ and the burn patient
can use up to 24h post burn but not after 24h
% radiation, evaporation, convection, conduction of heat loss in burn patient
60% radiation, 25% evaporation, 12% convection, 3% conduction
(in a normal patient, 60% radiation, 15-30% convection, 20% evaporation, <5% conduction)
patients become ________ after a burn which increases
hypermetabolic. increases O2 consumption, catabolism, HR, RR
initial and secondary response/phase of ECT induced seizures (CV, GI, neuro)
initial: increased PNS activity during the tonic phase (lasts ~15sec)
secondary: increased SNS activity during clonic phase (lasts several minutes)
absolute contraindications to ECT
recent MI (<4-6mo)
recent intracranial surgery (<3mo)
revent CVA (<3mo)
brain tumor
unstable cervical spine
pheo
relative contraindications to ECT
pregnancy
pacer/ICD
CHF
glaucoma
retinal detachment
severe pulmonary disease
ECT minimum recommended seizure duration
25 seconds
drugs (5) and other conditions (2) that increase seizure duration
etomidate, ketamine, alfentanil with propofol, aminophylline, caffeine
hyperventilation, hypocapnea
drugs and other conditions that decrease seizure duration
propofol, midazolam, lorazepam, fentanyl, lidocaine
hypoventilation, hypercarbia, hypoxia
drugs that have no effect on seizure duration
methohexital
dexmedetomidine
clonidine
esmolol
lithium and NMB’s
prolongs DOA of succ and non depolarizing NMB’s
MAOI’s and indirect acting sympathomimetics
these patients can experience hypertensive crisis
MH
time to onset
causes
key features
tx
time to onset: minutes
causes: halogenated anesthetics, succ
key features: hypercarbia, tachycardia, myoglobinuria, acidosis, muscle rigidity
tx: dantrolene and supportive care
sympathomimetic syndrome
time to onset
causes
key features
tx
time to onset: up to 30m
causes: amphetamines, coke
key features: agitation, hallucinations, arrhythmias, MI
tx: vasodilators, labetalol, supportive care
tricyclic antidepressant OD
time to onset
causes
key features
tx
time to onset: up to 6h
causes: TCA’s (amitriptyline, nortriptyline, imipramine, desipramine, clomipramine)
key features: HoTN, decreased LOC/coma, polymorphic VT
tx: magnesium, serum alkalization, supportive care
serotonin syndrome
time to onset
causes
key features
tx
time to onset: up to 12 hours
causes: SSRI’s, SNRI’s (venlafaxine, duloxetine), MAOI’s (phenelzine, trancyclopromine, selegiline), MDMA, methyline blue, meperidine, fentanyl
key features: akathisia, mydriasis, tremor, AMS, clonus, muscle rididity*
tx: cyproheptadine (5Ht2A antagonist), supportive care
anticholinergic syndrome
time to onset
causes
key features
tx
time to onset: up to 12 hours
causes: centrally acting anticholinergics (atropine, scopolamine)
key features: red, hot, dry skin, mydriasis, delirium
tx: physostigmine, supportive care
NMS
time to onset
causes
key features
tx
time to onset: up to 24-72h
causes: dopamine depletion in basal ganglia and hypothalamus, dopamine antagonists (metoclopramide, haldol, chlorpromazine, risperidone), withdrawal from dopamine agonists
key features: bradykinesia, decreased LOC/coma, rhabdo, myoglobinuria, acidosis, ANS instability, muscle rigidity
(apparently its important to cite that pupils are normal, must be Diff dx for anticholinergic syndrome)
tx: bromocriptine, dantroline, supportive care, ECT (succ is safe)
main blood supply to the eye
opthalmic artery
intraocular perfusion pressure
=MAP - IOP (normal is 10-20mmHg)
aqueous humor is produced by
and reabsorbed by
ciliary process (in posterior chamber)
reabsorbed by canal of schlemm (anterior chamber)
things that increase IOP
hypercarbia
hypoxemia
increased CVP
increased MAP
laryngoscopy/intubation
straining/coughing
succ
N2O (if SF6 bubble is in place)
trendelenburg position
prone position
external compression by face mask
things that decrease IOP
hypocarbia
decreased CVP
decreased MAP
volatile anesthetics*
nitrous oxide*
non depolarizing NMB
propofol
opioids
benzos
hypothermia
do anticholinergics increase IOP
no
succ use in a patient with open globe injury
OK to use because no reports of blindness
define glaucoma
chronically elevated IOP that leads to retinal artery compression
define open angle glaucoma
caused by sclerosis of trabecular mesh work. impairs aqueous humor drainage
define closed angle glaucoma
caused by closure of anterior chamber. creates mechanical outflow obstruction
drugs that decrease aqueous humor production (2)
acetazolamide inhibits carbonic anhydrase and decreases aqueous humor productioin
timolol is a non selective beta antagonist that decreases aqueous humor production
drugs that facilitate aqueous humor drainage (1)
ethophiophatate: irreversible cholinesterase inhibitor that promotes drainage via canal of schlemm
can prolong duration of succ and ester type LA’s
(if it causes miosis it helps facilitate drainage)
purpose of strabismus surgery and anesthetic considerations
corrects misalignment of extra ocular muscles and re establishes visual axis.
1. increased PONV
2. oculocardiac reflex
sulfur hexafluoride (SF6) anesthetic considerations
placed over retina during retinal reattachment, vitrectomy, macular hole repair
N2O can expand this bubble and cause permanent blindness. d/c N2O 15 min before bubble is placed and avoid it for 7-10d post
alternatives to SF6 and time to avoid N2O
silicone oil (0 days)
air bubble (5 days)
perfluoropropane aka C3F8 (30 days)
triangle of petit
landmarks of a tap block that include external oblique, latissimus dorsi, iliac crest
pain terminology and examples
allodynia
algogenic
analgesia
dysesthesia
hyperalgesia
neuralgia
neuropathy
parasthesia
define central sensitization and transmitters used
efficacy of descending inhibitory pathway is impaired. uses NE and serotonin as inhibitory transmitters
drugs to treat chronic pain (3 categories)
most significant side effects of TCA’s (2)
QT prolongation (block of Na channel)
and orthostatic HoTN
combo of SSRI and SNRI can cause
serotonin syndrome
complex regional pain syndrome and types
neuropathic pain with an autonomic involvement. risk factors: female, previous trauma, previous surgery. key distinction is that type 2 CRP’s are always preceded by nerve injury
type 1: reflex sympathetic dystrophy
type 2: causalgia
tx of complex regional pain syndrome (CRP)
ketamine infusion
memantadine (MDMA antagonist)
gaba
regional sympathetic blockade
PT
steroids
amitriptyline
thoracic paracervical block
LA injected into paracervical space (potential space) that targets ventral ramus of spinal nerve as it exits vertebral foramen
single shot, unilateral epidural block
analgesia for breast surgery, thoracotomy, rib fracture
celiac plexus block
useful for cancer pain of upper abdominal organs
ex) distal esophagus, stomach, liver, pancreas, small intestine, and colon (except descending colon)
complications of celiac plexus block
orthostatic HoTN, retroperitoneal hematoma, hematuria, diarrhea, AAA dissection, back pain, retrograde integration of injectade (problem if a neurolytic is used)
superior hypogastric plexus block
useful for management of cancer pain of pelvic organs
ex) uterus, ovaries, prostate, descending colon
complications of superior hypogastric plexus block
retrograde integration of injectade (problem if a neurolytic is used)
sphenopalantine block use
can be used to relieve PDPH.
retrobulbar block complications
LA injected into optic sheath can migrate to optic chasm where it can anesthetize CN 2 and 3 on opposite side of block. results in contralateral amaurosis (blindness)
post retrobulbar block apnea syndrome (reaches brainstem). see this 2-5 min post injection. spontaneous ventilation comes back after 15-20m but full recovery may take up to an hour
assess contralateral pupil before RBB. if it starts small but dilates shortly after block, be ready for post RBB apnea syndrome
examples of beta lactam abx and risks you should know
examples: PCN, cephalosporins, ampicillin
risks: most common for allergic rxn of all abx
examples of aminoglycoside abx and risks you should know
gentamicin, streptomycin
risks: ototoxicity, nephrotoxicity, skeletal muscle weakness (caution with NMB’s)
examples of tetracycline abx and risks you should know
doxycycline
risks: nephrotoxicity, hepatotoxicity
examples of fluoroquinolones abx and risks you should know
ciprofloxacin, levofloxacin, moxifloxacin
risks: GI intolerance, tendonitis and tendon rupture
examples of macrolide abx and risks you should know
erythromycin
risks: p450 inhibition
clindamycin risks
skeletal muscle weakness (caution with NMB’s)
allergic rxn
(re dose q4h intra)
vancomycin risks
HoTN following rapid transfusion (histamine) (infuse at 10-15mg/kg over 1 hour), can also give benadryl 1mg/kg and cimetidine 4mg/kg 1h before surgery
red man syndrome
SJS
metronidazole risks
peripheral neuropathy
ETOH intolerance
if patient has allergy to PCN, can receive cephalosporin IF (2)
- the reaction was not IgE mediated (anaphylaxis, bronchospasm, urticaria)
- did NOT produce exfoliative dermatitis (SJS)
if they did, do vanc or clinda
most common SE of prophylactic abx
pseudomembranous colitis
drugs that are contraindicated during pregnancy include
chloramphenicol
erythromycin
fluoroquinolones
tetracyclines
3 syndromes where you see muscle rigidity
MH (onset immediate)
serotonin syndrome (onset up to12h)
NMS (onset 24-72h)
