Unit 12 - Misc. Topics Flashcards
1
Q
most effective single method of perioperative warming
A
forced air warmer
2
Q
afferent limb of temperature regulation
A
thermoreceptors
- skin
- deep tissue
- spinal cord
3
Q
control center of temperature regulation
A
- hypothalamus (preoptic region)
- brainstem
4
Q
efferent responses to hypothermia
A
- vasoconstriction
- piloerection
- shivering
- nonshivering thermogenesis
5
Q
efferent response to hyperthermia
A
- vasodilation
- diaphoresis
6
Q
4 mechanisms of heat transfer
A
- radiation
- convection
- evaporation
- conduction
7
Q
how does a patient lose heat via infrared radiation
A
if the patient is warmer than the environment, then heat is lost to the environment
8
Q
what type of heat transfer does covering the patient reduce
A
radiant
9
Q
number 2 source of heat loss
A
convection
10
Q
what is convection?
what % of periop heat transfer does it account for?
A
transfer of heat by movement of matter
15-30%
11
Q
how is heat lost via convection?
A
air movement over the body whisks away heat that has radiated from the body
the body radiates more heat to replace what was taken away by airflow
12
Q
how does laminar flow affect the amount of heat lost to convection
A
increases
13
Q
amount of energy to vaporize water
A
latent heat of vaporization
14
Q
what % of heat transfer does evaporation account for in the periop pt
A
20%
15
Q
how can water be lost by evaporation during surgey?
A
- respirations
- wounds
- internal organ exposure
16
Q
the rate of this process is a function of the exposed surface area and the relative humidity of the environment
A
evaporation
17
Q
what is conduction?
what % of heat transfer does this account for in periop pt?
A
heat is lost when the patient comes into direct contact with a cooler object
< 5%
18
Q
examples of heat loss through conduction
A
- cold OR table
- cold IV fluids
- cold irrigation fluids
19
Q
the amount of conductive heat loss is a function of:
A
the temperature gradient and thermal conductivity of the object
20
Q
phase 1 of intraoperative heat transfer
how long does this phace last?
A
heat redistribution from core to periphery
first hour after induction of anesthesia
21
Q
what is phase 2 of intraoperative heat transfer?
when does this occur?
A
heat transfer is greater than heat production
hours 1-5 after induction
22
Q
what is phase 3 of intraoperative heat transfer?
when does this occur?
A
equilibrium develops between heat lost to environment and heat production
hours 5-7 after induction
23
Q
what causes heat redistribution during general, spinal, or epidural anesthesia?
A
redistribution of heat from central compartment to peripheral compartment
24
Q
perioperative events contributing to heat loss
A
- recalibration of the hypothalamic set point
- drug induced vasodilation
- impaired shivering
- core to peripheral temperature redistribution
- cool ambient temp
- cold OR table
- admin of room temp fluids and cold blood products
25
what is the most significant source of heat loss in the OR?
radiation
26
what is the least significant source of heat loss in the OR?
conduction
27
a heat lamp is an example of what type of heat transfer
radiation
28
what temp monitoring site offers the best combination of accuracy and safety over an extended period of time
esophageal
29
CV consequences of periop hypothermia
- SNS stimulation
- vasoconstriction, decreased tissue PaO2
- coagulopathy, plt dysfunction
- hgb S sickling
- oxyhgb dissociation curve shifts to the left
30
how does hypothermia affect the oxyhgb dissociation curve
shifts to the left
31
pharmacologic consequences of hypothermia
- slowed drug metabolism
- increased solubility of volatiles
32
how does shivering increase the risk of myocardial ischemia and infarction
increases O2 consumption by 400-500%
33
pharmacologic modalities used to treat postop shivering
- meperidine
- clonidine
- dexmedetomidine
34
how does hypothermia affect O2 consumption?
reduces by 5-7% for every 1 degree C reduction in body temp
35
when might induced hypothermia be useful?
- cerebral ischemia (stroke)
- cerebral aneurysm clipping
- TBI
- bypass
- cardiac arrest
- aortic cross clamping
- CEA
36
what type of temperature monitoring site reflects temp of vital organs?
core body temp
37
ideal position of esophageal temp probe
distal 1/3 to 1/4th of esophagus
38
placement of adult esophageal temp probe
38-42cm past incisors
39
placement of esophageal temp probe in an adult with a 2nd generation SGA
15-20 cm distal to drain tube
40
pediatric placement of esophageal temp probe
10 + (2x age in yrs) / 3 cm past incisors
41
why is esophageal temp increased if placed in stomach
due to heat created by liver metabolism
42
why may temp be decreased if esophageal temp probe is placed in proximal esophagus
- cool inspiratory gas
- continuous gastric suction
- thoracotomy
43
ideal position of nasopharyngeal temp prob and why
sensor contacts posterior nasopharyngeal wall posterior to soft palate
close to hypothalamus
44
what causes decreased temp reading of nasopharyngeal temp probe
leakage of inspiratory gas
45
ideal position of rectal temp probe
8 cm in adults, 3 cm in children
46
what causes temp reading of rectal temp probe to be increased or decreased
- increased: heat producing bacteria in the gut
- decreaesd: cool blood from lower extremities, stool
47
temperature measurement sites that lag during rapid warming and cooling
- rectal
- bladder
48
what causes bladder temp to read low?
inadequate UOP
49
when is temp reading via pulmonary artery not reliable?
- CBP
- thoracotomy
50
skin temp is often ___ deg C less than core temp
2-4
51
how can skin temp be used to assess onset of a regional block?
temp will rise if the block is good d/t sympathectomy-induced rise in peripheral blood flow
52
5 clinically relevant CV consequences of perioperative hypothermia
1. myocardial ischemia/arrythmias
2. decreased DO2
3. surgical site infection
4. increased blood loss (coagulopathy)
5. risk of sickle cell crisis in pts with SCD
53
why should saline be added to the ETT cuff vs. air for removal of vocal cord papilloma with laser
1. acts as a heat sink for thermal energy produced by the laser
2. if laser breaks the balloon, surgeon will see saline in surgical field (more obvious if dyed)
54
eye protection needed when CO2 laser is used
clear lenses
55
3 ingredients to produce a fire
(components of fire triangle)
1. ignition source (cautery, laser)
2. fuel (ETT, drapes, surgical supplies)
3. oxidizer (O2, N2O)
56
5 steps to take when fire is present in the OR
1. stop ventilation, remove ETT
2. stop flow of all airway gases
3. remove other flammable material from airway
4. pour water or saline into airway
5. if fire isn't extinguished on 1st attempt, use a CO2 fire extinguisher
57
3 steps to take after OR fire is controlled
1. re-establish ventilation via mask. avoid supplemental O2 or N2O
2. check ETT for damage - fragments may be in pt's airway
3. perform bronch to inspect for retained fragments
58
what is LASER an acronym for
Light Amplification by Stimulated Emission of Radiation
59
3 things that make laser light different from ordinary light
it is
1. monochromatic (light is a single wavelength)
2. coherent (light oscillates in same phase)
3. collimated (light exists as a narrow parallel beam)
60
which absorbs more water - long wavelength lasers or short?
long
61
which lasers penetrate deeper into tissue - long or short wavelength?
short
62
wavelength of CO2 lasers
10,600 nm
63
type of laser used in oropharyngeal and vocal cord surgeries
CO2
64
structure damaged by CO2 lasers
cornea
65
wavelength of Nd:YAG lasers
1064 nm
66
type of lasers used for tumor debulking and tracheal surgeries
Nd:YAG
67
structure damaged by Nd:YAG lasers
retina
68
eye protection for Nd:YAG lasers
green goggles
(Nd:YAG=Green)
69
wavelength of ruby lasers
694 nm
70
type of laser used for retinal surgery
ruby
71
structure damaged by ruby laser
retina
72
eye protection for ruby lasers
red goggles
(Ruby = Red)
73
wavelength of argon lasers
515 nm
74
type of surgery argon lasers are used for
vascular lesions
75
structure damaged by argon laser
retina
76
eye protection for Argon lasers
Amber goggles
(Argon = Amber)
77
which component of the ETT is the most vulnerable to lasers
cuff
78
T/F - laser resistant tubes have laser resistant cuffs
false
79
why do laser resistant ETTs have 2 cuffs
the proximal cuff is filled with saline/dye. if it is perforated by laser, the distal cuff will hopefully remain intact and permit continued PPV
80
what should determine the choice of ETT in laser surgeries
type of laser and its wavelength
81
which ETT is a good choice for CO2 laser use
LaserFlex
82
which ETT is a good choice for Nd:YAG laser
Lasertubus
83
techniques that do not require an ETT (removing 1 component of fire triangle)
- spontaneous ventilation
- intermittent PPV via facemask and apnea
- jet ventilation
84
why is gas embolus a risk of laser surgery?
gas may be used to cool the tip of the laser probe
85
T/F - laser resistant ETTs reduce the risk of fire when ESU cautery is used
false
86
how to protect pt's eyes in laser surgery
- tape eyes closed
- avoid petroleum-based lubricants
- cover eyelids with saline-soaked gauze
- use protective glasses
87
best ways to protect yourself against laser plume
- smoke evacuator
- high-efficiency masks
88
what creates a plume of fine particulates with lasers?
tissue vaporization
89
rule of nines (adult)
head = 10%
trunk = 36%
arm = 9%
leg = 18%
perineum = 1%
90
involvement of a 1st degree burn
epidermis only
91
involvement of a 2nd degree burn
superficial: epidermis to upper dermis
deep: epidermis to lower dermis
92
involvement of 3rd degree burn (full thickness burn)
subcutaneous tissue
complete destruction of epidermis and dermis
93
involvement of a 4th degree (full thickness) burn
extends to muscle and bone
94
what burn stages have no sensation d/t obliterated nerve endings
3rd & 4th degree
95
rule of nines (child)
head = 19% (9.5% per front/back)
trunk = 16% (each side)
leg = 15%
arm = 9.5%
palm (excluding fingers) = 1%
96
general rule for rule of nines and head surface area in children
for every year > 1 year up to 10 years, you can decrease the head surface area by 1% and increase each leg by 0.5%
97
best IV fluid to give in initial 24 hours after major burn
LR
98
why should albumin be avoided in the first 24 hours after a major burn?
lost to interstitial space
99
what creates a capillary leak immediately after a burn?
increased microvascular permeability
100
what consequences of capillary leak after burn injury result in edema formation
- increased vascular permeability
- loss of protein-rich fluid to interstitial space, decreased plasma oncotic pressure
101
what are fluid requirements in the first 24 hours following a burn?
fluid shifts and edema formation are the greatest in the first 12 hours and begin to stabilize by 24 hours
102
what lab value sugests inadequate volume resuscitation in the first few days of a burn
rising hgb
103
when to consider transfusion in burn pt
Hct < 20 (healthy pt)
Hct < 30 (pre-existing CV disease)
104
Parkland formula
first 24 hours:
- 4 mL LR x % TBSA burned x kg
- give 1/2 in first 8 hours
- 1/2 in next 16 hours
second 24 hours:
- D5W mainenance rate
- 0.5 mL colloid x % TBSA x kg
105
Modified Brooke Formula
first 24 hours:
- 2 mL LR x % TBSA x kg
- 1/2 in first 8 hours
- 1/2 in next 16 hours
second 24 hours:
- D5W MIVF
- 0.5 mL colloid x % TBSA burned x kg
106
clinical end points of burn resuscitation - UOP
adult: > 0.5 mL/kg/hr
child (<30 kg): > 1 mL/kg/hr
high voltage electrical injury: > 1-1.5 mL/kg/hr (myoglobin is nephrotoxic)
107
clinical end points of burn resuscitation: blood pressure
adult: MAP > 60
infant: SBP > 60
child: SBP 70-90 + (2 x age in yrs)
108
clinical end points of burn resuscitation: base deficit
< 2
109
clinical end points of burn resuscitation: oxygen delivery index
600 mL O2/min/m2
110
clinical end point of burn resuscitation: mixed venous oxygen tension (PvO2)
35-45 mmHg
111
why is it important to maintain a higher UOP with electrical burns
myoglobinemia is caused by extensive muscle damage - myoglobin is nephrotoxic
112
what defines abdominal compartment syndrome
IAP > 20 mmHg + evidence of organ dysfunction (HD instability, oliguria, increased PIP)
113
treatment of abd compartment syndrome
- neuromuscular blockade
- sedation
- diruesis
- abdominal decompression vs. laparotomy
114
CO binds to hgb with an affinity of ____x that of O2
200
115
how does carbon monoxide
affect the oxyhgb dissociation curve
shifts to the left, impairs offloading of O2 to tissues
(left = love)
116
acid-base abnormality seen in CO poisoning
metabolic acidosis (inadequate O2 delivery and utilization)
117
why is the pulse ox not accurate in CO poisoning?
it's unable to distinguish between HgbO2 and HgbCO
may be falsely elevated
118
treatment of CO poisoning
100% O2
hyperbaric oxygen
119
first priority in treatment of all burn pts
high FiO2
120
gold standard for diagnosing extent of airway inujry in burns
fiberoptic bronch
121
why should a surgical airway only be used as a last resort in burn pts
increases risk of pulmonary sepsis and late pulmonary complicaitons
122
when does upregulation of extrajunctional receptors begin in burn pts
what is the significance of this?
after 24 hours
succs is safe within first 24 hours after burn - use after 24 hours can cause lethal hyperkalemia
123
dosing nondepolarizing NMBs in burn pts
increase 2-3 fold (more receptors)
124
mechanisms of heat loss in a burn pt
- 60% radiation
- 25% evaporation
- 12% convection
- 3% conduction
*normal heat loss: radiation 60%, convection 15-20%, evaporation 20%, conduction < 5%
125
metabolic changes in burn pts
hypermetabolic
- increased catabolism
- increased O2 consumption
- increased HR
- increased RR
126
ANS activity during ECT
initial response: increased PNS activity during tonic phase (~15 seconds)
secondary response: increased SNS activity during clonic phase (lasts several minutes)
127
how does LIthium affect NMBs
prolongs succs and NDNMBs
128
neuro effects of the clonic phase of ECT-induced seizures
- increased ICP
- increased CBF
- increased IOP
129
absolute contraindications to ECT
- recent MI ( <4-6 months)
- recent intracranial surgery ( <3 months)
- recent stroke (<3 months)
- brain tumor
- unstable c spine
- pheochromocytoma
130
relative contraindications to ECT
- pregnancy
- pacemaker/ICD
- CHF
- glaucoma
- retinal detachment
- severe pulmonary disease
131
minimum recommended seizure duration for ECT
25 seconds
132
drugs that increase seizure duration
- etomidate
- ketamine
- alfentanil with propofol
- aminophylline
- caffeine
133
drugs that decrease seizure duration
- propofol
- versed
- ativan
- fentanyl
- lidocaine
134
gold standard anesthetic for ECTs. why?
methohexital - rapid recovery, no effect on sz duration
135
negative side effects of etomidate for ECTs
- myoclonus
- increased PONV
- more HTN
136
negative effects of ketamine for ECT
- increased SNS response
- prolonged recovery
137
why is glycopyrrolate used for ECTs
- antisialagogue
- reduced bradycardia/asystole
138
use of esmolol in ECTs
blunts SNS response
139
how do hyper and hypoventilation impact seizure duration with ECT
hypo: decreased
hyper: increased
140
interaction between MAOIs and indirect acting sympathomimetics
HTN crisis
141
are oral and gastric secretions increased during the initial or secondary response to ECT
initial
142
how does lidocaine affect sz duration in ECTs
decreased sz activity
143
does esmolol affect sz activity in ECTs?
nope
144
how does clonidine affect sz activity in ECTs
doesn't
145
cause of neuroleptic malignant syndrome
what is the antidote?
dopamine depletion in basal ganglia and hypothalamus
bromocriptine (restores dopamine concentrations in these regions)
146
cause of serotonin syndrome
what is the antidote
excess 5-HT activity in CNS and PNS
cyproheptadine (5-HT antagonist)
147
antitode for anticholinergic poisoning
physosigmine (only cholinesterase inhibitor that lacks quarternay ammonium and diffuses into CNS to increase ACh concentration)
148
key features of malignant hyperthermia
- hypercarbia
- tachycardia
- myoglobinemia
- acidosis
- muscle rigidity
149
symptoms that NMS and MH have in common
- muscle rigidity
- hyperthermia
- tachycardia
- acidosis
150
drug used to treat both NMS and MH
dantrolene
151
what drugs increase risk of serotonin syndrome when combined with SSRIs
fentanyl, meperidine
152
what drugs increase risk of serotonin syndrome when combined with MAOIs
meperidine, ephedrine
153
what drugs increase risk of serotonin syndrome when combined with methylene blue
other serotonergic drugs
154
intraocular perfusion pressure =
MAP - IOP
155
how long is N2O contraindicated for after an intraocular SF6 bubble is placed
10 days after
156
main blood supply to the eye
where does it branch off?
opthalmic artery
branches off internal carotid near circle of Willis
157
what transports venous blood to the cavernous sinus?
superior and inferior opthalamic veins
158
what is the main blood supply to the eye
opthalamic artery
159
what 3 components determine IOP
- chorodial blood volume
- aqueous fluid volume
- extraocular muscle tone
160
what is normal IOP
10-20 mmHg
161
what produces aqueous humor?
where is aqueous humor reabsorbed?
produced by ciliary process
reabsorbed by Canal of Schlemm
162
intraoperative events that increase IOP
- hypercarbia
- hypoxemia
- increased CVP
- increased MAP
- DL
- straining/coughing
- succinylcholine
- N2O (if SF6 bubble in place)
- Trendelenberg
- Prone
- external compression by facemask
163
intraoperative events that decrease IOP
- hypocarbia
- decreased CVP
- decreased MAP
164
anesthetic agents that decrease IOP
- volatiles
- N2O
- NDNMBs
- propofol
- opioids
- benzos
- hypothermia
165
do anticholinergics increase IOP
nope
166
how does LMA placement vs DL effect IOP
LMA: minimal
DL: increased
167
how does succinylcholine affect IOP
increases by 5-10 mmHg for up to 10 min
*not reliably blocked by defasciculating NMB
168
what NMB should be used in an open globe injury
full stomach/difficult airway - succs
otherwise - roc
169
dose of rocuronium for an open globe injury
1.2 mg/kg (RSI dose)
170
drugs that decrease aqueous humor production
- acetazolamide (inhibits carbonic anhydrase)
- timolol (nonselective beta agonist)
171
2 ways drugs can decrease IOP
- decrease aqueous humor production
- facilitate aqueous humor drainage
172
drug that facilitates aqeous humor drainage
anesthetic implications of this drug
echothiophate (irreversible cholinesterase inhibitor)
can prolong duration of succs and ester type LAs
173
2 key considerations for strabismus surgery
1. incrased risk PONV
2. increased risk of activating oculocardiac reflex
174
nerves that make up oculocardiac reflex
CN V (afferent)
CN X (efferent)
175
N2O considerations for eye surgery
if a sulfur hexafluoride bubble (SF6) is placed, N2O can expand the bubble and cause blindness
d/c 15 min before bubble placed
avoid for 7-10 days after bubble placed
176
SF6 alternatives and times to avoid N2O
silicone oil = 0 days
air bubble = 5 days
perfluopropane (C3F8) = 30 days
177
what causes open angle glaucoma
sclerosis of trabecular meshwork; impairs aqueous humor drainage
178
procedures TAP block is best suited for
abdominal procedures involving T9-L1 distribution (general, GYN, urologic)
179
abdominal wall structures from superficial to deep
- sub q tissue
- external oblique
- internal oblique
- transverse abdominis
- peritoneum
180
where does innervation of the anterolateral abdominal wall arise from?
how are these nerves blocked?
T7-L1
blocked by placing LA below fascial plane between IO and TA
181
where is US placed for TAP block
a few cm superior and parallel to iliac crest
182
2 pops felt during blind technique for TAP block
1. after needle transverses EO
2. after needle transverses IO
183
volume of LA injected for TAP block
15-20 mL per side
184
complications of TAP block
- peritoneal puncture
- liver hematoma
185
what is a TAP block?
unilateral peripheral nerve block that targets nerves of anterior and lateral abdominal wall
186
what 3 landmarks form the triangle of Petit?
1. EO
2. latissimus dorsi
3. iliac crest
187
where should LA be injected when placing a TAP block?
in fascial plane between IO and TA muscles
188
algogenic
stimulus that is expected to produce pain
189
pain due to a stimulus that doesn't normally produce pain is called:
allodynia
190
exaggerated pain response to a painful stimulus is called:
hyperalgesia
191
pain localized to a dermatome is called:
neuralgia
192
(ex. burning sensation from diabetic neuropathy) is called:
dysesthesia
193
paresthesia
abnormal sensation described as pins and needles
194
inhibitory neurotransmitters used by the descending inhibitory pain pathway
norepinephrine
serotonin
195
antidepressants that can be used to treat chronic pain
TCAs
SSRIs
SNRIs
196
CV side effects of TCAs
- prolonged QT
- orthostatic hypotension
197
what characterizes complex regional pain syndrome
neuropathic pain with autonomic involvement
198
risk factors for complex regional pain syndrome
- female
- previous trauma
- previous surgery
199
key distinction between type 1 and type 2 complex regional pain syndrome
type 2 always preceded by nerve injury; type 1 is not
200
treatments for complex regional pain syndrome
- ketamine
- memantine (NMDA antagonist)
- gabapentin
- regional sympathetic blockade
- PT
- steroids
- amitriptyline
201
what is a thoracic paravertebral block
LA injected into paravertebral space to target ventral ramus of spinal nerve as it exits vertebral foramen
202
what does a thoracic paravertebral block cover
unilateral sensory and sympathetic block along that specific dermatome
203
how many dermatomes are covered by a thoracic paravertebral block?
one - the level injected
204
what types of surgeries see pain relief with a thoracic paravertebral block
- breast
- thoracotomy
- rib fracture
205
block useful for cancer pain of upper abdominal organs
celiac plexus block
206
complications of a celiac plexus block
- orthostatic hypotension
- retroperitoneal hematoma
- hematuria
- diarrhea
- AAA dissection
- back pain
- retrograde migration of injectate
207
nerve block useful in management of cancer pain of pelvic organs
superior hypogastric plexus block
208
complications of hypogastric plexus block
retrograde migration of injectate
209
use of a sphenopalatine block
relieve postdural puncture headache
210
only cranial nerve that is part of the CNS
optic nerve
211
complication of retrobulbar block causing blindness (contralateral amaurosis)
LA injected into optic sheath (can migrate toward optic chiasm and anesthetize CN II & III on the side opposite the block)
212
what is post-retrobulbar block apnea syndrome
when is it usually evident?
LA that reaches the brainstem and causes apnea
2-5 min after injection
213
when does spontaneous ventilation normally return after post-retrobulbar block apnea syndrome
in 15-20 minutes
214
when should you anticipate development of post-retrobulbar block syndrome?
assess contralateral pupil - if pupil starts small but dilates shortly after the block, anticipate apnea syndrome
215
risks assoc. with aminoglycosides
examples of aminoglycosides
- ototoxicity, nephrotoxicity, skeletal muscle weakness
- gentamycin, streptomycin
216
adverse effects of tetracyclines
- hepatotoxicity
- nephrotoxicity
217
AEs of fluoroquinololes
examples of fluoroquinolones
- Gi intolerance, tendonitis, tendon rupture
- ciproflaxin, levofloxacin, moxifloxacin
218
anesthetic implcation of macrolides
CYP450 inhibition
219
antibiotics that cause skeletal muscle weakness
- aminoglycosides
- clindamycin
220
why is hypotension associated with vancomycin admin?
histamine release
221
likelihood of cross reactivity between PCNs and cephalosporins
report of up to 10% overstated - true rate < 1%
222
which cephalosporins are assoc, with lowest rate of cross reactivity with PCNs
3rd & 4th generation
223
acceptable alternatives to cephalosporins with true PCN allergy
- vancomycin
- clindamycin
224
most common side effect of prophylactic antibiotics
pseudomembranous colitis
225
MOA of cephalosporins
disrupt bacterial cell wall synthesis (peptidoglycan)
226
MOA of vancomycin
disrupts bacteral cell wall synthesis
227
how often should cefazolin be redosed during surgery
Q4H
228
drug of choice for pts with active MRSA
vancomycin
229
how to reduce histamine release and hypotension with vancomycin
admin at a rate of 10-15 mg/kg over 1 h
230
how to minimize response to vancomycin
1 mg/kg diphenhdyramine + 4 mg/kg cimetidine 1 hr before anesthesia
231
antibiotics contraindicated in pregnancy
- chloramphenicol
- erythromycin
- fluoroquinolones
- tetracyclines
232
preferred method of skin prep before CVL placement according to the CDC
chlorohexidine
233
consideration for use of alcohol based products for surgical prep
flammable, allow to dry for 2 minutes
234
SCIP protocol
- prophylactic antibiotic admin within 60 min of incision (vanc is 120 min)
- antibiotic choice det. by surgery site
- prophylactic abx d/c'd within 24 hours postop (48 hrs for heart pts)
- glycemic control required for cardiac surgery (<200 mg/dL)
- postop wound infection dx during initial hospitalization
- surgical pts receive appropriate hair removal
- colorectal pts normothermic upon arrival to PACU ( > 36 C)
235
seroconversion rates after exposure to HIV-infected blood
- needle stick = 0.3%
- mucous membrane exposure = 0.09%
236
what is Creutzfeldt-Jakob disease
3 etiologies
prion disease that can lead to encephalopathy and dementia
1. consuming contaminated animal protein
2. contaminated implants (corneal or dural tissue)
3. cadaveric pituitary hormone supplementation
237
precautions for Creutzfeld-Jakob disease
standard
238
main target of mycobacterium tuberculosis
anterior apical lung segments
239
s/s tuberculosis
- productive cough
- hemoptysis
- weight loss
- fever
- night sweats
- anorexia
- general malaise
240
positive TB skin test result
site of induration > 10 mm (>5 mm if pt is immunocompromised)
241
positive findings on CXR of TB pt
apical infiltrates and nodules
242
if a skin TB test is positive but a CXR is negative, is TB ruled out?
yes
243
first line agent for TB treatment
what are its side effects?
- isoniazid
- peripheral neuropathy, hepatotoxicity
244
what med can be added with isoniazid to reduce incidence of liver damage
pyridoxine
245
adverse effects of rifampin
- thrombocytopenia
- leukopenia
- anemia
- kidney failure
- orange urine/sweat/tears
246
procedure with the highest risk of skin test conversion in healthcare personnel
2nd highest?
bronchoscopy
2 - intubation
247
safety measures for pts with TB
- providers and staff wear N95
- HEPA filter placed between y-piece and airway
- bacterial filter on expiratory limb of circuit
- dedicated anesthesia machine and ventilator ideal
- pre and postop care in negative pressure isolation room
248
how long should elective procedures be delayed in pts with TB?
- pt on antituberculosis chemo
- 3 negative acid-fast bacillus tests
- demonstrates symptom improvement
249
most abundant WBC
what is its purpose
neutrophils
immune defense (bacterial and fungal)
250
granulocyte that is an essential component of allergic reactions
basophils
251
what is released by basophils in an allergic reaction
- leukotrienes
- histamine
- prostaglandins
252
how does epinephrine help in an allergic reaction?
prevents degranulation (release of intracellular contents) by binding to beta 2 receptors on cell membrane
253
granulocytes that defend against parasites
eosinophils
254
purpose of monocytes
fight bacterial, viral, and fungal infection (phagocytosis)
255
function of B-lymphocytes
humoral immunity (produce antibodies)
256
function of T-lymphocytes
cell-mediated immunity (does not produce antibodies)
257
function of natural killer cells
meds that reduce their function
limit spread of tumor and microbial cells
opioids reduce function (concern of cancer recurrence)
258
which agranulocyte releases cytokines
monocytes
259
anaphylaxis is an example of which type of hypersensitivity reaction?
type 1
260
ABO incompatibility is an example of which type of hypersensitivity reaction?
type 2
261
serum sickness after a snake bite is an example of which type of hypersensitivity reaction?
type 3
262
graft vs host reaction is an example of which type of hypersensitivity reaction?
type 4
263
what is the difference in an anaphylactic and an anaphylactoid reaction?
anaphylaxis requires prior sensitization or cross-reactivity
no prior exposure needed for anaphylactoid reactions
264
effects of H1 receptor activation
- vasodilation
- increased vascular permeability
- smooth muscle contraction (not vascular)
265
effects of H2 receptor activation
- tachycardia
- gastric acid secretion
266
metabolites of arachidonic acid
what are the effects of release
- leukotrienes
- prostaglandins
bronchoconstriction and vasodilation
267
CV effects of hypersensitivity reactions
- hypotension
- tachycardia
- arrythmia
- cardiac arrest
268
respiratory symptoms of hypersensitivity reaction
- bronchospasm
decreased ETCO2
decreased SaO2
increased PIP
- laryngeal edema
- increased mucous production
269
GI effects of hypersensitivity reactions
- abdominal cramping
- N/V/D
270
what causes a type 1 hypersensitivity reaction
antigen + antibody interaction in a patient who has previously been sensitized to the agent
271
which hypersensitivity reaction is IgE-mediated
type 1
272
which hypersensitivity reaction is an immediate reaction
type 1
273
extrinsic asthma is an example of what type of hypersensitivity reaction
type 1
274
what is the best lab test to determine if an allergic response has occured?
tryptase (released from mast cells during an allergic reaction)
275
which type of hypersensitivity reaction is antibody-mediated
type 2
276
antibodies involved in type 2 hypersensitivity reaction
IgG & IgM
277
what causes a type 3 hypersensitivity reaction
immune complex is formed and deposited into the patient's tissue (normally cleared from body)
278
which types of hypersensitivity reactions activate the complement cascade
type 2 & 3
279
how long is an allergic reaction delayed in a type 4 hypersensitivity reaction
at least 12 hours after exposure
280
dose of epi for intraoperative anaphylaxis
5-10 mcg IV for hypotension
0.1-1 mg IV for CV collapse
281
histamine antagonists that should be given during intraoperative anaphylaxis
- H1 blocker: diphenhydramine 0.5-1 mg/kg
- H2 blocker: ranitidine 50 mg Iv or famotidine 20 mg IV
282
dose and use of hydrocortisone in intraoperative anaphyalxis
250 mg IV - prevents delayed release of inflammatory compounds (no immediate effect)
283
med to use for refractory hypotension in intraoperative anaphylaxis
vasopressin - start at 0.01 unit/min
284
3 ways epinephrine treats anaphylaxis
1. prevents degranulation
2. CV support
3. airway dilation
285
top 3 most common causes of perioperative anaphylaxis
1. NMBs (succs most common)
2. latex
3. antibiotics (beta lactams most common)
286
groups at high risk for latex reaction
- spina bifida/myelomeningocele
- atopy
- health care workers
- allergy to banana, kiwi, mango, papaya, pineapple, tomato
287
side effects of cisplatin
acoustic nerve injury
nephrotoxicity
288
side effects of vincristine and vinblastine
peripheral neuropathy
289
side effects and anesthesia implications of bleomycin
pulmonary fibrosis
keep FiO2 < 30%
290
main adverse effect of doxorubicin
cardiotoxicity
291
most chemotherapeutic agents cause bone marrow suppression and thrombocytopenia. which is a key exception?
bleomycin
292
5 key hormones that regulate digestive activity
1. gastrin
2. secretin
3. cholecystokinin
4. gastric inhibitory peptide
5. somatostatin
293
function of gastrin
where is it produced
- increased gastric acid secretion when food enters stomach
- increased pepsinogen secretion (converts to pepsin and aids in protein digestion)
produced in G cells of stomach
294
function of secretin
where is it produced
- pancreatic bicarbonate secretion
- decreased gastrin secretion
- liver secretes bile
produced in S cells of small intestine
295
function of cholecystokinin
where is it produced
- gallbladder contraction
- increased pancreatic enzyme secretion
produced in I cells of small intestine
296
function of gastric inhibitory peptide
where is it produced
- increased insulin reelase
- slows gastric emptying
- decreased gastric motility
K cells of small intestine
297
hormone that is the universal "off" switch for digestion (decreases all GI function)
somatostatin
298
where is somatostatin produced
D cells in pancreatic islet, stomach, small intestine
299
digestive hormone increased in Zolliger-Ellison syndrome
gastrin
300
digestive enzyme that causes gallbladder pain after a fatty meal
cholecystokinin
301
digestive enzyme that is the treatment for carcinoid tumors
somatostatin
302
what determines the likelihood of gastroesophageal reflux
barrier pressure
increased barrier pressure = decreased likelihood of reflux
303
3 things that reduce gastric barrier pressure
- anticholinergics (dec. LES tone)
- cricoid pressure ( dec. LES tone)
- pregnancy (dec. LES tone and inc. intragastric pressure)
304
what drug increases gastric barrier pressure
metoclopramide (inc. LES tone)
305
does succs affect gastric barrier pressure?
no - increased LES tone + increased intragastric pressure = 0 net change
306
gastric barrier pressure =
LES pressure - intragastric pressure
307
where does ondansetron antagonize serotonin receptors?
1. chemoreceptor trigger zone
2. peripheral receptors in GI tract and vagus nerve
308
where is the vomiting center located
nucleus tractus solitarus (medulla)
309
where does sensory input to the vomiting center arise from?
chemoreceptor trigger zone, GI tract, and vestibular system
310
receptors in the CTZ
- serotonin (5HT3)
- substance P (NK-1)
- dopamine
- opioid
311
5-HT3 antagonists used as antiemetics & their normal doses
- ondansetron: 4-8 mg
- granisetron: 1 mg
- dolasetron: 12.5 mg
312
NK-1 antagonist used as an antiemetic
aprepitant
313
dopamine antagonists used as antiemetics & normal doses
- metoclopramide: 10-20 mg
- droperidol: 0.625-1.25 mg
- haloperidol: 0.5-2 mg
- midazolam (may antagonize dopamine receptors in CTZ)
314
receptors associated with the vestibular apparatus
what drugs antagonize these receptors?
histamine (H1) - diphenhydramine
acetylcholine - scopolamine
315
opioid receptors reside in what sensory inputs to the vomiting center
vestibular apparatus
CTZ
316
how does the GI tract stimulate the vomiting center?
via CN 10
317
antiemetics that target the GI tract
5-HT3 antagonists
NK-1 antagonist (Aprepitant)
318
normal Aprepitant dose
40 mg
319
patient risk factors for PONV
- female
- nonsmoker
- history of motion sickness
- previous PONV
- younger age (loose association)
320
surgical risk factors for PONV
- long duration (>1 hour)
- GYN procedures
- laparoscopy
- breast
- plastics
- peds: strabismus, orchiopexy, T&A
321
anesthetic risk factors for PONV
- halogenated anesthetics
- N2O > 50%
- opioids
- etomidate
- neostigmine
322
what explains why the CTZ is stimulated by noxious chemicals
BBB poorly developed at CTZ
323
most common SEs of ondansetron
- HA
- diarrhea
324
when should decadron be given for PONV prophylaxis?
during induction
325
antiemetics that are contraindicated in pts with Parkinson's
dopamine antagonists (phenothiazines, metoclopramide) - can cause extrapyramidal symptoms
326
antiemetic contraindicated in bowel obstruction
metoclopramide (d/t prokinetic effect)
327
what causes motion-induced nausea
M1 & H1 stimulation in vestibular system of inner ear
328
what type of antiemetic should pts undergoing middle ear surgery receive?
agents that target vestibular system
329
best time to apply scopolamine?
how long does it last
>4 hours before anesthesia induction
lasts for 72 hours
330
dose of propofol that produces an antiemetic effect
10-20 mg
331
how can midazolam reduce PONV?
decreasing dopamine activity in CTZ
332
how does ephedrine affect PONV?
25 mg IM may reduce by maintaining BP and cerebral perfusion
333
significance of P6 acupressure point
nonpharmacologic method of reducing PONV - located 3 fingerbreadths below wrist on inner forearm in between 2 tendons
334
when should ondansetron be admin for PONV prophylaxis?
30 min before emergence
335
best class of antiemetics for patients undergoing mastoidectomy
anticholinergics
336
transient physiologic changes after release of pneumatic tourniquet
- increased ETCO2
- increased core body temp
- decreased BP
- decreased SvO2 (SaO2 usually normal)
- metabolic acidosis
337
symptoms of bone cement implantation syndrome
- V/Q mismatch (increased dead space)
- right heart failure in extreme cases
- bradycardia
- dysrhythmias
- hypotension (dec. SVR)
- pHTN (inc. PVR)
- hypoxia
- cardiac arrest
338
surgery assoc. with highest risk of BCIS
other surgeries with high risk
hip arthroplasty
knee arthroplasty, vertebroplasty, kyphoplasty
339
first signs of BCIS in awake patient under regional anesthesia
- dyspnea
- AMS
340
first sign of BCIS in anesthetized pt
decreased ETCO2
341
first line treatment of BCIS
- 100% FiO2
- IV hydration
- phenylephrine for hypotension
342
when is fat embolization syndrome risk greatest?
within first 72 hours of long bone injury
343
risk factors for fat embolization syndrome
- pelvic fracture
- femoral fracture
- instrumentation of femoral medullary canal
344
triad of fat embolization syndrome
- respiratory insufficiency (hypoxemia, bil. CXR infiltrates, ARDS)
- neuro involvement (confusion to coma)
- petechial rash (neck, axilla, oral mucosa, conjunctiva)
345
treatment of fat embolization syndrome
supportive; corticosteroids may or may not improve outcomes (controversial)
346
pneumatic tourniquet inflation pressure for upper extremity surgery
70-90 mmHg above SBP
347
pneumatic tourniquet inflation pressure for lower extremity surgery
2x over SBP
348
why does the tourniquet for a bier block have to be inflated for at least 20 min
premature release increases risk of seizure/cardiac arrest with LAST
349
tourniquet inflation pressure for upper extremity bier block
250 mmHg or 100 mmHg over SBP (whichever is higher)
350
tourniquet inflation pressure for lower extremity bier block
350-400 mmHg
351
what is Samter's triad and what are the 3 components
aspirin-exacerbated respiratory disease - can develop life threatening bronchospasm after aspirin admin
- asthma
- allergic rhinitis
- nasal polyps
352
effects of COX-1 inhibition
- impaired platelet function
- gastric irritation
- reduced renal blood flow
353
which COX enzyme is expressed during inflammation
COX-2
354
effects of COX-2 inhibition
- analgesia (ceiling effect)
- anti-inflammatory effects
- antipyretic effects
355
CV complications of NSAIDs
increased risk of HTN, MI, HF (COX-2 inhibitors > COX-1)
356
pulmonary complication of NSAIDs
dec. prostaglandins = leukotrienes = bronchospasm
357
hematologic complication of NSAIDs
platelet inhibition = increased bleeding risk
358
renal complication of NSAIDs
decreased prostaglandins = decreased renal blood flow (avoid in renal disease)
359
CNS complication of NSAIDs
tinnitus
360
bone related complication of NSAIDs
decreased osteoclast and osteoblast activity may impair bone healing
361
GI complications of NSAIDs
gastric ulceration and bleeding
362
NSAID drug interactions
NSAIDs displace albumin bound drugs and increase their plasma concentration (warfarin, phenytoin, valproic acid)
363
why have most COX-2 inhibitors been removed from the market
concerns about CV risk
364
max amount of time ketorolac can be taken
5 days
365
___ mg ketorolac = 10 mg morphine
30
366
MOA of aspirin
irreversibily inhibits COX-1 and COX-2
platelet inhibition lasts for the life of the platelet
367
suggested MOA of acetaminophen
inhibits prostaglandin synthesis (COX-3 inhibition?)
analgesia may be from activation of descending inhibitory pain pathway in spinal cord
368
acid base imbalance seen with aspirin toxicity
gap metabolic acidosis
369
max daily dose of tylenol
4g/day
370
6 drugs that inhibit the COX-2 pathway
1. aspirin
2. ibuprofen
3. naproxen
4. ketorolac
5. diclofenac
6. indomethacin
371
perioperative implication of licorice as an herbal supplement
may mimic Conn's syndrome:
- mimics effects of aldosterone
- sodium and water retention with decreased K+
372
perioperative implications of valerian root as an herbal medication
- decreases MAC (increased GABA)
- may prolong duration of anesthetics
- abrupt discontinuation can cause withdrawal
373
perioperative implication of St. Jon's Wort as an herbal medication
when should it be d/c'd before surgery?
- serotonin syndrome with MAOIs
- CYP3A4 induction
- decreased serum level of warfarin, protease inhibitors, digoxin
- may prolong anesthetic agent duration
d/c 5 days preop
374
perioperative implication of garlic as an herbal medication
when should it be d/c'd before surgery?
- increased bleeding risk
- decreased serum glucose
d/c 7 days preop
375
ephedra (Ma Huang) interactions and toxicity
- serotonin syndrome with MAOIs
- catecholamine depletion with long term use (HD instability)
- sympathomimetic effects
376
anesthetic implications of ginger as an herbal supplement
increased bleeding risk
377
anesthesia implications of ginseng as an herbal supplement
- increased bleeding risk
- enhanced SNS effects of sympathomimetics
- may cause hypoglycemia (risk in fasting patient)
378
anesthesia implicaitons of kava kava as an herbal supplement
- decreased MAC (increased GABA)
- may prolong duration of anesthetic agents
379
anesthetic implications of Saw Palmetto
increased bleeding risk
380
4 herbal supplements that increase the risk of bleeding
- Garlic
- Ginger
- Gingko
- Ginseng
(4 G's)
381
ASA Pre-Anesthesia Checkout Procedure recommendations - tasks to complete before every patient
- verify suction
- check function of monitors and alarms
- check vaporizers filled, ports closed
- check CO2 absorbent
- high pressure leak test
- assess unidirectional valves
- document
382
what agency sets the standards for required components of the anesthesia machine
american society for testing and materials
383
agency that sets the standards for compressed gas cylinders
US department of transportation
384
agency that sets the standards for food and drugs
FDA
385
agency that created the 1993 Anesthesia Machine Pre-Use Checkout procedures
FDA
386
agency that sets standards for acceptable occupational exposure to volatiles
OSHA
387
agency that certifies hospitals that meet specific safety standards
Joint Commission (JCAHCO)
388
MRI zone 1
public access, requires no supercision
ex- hallway outside MRI Suite
389
MRI zone 2
public access + minimal supervision
ex- entrance to MRI suite
390
MRI safety zone 3
limited access + strict supervision
ex- MRI control room
391
MRI zone 4
very limited access + very strict supervision
ex- MRI scanner room
392
T/F - ferromagnetic objects are allowed in MRI zone 4
nope
393
safe metals in MRI suite
stainless steel
titanium
aluminum
copper
394
common side effect of IV contrast media
nausea
395
EKG changes that may be seen in MRI
T wave and ST segment artifacts
396
what indicates an MRI safe gas cylinder
silver with a color code at the top
397
estimated anesthetic mortality assoc. with each ASA class
1 - 0.04 per 10,000 anesthetics
2 - 0.5 per 10,000
3 - 2.7 per 10,000
4 - 5.5 per 10,000
398
according to closed claims analysis, what are the 4 most common causes of injury (in order) that result in claims filed?
1. regional anesthesia (20%)
2. respiratory events (17%)
3. CV events (13%)
4. equipment failure (10%)
399
what is the modified Aldrete scoring system
used to quantify readiness for discharge from PACU
assesses 5 things:
activiy, respiration, circulation, consciousness, O2 sat
400
modified Aldrete score that suggests readiness for PACU discharge
score of 9 or greater
401
modified Aldrete scoring system: Activity
2: moves all extremities voluntarily or on command and can lift head
1: moves 2 extremities voluntarily or on command and can lift head
0: cannot move extremities or lift head
402
modified Aldrete scoring system: Respirations
2: breathes normally, can cough effectively
1: dyspneic, shallow, or otherwise inadequate breathing
0: apneic
403
modified Aldrete scoring system: Circulation
2: BP within 20 mmHg of preanesthetic value (min SBP = 90)
1: BP within 20-50 mmHg of preanesthetic value
0: BP > 50 mmHg of preanesthetic value
404
modified Aldrete scoring system: Consciousness
2: fully awake
1: arousable to voice
0: unresponsive to voice but may be responsive to painful stimuli
405
modified Aldrete scoring system: O2 sat
2: SpO2 > 92% on RA
1: SpO2 > 90% but needs supplemental O2
0: SpO2 < 90% on supplemental O2
406
time to onset of sympathomimetic syndrome
up to 30 min
407
causes of sympathomimetic syndrome
amphetamines
cocaine
408
key features of sympathomimetic syndrome
- agitation
- hallucinations
- arrhythmias
- myocardial ischemia
409
treatment of symapthomimetic syndrome
vasodilators
labetolol
410
time to onset of TCA overdose
up to 6 hours
411
key features of TCA overdose
- hypotension
- dec. LOC/coma
- polymorphic VT
412
treatment of TCA overdose
magnesium
serum alkalization
413
time to onset of serotonin syndrome
up to 12 hours
414
drugs that can cause serotonin syndrome
- SSRIs
- SNRIs
- MAOIs
- ecstasy
415
key features of serotonin syndrome
- akathisia
- mydriasis
- tremor
- AMS
- clonus
- muscle rigidity
416
treatment of serotonin syndrome
cyproheptadine (5-HT2A blocker)
417
time to onset of anticholinergic syndrome
up to 12 hours
418
causes of anticholinergic syndrome
atropine
scopolamine
419
key features of anticholinergic syndrome
- red, hot, dry skin
- mydriasis
- delirium
420
time to onset of NMS
up to 24-72 hours
421
key features of NMS
- bradykinesia
- dec. LOC/coma
- rhabdo
- myoglobinuria
- acidosis
- ANS instability
- muscle rigidity
- normal pupils
422
treatment of NMS
bromocriptine
dantrolene
ECT
