spine/thyroid/obesity Flashcards
(108 cards)
1
Q
2 most common reason for spine sx
A
disc herniation and spinal stenosis
2
Q
whats the biggest anesthetic challenge for spine cases
A
positioning: use of prone, supine, lateral , or a combination
3
Q
5 challenges for spine cases
A
- positioning
- high blood loss
- use of IONM and impact on anesthetic plan
- the need for multimodal pain mgmt
- often in elderly or peds with other comorbidities
4
Q
why should the head be kept in a neutral position in spinal cases? (name degree and location of compromise)
A
60 degree rotation = restricted contralateral vertebral artery flow
80 degree rotation = occluded contralateral vertebral artery flow
5
Q
concerns with the use of the wilson frame (3)
A
- head is lower than the heart making BP monitoring challenging
- RF for POVL
- risk for VAE
6
Q
what are the 2 main types of POVL
A
-CRAO: central retinal vascular occlusion (compression)
-ION: ischemic optic neuropathy (hypoperfusion)
7
Q
7 RF for POVL
A
- male
- obesity
- wilson frame
- long sx time (>6h)
- hypotension
- Prone spine cases (also high risk with cardiac cases)
- high EBL
(8. some sources say use of colloids but others advocate for it)
8
Q
presentation of POVL
A
painless, bilateral vision loss. loss of light perception. decrease or loss of color perception. non-reactive pupils. occus 24-48h post-op
9
Q
most important goal of ERAS for spine
A
return to baseline functional capacity
10
Q
4 risks/complications assoc with ACDF
A
- nerve injury
- vessel injury
- esophageal injury
- PTX
11
Q
considerations for ACDF induction and most common type of anesthesia
A
-careful airway exam…assess c-spine mobility and assoc symptoms
-prob will need VL
-GA+ ETT
12
Q
can you use inhalationals with ACDF and SSEP monitoring
A
<1 MAC with SSEP
13
Q
what 2 drugs are contraindicated with MEP
A
Mag
NeuroMuscular blockers
(MEP: MMNM)
also avoid inhalationals
14
Q
emergence considerations for ACDF (4)
A
-extubate awake to check neuro function (must assess neuro function before leaving the OR)
-avoid coughing and bucking due to risk for hematoma which requires immediate sx evacuation
-assess for RLN injury (know uni/bi lat presentation)
-may require a brace per surgeon
15
Q
what is the leading cause of work absences and what is the most common site of injury
A
back injuries, L4/5 or L5/S1
16
Q
what type of anesthesia is contraindicated with IONM
A
regional (both spinal and epidural bc they interrupt both sensory and motor function)
17
Q
what should you always do after changing pt position
A
reassess ETT placement
18
Q
what does sudden profound hypotension suggest during spine sx
A
major vessel injury
19
Q
in prone, whats the max ml/kg of crystalloid to give and why
A
40ml/kg, risk of ION POVL if more
20
Q
above what level do you need a DL ETT to collapse the lung on operative side for thoracic spine surgery
A
T8
21
Q
what is a risk with thoracic fusions
A
Spinal cord injury
22
Q
what is a risk with thoracoabdominal approach for spinal sx
A
respiratory compromise
(may also require rib removal)
23
Q
what is the most frequent non-traumatic cause of SC transection
A
MS
24
Q
what level SC transection is incompatible with life unless intubated
A
C2-4
25
where is temp regulation lost in the setting of SCI
BELOW the level of injury
26
do you still need to anesthetize patients with autonomic hyperreflexia/loss of innervation
YES: they still have hyperactive ANS. anesthesia attenuates the ANS and hyperactivity to avoid HTN and low HR
27
at what level are you concerned about autonomic hyperreflexia
above T6
28
s/s of autonominc hyperreflexia
severe HTN and bradycardia
(HA, pallor, cool, sweating)
29
when is scoli sx indicated regarding the Cobb angle
>40-50 degrees or rapidly progressing
30
what lung pathology is seen with scoli patients
restrictive lung disease
31
implication of PFTs and scoli sx? if VC is...
<40% of predicted, keep intubated post-op
32
POVL is characterized by:
loss of pupil rxn and occurs 24-48h post-op
(Kahoot answer)
33
leading cause of death in chronic SCI patients
renal injury
34
most appropriate type (not agent) of anesthetic for IONM
GA (you cannot use regional)
35
effect etomidate has on IOMN
increases amp and increases latency
36
what agents decrease amplitude and increase latency
N2O, sevo, brevital (from kahoot)
37
where is the thyroid gland located
-anterior to the trachea
-caudad to the hyoid bone, cricoid cart, and thyroid cart
-cephalad to the suprasternal notch
38
what supplies blood to the thyroid gland
superior and inferior thyroid arteries provide an extensive blood supply
39
what nerve borders the thyroid gland b/l
RLN
40
what are the functional units of the thyroid gland and what do they do
-follicles (surrounded by epithelial cells, center is made of a colloid called thyroglobulin)
-make and store thyroid hormones (controlled by TSH)
--tyrosine and iodine are needed to make
41
what is the rate limiting step of thyroid synthesis
iodine trapping
42
where is TSH released from
anterior pituitary
43
describe T3 and T4
T3: active/less bound, potent form, only 7% of released thyroid hormone, t1/2 = 24h
T4: bound, less active/potent form. gets deiodinated to T3. T1/2 = 6-7d
44
what feedback loop does T4 have
Negative (on the hypothalamus and ant pit)
hypothal --> TRH --> ant pit --> TSH --> thyroid --> T3/4
45
relationship of calcium and phosphorus
inverse
46
effect of alkalosis on ical
alk shifts ical into PB and REDUCES serum levels
high pH = low ical
47
effect of acidosis on ical
acidosis release PB of ical
low pH = high ical
48
what does calcitonin do
lowers ical
(opposite effect of PTH...inhibits osteoclasts)
49
what type of aneshesia is most common for thyroid/pth surgery? what NMB would you use?
GA with std induction/maint
succ bc of short DOA (cannot use paralytics with NIM ETT)
inhaled and TIVA can be used, but TIVA is most common per Cassie
50
What does the NIM ETT tube do
monitors VC and RLN function
51
2 drugs to avoid with NIM ETT
paralytics and lido (tracheal/laryngeal application)
52
3 complications of thyroidectomy
1. RLN injury
2. hypoPTH/hypocal (intentional or accidental removal of PTH)
3. hematoma
53
unilat vs bilat RLN injury post thyroidectomy
uni (ipsilateral VC remains midline)= hoarseness that usually improves
bilat = aphonia, stridor, airway obstruction...emergency
54
signs of hypocal and treatment
long QT, hypotension, laryngospasm/stridor, myocardial depression, tingling in lips/fingers, tetany, seizures, muscle spasms, hyperactive DTR, +chvostek & trousseau sign
Treat: give cal chl or cal glu
55
why is a hematoma post thyroidectomy concerning and what is the treatment?
how can we help avoid this?
-airway obstruction
-surgical evacuation
-avoid coughing/bucking on emergence (use remifent)
56
s/s of hypercalcemia and treatment
HTN, short QT, conduction disturbance, confusion/lethargy, bone pain, osteopenia/fractures, anorexia, n/v, pancreaatitis, polyuria, polydipsia, kidney stones
-give isotonic IVF (not LR) to dilute it, loop diuretics to excrete it
-monitor ECG & renal function
57
CV differences for hypo/hypercal
hypo: long QT, hypoTN, myocardial depression
hyper: short QT, HTN, conduction disturbances
58
what labs are monitored intra and post op parathyroidectomy
calcium and PTH levels
(mag and phos may also be monitored)
59
when do calcium levels drop post-parathyroidectomy? what do you need to watch for?
immediatey
-neuromuscular excitability --> laryngospasm
60
should patient continue thyroid meds peri-op?
yes- the goal is for patient to be euthyroid
61
s/s of hypothyroid (15 from cassies slide)
goiter, slow metabolism, cold intolerance, fatigue, depression, joint & muscle pain, dry/brittle hair and skin, puffy face
CV: labile BP, arrhythmia, cradiomegaly, poor contractility, abnormal baroreceptor function, HF
62
primary vs secondary hypothyroid
primary = high TSH, low T3/T4
secondary = low TSH, low T3/T4
63
is ventilatory reponse to hypoxia and hypercarbia impaired with hypothyroid?
yes
64
3 possible airway concerns with hypothyroid
goiter, enlarged tongue, tracheal deviation/compression
-pre-op imaging may be needed, consider FIB intubation
65
anes for hypothy (box 37.13)
1. euthyroid? y/n
2. should you assess for goiter? y/n
3. continue meds day of?
4. effect of anes on CNS
5. hepatic/renal effects & dosing?
6. will pt be warm or cool?
7. effect of NMBs?
8. blunted ventiatory response?
9. CV effect?
10. increase or decerae in plasma volume when calculating fluid replacement?
1. yes
2. yes
3. yes
4. exaggerated CNS depression
5. may decrease dose due to impaired metabolism
6. cool. use warming devices
7. may be profound if existing weakness
8. yes
9. depressed
10. reduction
66
myxedema coma
-4 hypo...
-plan?
-severe hypothyroid
-hypoBP, hypoventilation, hypothermia, hypoNa
-intubate (usually) and delay surgery
67
biggest cause of hyperthyroidism
graves disease
68
4 RF for hyperthyroidism
female, genetics, stress, cigarette smoking
69
what drug can affect thyroid levels
amio (hyper or hypo)
70
primary hyperthyroid vs subclinical hyperthyroid
primary = low TSH, high T3/4
subclinical = Low TSH & T3/4
71
s/s hyperthyroidism
hypermetabolic stte, tachycardia, wam/moist skin, tremor, diarrhea, osteopenia, muscle weakness, wt loss, anxiety, heat intolerance, ocular abnormaliteies
72
3 RF for thyroid cancer
female, radiation exposure, inherited syndromes
73
3 anesthetic choices for thyroidectomy
1. GETA (most common)
2. LMA
3. local & sedation with b/l cervical plexus blocks
74
what might be the best option for intubation for throidectomy
awake fiberoptic intubation
75
what drugs to avoid with thyroidectomy (for hyperthyroidism)
drugs that stimulate the SNS: ketamine, glyco, vagolytics, panc
76
should you use direct or indirect acting vasopressors with thyroidectomy
direct bc if high catecholamines at baseline, indirects will release more and can cause CV effects
77
what body part should be protected and monitored during thyroidectomy
eyes
78
s/s of thyroid storm (10) and when does it most often occur peri-op
temp >38.5c, HTN, tachy, confsion, agitation, tremor, weakness, arrhythmia, n/v, HF
-6-18h post op
79
should you use salycilates for thyroid storm?
no it can displace T3/4 from proteins and raise levels further
-use tylenol
80
what does PTH do
-increase calcium and decrease phos
-activates osteoclasts to break down bone to release cal
-activates vit d to promote cal absorption in GI tract
81
effect of obesity on respiratory function
-restrictive ventilatory effect from excess weight. makes it harded for chest wall to expand and get air IN
-rapid shallow breathing
82
is O2 consumption increased or decreased w obesity?
CO2 production?
why
-O2 consumption is increased and CO2 production is increased
-fat is metabolically active
83
2 functions of adipose tissue
reservoir of usable energy, maintain heat/insulation
84
when does adipose tissue become pathologic
when it releases free fatty acid and cytokines. this leads to end-organ injury, insulin reisitance, and inflammaation
85
what lung volumes/capacity are decreased with obesity
TLC, VC, FRC, ERV, RV, IRV
(all except 1)
86
what is the only lung vol/capacity increased with obesity?
closing volume
87
what happens when FRC < closing volume
small airways collapse, causing VQ mismatch, shunting, hypercarbia, hypoxia
88
what is the most senstive indicator of the effect of obesity on pulmonary function
ERV
89
relationship of FRC and BMI
inverse
90
effect of obesity on CO
CO is increased
91
how does obesity lead to hypertension
release of inflamatory mediators --> increase RAAS/SNS --> vasoconstriction --> HTN, tachy, high CO
92
is total blood vol increased or decreased w/ obesity?
is relative blood volume increased or decreased with obesity?
total is increased, relative is decreased
93
whats EBV for obese
45ml/kg
94
cause of excess adipose tissue
excess consumption & decreased activity
95
how does obesity cause insulin resistance
high levels of free fatty acids in circulation block the transport mechanism so glucose cannot move into the cell
96
android vs gynecoid fat
android: central, apple shape, assoc with inc O2 consumption, DM, and CV disease. more dangerous
gynecoid: peripheral, pear shape, fat is less metabolically active, less CV risk
97
what measurement is now used for a standard marker of abdominal obesity? and what is # for M/F
-abdominal girth
Male >102cm
Female > 88cm
98
BMI formula
wt (kg)/ht (m^2)
99
obesity classifications
normal 18.5-24.9
over 25-29.9
obese 30+
class 1 = 30-34.9
class 2 = 35-39.9
class 3 = 40+
100
concern with using TBW with obese
overdosing
101
IBW formulas
M: IBW=height (cm)-100
F: IBW= ht (cm)-105
102
LBW formula
LBW = IBW x 1.3
LBW accounts for body composition to an extent
103
adjusted body weight
derivative of IBW used to prevent overdosing
-correction factor added to IBW
IBW + 20% or +40%
104
issue with using IBW
under-doses
105
what is the best weight to use with obese
LBW
106
when using lipophilic drugs what weight is the best
LBW
107
when using hydrophilic drugs what weight is best to use
IBW + 20%
(to acct for the increase in lean body tissue)
108
