5. OR Concepts Flashcards

1
Q

baroreceptros

A

pressure sensors
detect pressure of blood flowing through arteries

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2
Q

baroreceptor locations

A

carotid sinuses
aortic arch

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3
Q

baroreceptor reflex

A

helps mx normal cardiac output with high or low BP

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4
Q

baroreceptor reflex process

A
  1. sense change in BP
  2. send signal to brain to correct BP
    • Low BP: ANS increase HR (CO)
    • High BP: ANS decrease HR (CO)
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5
Q

reflex bradycardia

A

vasoconstriction (high BP) causes HR to decrease

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6
Q

reflex bradycardia commonly caused by what drug

A

phenylephrine

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7
Q

reflex tachycardia

A

vasodilation (low BP) causes HR to increase

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8
Q

drugs that can trigger reflex tachycardia

A

propofol or hydralazine

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9
Q

carotid body

A

chemoreceptors that sense hypoxia
stimulate respirations (hypoxic drive)

also sense: temp, pH, CO2

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10
Q

carotid sinus

A

baroreceptors adjust HR to mx normal CO/BP

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11
Q

cerebral vascular accident (CVA)

A

stroke
sudden brain cell death cause by inadequate blood flow

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12
Q

causes of stroke

A

blood clot
intracranial hemorrhage
prolonged hypotension
hypertension

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13
Q

Ischemic stroke

A

Blood clot

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14
Q

intracranial hemorrhage

A

hemorrhagic stroke

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15
Q

prolonged hypothension can be caused by

A

inadequate brain perfusion

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16
Q

hypertension can lead to

A

stress on walls of blood vessels
intracranial hemorrhage

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17
Q

DVT

A

blood clot in vein (usually in leg)
more likely to develop if blood from is static

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18
Q

Pts at risk for blood clots

A

bedridden pts
heart arrythmias that decrease BF through heart
- afib

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19
Q

pulmonary embolism

A

DVT dislodged from legs that moves to heart and lungs
life threatening emergency

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20
Q

DVT prevention

A

walking/movement
blood thinners
sequential compression stockings during surgery

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21
Q

intracellular fluid
(ICF)

A

inside cells
65%

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22
Q

extracellular fluid
(ECF)

A

outside cells
35%

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23
Q

2 divisions of ECF

A

interstitial fluid
intravascular fluid

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24
Q

edema

A

swelling
excess fluid in interstitial space

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25
Q

pulmonary edema

A

excess fluid in alveoli
commonly caused by some degree of heart failure

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26
Q

interstitial fluid

A

any fluid not inside cells or inside intravascular space (arteries/veins)

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27
Q

transmural pressure

A

difference in pressure between 2 sides of a wall

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28
Q

pulmonary edema causes

A

pressure in lungs is drastically reduced
pressure in capillaries is relatively higher

Plungs<Pcapillaries

blood moves from capillaries into lungs

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29
Q

common causes of negative pressure pulmonary edema

A

biting on ETT
laryngospasm
kinked tube
obstructed airway

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30
Q

how to treat negative pressure pulmonary edema caused by biting on ETT

A

pull tube
or
relax bite w/propofol/sux

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31
Q

prevent pt from biting on ETT

A

place bite block prior to emergence

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32
Q

treat pt biting on LMA

A

deflate cuff
air can now move around the cuff into trachea

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33
Q

preload

A

volume of blood returning to RV
blood available to be pumped on next contraction

venous return

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34
Q

afterload

A

resistance the LV pumps against

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35
Q

preload is proportional to

A

pts volume status
- hypovolemia = low preload
- hypervolemia = high preload
pts position
- head up = high preload
- head down = low preload

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36
Q

how is preload measured

A

central venous pressure (CVP)
only measured w/central line

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37
Q

CVP

A

blood pressure within the superior vena cava
normal: 5-12 mmHgce

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38
Q

central lines are placed in

A

internal jugular
subclavian
(large central vein)

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39
Q

low CVP indicates

A

low preload
(hypovolemia)

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40
Q

high CVP indicates

A

fluid overload

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41
Q

high CVP is common in what pts

A

heart failure
renal failure

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42
Q

afterload is proportional to

A

level of vasoconstriction
- vasoconstriction = high afterload
- vasodilation = low afterload
blood pressure
- high BP = high afterload
- low BP = low afterload

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43
Q

when can you have high afterload and low blood pressure?

A

if pt is bleeding to death (exsanguinating)

low BP due to hypovolemia

vasoconstriction to try to keep blood pressure high would cause high afterload

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44
Q

systemic vascular resistance (SVR)

A

AKA afterload

AKA peripheral vascular resistance

arterial vasoconstriction = high SVR
arterial vasodilation = low SVR

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45
Q

pulmonary vascular resistance
(PVR)

A

resistance that the right ventricle must pump against
afffected by vascular tone of pulmonary arteries

pulmoary artery vasoconstriction = high PVR
pulmonary artery vasodialtion = low PVR

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46
Q

positive intrathoracic pressure

A

**decrease BP

compresses heart/veins
incr resistance to BF
decr preload/venous return
decr SV
decr CO
decr BP

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47
Q

types of positive intrathoracic pressure

A

PPV
PEEP
valsalva maneuver

drops BP

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48
Q

negative intrathoracic pressure

A

reduces pressure to heart/veins
decr resistance to BF
incr preload/venous return

decr SV

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49
Q

types of negative intrathoracic pressure

A

spontaneous ventilation

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50
Q

cautery

A

cautery pen = bovie
cuts tissue
burns/coags blood vessels
requires grounding pad

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51
Q

cautery electrical loop

A

required for current to flow

  1. machine
  2. bovie
  3. patient
  4. grounding
  5. machine

if you do not have grounding pad, current cannot flow

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52
Q

grounding pad

A

return electrode to the eletrocautery unit

required for current to flow

large surface area
place over well perfused muscle to dissipate heat (thigh)

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53
Q

unipolar bovie

A

superior coagulation
requires grounding pad
more current flow

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54
Q

bipolar bovie advantages

A

2 cautery tips
- less current flows between tips
- more controlled == delicate areas
(nerves)

no grounding required

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55
Q

bipolar bovie disadvantage

A

cauterizes small areas
not good for controlling large bleeding

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56
Q

cautery safety

A

minimal electrocution risk
high current freq (>200,000Hz)

pts with interior metal are burn risk
- remove jewelry
- place pad away from internal metal

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57
Q

implications of Pnemoperitoneum (CO2 insufflation) (8)

A
  1. intubation required
  2. atelectasis more likely
  3. hypercarbia more likely
  4. vagal response
  5. CO decreases
  6. BP fluctuation
  7. referred pain in shoulder
  8. partial pneymothorax
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58
Q

why can CO2 insufflation cause atelectatsis?

A

diaphragm compression
resistance to lung expansion
decrease FRC

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59
Q

why is hypercarbia more likely w/CO2 insufflation?

A

CO2 diffuses to arteries

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60
Q

what are the impacts of a vagal response during CO2 insuflation?

A

bradycardia
hypotension

during insufflation

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61
Q

why does CO decrease during CO2 insufflation?

A

CO2 compresses vena cava
venous pooling in legs
decreased venous return to heart
(decreased preload)

62
Q

what causes BP fluctuation during CO2 insufflation?

A

BP down:
- decr venous return
- decr CO

BP up:
- vasoconstriction (SVR incr) due to compensation for CO decrease

63
Q

why can pts get shoulder pain with CO2 insufflation?

A

diaphragm and shoulder are innervated by the phrenic nerve

64
Q

how can CO2 insufflation cause a partial pneumothorax?

A

if CO2 gets into the thoracic cavity
can partially collapse lung

65
Q

CO2 gas embolism

A

accidental injection of CO2 into artery/vein
blockage of right ventricle or pulmonary artery
28% mortality rate

cause:
veres needle incorrectly place into vein or parenchymal organ

66
Q

SubQ Emphysema

A

trapped air beneath the skin

67
Q

Causes of SubQ emphysema (6)

A

multiple attempts at abdominal entry
improper cannula placement
incr intraabdominal pressure
long procedures (>3.5hrs)
gas flow rate
high total gas volume

68
Q

SubQ CO2 insufflation safe range

A

0-20 mmHg

69
Q

SubQ CO2 insufflation recommended range

A

12-14 mmHg

70
Q

SubQ emphysema clinical significance

A

hypercarbia
acidosis

EtCO2 elevates at end of surgery
airway swelling
crepitus (crackling skin)

extubation likely contraindicated until symptoms resolved

71
Q

gastric tube

A

orogastric tube: into mouth (OG)
nasal gastric tube: into nose (NG)

72
Q

OG/NG tube purpose

A
  1. decompress stomach
    • laproscopic surgery
    • bowel obstruction
    • drug overdose/poisoning
  2. feeding tube
73
Q

OG tube indications

A

temporary

74
Q

NG tube indications

A

more permanent

open abdominal
- vent intestinal gases to avoid ileus
- ask surgeon if they want OG or NG

75
Q

ileus

A

temporary surgical induced gastroparesis
(bowel obstruction)

76
Q

NG tube contraindications

A

facial fractures

77
Q

OG/NG tube contraindications

A

pts w/prior gastric surgery
- risk of intestinal perforation
liver failure/cirrhosis
- esophageal varices can rupture

78
Q

anaphylaxis

A

mast cells destabilize
release histamine
1. vasodilation
2. bronchoconstriction
- wheezing
- difficult ventilation

79
Q

anaphylaxis diagnosis

A

low tidal volume
high circuit pressure
hives

80
Q

anaphylaxis treatment

A
  1. epi pen (300mcg IM)
  2. Beta 2 agonist (bronchodilator)
    • albuterol
    • terbutaline (0.25mg) injection
  3. volatile agent (bronchodilator)
    • sevo or iso
  4. antihistamine
    • benadryl H1 blocker
    • pepcid H2 blocker
  5. steroids (swelling reduction)
    • solumedrol
    • solucortef
81
Q

compartment syndrome

A

decrease in BF/perfusion to body compartment due to increase in pressure inside compartment

can lead to permanent injury or amputation

82
Q

causes of compartment syndrom

A

fracture
infiltrated IV
tight cast

83
Q

compartment syndrome treatment

A

fasciotomy

incision into compartment to relieve pressure buildup/decompress vessels

84
Q

vagal response

A

sudden onset of:
bradycardia
hypotension

mimics symptoms of vagal nerve stimulation

85
Q

vagal response common causes

A

CO2 insufflation for lap surgery
eye surgery
abdominal/uterine surgery

86
Q

steroids

A

enhance effectiveness of catecholamines

87
Q

“stress dose” of steroids

A

given to pts if vasopressor therapy is not effective

likely needed for pts on chronic steroids
- more susceptible to hypotension

88
Q

“stress dose” drugs

A

solu-medrol (methyprednisolone)
-most common
solu-cortef (hydrocortisone)

89
Q

abdominal splinting

A

hypoventilation cause by pain of breathing

shallow breathing

90
Q

abdominal splinting causes

A

abdomina/thoracic procedures

91
Q

abdominal splinting prevention

A

adequate pain meds
nerve blocks (TAP, intercostal)
local anesthetic at surgical site

92
Q

higher dose drug

A

fast onset
longer duration

93
Q

lower dose drug

A

slower onset
shorter duration

94
Q

fentanyl low vs high dosing

A

1mcg/kg bolus: 45 mins
5 mcg/kg bolus: hours

95
Q

rocuronium low vs high dosing

A

100mg: fast onset/long lasting
20 mg: slow onset/short lasting

96
Q

adverse opioid effects

A
  1. respiratory depression
  2. gastroparesis (full stomach)
  3. urinary retention
  4. itching
  5. constipation
  6. stiff chest syndrome (diaphragm)
  7. addiction
97
Q

stiff chest syndrome treatments

A

succinycholine

98
Q

best way to dose opioids

A

according to respiratory rate
- for SV pts only

99
Q

dosing for mechanically ventilated pts

A

vital sings can indicate pain
tachycardia
hypertension

100
Q

dosing of opioid based on procedure

A

some procedures are more painful

Ex lap/thoracotomy > cystoscopy

101
Q

fentanyl dosing

A

2 mcg/kg per hour of surgical time

102
Q

more painful surgeris

A

cardiothoracic
orthopedic
open abdominal

103
Q

remifentanil uses

A

neuromonitoring cases when muscle relaxants and high doses of agent cannot be used (<0.5 MAC)

infusion allow profound analgesia w/minimal respiratory depression

104
Q

toradol

A

IV NSAID
profound analgesia
minimal respiratory depression

105
Q

toradol contraindications (10)

A
  1. allergies to NSAIDs
  2. bleeding risk (increases bleeding)
  3. renal disease
  4. geriatrics
    -1/2 dose
  5. Hx GI ulcers/bleedings
  6. Hx asthma
  7. lithium use
  8. neonates/labor pts
  9. gastric bypass pts
  10. bone surgery
106
Q

torado renal impacts

A

decreases renal blood flow
increases renal vascular resistance

107
Q

toradol infants impacts

A

promotes prematures closure of ductus arteriosus

108
Q

toradol bone impacts

A

impair bone healing due to inhibition of prostaglandins

109
Q

Ofirmev

A

IV acetominophen

analgesic
minimal respiratory depression
reduction of post-op shivering

110
Q

Ofirmev onset

A

5-10 mins
peak effect: 1 hr

111
Q

Ofimev contraindications

A
  1. pt w/liver disease
  2. alcoholics
  3. pts on vicodin or norco
    • these contain acetominophen
112
Q

precedex (dexmedetomidine)

A

analgesic
minimal respiratory depression
sedative

alpha 1 agonist

113
Q

precedex common dosing

A

0.2-0.5 mcg/kg boluses at beginning and end of procedure

114
Q

precedex side effects

A

decrease BP
decrease HR

115
Q

induction agents onset/duration

A

onset: seconds
duration: 3-5 mins

116
Q

what is the last sense to be suppressed by induction agents?

A

hearing

117
Q

propofol advantages

A

minimal long term side effects
antiemetic propertiespro

118
Q

propofol disadvantages

A

profound cardiac depressant
- high SV decrease
vasodilation
- profound BP decrease
profound respiratory depressant

119
Q

Etomidate advantages

A

cardiovascularly stable
- minimal BP impacts
- hypertension after intubation
minimal respiratory depression

120
Q

Etomidate disadvantages

A

PONV
adrenal suppression
hypertension post-intubation

121
Q

Etomidate cauton

A

increased overall 30 day mortality when used

short term gain: stable induction
long term loss: adrenal suppression

122
Q

Ketamine advantages

A

analgesic
bronchodilation
minimal respiratory depression
increase HR / BP

123
Q

Ketamine disadvantages

A

increase airway secretions
increase PONV
hallucinations

124
Q

low dose ketamine

A

25-50mg perioperatively reduces post-op pain, decrease opioid reqs

minimizes negative side effects

125
Q

short sedation (MAC) with ketamine

A

mix 50mg ketamine into 20mL syringe of propofol

more analgesia
less respiratory depression

126
Q

succinylcholine onset/druation

A

onset: 30-60 seconds
duration: 3-5 mins

127
Q

succinylcholine indications

A

RSI for full stomach pts

128
Q

succinylcholine contraindications

A

long operations
only used for intubation paralysis

MH

129
Q

succinylcholine intubation dosing

A

0.3-0.5 mg/kg is adequate for intubation

drug card says: 1 mg/kg

130
Q

non depolarizing muscle relaxants

A

roc
vec
cisatracurium

131
Q

higher dose NDMR

A

speeds up onset
prolongs duration

avoid high dose for short cases

132
Q

lower dose NDMR

A

slows onset
shortens duration

ideal for short cases

133
Q

nondepolarizers “priming dose”

A

Roc - 0.5 mL
given prior to propofol

allows Roc to have faster onset when dosed for intubation

134
Q

nondepolarizers “defasiculating dose”

A

0.5 mL Roc prior to succinylcholine

decreases Sux fasiculations
decreases post-op myalgia

135
Q

metorpolol

A

beta 1 antagonist
decreases HR

136
Q

esmolol

A

beta 1 antagonist
decreases HR

faster onset/shorter duration than metoprolol

137
Q

labetalol

A

beta 1 antagonist
alpha 1 antagonist

decreases HR and BP

138
Q

hydralazine

A

vasodilator (not beta blocker)
decreases BP

139
Q

hydralazine indication

A

treat hypertension in pt with low or normal HR

140
Q

hydralazine onset/duration

A

onset: 10 mins
duration: 2-4 hrs

141
Q

lasix (furosemide) indications

A

give to fluid overloaded pts

142
Q

lasix mechanism

A

blocks Na+ and H2O reabsorption in the loop of henle

diuresis

143
Q

lasix contraindications

A

sulfa allergy

144
Q

mannitol indications

A

renal protection
decreasing ICP (brain surgery)

145
Q

mannitol mechanism

A

increasing osmolarity of blood

draws H2O out of blood
cells shrink
blood volume increases

146
Q

mannitol effects

A

increase blood volume
increased renal perfusion
diuresis

147
Q

mannitol contraindications

A

do not give if fluid overloaded

148
Q

narcaon

A

reversal agent for narcotic overdose

149
Q

flumazenil

A

reversal for versed overdose

150
Q

LTA kit

A

numbs trachea prior to intubation

ETT less stimulating
- less coughing/bronchospasms

151
Q

LTA kit indication

A

prevent coughing in shorter surgeries
non-paralyzed pts

152
Q

LTA kit duration

A

20-30 mins
(1 hr maybe due to anesthetic pooling around inflated cuff)