5. OR Concepts Flashcards
1
Q
baroreceptros
A
pressure sensors
detect pressure of blood flowing through arteries
2
Q
baroreceptor locations
A
carotid sinuses
aortic arch
3
Q
baroreceptor reflex
A
helps mx normal cardiac output with high or low BP
4
Q
baroreceptor reflex process
A
- sense change in BP
- send signal to brain to correct BP
- Low BP: ANS increase HR (CO)
- High BP: ANS decrease HR (CO)
5
Q
reflex bradycardia
A
vasoconstriction (high BP) causes HR to decrease
6
Q
reflex bradycardia commonly caused by what drug
A
phenylephrine
7
Q
reflex tachycardia
A
vasodilation (low BP) causes HR to increase
8
Q
drugs that can trigger reflex tachycardia
A
propofol or hydralazine
9
Q
carotid body
A
chemoreceptors that sense hypoxia
stimulate respirations (hypoxic drive)
also sense: temp, pH, CO2
10
Q
carotid sinus
A
baroreceptors adjust HR to mx normal CO/BP
11
Q
cerebral vascular accident (CVA)
A
stroke
sudden brain cell death cause by inadequate blood flow
12
Q
causes of stroke
A
blood clot
intracranial hemorrhage
prolonged hypotension
hypertension
13
Q
Ischemic stroke
A
Blood clot
14
Q
intracranial hemorrhage
A
hemorrhagic stroke
15
Q
prolonged hypothension can be caused by
A
inadequate brain perfusion
16
Q
hypertension can lead to
A
stress on walls of blood vessels
intracranial hemorrhage
17
Q
DVT
A
blood clot in vein (usually in leg)
more likely to develop if blood from is static
18
Q
Pts at risk for blood clots
A
bedridden pts
heart arrythmias that decrease BF through heart
- afib
19
Q
pulmonary embolism
A
DVT dislodged from legs that moves to heart and lungs
life threatening emergency
20
Q
DVT prevention
A
walking/movement
blood thinners
sequential compression stockings during surgery
21
Q
intracellular fluid
(ICF)
A
inside cells
65%
22
Q
extracellular fluid
(ECF)
A
outside cells
35%
23
Q
2 divisions of ECF
A
interstitial fluid
intravascular fluid
24
Q
edema
A
swelling
excess fluid in interstitial space
25
pulmonary edema
excess fluid in alveoli
commonly caused by some degree of heart failure
26
interstitial fluid
any fluid not inside cells or inside intravascular space (arteries/veins)
27
transmural pressure
difference in pressure between 2 sides of a wall
28
pulmonary edema causes
pressure in lungs is drastically reduced
pressure in capillaries is relatively higher
Plungs
29
common causes of negative pressure pulmonary edema
biting on ETT
laryngospasm
kinked tube
obstructed airway
30
how to treat negative pressure pulmonary edema caused by biting on ETT
pull tube
or
relax bite w/propofol/sux
31
prevent pt from biting on ETT
place bite block prior to emergence
32
treat pt biting on LMA
deflate cuff
air can now move around the cuff into trachea
33
preload
volume of blood returning to RV
blood available to be pumped on next contraction
venous return
34
afterload
resistance the LV pumps against
35
preload is proportional to
pts volume status
- hypovolemia = low preload
- hypervolemia = high preload
pts position
- head up = high preload
- head down = low preload
36
how is preload measured
central venous pressure (CVP)
only measured w/central line
37
CVP
blood pressure within the superior vena cava
normal: 5-12 mmHgce
38
central lines are placed in
internal jugular
subclavian
(large central vein)
39
low CVP indicates
low preload
(hypovolemia)
40
high CVP indicates
fluid overload
41
high CVP is common in what pts
heart failure
renal failure
42
afterload is proportional to
level of vasoconstriction
- vasoconstriction = high afterload
- vasodilation = low afterload
blood pressure
- high BP = high afterload
- low BP = low afterload
43
when can you have high afterload and low blood pressure?
if pt is bleeding to death (exsanguinating)
low BP due to hypovolemia
vasoconstriction to try to keep blood pressure high would cause high afterload
44
systemic vascular resistance (SVR)
AKA afterload
AKA peripheral vascular resistance
arterial vasoconstriction = high SVR
arterial vasodilation = low SVR
45
pulmonary vascular resistance
(PVR)
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
46
positive intrathoracic pressure
**decrease BP
compresses heart/veins
incr resistance to BF
decr preload/venous return
decr SV
decr CO
decr BP
47
types of positive intrathoracic pressure
PPV
PEEP
valsalva maneuver
drops BP
48
negative intrathoracic pressure
reduces pressure to heart/veins
decr resistance to BF
incr preload/venous return
decr SV
49
types of negative intrathoracic pressure
spontaneous ventilation
50
cautery
cautery pen = bovie
cuts tissue
burns/coags blood vessels
requires grounding pad
51
cautery electrical loop
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
52
grounding pad
return electrode to the eletrocautery unit
required for current to flow
large surface area
place over well perfused muscle to dissipate heat (thigh)
53
unipolar bovie
superior coagulation
requires grounding pad
more current flow
54
bipolar bovie advantages
2 cautery tips
- less current flows between tips
- more controlled == delicate areas
(nerves)
no grounding required
55
bipolar bovie disadvantage
cauterizes small areas
not good for controlling large bleeding
56
cautery safety
minimal electrocution risk
high current freq (>200,000Hz)
pts with interior metal are burn risk
- remove jewelry
- place pad away from internal metal
57
implications of Pnemoperitoneum (CO2 insufflation) (8)
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
58
why can CO2 insufflation cause atelectatsis?
diaphragm compression
resistance to lung expansion
decrease FRC
59
why is hypercarbia more likely w/CO2 insufflation?
CO2 diffuses to arteries
60
what are the impacts of a vagal response during CO2 insuflation?
bradycardia
hypotension
during insufflation
61
why does CO decrease during CO2 insufflation?
CO2 compresses vena cava
venous pooling in legs
decreased venous return to heart
(decreased preload)
62
what causes BP fluctuation during CO2 insufflation?
BP down:
- decr venous return
- decr CO
BP up:
- vasoconstriction (SVR incr) due to compensation for CO decrease
63
why can pts get shoulder pain with CO2 insufflation?
diaphragm and shoulder are innervated by the phrenic nerve
64
how can CO2 insufflation cause a partial pneumothorax?
if CO2 gets into the thoracic cavity
can partially collapse lung
65
CO2 gas embolism
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
SubQ Emphysema
trapped air beneath the skin
67
Causes of SubQ emphysema (6)
multiple attempts at abdominal entry
improper cannula placement
incr intraabdominal pressure
long procedures (>3.5hrs)
gas flow rate
high total gas volume
68
SubQ CO2 insufflation safe range
0-20 mmHg
69
SubQ CO2 insufflation recommended range
12-14 mmHg
70
SubQ emphysema clinical significance
hypercarbia
acidosis
EtCO2 elevates at end of surgery
airway swelling
crepitus (crackling skin)
extubation likely contraindicated until symptoms resolved
71
gastric tube
orogastric tube: into mouth (OG)
nasal gastric tube: into nose (NG)
72
OG/NG tube purpose
1. decompress stomach
- laproscopic surgery
- bowel obstruction
- drug overdose/poisoning
2. feeding tube
73
OG tube indications
temporary
74
NG tube indications
more permanent
open abdominal
- vent intestinal gases to avoid ileus
- ask surgeon if they want OG or NG
75
ileus
temporary surgical induced gastroparesis
(bowel obstruction)
76
NG tube contraindications
facial fractures
77
OG/NG tube contraindications
pts w/prior gastric surgery
- risk of intestinal perforation
liver failure/cirrhosis
- esophageal varices can rupture
78
anaphylaxis
mast cells destabilize
release histamine
1. vasodilation
2. bronchoconstriction
- wheezing
- difficult ventilation
79
anaphylaxis diagnosis
low tidal volume
high circuit pressure
hives
80
anaphylaxis treatment
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
compartment syndrome
decrease in BF/perfusion to body compartment due to increase in pressure inside compartment
can lead to permanent injury or amputation
82
causes of compartment syndrom
fracture
infiltrated IV
tight cast
83
compartment syndrome treatment
fasciotomy
incision into compartment to relieve pressure buildup/decompress vessels
84
vagal response
sudden onset of:
bradycardia
hypotension
mimics symptoms of vagal nerve stimulation
85
vagal response common causes
CO2 insufflation for lap surgery
eye surgery
abdominal/uterine surgery
86
steroids
enhance effectiveness of catecholamines
87
"stress dose" of steroids
given to pts if vasopressor therapy is not effective
likely needed for pts on chronic steroids
- more susceptible to hypotension
88
"stress dose" drugs
solu-medrol (methyprednisolone)
-most common
solu-cortef (hydrocortisone)
89
abdominal splinting
hypoventilation cause by pain of breathing
shallow breathing
90
abdominal splinting causes
abdomina/thoracic procedures
91
abdominal splinting prevention
adequate pain meds
nerve blocks (TAP, intercostal)
local anesthetic at surgical site
92
higher dose drug
fast onset
longer duration
93
lower dose drug
slower onset
shorter duration
94
fentanyl low vs high dosing
1mcg/kg bolus: 45 mins
5 mcg/kg bolus: hours
95
rocuronium low vs high dosing
100mg: fast onset/long lasting
20 mg: slow onset/short lasting
96
adverse opioid effects
1. respiratory depression
2. gastroparesis (full stomach)
3. urinary retention
4. itching
5. constipation
6. stiff chest syndrome (diaphragm)
7. addiction
97
stiff chest syndrome treatments
succinycholine
98
best way to dose opioids
according to respiratory rate
- for SV pts only
99
dosing for mechanically ventilated pts
vital sings can indicate pain
tachycardia
hypertension
100
dosing of opioid based on procedure
some procedures are more painful
Ex lap/thoracotomy > cystoscopy
101
fentanyl dosing
2 mcg/kg per hour of surgical time
102
more painful surgeris
cardiothoracic
orthopedic
open abdominal
103
remifentanil uses
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
toradol
IV NSAID
profound analgesia
minimal respiratory depression
105
toradol contraindications (10)
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
torado renal impacts
decreases renal blood flow
increases renal vascular resistance
107
toradol infants impacts
promotes prematures closure of ductus arteriosus
108
toradol bone impacts
impair bone healing due to inhibition of prostaglandins
109
Ofirmev
IV acetominophen
analgesic
minimal respiratory depression
reduction of post-op shivering
110
Ofirmev onset
5-10 mins
peak effect: 1 hr
111
Ofimev contraindications
1. pt w/liver disease
2. alcoholics
3. pts on vicodin or norco
- these contain acetominophen
112
precedex (dexmedetomidine)
analgesic
minimal respiratory depression
sedative
alpha 1 agonist
113
precedex common dosing
0.2-0.5 mcg/kg boluses at beginning and end of procedure
114
precedex side effects
decrease BP
decrease HR
115
induction agents onset/duration
onset: seconds
duration: 3-5 mins
116
what is the last sense to be suppressed by induction agents?
hearing
117
propofol advantages
minimal long term side effects
antiemetic propertiespro
118
propofol disadvantages
profound cardiac depressant
- high SV decrease
vasodilation
- profound BP decrease
profound respiratory depressant
119
Etomidate advantages
cardiovascularly stable
- minimal BP impacts
- hypertension after intubation
minimal respiratory depression
120
Etomidate disadvantages
PONV
adrenal suppression
hypertension post-intubation
121
Etomidate cauton
increased overall 30 day mortality when used
short term gain: stable induction
long term loss: adrenal suppression
122
Ketamine advantages
analgesic
bronchodilation
minimal respiratory depression
increase HR / BP
123
Ketamine disadvantages
increase airway secretions
increase PONV
hallucinations
124
low dose ketamine
25-50mg perioperatively reduces post-op pain, decrease opioid reqs
minimizes negative side effects
125
short sedation (MAC) with ketamine
mix 50mg ketamine into 20mL syringe of propofol
more analgesia
less respiratory depression
126
succinylcholine onset/druation
onset: 30-60 seconds
duration: 3-5 mins
127
succinylcholine indications
RSI for full stomach pts
128
succinylcholine contraindications
long operations
only used for intubation paralysis
MH
129
succinylcholine intubation dosing
0.3-0.5 mg/kg is adequate for intubation
drug card says: 1 mg/kg
130
non depolarizing muscle relaxants
roc
vec
cisatracurium
131
higher dose NDMR
speeds up onset
prolongs duration
avoid high dose for short cases
132
lower dose NDMR
slows onset
shortens duration
ideal for short cases
133
nondepolarizers "priming dose"
Roc - 0.5 mL
given prior to propofol
allows Roc to have faster onset when dosed for intubation
134
nondepolarizers "defasiculating dose"
0.5 mL Roc prior to succinylcholine
decreases Sux fasiculations
decreases post-op myalgia
135
metorpolol
beta 1 antagonist
decreases HR
136
esmolol
beta 1 antagonist
decreases HR
faster onset/shorter duration than metoprolol
137
labetalol
beta 1 antagonist
alpha 1 antagonist
decreases HR and BP
138
hydralazine
vasodilator (not beta blocker)
decreases BP
139
hydralazine indication
treat hypertension in pt with low or normal HR
140
hydralazine onset/duration
onset: 10 mins
duration: 2-4 hrs
141
lasix (furosemide) indications
give to fluid overloaded pts
142
lasix mechanism
blocks Na+ and H2O reabsorption in the loop of henle
diuresis
143
lasix contraindications
sulfa allergy
144
mannitol indications
renal protection
decreasing ICP (brain surgery)
145
mannitol mechanism
increasing osmolarity of blood
draws H2O out of blood
cells shrink
blood volume increases
146
mannitol effects
increase blood volume
increased renal perfusion
diuresis
147
mannitol contraindications
do not give if fluid overloaded
148
narcaon
reversal agent for narcotic overdose
149
flumazenil
reversal for versed overdose
150
LTA kit
numbs trachea prior to intubation
ETT less stimulating
- less coughing/bronchospasms
151
LTA kit indication
prevent coughing in shorter surgeries
non-paralyzed pts
152
LTA kit duration
20-30 mins
(1 hr maybe due to anesthetic pooling around inflated cuff)
