Exam II: Deliberate Hypotension Flashcards
(118 cards)
1
Q
Deliberate Hypotension (DH): controlled, _____, _____
A
controlled, induced, elective
2
Q
Deliberate Hypotension (DH): A reduction of _____ blood pressure to 80 to 90 mm Hg
A
systolic
3
Q
Deliberate Hypotension (DH): A decrease in ____ to 50 to 65 mm Hg in normotensive patients
A
MAP
4
Q
Deliberate Hypotension (DH): A ____ reduction of baseline MAP
A
30%
5
Q
Benefits of DH:
Reduced blood ____
Conserve blood _____
Avoidance of _____ reactions
Decreased transmission of ____-____ _____
A
loss
supply
transfusion
blood-borne disease
6
Q
Benefits of DH:
Facilitation of surgical dissection -
Microscopic surgical (___, intracranial ___ ______)
Identification of _____ vs. non______ tissue, vital structures
A
(ENT, intracranial AV malformation)
malignant vs nonmalignant
7
Q
Benefits of DH:
Facilitation of surgical dissection -
Reduction of amount of _______ tissue, debris and wound infection
Reduction in _____ time
A
cauterized
operative
8
Q
Benefits of DH:
Reduction of _____ beneath skin flaps
Better _____ outcome, improved ____ _____
A
oozing
plastics
wound healing
9
Q
Benefits of DH:
Prevention of ______ rupture (i_____, a_____)
A
aneurysmal
intracranial, aortic
10
Q
Benefits of DH:
Reduction in intravascular _____
_____ of the aorta
A
tension
coarctation
11
Q
Indications for DH:
_____surgery - _____vascular
A
neurosurgery - cerebrovascular
12
Q
Indications for DH:
Large _____ procedures – total ___ _____, spinal fusions
A
orthopedic
hip arthroplasty
13
Q
Indications for DH:
Surgery on large ____ – pelvic
A
tumors
14
Q
Indications for DH:
Surgery on the head and neck – ____-____, middle ____
A
maxillo-facial
ear
15
Q
Indications for DH:
_____ surgery
A
plastic
16
Q
Indications for DH:
Patients in whom _____ is undesirable
A
transfusion
17
Q
Contraindications:
Improved ____ and ______ have allowed patients who previously would have been excluded to be eligible for DH
A
drugs and monitoring
18
Q
Contraindications:
Relative – H/O _____ disease, r____ dysfunction, l____ dysfunction, severe peripheral c______, myocardial infarction or angina
A
cerebrovascular
renal
liver
claudication
19
Q
Contraindications:
Hypo____
A
Hypovolemia
20
Q
Contraindications:
severe _____
A
anemia
21
Q
Contraindications:
Untreated _____ – increased risk of death and morbidity during DH (Treatment of hypertension returns cerebral ______ toward normal – DH safe for ______-controlled hypertension.)
A
HTN
autoregulation
medically
22
Q
Influences of bleeding perioperatively:
Arterial – related to ____ – abolished by tourniquet, reduced by decreased ____, ____
A
MAP
MAP, HR
23
Q
Influences of bleeding perioperatively:
_____ – dependent on local flow in the _____ _____ – reduced by decreased BP and local vaso______ (infiltration)
A
capillary
capillary bed
vasoconstriction
24
Q
Influences of bleeding perioperatively:
Venous – related to venous ____, venous ____ and dependent on _____ – abolished by spinal or epidural and direct acting vasodilators
A
return
tone
posture
25
Methods to achieve hypotension (physiologic):
Body positioning – operative site above the level of the ____(for each ___ cm of vertical height above the heart, the local arterial pressure is reduced by ___ mm Hg)
Aiding the ____ _____ in vasodilated capacitance vessels
___-___ position
heart
2.5 cm
2 mmHg
venous pooling
head-up
26
Methods to achieve hypotension (physiologic):
____ ____ _____ – decreased venous return, and thus CO
positive pressure ventilation
27
Methods to achieve hypotension (physiologic):
PEEP – decreased ____ ____
venous return
28
Methods to achieve hypotension (physiologic):
Decreased ____ and ____
SV and HR
29
Methods to achieve hypotension (physiologic):
Other ways you may have heard this:
Invasive and Non-Invasive BP Monitoring -
(2) ___ cm of height = 0.75 mmHg; and later…
(3) ___ cmH20 = 7.5 mmHg
Neurosurgical Anesthesia - (4) ___ mmHg for each 1.25 cmH20
1 cm
10 cmH2O
1 mmHg
30
Methods to achieve hypotension (mechanical):
Tourniquets –
Monitor duration - __ min upper limb and ___ min for lower limb – ischemia can occur in ___ time than this
60 min
90 min
less
31
Methods to achieve hypotension (mechanical):
Tourniquet -
Monitor pressure – ___ mm Hg in arm; ___ mm Hg in leg
250
300
32
Methods to achieve hypotension (mechanical):
Tourniquet -
Don't use on ___ ___ patients
sickle cell
33
Methods to achieve hypotension (mechanical):
Local infiltration with _____
epinephrine
34
Methods to achieve hypotension (mechanical):
Local infiltration with epinephrine -
local ______
vasoconstriction
35
Methods to achieve hypotension (mechanical):
Local infiltration with epinephrine -
concentrations 1:_____ to 1:______
1:200,000
1:400,000
36
Methods to achieve hypotension (pharmacologic):
____ anesthetic agents
volatile
37
Methods to achieve hypotension (pharmacologic):
_____ ganglionic blockers
sympathetic
38
Methods to achieve hypotension (pharmacologic):
____-adrenergic blockers
alpha
39
Methods to achieve hypotension (pharmacologic):
____-adrenergic blockers
beta
40
Methods to achieve hypotension (pharmacologic):
_____dilators
vasodilators
41
Methods to achieve hypotension (pharmacologic):
_____ and ____ anesthesia
spinal and epidural
42
Isoflurane: Minimal effect on myocardial _____ at low concentrations
contractility
43
Iso: Vasodilation effect is readily ____
adjusted
44
Iso: Great for _____reduction in BP
moderate
45
Iso: Less of an effect on ___ than halothane
ICP
46
Iso: Depresses cerebral _____ (_____)
metabolism (CMRO2)
47
Iso: Minimizes reflex _____ or ______ (CNS depressant)
vasoconstriction or tachycardia
48
Sevo: Shown to minimize the heart rate fluctuations that occur with use of n_____, n_____, or a_____ (PGE) to achieve hypotension. Decreased _____ activity. Study looked at combination with N2O
nitroglycerin, nicardipine, or alprostadil
sympathetic
49
Sympathetic ganglionic blocker - Trimethaphan (Arfonad):
Interruption of _____ outflow, vaso_____
sympathetic
vasodilation
50
Sympathetic ganglionic blocker - Trimethaphan (Arfonad):
Urinary ____, m_____ (mistaken for cerebral ischemia), _____ due to parasympathetic block (bleeding)
retention
mydriasis
tachycardia
51
Sympathetic ganglionic blocker - Trimethaphan (Arfonad):
T_____
Tachyphylaxis
52
Pretreatment with ____ po reduces the required infusion of PGE 1 needed to maintain DH and reduces the blood loss by ___%.
clonidine
45%
53
Use of _____ combined with ______ to provide controlled hypotension during posterior spinal fusion
dexmedetomidine
remifentanil
54
Patients with gynecologic cancer to undergo radical hysterectomy. Doses of ____ of 75 mcg and 150 mcg were given 60 minutes before induction of anes. Blood loss was _____.
clonidine
reduced (from 1461 to 805 and 931.)
55
Additional benefits of dexmedetomidine for max-face cases:
-a_____ – reduced opioids post-op
-a_____
-___ stability
-h_____
-minimal vent depression on emergence
analgesia
anxiolytic
CV
hypotension
56
Alpha adrenergic blockers - Phentolamine (Regitine), droperidol
Vaso____
Increased ___ and myocardial oxygen ____ due to beta stimulation
vasodilation
HR
demand
57
Beta-adrenergic blockers - Propranolol, atenolol, esmolol, (labetalol*):
Big advantage is decreased ___ and ___
HR
CO
58
Beta-adrenergic blockers - Propranolol, atenolol, esmolol, (labetalol*):
Used along with _____
vasodilators
59
Beta-adrenergic blockers - Propranolol, atenolol, esmolol, (labetalol*):
Prevents ____ ____ in BP (vasospasm re: subarachnoid hemorrhage)
wide variations
60
Beta-adrenergic blockers - Propranolol, atenolol, esmolol, (labetalol*):
_____ not as potent, no increase in ICP
labetolol
61
Beta-adrenergic blockers - Propranolol, atenolol, esmolol, (labetalol*):
Labetalol masks the _____ response to acute ___ ____ (long duration lasts in postop period)
adrenergic
blood loss
62
Beta-adrenergic blockers - Propranolol, atenolol, esmolol, (labetalol*):
Propranolol _____ reduced the dose of SNP and the ____ _____ upon discontinuation
pretreatment
rebound HTN
63
Beta-adrenergic blockers - Propranolol, atenolol, esmolol, (labetalol*):
Esmolol reduced ___ ____ ___ – improved stability; greater reduction in CO
plasma renin activity
64
All three reduced MAP. Esmolol was the only one to decrease HR and CO. Significant decrease in SVR for iso and nipride; esmolol does not block alpha, should not block beta2 either. Change in CO impacts CVP, PCWP. Increased plasma-renin activity for both iso and nipride which will result in increased Na and water retention; not seen with esmolol.
65
Vasodilators - Sodium nitroprusside:
“dial-a-___”
Good for ___ periods
pressure
short
66
Vasodilators - Sodium nitroprusside:
Increased ____ - caution
ICP
67
Vasodilators - Sodium nitroprusside:
____ ____ – monitor acid/base balance
Cyanide toxicity
68
Vasodilators - Sodium nitroprusside:
No adverse effect on ____ ____
myocardial contractility
69
Vasodilators - Sodium nitroprusside:
Pretreat with ____ or _____ to reduce dose of SNP and avoid rebound ____tension (or enalapril 2.5 mg 60 min p)
propranolol or captopril
hypertension
70
Vasodilators - Nitroglycerin:
Less dramatic decrease in ___
BP
71
Vasodilators - Nitroglycerin:
Decreases ____ more than _____ (maintains flow)
systolic
diastolic
72
Vasodilators - Nitroglycerin:
less ____ recovery
rapid
73
Vasodilators - Nitroglycerin:
____ _____ perfusion better
coronary artery
74
Vasodilators - Nitroglycerin:
___ ____ in some patients
less effective
75
Vasodilators - Nitroglycerin:
increase in ____ - Caution
ICP
76
3-inch NTG transdermal – reduced blood loss by almost ___% and reduced the need for _____ of patients having ORIF of femur fractures
“induction of _____ hypotension”
50%
moderate
(Blood loss was reduced from 950 ml to 443 ml in placebo group to nitro group.)
77
Spinal and epidural anesthesia:
Vasodilation of both arterial and venous due to _____
sympathectomy
78
Spinal and epidural anesthesia:
If __-__ are blocked, tachycardia is prevented
T1-4
79
Spinal and epidural anesthesia:
Used in lower abdominal and pelvic surgery – ___ ____ ____
pelvic venous plexuses
80
Spinal and epidural anesthesia:
If _____ is added to the local, the hypotensive effect of the block might be ______.
Consider intermittent ____ or continuous epidural _____.
epinephrine
counteracted
bolus
infusion
81
Hypotension - organ function:
It is best to reduce BP by decreasing ___ rather than ___ so blood flow to tissues can be maintained.
SVR
CO
82
Hypotension - organ function: Ischemia of the ___ & ____ are the principal hazards of deliberate hypotension.
brain and myocardium
83
Hypotension - organ function: CNS - Principle of _____ is key.
autoregulation
84
Hypotension - organ function: “Safe” lower limit is __ to __ mm Hg in normotensive patient because that is the lowest pressure at which autoregulation of ____ is maintained.
50 to 55
CBF
85
During normotension, CBF changes linearly with PaCO2 when PaCO2 is __-__ mm Hg. When the MAP falls below __ mm HG, CBF ______ responds to changes in PaCO2.
20-70
50
no longer
86
Heart – maintain balance between myocardial ___ ____ and ____. AVOID– t____, myocardial d____, coronary artery perfusion alteration
oxygen supply and demand
tachycardia
depression
87
Lungs – with hypotension: Increased PaCO2 due to increased _____. Must maintain ___ with ____ replacement
deadspace
CO
fluid
88
Lungs – with hypotension: Decreased PaO2 due to increased ____. Seen with use of ____, but not with ____. Seen with normal lungs, but not with ____.
shunt
Nipride
isoflurane
COPD
89
Lungs – with hypotension: Necessitates _____ ventilation, increased ______
controlled
oxygenation
90
Lungs – with hypotension: Dead space – ventilation of alveoli where the blood doesn’t reach – decreased pressure causes decreased perfusion through pulmonary capillaries. Seen especially with increased mean _____ pressure, ____-_____, and hypo_____. To minimize, maintain CO with fluid replacement.
airway
reverse-trendelenburg
hypovolemia
91
Kidneys - Glomerular filtration rate is _____ when MAP falls below ____ mm Hg
reduced
75
92
Kidneys - Metabolic needs of kidneys still met, but _____ occurs
oliguria
93
Kidneys - Normovolemic patients have rapid ____ of urine production when hypotension is dc’d. Strict maintenance of ___ ____ during deliberate hypotension is ____ necessary
recovery
urine output
not
94
Kidneys - Renal function was better preserved with combination of ____ and _____ than with higher concentrations of ____ alone.
isoflurane and labetalol
isoflurane
95
Splanchnic Circulation - Liver perfusion is altered due to limited autoregulation for the ___ ____ and no autoregulation for the ___ ____ _____
hepatic artery
portal venous circulation
96
Splanchnic Circulation - Increased ____ outflow (baroreceptor mediated in response to decrease BP) causes splanchnic ______ and decreased blood flow to the ____ and the _____.
sympathetic
vasoconstriction
liver and the intestine
97
Eye - Decreased blood flow to the eyes causes ___ ___ ____ and rarely _____
blurring of vision
blindness
98
Eye - Position carefully to avoid increased intraocular pressure which would oppose blood flow even further.
Factors for this include ____ _____ and ___ ____ - neutral position
external pressure and venous congestion
99
Eye - Maintain ____
Hgb
100
Eye - _____ v. _____ – minimize edema
Colloid v. crystalloid
101
Monitoring - ____ – signs of inadequate myocardial perfusion like ST depression and ectopic beats
ECG
102
Monitoring - Pulse oximetry – signs of decreased _____ and peripheral _____
oxygenation
perfusion
103
Monitoring - Temperature - body heat lost more rapidly from ______
vasodilation
104
Monitoring - ___ ___ – beat to beat measurement of BP
allows sampling of ____s
place transducer at level of ___ ____ (CPP)
arterial line
ABGs
internal carotid
105
Monitoring -
ETCO2 – not completely accurate due to increased _____, decreased ____, and changes in body ______
Sudden decrease may indicate ____
Use as guide to avoid hyperventilation which would further decrease ____.
deadspace
CO
metabolism
PE
CBF
106
Monitoring - Central venous line – ____ replacement and monitor ____
fluid
CVP
107
Monitoring - UOP – especially ___ cases
long
108
Monitoring - e____ ____, EEG, serum ______, ABGs, h_____
evoked potentials
electrolytes
hematocrit
109
Complications - Mortality is ___ ____ from that of all anesthetics
not different (0.01 to 0.007%)
110
Complications - Nonfatal complications
CNS related – dizziness, prolonged awakening, cerebral artery thrombosis
Retinal thrombosis
Anuria, oliguria
Postoperative bleeding
111
Complications - Inadequate hypotension – use ___ ___
second agent
112
Complications - ____ hypotension
excessive
113
Complications - Many patients have underlying ___ ____ that is undiagnosed by routine examine; these patients are at risk for complications due to hypotension / hypoperfusion. Patients should be thoroughly evaluated prior to using deliberate hypotension; the decision should not be one that is made ___ ___ ___, but well in _____.
organ dysfunction
in the OR
advance
114
Types - Slow onset, ___ ____ hypotension with ____ return to normal - Plastic, maxillo-facial, ear, nose, throat
sustained moderate
slow
115
Types - Moderate sustained hypotension with ___ ____ - when massive ___ ___ is anticipated
reduced HR
blood loss
116
Types - Profound hypotension with ___ ____ of excessively small pressures. Clipping ___ ____.
short periods
cerebral aneurysm
117
Background anesthesia -
B____ anesthetic
Omit a____
Use generous sedation or analgesia
Neuromuscular blocker
During hypotension, increase ____
Continue in PACU – avoid CO2 retention, hypoxia, use patient’s position
balanced
atropine
FiO2
118
Important guidelines -
Don’t reduce the systolic pressure during the _____ to less than the ____ ____ ____.
operation
pre-op diastolic pressure
