AP 3 Test 2 Flashcards
(400 cards)
1
Q
Do regurgitant valves cause a pressure overload or a volume overload?
A
Volume overload
2
Q
Do stenotic valves cause a pressure overload or a volume overload?
A
Pressure overload
3
Q
What is the ventricles response to a pressure overload lesion?
A
Hypertrophy
4
Q
Do hypertrophied ventricles normally have systolic dysfunction or diastolic dysfunction?
A
Diastolic dysfunction because it is so stiff that it cannot relax fully and fill adequately
5
Q
Hypertrophied ventricles are very dependent on what component of blood flow through the heart?
A
Preload, it needs a high atrial kick to maintain cardiac output
6
Q
What is the final response to a chronically hypertrophied ventricle
A
Ventricular dilation and failure
7
Q
What is the ventricles response to a volume overload lesion?
A
Dilation to accommodate for the increased volume (regurgitant volume)
8
Q
What is eccentric hypertrophy?
A
An increase in chamber size relative to the overall heart size
9
Q
What is concentric hypertrophy?
A
An increase in wall thickness of the chamber, but the size inside the chamber stays the same
10
Q
Which type of hypertrophy is seen in mitral regurgitation?
A
Eccentric
11
Q
Which type of hypertrophy is seen in aortic stenosis?
A
Concentric
12
Q
How does aortic stenosis affect afterload?
A
Increases afterload
13
Q
How does preload affect afterload?
A
With increases in preload, you get increases in afterload
14
Q
How are systolic and diastolic pressures affected by aortic stenosis?
A
Systolic pressure decreases, diastolic pressure increases
15
Q
Common clinical presentation of aortic stenosis
A
- Angina: due to impaired coronary blood flow
- Dyspnea: due to increased LVEDP
- Syncope: due to orthostatic hypotension
16
Q
Common clinical presentation of mitral regurgitation
A
- Pulmonary edema and congestion
- Dysrhythmias: due to long standing atrial enlargement
17
Q
What factors affect CaO2?
A
- Hemoglobin concentration
- SpO2
18
Q
What factors affect cardiac output?
A
- HR
- Stroke volume
19
Q
How do we commonly measure oxygen delivery to the tissues?
A
- Lactate
- SvO2
20
Q
SvO2 can be an inaccurate indication of oxygen delivery under what circumstance?
A
With transfusion - old blood decreases offloading of oxygen and can give us a falsely high SvO2
21
Q
How should we manage preload in a patient with aortic stenosis?
A
Keep it increased, they are very preload dependent so we need to give them fluids to maintain stroke volume
22
Q
How should we manage contractility in a patient with aortic stenosis?
A
Maintain it
23
Q
How should we manage afterload in a patient with AS?
A
Increase it to drive coronary perfusion pressure
24
Q
How should we manage heart rate in a patient with AS?
A
Keep it low and maintain sinus rhythm to give adequate diastolic filling time
25
How should we manage preload in a patient with mitral regurgitation?
Maintain it - avoid overload because these patients are already volume overloaded. These patients usually come in pretty dry because they are almost always on Lasix.
26
How should we manage contractility in a patient with MR?
Increase it with epi, dobutamine, etc. since systolic function is impaired
27
How should we manage afterload in a patient with MR?
Decrease it to promote forward flow and decrease regurgitant volume
28
How should we manage heart rate in a patient with MR?
Have them at a "high normal"
29
Which patient can tolerate a-fib better - a patient with MR or AS?
MR because the atria are full and have high pressures
30
Most common anesthetic technique for a patient with AS
General
31
Why is a spinal anesthetic relatively contraindicated in a patient with AS?
Because it decreases afterload and preload and reflexively increases heart rate
32
Why is a general anesthetic great for a patient with MR?
It drops preload and afterload
33
Patients with which valvular lesion are the least tolerant of general anesthesia?
Severe mitral stenosis
34
Hemodynamic goals for managing a patient with mitral stenosis
- Slow HR to have as much filling time as possible
- Good afterload to maintain perfusion
- Maintain preload but don't overload
35
Can patients with MS tolerate a-fib?
No - it is very detrimental to them
36
Is tricuspid regurgitation a volume overload or pressure overload lesion?
Volume overload
37
What usually causes tricuspid regurgitation?
Right ventricular dilation due to pulmonary hypertension
38
Effect of tricuspid regurgitation on other body systems
- JVD
- Liver congestion
- Coagulopathies
39
Can you use a CVP wave to determine degree of regurgitation?
No because we are trying to determine regurgitant volume but the CVP waveform gives us pressure
40
What tube sizes should be set out for a cardiac case
Big tubes - 8.5 for men and 8.0 for women
41
What is the order that the drips should be placed on the pole while setting up for cardiac cases?
1) Insulin on top
2) Phenylephrine
3) Norepinephrine on bottom
42
What drug is commonly given through a buretrol in cardiac cases?
Protamine
43
Induction drugs to have set up for a cardiac case
- Propofol in 20cc
- Fentanyl in 20cc
- Roc in 10cc
- Lidocaine in 5-10cc
44
Pressors to have set up for a cardiac case
- Norepi (16mcg/ml)
- Epi (16mcg/ml)
- Phenylephrine
- Vasopressin (1-2units/ml)
- Ephedrine
45
Concentration of esmolol
10mg/ml
46
Concentration of nicardipine
100mcg/ml
47
Concentration of nitroglycerin
50mcg/ml
48
Concentration of calcium
100mg/ml
49
Which drug should you have available but NOT draw up while setting up for cardiac cases?
Protamine
50
A-line and CVPs should be placed using what technique?
Sterile
51
What surgeries can you expect to have to place your a-line in the right arm?
- CABG with radial harvest
- Descending aorta
- VA ECMO
52
What surgeries can you expect to have to place your a-line in the left arm?
- Ascending aorta with circulatory arrest
- Aortic arch
- Redo case with axillary cannulation
- Minimally invasive valves
53
How should the patient be prepared before placing morning lines for a cardiac case?
- Light sedation
- Nasal cannula
- Monitors
* Don't turn off pre-existing heparin/nitro drips unless instructed
54
Order of events for a cardiac case
1. Set up
2. Start IV/a-line
3. Induction/intubation
4. TEE
5. Central line
6. Echo (during or after central line)
7. Draw baseline labs/ACT while surgery team is prepping
55
Heparin dosing for off pump cardiac procedures
200units/kg
56
Goal ACT for off pump cardiac procedures
Over 300
57
What is a LIMA?
Left internal mammary artery
58
Airway management for a robotic CABG
Double lumen tube or bronchial blocker and one lung ventilation
59
Heparin dosing for robotic CABG
200units/kg
60
Extra setup considerations for redo sternotomies
- R2 pads
- 4 units of blood checked and in the room
- Large bore access
61
6 different approaches to transcatheter aortic valve replacements
1. Femoral
2. Transapical
3. Transaortic
4. Transcaval
5. Transcarotid
6. Valve in valve
62
What drug class should be limited or avoided while managing cardiac patients?
Benzodiazepines
63
The brain uses __% of total oxygen body consumption
20
64
Standard CMRO2 value
3.5ml/100g/min
65
Which part of the brain has the highest CMRO2?
Gray matter in cerebral cortex
66
Average value for cerebral blood flow
50ml/100g/min (750ml/min)
67
What extrinsic mechanisms modulate cerebral blood flow
- Respiratory gas tension
- Temperature
- Viscosity
- Autonomic influences
68
Normal range for cerebral perfusion pressure
80-100
69
CPP at which the EEG is flatlined
25-40mmHg
70
There is irreversible brain damage at CPPs below
25mmHg
71
CBF is directly proportional to PaCO2 between what ranges of PaCO2
20-80mmHg
72
How much does CBF increase per mmHg change in PaCO2?
1-2ml/100g/min
73
How much does CBV increase per 1 mmHg increase in PaCO2?
0.05ml/100g
74
PaO2 increases CBF when it falls below what value
50mmHg (severe hypoxemia)
75
How much does CBF change per 1 degree celsius change in temperature?
5-7%
76
How does hypothermia affect CBF
Decrease
77
How does hyperthermia affect CBF
Increase
78
How does sympathetic stimulation affect CBF
Decreases via vasoconstriction
79
What substances can pass the BBB?
Lipid soluble substances
80
What substances are restricted from crossing the BBB?
Ionized molecules or those with large molecular weights
81
Passage into the BBB is dependent on what 4 factors?
1. Size
2. Charge
3. Lipid solubility
4. Degree of protein binding in the blood
82
Normal rate of production of CSF
0.3-0.4ml/min (500ml/day)
83
Average total volume of CSF in circulation
150ml
84
What drug classes decrease CSF production?
- Corticosteroids
- Diuretics
- Vasoconstrictors
85
Definition of intracranial pressure
Supratentorial CSF pressure measured in the lateral ventricles or over cerebral cortex
86
Components contributing to ICP
- Brain 80%
- Blood 12%
- CSF 8%
87
Normal values for ICP
5-10mmHg
88
Different techniques for measuring ICP
- Ventriculostomy catheter
- Intraparenchemal fiberoptic device
- Subarachnoid screw
- Epidural transducer
- Subarachnoid catheter
89
Definition of intracranial hypertension
Sustained ICP over 15mmHg
90
Possible causes for intracranial HTN
- Expanding tissue/fluid mass (tumor)
- Depressed skull fracture
- Abnormalities with CSF absorption
- Excessive CBF
- Brain edema resulting from systemic disturbances (i.e. kidney failure)
91
Signs and symptoms of intracranial HTN
- Headache
- N/V
- Papilledema (swelling of optic disk, eyes divert)
- Mental status changes
- Blurred vision
- Cushing reflex
- Fixed, dilated pupils
- Decerebrate posture
- Seizures
- Altered breathing patterns
92
How does intracranial HTN affect cushing reflex?
When ICP goes up, blood pressure goes up to maintain cerebral perfusion pressure which causes HTN and reflex bradycardia
93
Treatment for intracranial HTN
- Resolve cause
- Fluid restrict
- Decrease CSF volume
- Decrease CBF
- Decrease brain volume
94
Methods to decrease CSF volume
- CSF drainage
| - Loop diuretics
95
Methods to decrease CBF
- Hyperventilation to a PaCO2 of 30-33
| - PaO2 over 100mmHg
96
Methods to decrease brain volume
- Steroids (Decadron 20-100mg)
| - Osmotic agents (Mannitol 1g/kg)
97
What is intracranial compliance
Change in ICP in response to change in intracranial volume
98
What are the compensatory mechanisms the brain uses to maintain intracranial compliance
- CSF movement from cranial to spinal compartment
- Increase CSF absorption
- Decrease CSF production
- Decrease cerebral blood volume
99
Abnormal posture associated with herniation of cerebral structures
Decerebrate
100
Abnormal posture associated with herniation of corticospinal structures
Decorticate
101
What is the preferred inhaled anesthetic for neuro procedures and why?
Isoflurane because of the decrease in CMRO2 and improved CSF absorption
102
What is the only IV anesthetic agent that will increase cerebral blood flow?
Ketamine
103
Which inhaled anesthetic increases CSF production?
Desflurane
104
How does LIGHT anesthesia (small doses) and surgical stimulation affect the EEG?
Increase frequency, decrease voltage
105
How does deep anesthesia and cerebral compromise affect the EEG?
Decrease frequency, increase voltage
106
Which evoked potential monitor tests the integrity of the dorsal spinal column and sensory cortex?
Somatosensory
107
Which evoked potential monitor tests the adequacy of spinal cord perfusion?
Motor
108
Which evoked potential monitor tests the integrity of CN8 and the auditory pathways above the pons?
Brainstem-auditory
109
Which evoked potential monitor monitors the optic nerve and upper brainstem during resections of large pituitary tumors?
Visual
110
How long can the brain tolerate cerebral ischemia before there is irreversible neuronal injury?
3-8 minutes
111
What is focal ischemia
Cerebral ischemia characterized by presence of surrounding non-ischemic brain, possible collateral blood flow to ischemic region
112
What is global ischemia
Insufficient blood supply or O2 delivery to entire brain
113
What is "global complete" ischemia?
Absence of CSF
114
What is ischemic penumbra?
Brain tissue that surrounds a damaged area that has functional impairment but is still viable
115
What type of ischemia is ischemic penumbra?
Focal ischemia
116
Ischemic penumbras do not receive blood flow higher than what value
15ml/100g/min
117
How does hypothermia serve as a brain protection strategy
Decreases brain metabolic requirements
118
What is the most effective form of brain protection during focal and global ischemia?
Hypothermia
119
What anesthetic agents are used for brain protection?
- Barbs
- Propofol, etomidate
- Isoflurane
120
Anesthetic agents provide protection against which type of ischemia?
Focal
121
Which class of drugs (often used for blood pressure) are used for brain protection? Why?
Calcium channel blockers - nimodipine and nicardipine. Treats vasospasm
122
Strategies to maintain optimal CPP for brain protection
- Normal or high BP
- Avoid increases in ICP
- Maintain normocarbia
- Avoid hyperglycemia above 150mg/dl
123
Various causes of mass lesions
- Congenital
- Neoplastic
- Infectious
- Vascular
124
Primary tumor sites for brain tumors
- Glial cells
- Ependymal cells
- Supporting tissues
125
Where are the majority (70%) of mass lesions located
Supratentorial
126
Signs/symptoms of mass lesions
- Headache
- Seizures
- Decline in cognition and speech
- Focal neurological deficits
127
Types of supratentorial masses (3)
- Meningiomas
- Gliomas
- Metastatic lesions
128
Signs/symptoms of supratentorial masses
- Seizures
- Hemiplegia
- Aphasia
129
Main type of infratentorial mass
Posterior fossa
130
Signs/symptoms of infratentorial masses
- Cerebellar dysfunction (ataxia, nystagmus, dysarthria)
| - Brain stem compression (cranial nerve palsies, altered consciousness, abnormal respirations)
131
What is an astrocytoma
Slow growing lesion in cerebral hemisphere derived from astrocyte brain cells
132
What is the most aggressive type of primary brain tumors
Gliomas
133
There is poor prognosis with morbidity when a glioblastoma has lasted over __ months
18
134
Which tumor type commonly arises in the cerebellum of children
Medullablastoma
135
Characteristics of meningioma
- Slow growing
- Benign
- Highly vascular
- Infiltrates skull
136
Signs/symptoms of pituitary adenoma
- Headaches
- Impaired vision
- Cranial nerve palsies
- Hypopituitarism
137
Hypersecreting pituitary adenomas secrete which hormones?
- Prolactin
| - Growth hormone
138
Most common primary sites for metastatic tumors
- Lung
| - Breast
139
At what anatomical point do intracranial aneurysms form?
Arterial bifurcations
140
What gender is more prone to intracranial aneurysms
Females
141
Risk factors for subarachnoid hemorrhage
- Cigarette smoking
- HTN
- Alcohol consumption
- Cocaine/amphetamine abuse
- Oral contraceptives
- Hypercholesterolemia
- Familial
142
Classic presentation of a subarachnoid hemorrhage
- Acute severe headache
- Stiff neck
- Photophobia
- N/V
- Transient loss of consciousness
143
Complications following subarachnoid hemorrhage
- Rerupture
- Reactive vasospasm
- Intracranial HTN
- Hydrocephalus
- Hyponatremia
- Seizures
144
Acute vasospasms occur how soon after a subarachnoid hemorrhage (SAH)
5-30min after
145
Long term vasospasms occur how soon after a SAH
3-12 days after
146
Grade I SAH
Asymptomatic
147
Grade II SAH
Moderate headache, nuchal rigidity, no neurological deficit
148
Grade III SAH
Confusion
149
Grade IV SAH
Coma, hemiparesis
150
Grade V SAH
Moribund, decerebrate posture
151
What are arteriovenous malformations
Congenitally malformed capillary beds comprised of high flow, low resistance vessels. Blood flow basically goes from arteries to veins without passing through proper capillaries
152
AV malformations are associated with what phenomenon?
Steal phenomenon which causes cerebral ischemia
153
Anatomical components of AV malformations
- Arterial feeders
- Nidus (central point)
- Arterial collaterals
- Venous outflow
154
Definition of a stroke
Sudden neurologic insult that results from restriction/cessation of blood flow
155
85% of strokes are classified as what type of stroke?
Ischemic/infarction
156
15% of strokes are classified as what type of stroke?
Hemorrhagic
157
What is the grave complication associated with strokes?
Loss of autoregulation to that portion of the tissue, CPP becomes much more dependent on blood pressure
158
Most common cause of thrombolytic ischemic strokes
Atherosclerosis
159
Most common cause of embolitic ischemic strokes
A-fib
160
Top 3 causes of ischemic strokes
1. Thrombosis
2. Embolism
3. Vasoconstriction
161
What is a subdural hematoma
Blood collection between the dura and cerebral cortex
162
Signs/symptoms of subdural hematomas
- Balance problems
- Gait changes
- Mental status changes
- Seizures
163
What is hydrocephalus
Imbalance between CSF production and reabsorption resulting in increased ICP
164
What causes hydrocephalus
- CSF overproduction by choroid plexus
- Venous drainage obstruction
- CSF flow obstruction
165
2 types of hydrocephalus
- Noncommunicating
| - Communicating
166
What is pseudotumor cerebri
Idiopathic intracranial hypertension without a mass lesion caused by a CSF reabsorption anomaly or venous obstruction
167
Treatment for pseudotumor cerebri
VP shunt
168
Pathophysiology of seizures
Abnormal synchronized electrical activity in the brain and loss of inhibitory GABA activity. Characterized by enhanced excitatory amino acid release and neuronal firing due to abnormal voltage regulated Ca2+ channels
169
2 classifications of seizure disorders
- Partial (focal)
| - Generalized
170
What is a partial (focal) seizure disorder
Motor, sensory, or autonomic symptoms - depending on the affected area of the brain
171
3 subclasses of generalized seizure disorders
1) Non-convulsive
2) Convulsive
3) Unclassified
172
3 classes of non-convulsive seizures
1) Absence
2) Myoclonic
3) Atonic
173
3 classes of convulsive seizures
1) Tonic-clonic
2) Tonic
3) Clonic
174
Signs/symptoms of seizure disorders
- Muscle spasms
- Paresthesias
- Pallor, sweating, vomiting
- Memory distortions
175
What should we focus on when doing a preop evaluation of a patient with a seizure disorder?
Focus on cause and type of seizure activity and current medication
176
Chronic therapy for seizure disorders can cause resistance to which drug class commonly used under general anesthesia?
Nondepolarizing muscle relaxants
177
Which anesthetics should be avoided in a patient with a seizure disorder?
- Ketamine
- Etomidate
- N2O
178
What are the steps to take if a seizure occurs under our care
- Maintain open airway and adequate oxygenation
| - Administer appropriate drugs for seizure management
179
Dose of propofol for seizure management
50-100mg
180
Dose of thiopental for seizure management
50-100mg
181
Dose of midazolam for seizure management
1-5mg
182
Dose of diazepam for seizure management
5-10mg
183
Dose of phenytoin for seizure management
500-1000mg SLOWLY
184
What is epilespy
A seizure disorder caused by recurrent paroxysm of cerebral function and characterized by sudden, brief attacks of altered consciousness, motor activity, sensory phenomena, or inappropriate behavior
185
What is status epilepticus?
A neurologic emergency caused by continuous or intermittent seizure activity lasting longer than 20 minutes during which the patient does not regain consciousness
186
Types of cerebral palsy
- Spastic (70-80%)
- Athetoid/dyskinetic (10-20%)
- Ataxic (5-10%)
- Mixed
187
Signs/symptoms of cerebral palsy
- Involuntary movements with or without posture instability
| - Associated with mental retardation
188
Etiology of cerebral palsy
- Hypoxia/ischemia at birth
| - Kernicterus (bilirubin-induced brain dysfunction)
189
Pathophysiology of Parkinson's disease
- Loss of dopamine producing neurons in substantia nigra
- Increased GABA activity in basal ganglia which inhibits thalamic and brainstem nuclei
- Thalamic inhibition suppresses motor system which results in hallmark symptoms
190
Parkinson's is more common in which gender?
Men
191
Signs/symptoms of Parkinson's
- Resting tremor
- Trembling
- Rigidity
- Bradykinesia
- Postural instability/impaired balance
192
Should Parkinson's medications be continued or discontinued perioperatively?
Continued
193
Which 2 medications are contraindicated in Parkinson's patients?
- Metoclopramide
| - Droperidol
194
Which 2 classes of medications are effective against acute symptoms of Parkinson's?
- Anticholinergics (atropine)
| - Antihistamines (benadryl)
195
What drug should be used to treat hypotension in a patient with Parkinson's?
Phenylephrine
196
Pathophysiology of Alzheimer disease
- Marked cortical atrophy with ventricular enlargement
| - Severe loss of hippocampal and cortical neurons (short term memory/reasoning)
197
Signs/symptoms of Alzheimer disease
- Slow decline in intellectual function
- Memory loss
- Language deterioration
- Poor judgement
- Confusion
- Restlessness
198
Anesthetic management concerns for a patient with Alzheimers
- Disoriented/uncooperative patient
- Altered responses to drugs
- DO NOT GIVE PREMED
- Confusion after extubation
199
If a patient has a right temporal lobe tumor, he may be weak on the left side. How would this affect a NMB monitor reading on the left side?
You would get a hyper-response on the left side, so you may think the patients isnt adequately blocked when they actually are
200
What should your IV access be before neuro surgery begins?
AT LEAST 2 good running IVs because the table is turned 90 degrees and we only have access to 1 arm
201
How should the ETT tube be secured for neuro cases?
- Secured to the side of the head that will be facing you
| - Insert bite blocks so the tube doesn't kink
202
To what general depth should you insert the ETT tube if the head will be flexed during neuro surgery?
Insert the tube shallower than normal because it will go deeper once the head is flexed during positioning
203
To what general depth should the ETT tube be inserted if the head will be extended during neuro surgery?
Insert the tube deeper because it will rise up once the head is positioned
204
Why is it hard to estimate EBL in neuro surgeries?
There is a very large amount of irrigation fluids used
205
When does a lot of the blood loss occur during neuro surgeries?
During closure of the scalp because it is very vascular
206
What drugs are used to decrease the brain's water content for neuro surgeries?
Diuretics - mannitol or lasix
207
Appropriate fluid management for neuro cases
1. Enough fluids for cardiovascular stability
2. Avoid hyperglycemia
3. Avoid hyper/hyponatremia
4. No "free water" (hypoosmolar fluid)
5. Mannitol (can cause hypotension)
208
What fluid should NOT be used for neuro cases?
Hypo osmolar fluids such as D5 0.45% saline
209
You should consider treating any glucose above __ in neuro cases
140
210
Osmolarity of plasma
295
211
When does anesthesia need to be "deep" during neuro cases?
Only during opening and closing - that is the only time surgical stimulus is high
212
Which neuro surgery has a very quick recovery and wake up time?
CHRONIC subdural hematomas in older patients
213
1mmhg increase in CO2 increases CBF by __%
2
214
What is the critical CBF at which you start losing brain cells
18ml/100gm
215
What factors can shift the CBF autoregulation curve to the left?
- Vasodilation
- Hypercarbia
- Deep inhalation agents
216
What physical states cause global ischemia?
- Cardiac arrest
- Severe hypotension
- Hypoxia
217
How do inhalational anesthetics affect CBF?
All increase CBF in a dose dependent fashion
218
Which inhalational agent increases CBF the most?
Halothane
219
How do inhalational agents affect CMRO2?
Decrease
220
What is the only anesthetic agent that increases CBF?
Ketamine
221
What are the best agents to treat blood pressure during brain surgery?
Alpha agents since they are not physiologically active in the brain
222
What drug can you not use on a patient who had a stroke 2 weeks ago due to high K+?
Succinylcholine
223
Normal ICP
10-15mmhg
224
ICP is considered severely increased if it exceeds...
40mmHg
225
Most common method used to drain CSF
Ventriculostomy
226
Risk associated with ventriculostomies
Very invasive and can cause infection
227
Subdural bolts are used to drain CSF in which patients
- Acute hepatitis
| - Coagulopathy
228
Why is an increase in ICP so detrimental during neuro surgery?
- Decreases CPP
- Risk of herniation
- Hard to operate
- Inadequate brain exposure
- Retractor's ischemia
- Injury to brain
229
What factors increase intracellular fluids in the brain during neuro surgery?
- Acute hyponatremia
| - Cellular damage (physical, ischemia, hypoxia)
230
What factors increase extracellular fluids in the brain during neuro surgery?
- Venous engorgement
- Extreme hypertension
- Hypervolemia
231
What factors decrease intra/extracellular fluids in the brain during neuro surgery?
- Diuretics
- Venous drainage
- Decadron
232
Which diuretic is generally best to use during neuro surgery?
Lasix. Mannitol causes a transient increase in ICP which can be damaging and interfere with surgery
233
How does mannitol affect electrolyte values
- Transient hyponatremia because it dilutes sodium in the plasma initially
- Hyperkalemia
234
Average cerebral blood volume
150cc
235
How much cerebral blood volume is in the venous system
75%
236
Acute consequences of venous obstruction
Increase in cerebral blood volume thus increase in ICP
237
Long term consequences of venous obstruction
Edema formation and decrease in CSF absorption
238
Normal volume of CSF
75-100cc
239
What factors decrease CSF?
- Drainage
| - Enhancing absorption by lowering venous pressure in cerebral sinuses
240
Anesthetic drugs to use during neuro surgery to aim for a prompt recovery
1. Barbituates
2. Propofol
3. Short acting narcotics
4. Less than 1 MAC of inhalational agents
241
What are the goals for emergence from a neuro case?
1. No coughing
2. No hypertension
3. Prompt
4. Minimal hypercarbia
242
What neuro patients are not expected to wake up quickly?
1. Acute subdural hematoma
2. Closed head injury
3. Patients with a lot of traction on brain
4. Patients with surgery around brain stem
243
What are the 2 major problems associated with intracranial aneurysms?
- Rebleeding
| - Vasospasm
244
When is the highest incidence of rebleeding after an intracranial aneurysm rupture?
A few days after the hemorrhage
245
When does the chance of vasospasm after intracranial aneurysm rupture peak?
7-10 days
246
What changes can be seen on an ECG of a patient presenting with an intracranial aneurysm?
- Subendocardial infarcations
- PVCs
- ST segment changes
247
Treatment for hyponatremia caused by SIADH
Restrict fluids
248
Treatment for hyponatremia caused by cerebral salt wasting syndrome
More fluids
249
Sequalae of prolonged bed rest and CNS depression of a patient with intracranial aneurysm
- Aspiration
- Atelectasis
- Hypovolemia
250
Standard monitors applied to a patient with intracranial aneurysm
- Standard ASA
- Aline
- CVP or Swan Ganz
- Intra-op angiography
251
What should be avoided by all means during induction of a patient with intracranial aneurysm?
Hypertension
252
How long can a clip be applied to an aneurysm intraoperatively and cause no problems to the patient?
18 minutes
253
How should blood pressure be managed during temporary clipping of an intracranial aneurysm?
Temporary hypertension to increase blood flow to the brain
254
What drugs should be administered during temporary clipping of an intracranial aneurysm to decrease CMRO2?
- Propofol 100mcg/kg/min
| - Etomidate
255
How should CO2 levels be maintained during temporary clipping of an intracranial aneurysm?
Mild hypocarbia to prevent steal phenomenon
256
What should be done if the aneurysm ruptures during surgery?
- Keep up with blood loss
- Controlled hypotension
- Adenosine
- Propofol
257
Methods for brain protection during neurosurgery
- Relaxed brain
- Decrease CMRO2 (hypothermia, drugs)
- Increase focal blood flow (hypocarbia, hypertension)
258
Clinical presentation of vasospasm following intracranial aneurysm rupture
Focal deficit, decreased level of consciousness
259
Ultimate method for diagnosis of vasospasm
Angiography
260
Treatment options for vasospasm
- Nimodipine
- Magnesium sulfate
- HHH therapy AFTER CLIPPING
- Angioplasty
261
Signs/symptoms of AV malformation
- Headache
- Seizures
- Bleeding
- Focal ischemia
262
Treatment for AV malformation
- Embolization
- Resection
- Gamma knife
263
Blood loss for AVM surgery
Protracted and massive
264
Blood loss for aneurysm surgery
Minimal unless it ruptures
265
Which incidence has a risk of vasospasm - AVM or aneurysm?
Aneurysm
266
Which incidence has a risk of hyperperfusion phenomenon - AVM or aneurysm?
AVM
267
How should blood pressure be managed following surgery for AVM?
Keep BP low
268
How should BP be managed following surgery for aneurysm?
Keep BP high
269
How should blood volume be managed following surgery for AVM?
Normal
270
How should blood volume be managed following surgery for aneurysm?
High
271
Mean weight gain during pregnancy
12kg (17%)
272
Metabolism increases by approximately __% during pregnancy
60
273
What causes difficult nasal breathing for the mother during pregnancy?
Increased blood flow causes capillary engorgement of the oropharynx, nasal mucosa, and larynx
274
What risk associated with nasal intubation is increased during pregnancy?
Epistaxis due to increased blood flow
275
How does airway conductance of the mother change during pregnancy?
Increases due to dilation of large airways
276
How does the position of the diaphragm change during pregnancy?
Elevates
277
During what point of pregnancy is blood volume the highest?
3rd trimester
278
What is the average blood volume for a pregnant woman in ml/kg
90ml/kg
279
When does the largest increase in cardiac output occur during pregnancy?
Immediately post partum
280
How much does cardiac output increase during pregnancy?
40%
281
How much does stroke volume increase during pregnancy?
30%
282
How much does heart rate increase during pregnancy?
15-30% (15-20BPM)
283
How much does contractility increase during pregnancy?
10%
284
How much does SVR decrease during pregnancy?
20%
285
How much does PVR decrease during pregnancy?
30%
286
Where does the mom shift on the oxyhemoglobin curve during pregnancy?
To the right and releases O2 more readily at tissues
287
Where does the baby shift of the oxyhemoglobin curve during pregnancy?
To the left, tries to hold on to oxygen
288
What is the P50 of fetal hemoglobin?
19
289
P50 of mother's hemoglobin
30
290
By how much does uterine blood flow increase during pregnancy?
From 50ml/minute to 600-700ml/minute
291
Where does the majority of increased blood flow to the uterus go?
To the intervillous space
292
Renal plasma flow is increased by __% at 16 weeks
75
293
Renal plasma flow is increased by __% at 26 weeks
85
294
Renal plasma flow is increased by __% at term
60
295
How much does skin blood flow increase during pregnancy
3-4 times normal flow
296
How much does systolic blood pressure decrease throughout pregnancy?
6-8%
297
How much does diastolic blood pressure decrease throughout pregnancy?
20-25% early, returns to normal at term
298
What factors impair uterine blood flow?
- Decreased uterine arterial pressure
- Increased uterine venous pressure
- Increased uterine vascular resistance via vasoconstrictors
299
What intra-op factors can impair uterine blood flow via decreasing uterine arterial pressure?
- Supine position
- Hypovolemia
- Drug-induced hypotension
300
What intra-op factors contribute to decreased uterine perfusion pressure by increasing uterine venous pressure?
- Vena caval compression
- Uterine contractions
- Drug-induced uterine hypertonus (oxytocin, local anesthetics)
- Skeletal muscle hypertonus (seizures, valsalva)
301
What endogenous vasoconstrictors are often released intra-op and contribute to increased uterine vascular resistance?
- Catecholamines (stress)
| - Vasopressin (hypovolemia)
302
What exogenous vasoconstrictors cause increased uterine vascular resistance?
- Epinephrine
- Pressors (Phenylephrine more so than ephedrine)
- Local anesthetics
303
Uterine blood flow is ______ dependent, not auto regulated.
Pressure
304
What patient position causes partial caval obstruction but maintains venous return?
Lateral decubitus
305
What patient position completely obstructs inferior vena cava and decreases venous return?
Supine
306
How much does the supine position decrease the cardiac output of a pregnant woman?
25-40%
307
When during pregnancy does caval compression begin?
13-16 weeks
308
The supine position significantly compresses the aorta at what spinal levels
L3-L5
309
How much does tidal volume increase during pregnancy?
40%
310
How much does FRC decrease during pregnancy?
25%
311
How does inspiratory capacity change with pregnancy?
Increases by 15%
312
How much does residual volume decrease during pregnancy?
15%
313
How is total lung capacity changed during pregnancy?
Decreased by ~5%
314
How does respiratory rate of mother change during pregnancy
0-15%
315
How does minute ventilation and alveolar ventilation change during pregnancy
Increase by 40%
316
What is the biggest contributor to the increase in minute ventilation of a pregnant woman?
Increase in tidal volume
317
PaCO2 changes in pregnant women
Decreases down to 30 (normal is 40)
318
PaO2 changes in pregnant women
Increases to 103-107 (normal is 100 on room air)
319
pH changes in pregnant women
Increases to 7.44 (normal is 7.4)
320
Bicarbonate changes in pregnant women
Decreases to 20-21 (normal is 24)
321
How does MAC change in pregnant women?
Decreases by as much as 40%
322
How does the nervous system change during pregnancy?
Progesterone mediated CNS depression
323
How does dosing for local anesthetics change during pregnancy?
Decreased by 33%
324
What factors contribute to the need for a decrease in local anesthetic dosing?
- Increased epidural blood volume can increase risk of puncturing vein
- Decreased CSF volume causes enhanced cephalad spread
325
Renal changes of the mother during pregnancy
- Increased renal blood flow
- Increased GFR
- Decreased BUN/Cr
326
How do levels of plasma cholinesterase change during pregnancy?
Decrease by 30%
327
Colloid osmotic pressure decreases by __mmHg at term
5
328
How do total protein values change during pregnancy
Decrease to ~7.0% (normal is 7.8%)
329
How do albumin values change during pregnancy
Decrease from 3.9 to 3.6 to 3.3% throughout pregnancy (normal is 4.5%)
330
What is the only plasma protein to increase during pregnancy?
Globulin
331
How is coagulation changed during pregnancy
Accelerated, compensated coagulation with enhanced platelet turnover, clotting, and fibrinolysis
332
PT is shortened by __% during pregnancy
20
333
PTT is shortened by __% during pregnancy
20
334
Bleeding time is shortened by __% during pregnancy
10
335
What test demonstrates the hypercoagulable state of pregnant women?
Thromboelastograph
336
What is the most common part of the endocrine system that is changed during surgery?
Thyroid
337
Thyroid changes during surgery
Thyroid gland commonly hypertrophies due to increased estrogen which results in increased iodine uptake and increased T3/T4 levels
338
The metabolic state of the mother during pregnancy mimics what endocrine state
Hyperthyroidism
339
Parathyroid function is important to what aspect of pregnancy?
Fetal growth
340
How does insulin change during pregnancy?
There is insulin resistance by mid 2nd trimester and release of growth producing hormones by the placenta
341
GI changes during pregnancy
- Delayed gastric emptying
- Decreased GI mobility
- Silent regurgitation
- Changes in gastric volume and pH
- Relaxed lower esophageal sphincter
342
The GI changes during pregnancy lead to an increased risk of...
Aspiration
343
The reduced tissue sensitivity to insulin causes what phenomena in pregnant women?
Fasting hypoglycemia
344
Pregnancy predisposes the mother to what gallbladder problem
Gall stone formation
345
Considerations for ETT size for pregnant women
Chose smaller ETT because of increased edema, tissue, and breast size
346
How does maternal oxygenation change under general anesthesia?
- Increase physiologic shunt when supine
- Increased rate of denitrogenation
- Increased rate of decline of PaO2 during apnea
347
Protocol for a pregnant surgical patient coming in for elective surgery
Delay until postpartum
348
Protocol for a pregnant patient in their 1st trimester coming in for ESSENTIAL surgery
- If no risk, consider delayed until mid-gestation
| - If high risk, proceed with surgery
349
Protocol for a pregnant patient in their 2nd/3rd trimester coming in for ESSENTIAL surgery
Proceed with surgery
350
Protocol for pregnant patient coming in for an EMERGENCY surgery
Proceed with surgery
351
What are the 3 stages of labor
Stage 1: Latent phase (onset of labor, minimal dilation) then active phase (increased contractions, dilation up to 10cm)
Stage 2: full dilation, fetal descent and delivery
Stage 3: delivery of placenta
352
Once the water of a pregnant patient breaks, there is an increased risk of...
Infection
353
Maternal minute ventilation increases by ___% during intense contractions
300
354
O2 consumption increases acutely by __% during labor
60
355
How much blood is displaced from the uterus to central circulation with EACH contraction?
300-500ml
356
Effects of opioids on fetus
Can cross the placenta and cause respiratory depression in baby, use with caution
357
Function of Pitocin (oxytocin) during labor
Progresses labor by stimulating uterine smooth muscle contractions
358
Function of Methergine and Hemabate during labor
Given POST PARTUM intramuscularly to contract uterus and control bleeding
359
Function of Magnesium during contractions
Stops contractions, given to eclamptic patients to avoid a seizure
360
What drug class is contraindicated during pregnancy?
Benzodiazepines
361
Effect of nitrous oxide on the progression of labor
No effect
362
Effect of inhaled anesthetics on the progression of labor
Causes uterine relaxation and slows progression of labor
363
Effect of high doses of inhaled anesthetics on labor
Causes uterine atony (loss of muscle tone) and increased bleeding at delivery
364
What is pre-eclampsia (PIH)?
A triad of
1) Hypertension (Over 140/90 or 20% over baseline)
2) Proteinuria (Over 300mg/day)
3) Edema
365
What is HELLP syndrome?
Pregnancy induced hypertension associated with...
1) Hemolysis
2) Elevated Liver Enzymes
3) Low Platelets
366
What is eclampsia?
When preeclampsia is accompanied by generalized tonic-clonic seizures
367
Effect of preeclampsia on the baby
There is decreased transfer of nutrients to the baby so it is smaller and often delivered early
368
Preeclampsia is exhibited after __ weeks of gestation
20
369
What is the root of the problem of preeclampsia?
Placental ischemia causing cell damage
370
What abnormalities can occur in the endothelium of the placenta and cause preeclampsia to develop?
- Increase in: vascular tone, permeability, fibrin deposition
- Release of: vasoconstrictors, procoagulants, other humoral factors
371
A decrease in which 3 blood components can cause the development of preeclampsia?
- Platelets
- Prostacyclin
- Antithrombin III
372
An increase in which 5 blood components can cause development of preeclampsia?
- Thromboxane A2
- von Willebran factor
- Factor VII activity
- Neutrophil activation
- Free radicals
373
What abnormal functional states of blood can cause preeclampsia?
- DIC (disseminated intravascular coagulation)
| - Hemolysis
374
What is the immediate action that should be taken when an eclamptic patient has a seizure?
Airway management
375
What should be ruled out during a differential diagnosis of eclampsia?
- Epilepsy
- LAST
- Embolism
376
Patients with eclampsia may have what response to NMB drugs
The effect of the drugs may be prolonged because these patients are often on magnesium therapy
377
Renal complications associated with PIH
- Proteinuria
- Sodium retention
- Decrease GFR
- Renal failure
378
Occurrence of an acute fatty liver in pregnant women
Rare but high mortality
379
When do symptoms of acute fatty liver present during pregnancy?
3rd trimester
380
Symptoms of acute fatty liver
- N/V
- Epigastric pain
- Jaundice
- Decrease serum glucose
- Increased liver enzymes
381
Treatment of acute fatty liver
Treat hypoglycemia with D50, fluids, FFP, platelets
382
What is an amniotic fluid embolism?
When amniotic fluid from uterus gets absorbed into mother's circulation due to vascular tear, delivery, or trauma and there is an anaphylactic response to absorption
383
When does an amniotic fluid embolism most commonly present?
During vaginal delivery
384
Symptoms of amniotic fluid embolism
- Sudden unexpected CV collapse
- Hypotension
- Resp. depression
- Cyanosis
- Seizure
- DIC
385
Treatment of amniotic fluid embolism
- Supportive care
| - Delivery baby via c section
386
What is DIC (disseminated intravascular coagulation)?
Widespread systemic activation of coagulation, resulting in intravascular formation of fibrin and ultimately thrombotic formation occlusion of small and mid sized vessels
387
Causes of DIC
- Trauma
- Sepsis
- Acute fatty liver
- Amniotic fluid embolism
388
Treatment for DIC
- Clotting factors
| - Platelets
389
What is thromboembolic disease
When pregnancy causes an increase in most clotting factors and gravid uterus causes venous stasis
390
What factors increase the risk of thromboembolic disease
- Smoking
- Obesity
- Age
- Genetics
391
Diagnosis of DVT/PE
Doppler ultrasound
392
Treatment of DVT/PE
Anticoagulation
393
Anesthetics considerations for a pregnant patient with DVT/PE
- Have a clotting screen done before epidural placement
- Have blood ready
- Don't keep patient supine for too long
394
How is pre-existing asthma tolerated during pregnancy
It is benign for the pregnancy. Epidurals are still well tolerated and prednisone/B2 agonists are tolerated and can be given
395
What pre-existing respiratory disease is responsible for 10% of maternal death
Cystic fibrosis
396
What thyroid disorder is most common in pregnant women
Hyperthyroidism
397
Which type of diabetes should be very closely monitored in pregnant women
Type I
398
Pregnant patients with a history of a renal transplant tend to do well if the transplant happened how long before pregnancy
2 years before pregnancy
399
What pre-existing neurologic disease's medications are contraindicated during pregnancy?
Epilepsy - anti-seizure meds are contraindicated
400
Risks associated with morbidly obese pregnant patient
- Decreased blood volume per kilo
- Increased risk of diabetes
- Difficult epidural placement
- Difficult vaginal delivery
