Neuraxial Detailed Flashcards
(298 cards)
1
Q
What are the order of meningeal layers surrounding the spinal cord?
A
Dura Mater, Arachnoid Mater, Pia Mater.
2
Q
Which meningeal layer is the innermost and directly covers the spinal cord?
A
Pia Mater.
3
Q
Where is the Epidural Space located in relation to the dura mater?
A
The Epidural Space is located outside the dura mater.
4
Q
What is found in the Epidural Space?
A
The Epidural Space contains fat and small blood vessels (epidural veins).
5
Q
Describe the Subarachnoid Space and its contents.
A
The Subarachnoid Space is between the arachnoid mater and pia mater, filled with cerebrospinal fluid (CSF) that cushions and protects the spinal cord.
6
Q
What are the boundaries of the Epidural Space?
A
Cranial border near the foramen magnum, caudal border near the sacrococcygeal ligament, anterior border lined by posterior longitudinal ligament, lateral borders marked by vertebral pedicles, and posterior borders framed by ligamentum flavum and vertebral lamina.
7
Q
What are the contents of the Epidural Space?
A
The Epidural Space contains nerves, fatty tissue, lymphatics, and blood vessels.
8
Q
How does the fatty tissue in the Epidural Space affect drug absorption?
A
Fatty tissue can absorb drugs, leading to decreased drug availability; for example, bupivacaine is absorbed more than lidocaine, fentanyl, or morphine.
9
Q
Describe the characteristics of Epidural Veins (Batsons Plexus).
A
Epidural veins are valveless and form a plexus to drain blood from the spinal cord and its linings. The density of veins increases laterally.
10
Q
How do conditions like obesity or pregnancy affect Epidural Veins?
A
Under conditions like obesity or pregnancy, Epidural Veins can become engorged, increasing the risk during needle procedures in the Epidural Space.
11
Q
What is the controversy surrounding the existence of Plica Mediana Dorsalis?
A
The presence of Plica Mediana Dorsalis is controversial and not definitively confirmed.
12
Q
Where is the Plica Mediana Dorsalis located?
A
Plica Mediana Dorsalis is thought to be a band of connective tissue located between the ligamentum flavum and the dura mater.
13
Q
How might the potential existence of Plica Mediana Dorsalis impact the Epidural Space?
A
If it exists, the Plica Mediana Dorsalis might act as a barrier within the Epidural Space, affecting how medications spread when injected.
14
Q
In what clinical scenarios is the Plica Mediana Dorsalis relevant?
A
The Plica Mediana Dorsalis is considered in catheter insertion, potentially causing complications, and in cases of unilateral blocks where both sides are not equally affected.
15
Q
Where is the subarachnoid space located?
A
It is situated deep to the arachnoid mater in the spinal cord.
16
Q
What are the contents of the subarachnoid space?
A
It contains cerebrospinal fluid (CSF), nerve roots, and the spinal cord itself.
17
Q
Why is the subarachnoid space the primary target during spinal anesthetic procedures?
A
It is the primary target as it contains CSF and is where spinal anesthesia is typically administered.
18
Q
What risk is associated with advancing the needle too far anteriorly in the subarachnoid space?
A
Advancing the needle too far may lead to passing through multiple layers (pia mater, spinal cord, ligaments) before reaching bone.
19
Q
What characteristic sensation is often felt during spinal anesthesia as the needle traverses the outer membrane?
A
A distinct ‘pop’ sensation is often felt when the needle traverses the dura mater.
20
Q
Where is the subdural space located?
A
It is a potential space between the dura mater (outer layer) and the arachnoid mater (middle layer) surrounding the spinal cord.
21
Q
What effect can occur if local anesthetic is inadvertently injected into the subdural space during an epidural?
A
It can lead to a ‘high spinal’ effect, causing the medication to affect a larger area than intended.
22
Q
What consequence may result from an accidental injection into the subdural space during spinal anesthesia?
A
It can result in a failed spinal block if the injection occurs in this space.
23
Q
What is the function of the Dura Mater within the meninges?
A
It is a tough fibrous shield protecting the spinal cord.
24
Q
Where does the Dura Mater begin and end within the spinal cord?
A
It starts at the foramen magnum and extends to the dural sac.
25
Which meningeal layer is the first encountered by a needle in the epidural space?
The Dura Mater is the first layer encountered in the epidural space.
26
Describe the Arachnoid Mater in terms of its location and function.
It is a thin layer of connective tissue beneath the Dura Mater, acting as a protective middle layer between the Dura Mater and Pia Mater.
27
What are the characteristics of the Pia Mater within the meninges?
It is a highly vascular, delicate innermost layer covering the spinal cord.
28
Why should the Pia Mater never be punctured during spinal anesthesia procedures?
It should not be punctured as it is directly attached to the surface of the spinal cord.
29
How many pairs of spinal nerves are found in the spinal cord?
There are 31 pairs of spinal nerves in the spinal cord.
30
Where do the Cervical nerves exit in relation to their corresponding vertebrae?
Each Cervical nerve exits above its corresponding vertebra except for C8, which exits below the C7 vertebra.
31
What is the exception in the exit pattern of the Cervical nerves in comparison to the others?
The C8 nerve exceptionally exits below the C7 vertebra unlike other Cervical nerves.
32
What types of nerves are formed by the joining of different nerve roots in each spinal nerve?
Each spinal nerve consists of an Anterior (Ventral) Nerve Root and a Posterior (Dorsal) Nerve Root.
33
What information does the Anterior (Ventral) Nerve Root carry?
It carries motor and autonomic information from the spinal cord to the body.
34
What information is transmitted by the Posterior (Dorsal) Nerve Root?
It transmits sensory information from the body back to the spinal cord.
35
What is a dermatome?
A dermatome is an area of skin innervated by sensory nerves from a single spinal nerve root.
36
Explain the misconception related to dermatomes and spinal nerves.
Despite physical appearances, a dermatome may not align with the corresponding part of the spine but may be connected to a different spinal nerve root.
37
Provide an example of a dermatomal discrepancy.
The umbilicus (belly button) is typically associated with the L3 nerve but is actually served by the T10 nerve.
38
How is sensory information from the face transmitted?
Sensory information from the face is not carried by spinal nerves but is transmitted via the trigeminal nerve (Cranial Nerve V).
39
What areas does the V1 - Ophthalmic Nerve of the trigeminal nerve innervate?
The V1 - Ophthalmic Nerve is responsible for sensation from the forehead, scalp, and upper eyelids.
40
Which regions are served by the V2 - Maxillary Nerve of the trigeminal nerve?
The V2 - Maxillary Nerve handles sensory input from the lower eyelids, cheeks, nostrils, upper lip, and upper teeth.
41
What sensations are conveyed by the V3 - Mandibular Nerve of the trigeminal nerve?
The V3 - Mandibular Nerve conveys sensations from the lower jaw, lower teeth, lower lip, and part of the tongue.
42
Where is the site of action for local anesthetics in the spinal cord?
Local anesthetics act on the myelinated preganglionic fibers in the subarachnoid space of the spinal cord.
43
Describe the location of the spinal epidural space in relation to the dura mater.
The spinal epidural space is located outside the dura mater surrounding the spinal cord.
44
How do local anesthetics reach nerve roots in the epidural space?
Local anesthetics diffuse through the dural cuff and can also leak through the intervertebral foramen to reach nerve roots.
45
List controllable factors affecting local anesthetic distribution in the spinal space.
Controllable factors include baricity, patient position, dose, and site of injection.
46
What are non-controllable factors that influence local anesthetic distribution in the spinal space?
Non-controllable factors include volume of cerebrospinal fluid, increased intra-abdominal pressure, and age.
47
How does a low cerebrospinal fluid volume impact the spread of local anesthetics?
Low cerebrospinal fluid volume correlates with extensive spread of local anesthetics in the intrathecal space.
48
Why is dose considered crucial in affecting the spread of local anesthetic?
Dose is crucial as it is the most reliable factor influencing the spread of anesthetic using hypo- or isobaric solutions.
49
What role does baricity play in determining the spread of local anesthetics?
Baricity matters, as the relative density of the anesthetic compared to CSF determines its spread, especially for hyperbaric solutions.
50
How does advancing age affect the vulnerability of neural nerves to local anesthetics?
In advanced age, neural nerves become more vulnerable to local anesthetics as cerebrospinal fluid volume decreases.
51
What impact does pregnancy have on cerebrospinal fluid volume and local anesthetic distribution?
Pregnancy leads to decreased cerebrospinal fluid volume due to increased intraabdominal pressure, affecting local anesthetic spread.
52
What is the most important drug-related factor affecting local anesthetic spread and block height?
The local anesthetic volume is the most important drug-related factor.
53
Which factor is considered the most important procedure-related factor influencing local anesthetic spread and block height?
The level of injection is the most important procedure-related factor.
54
Name a non-controllable factor that can affect local anesthetic spread and block height.
Pregnancy is a non-controllable factor.
55
How does the local anesthetic concentration impact local anesthetic spread and block height?
It is a controllable factor that can influence the distribution and block height.
56
What role does the patient's position play in local anesthetic spread and block height?
Patient position is a controllable factor that can affect the spread and block height.
57
In what way can the additives in the anesthetic impact local anesthetic spread and block height?
Additives can modify onset time or duration but not the spread of the local anesthetic.
58
How does the direction of the bevel of the needle affect local anesthetic spread?
The needle bevel direction does not influence the spread of the local anesthetic.
59
What factors do not affect the spread of spinal anesthetic?
The speed of injection, barbotage, direction of bevel, gender and vasoconstrictors
60
What determines the block height in the spinal or epidural space?
The spread of the local anesthetic in the spinal is determined by the dose. In the epidural space the volume determines the block height.
61
How does the spread of local anesthetic differ in the lumbar region during an epidural injection?
It mostly spreads cephalad in the lumbar region during an epidural injection.
62
Describe the spread dynamics of local anesthetic in the mid-thoracic region during an epidural injection.
The spread is balanced both cephalad and caudad in the mid-thoracic region.
63
In which direction does local anesthetic spread in the cervical region during an epidural injection?
In the cervical region, the local anesthetic spreads caudad.
64
What is meant by the term 'differential blockade' in the context of nerve fibers?
Differential blockade refers to varying sensitivities of nerve fibers to local anesthetics, affecting block levels.
65
How does sensory blockade differ from autonomic blockade in terms of local anesthetic sensitivity?
Sensory blockade occurs at lower concentrations, while autonomic blockade requires even lower concentrations.
66
Which nerve fibers are associated with autonomic preganglionic function and venodilation?
The B fibers are related to autonomic preganglionic function and venodilation.
67
What functions are attributed to A-delta fibers in the context of nerve sensitivity?
A-delta fibers are associated with pain and temperature sensation.
68
Identify the nerve fiber type responsible for motor tone.
A-gamma fibers are responsible for motor tone.
69
Which nerve fibers are linked to touch and pressure sensation?
A-beta fibers are associated with touch and pressure sensation.
70
What functions are attributed to A-alpha fibers in the context of nerve sensitivity?
A-alpha fibers are related to motor function and proprioception.
71
What happens at lower concentrations of Local Anesthetic in Sensory Blockade?
Sensory Blockade occurs, affecting sensory neurons but not motor neurons.
72
How does Sensory Blockade compare to motor blockade in terms of block level?
Sensory level is 2 levels higher than motor level
73
At what concentrations does Autonomic Blockade occur in relation to Local Anesthetic?
Autonomic Blockade requires even lower concentrations of Local Anesthetic.
74
Which neurons are affected by Autonomic Blockade?
Autonomic Blockade does not affect sensory or motor neurons.
75
What level of blockade does Autonomic Blockade lead to?
Autonomic Blockade leads to the highest level of blockade.
76
How does the sensory level compare to the motor level in Differential Blockade Zones?
The sensory level is 2 levels higher than the motor level in Differential Blockade Zones.
77
What are the functions of Type B-fibers?
B-fibers are associated with sympathetic function.
78
What type of sensation is lost with C and A-delta fibers in nerve fiber classification?
Loss of pain and temperature sensation occurs with C and A-delta fibers.
79
What is the impact of A-gamma fibers being affected in nerve fiber classification?
Loss of motor tone occurs when A-gamma fibers are affected.
80
Which sensations are affected by A-beta fibers in nerve fiber classification?
A-beta fibers are associated with the loss of touch and pressure sensation.
81
What functions are impaired when A-alpha fibers are affected according to nerve fiber classification?
Motor function and proprioception are lost when A-alpha fibers are affected.
82
What is the clinical progression stage characterized by Nerve Block Onset?
Nerve Block Onset order:
Type B (sympathetic)
Type C and Type A-delta (pain and temp)
Type A-gamma (motor tone)
Type A-beta (touch/pressure)
Type A-alpha (motor function/proprioception)
83
What does Nerve Block Recovery signify in the clinical progression of differential blockade?
Nerve Block Recovery refers to the regaining of nerve function post-local anesthesia, indicating the resolution of nerve block effects.
84
Which sense is typically the first to be blocked during anesthesia?
Temperature sensation is the first sense to be blocked during anesthesia.
85
How can the loss of temperature sensation be demonstrated in a patient under anesthesia?
Patients may not feel cold from an alcohol pad as a demonstration of the loss of temperature sensation under anesthesia.
86
What is the second sense to be blocked during anesthesia?
Pain sensation is the second sense to be blocked during anesthesia.
87
How can pain sensation be assessed in a patient under anesthesia?
Pain sensation can be assessed using stimuli like a pinprick.
88
Which sense is typically the last to be blocked during anesthesia?
Touch or pressure sensation is the last sense to be blocked during anesthesia.
89
What is utilized for monitoring sensory block during anesthesia?
The Modified Bromage Scale is utilized for monitoring sensory block during anesthesia.
90
What does a level of '0' on the Modified Bromage Scale indicate?
A level of '0' indicates no motor block according to the Modified Bromage Scale.
91
Describe the motor block at level '1' on the Modified Bromage Scale.
Level '1' reflects a slight motor block where the patient cannot raise an extended leg but can still move the knees and feet.
92
What does a level of '2' on the Modified Bromage Scale represent?
A level of '2' represents a moderate motor block where the patient cannot raise an extended leg or move the knee but can move the feet.
93
What does a level of '3' signify on the Modified Bromage Scale?
A level of '3' signifies a complete motor block where the patient cannot move the legs, knees, or feet.
94
What aspect of nerve function does the Modified Bromage Scale evaluate?
The Modified Bromage Scale evaluates the function of lumbosacral nerves.
95
Which regions does the Modified Bromage Scale focus on during assessment?
The Modified Bromage Scale focuses on the lower spine and sacral nerve areas during assessment.
96
What areas are not assessed by the Modified Bromage Scale?
The Modified Bromage Scale does not assess movement above the lower spine and sacral nerve areas.
97
How does sympathectomy affect preload in the cardiovascular system?
Sympathectomy causes veins to dilate, leading to blood pooling in the periphery and reducing blood return to the heart.
98
What effect does sympathectomy have on afterload in the cardiovascular system?
Sympathectomy partially dilates arterial circulation, decreasing afterload.
99
How does Systemic Vascular Resistance (SVR) change in healthy patients under neuraxial anesthesia?
Healthy patients experience a decrease in SVR by approximately 15%.
100
In elderly or cardiac patients, by how much can Systemic Vascular Resistance (SVR) decrease under neuraxial anesthesia?
In elderly or cardiac patients, SVR can decrease by up to around 25%.
101
How does a decrease in venous return and SVR impact Cardiac Output (CO) under neuraxial anesthesia?
The decrease in venous return and SVR leads to reduced stroke volume and subsequently reduced Cardiac Output.
102
Describe the initial response of Cardiac Output (CO) to changes caused by neuraxial anesthesia.
Cardiac Output may initially increase, then decrease over time due to changes in blood vessel dilation speeds.
103
What causes a decrease in heart rate under neuraxial anesthesia?
Blockade of Cardiac Accelerator Fibers reduces sympathetic tone, leading to decreased heart rate.
104
How does the Bezold-Jarisch Reflex contribute to changes in heart rate during neuraxial anesthesia?
The Bezold-Jarisch Reflex responds to ventricular underfilling, potentially causing significant bradycardia and asystole.
105
What is the Reverse Bainbridge Reflex, and how does it affect heart rate?
The Reverse Bainbridge Reflex is triggered by reduced stretching of the heart's right atrium, influencing heart rate.
106
What are the potential consequences of unopposed parasympathetic tone during neuraxial anesthesia?
Unopposed parasympathetic tone can lead to profound bradycardia, hypotension, and sudden cardiac arrest.
107
When does sudden cardiac arrest typically occur after the onset of spinal anesthesia?
Sudden cardiac arrest typically occurs 20 to 60 minutes after the onset of spinal anesthesia.
108
What ratio of occurrence is observed for sudden cardiac arrest in relation to spinals and epidurals?
In young adults with high parasympathetic tone, the ratio is 7 in 10,000 for spinals and 1 in 10,000 for epidurals.
109
What factors are associated with sudden cardiac arrests during neuraxial anesthesia?
Sudden cardiac arrests are often associated with large blood loss and orthopedic cement placement.
110
Why is delaying treatment for spinal-anesthesia induced hypotension dangerous?
Delaying treatment can lead to increased mortality.
111
How does phenylephrine help prevent spinal-anesthesia induced hypotension?
Vasopressors like phenylephrine maintain blood pressure by constricting blood vessels.
112
Which drug can mitigate reflexes causing hypotension in spinal-anesthesia?
5-HT3 antagonists like ondansetron can mitigate reflexes like the Bezold-Jarisch reflex that lead to hypotension.
113
What is the recommended method of fluid administration immediately after a spinal block to prevent hypotension?
Co-loading with intravenous fluids (around 15 mL/kg) is recommended to prevent drops in blood pressure.
114
Why is pre-block hydration not routinely recommended for preventing spinal-anesthesia induced hypotension?
Pre-block hydration is not routinely recommended due to its minimal impact on preventing hypotension.
115
How does excessive fluid intake impact patients at risk of spinal-anesthesia induced hypotension?
Excessive fluid can overload the circulatory system, especially in patients with heart problems.
116
What role does positioning play in preventing spinal-anesthesia induced hypotension?
Positioning, like slight pelvic tilting, optimizes blood flow and reduces risks of hypotension.
117
How are ephedrine and epinephrine used in the treatment of spinal-induced hypotension?
They are utilized based on the patient's heart rate and symptoms. Ephedrine preferred hypotension with bradycardia.
Phenylephrine preferred for hypotension with elevated or normal heart rate.
118
What anticholinergic medication may be administered for bradycardia in spinal-induced hypotension?
Atropine may be given to patients experiencing bradycardia.
119
What types of fluids are commonly used for maintaining adequate blood volume in spinal-induced hypotension?
Crystalloids or colloids are employed in fluid management for maintaining blood volume.
120
What caution is advised regarding the Trendelenburg position in the treatment of spinal-induced hypotension?
Caution is advised as a tilt greater than 20 degrees can reduce cerebral perfusion by impeding venous brain drainage.
121
How does the gravity or positioning impact the block height in the context of spinal anesthesia-induced hypotension?
Gravity can affect the block height if the block has not been set yet, emphasizing the influence of positioning on block effectiveness.
122
Why is prompt treatment essential in the management of spinal anesthesia-induced hypotension?
Prompt treatment is crucial to prevent increased mortality rates associated with spinal-induced hypotension.
123
How does high thoracic level dermatome spread impact respiratory function?
Minimal impact on tidal volume, respiratory rate, inspiratory reserve volume, but decreased expiratory reserve volume.
124
What consequence does high thoracic blockade have on vital capacity?
It leads to small decreases in vital capacity due to the loss of abdominal muscle contribution in forced expiration.
125
What muscles can be affected by high thoracic blockade leading to respiratory issues?
Accessory muscles of respiration such as intercostal and abdominal muscles may be blocked.
126
Why is caution required in patients with COPD and Pickwickian syndrome during neuraxial anesthesia?
Due to potential feelings of dyspnea and the common post-anesthesia loss of sensory feedback from the chest area.
127
What are the effects of neuraxial anesthesia on the ability to breathe deeply and cough effectively?
It may lead to a loss of ability to take deep breaths and cough strongly.
128
How may apnea occur during neuraxial anesthesia?
Apnea may occur due to reduced blood flow to the brainstem affecting the brain's breathing centers.
129
High concentrations of local anesthetics in the spinal fluid can lead to this rare occurrence?
High concentrations of local anesthetics in the spinal fluid **rarely** causes nerve paralysis that stops breathing
130
Which nerve primarily provides parasympathetic innervation to the GI system?
The vagus nerve originating from the medulla provides parasympathetic innervation to the GI system.
131
What sensations are transmitted by parasympathetic afferent fibers in the GI system?
Sensations of satiety, distension, and nausea are transmitted by parasympathetic afferent fibers.
132
What functions are regulated by parasympathetic efferent fibers in the GI system?
Tonic contractions, sphincter relaxation, peristalsis, and secretion are regulated by parasympathetic efferent fibers.
133
From where to where does sympathetic innervation of the GI tract range?
Sympathetic innervation of the GI tract ranges from T5 to L2.
134
What role do sympathetic afferent fibers play in the GI system?
Sympathetic afferent fibers transmit visceral pain in the GI system.
135
What functions are influenced by sympathetic efferent fibers in the GI system?
Sympathetic efferent fibers inhibit peristalsis and gastric secretion, cause sphincter contraction, and induce vasoconstriction.
136
Where does sympathetic innervation of the GI tract originate?
Sympathetic innervation of the GI tract originates from T5 - L2.
137
What GI changes occur due to the unopposed vagal tone resulting from neuraxial anesthesia?
Relaxation of sphincters, enhancement of peristalsis, small contracted gut with active peristalsis, increased GI blood flow, and reduced postoperative ileus incidence.
138
What is the impact of neuraxial anesthesia on the incidence of nausea and vomiting?
The incidence of nausea and vomiting is around 20% due to the changes in vagal tone and GI tract activity.
139
How does neuraxial anesthesia impact renal blood flow?
There is no significant change in renal blood flow when Mean Arterial Pressure (MAP) is maintained.
140
How does sympathetic blockade above T10 influence bladder control during neuraxial anesthesia?
It leads to relaxation of urinary sphincter tone, affecting bladder control.
141
What consequences can arise from the alterations in bladder control due to neuraxial anesthesia?
These alterations can result in urinary retention or incontinence, often requiring the use of a foley catheter.
142
What activates somatic and visceral afferent fibers leading to the release of cortisol, epinephrine, norepinephrine, and vasopressin?
Pain, tissue trauma, and inflammation.
143
What does the activation of afferent fibers trigger?
It triggers the activation of the renin-angiotensin-aldosterone system.
144
How does neuraxial blockade affect the neuroendocrine response in major invasive surgery?
Neuraxial blockade can partially suppress the neuroendocrine response.
145
For lower extremity procedures, how does neuraxial blockade affect the neuroendocrine response?
Neuraxial blockade can completely block the neuroendocrine response.
146
When is the optimal benefit of neuraxial blockade achieved in relation to the surgical stimulus?
The optimal benefits are achieved when neuraxial blockade is administered prior to the surgical stimulus.
147
At what levels is the highest level of neuraxial anesthesia typically found?
The highest level is typically at C3 and L3 (Apex).
148
Where is the lowest level of neuraxial anesthesia usually found?
The lowest level is usually at T6 and S2 (Trough).
149
What are some of the concentrations used for epidural surgical analgesia dosing?
Concentrations such as 3%, 2%, 0.75%, and 0.5% are used.
150
How does aspirin prevent platelet aggregation?
Aspirin inhibits cyclooxygenase, preventing the formation of thromboxane A2, which induces platelet aggregation.
151
What effect do NSAIDs have on cyclooxygenase and platelet aggregation?
Like aspirin, NSAIDs also inhibit cyclooxygenase, thus impacting platelet aggregation.
152
How does aspirin help prevent clot formation?
Due to its antiplatelet properties, aspirin helps prevent clot formation in the body.
153
What is the difference between primary and secondary prophylaxis with aspirin?
Primary prophylaxis aims to prevent the first event, while secondary prophylaxis prevents recurrent events.
154
What risks are associated with discontinuing aspirin in cases of secondary prophylaxis?
Discontinuing aspirin in secondary prophylaxis poses a high risk, with around 10% of acute cardiovascular syndromes occurring after withdrawal.
155
How long should aspirin be held before high-risk and intermediate-risk procedures?
Aspirin should be held for 4-6 days before high-risk and intermediate-risk procedures.
156
Is it necessary to discontinue aspirin usage before low-risk procedures?
Generally, there is no need to discontinue aspirin usage before low-risk procedures.
157
What precautions are recommended for aspirin use in central neuraxial blocks?
No additional precautions are required regarding aspirin use in central neuraxial blocks.
158
Do current guidelines differentiate between low-dose and regular-dose aspirin in clinical scenarios?
No, current guidelines do not distinguish between low-dose (81mg) and regular-dose (325mg) aspirin in various clinical scenarios.
159
What factor should be considered when deciding on aspirin therapy in individual cases?
The benefits of aspirin therapy should be assessed on a case-by-case basis.
160
How do NSAIDs and Aspirin impact platelet aggregation?
They inhibit cyclooxygenase, preventing the formation of thromboxane A2, crucial for platelet aggregation.
161
What are the cardiac risk categories based on percentage?
Low (<1%): Endoscopic, cataract, breast surgeries. Intermediate (1-5%): Orthopedic, prostate surgeries. High (>5%): Aortic, peripheral vascular surgeries.
162
How do Tirofiban, Eptifibatide, and Abciximab inhibit platelet aggregation?
They inhibit platelet aggregation via surface receptors.
163
How long should Abciximab be held before regional anesthesia?
Hold for 24-48 hours.
164
What regional anesthesia consideration needs to be taken to account in regards to Glycoprotein IIB/IIIA Antagonists
Avoid regional anesthesia until platelet function has recovered.
165
What is the recommended timing for holding Tirofiban and Eptifibatide before regional anesthesia?
Hold for 4-8 hours.
166
What is the mechanism of action for Clopidogrel, Prasugrel, and Ticlopidine in regional anesthesia?
These medications inhibit platelet aggregation by blocking ADP transferase.
167
Name the medications that fall under the category of Clopidogrel, Prasugrel, and Ticlopidine.
The medications are Clopidogrel (Plavix), Prasugrel (Effient), and Ticlopidine (Ticlid).
168
How long should Clopidogrel be held before regional anesthesia?
Clopidogrel should be held for 5 - 7 days before regional anesthesia.
169
What is the recommended hold duration for Prasugrel before regional anesthesia?
Prasugrel should be held for 7 - 10 days before regional anesthesia.
170
How long should Ticlopidine be held prior to regional anesthesia?
Ticlopidine should be held for 10 days before regional anesthesia.
171
What is the mechanism of action of Heparin in regional anesthesia?
Heparin potentiates antithrombin, inhibiting thrombin (factor 2) and factors 9, 10, 11, 12.
172
How is Heparin administered for DVT prophylaxis, and what are the hold durations for different doses?
Heparin is administered subcutaneously for DVT prophylaxis. Hold low-dose for 4 - 6 hours, higher dose for 12 hours, and therapeutic dose for 24 hours.
173
When should a platelet count be checked before central neuraxial block in patients on unfractionated Heparin?
A platelet count should be checked before the central neuraxial block if on unfractionated Heparin for more than 4 days.
174
What is the mechanism of action for Enoxaparin, Dalteparin, and Tinzaparin in regional anesthesia?
These medications inhibit factor 10a.
175
What precautions should be taken before using Enoxaparin, Dalteparin, or Tinzaparin in regional anesthesia?
Ensure coagulation status appears normal and avoid using other blood thinners.
176
How long should you wait after a prophylactic dose of Enoxaparin, Dalteparin, or Tinzaparin before regional anesthesia?
Delay at least 12 hours after a prophylactic dose before regional anesthesia.
177
In what situations should the anti-factor 10a activity be checked when using Enoxaparin, Dalteparin, or Tinzaparin?
Consider checking anti-factor 10a activity in the elderly or if there is renal insufficiency.
178
Which clotting factors does warfarin impair?
Warfarin impairs vitamin K-dependent clotting factors 2, 7, 9, and 10.
179
How long should warfarin be held before regional anesthesia, and what should the normal INR be?
Warfarin should be held for 5 days before regional anesthesia, ensuring the INR is less than 1.5.
180
What is the mechanism of action of fibrinolytics in the presence of warfarin?
In the presence of warfarin, fibrinolytics convert plasminogen to plasmin, leading to fibrin cleavage and clot dissolution.
181
What factor do apixaban, betrixaban, edoxaban, rivaroxaban, and dabigatran inhibit?
Apixaban, betrixaban, edoxaban, rivaroxaban, and dabigatran inhibit factor 10a.
182
When should drugs like apixaban, betrixaban, edoxaban, rivaroxaban, and dabigatran be discontinued before a regional block?
Drugs like apixaban, betrixaban, edoxaban, rivaroxaban, and dabigatran should be discontinued at least 72 hours before a regional block.
183
What herbal interactions should be considered with apixaban, betrixaban, edoxaban, rivaroxaban, and dabigatran?
Herbal interactions with garlic, ginkgo, and ginseng should be considered with apixaban, betrixaban, edoxaban, rivaroxaban, and dabigatran.
184
Is neuraxial anesthesia feasible for a patient on apixaban, betrixaban, edoxaban, rivaroxaban, or dabigatran without other anticoagulant medications?
Neuraxial anesthesia is feasible for a patient on apixaban, betrixaban, edoxaban, rivaroxaban, or dabigatran if not on other anticoagulant medications.
185
What happens when a dura puncture site fails to properly seal?
Continuous leak of cerebrospinal fluid (CSF), leading to reduced CSF volume and lowered pressure in the brain area.
186
How does the lowered pressure in the brain area contribute to post-dural puncture headache (PDPH)?
It causes the brain to sag slightly and stretch surrounding membranes, resulting in a headache.
187
Describe the typical symptom presentation of PDPH.
Headache worsens when sitting or standing but improves when lying down, felt from the forehead to the back of the head.
188
When does PDPH usually manifest post puncture, and where is it typically felt?
Manifests 2-3 days post puncture and is usually felt from the forehead to the back of the head (Frontal - Occipital).
189
What are some other symptoms commonly associated with PDPH?
Nausea, sensitivity to light, double vision, and ringing in the ears.
190
How do factors like age, gender, and pregnancy influence the risk of developing PDPH?
Being younger, female, or pregnant increases the risk of developing PDPH.
191
Which practitioner factors can affect the likelihood of PDPH?
Using a needle with a cutting tip, a large diameter needle, air for loss of resistance (LOR) with epidural, and positioning the needle perpendicular to spine's long axis.
192
What is the main treatment for severe headaches after dural puncture?
Epidural Blood Patch involves injecting the patient's own blood into the epidural space, with a high success rate.
193
How much blood is typically injected in an Epidural Blood Patch?
10 - 20 mL of the patient's own blood is injected into the epidural space during the procedure.
194
What is the success rate of Epidural Blood Patch in treating severe headaches?
Epidural Blood Patch has an approximately 90% effectiveness rate in resolving severe headaches.
195
What should be considered if two Epidural Blood Patches are ineffective?
If two patches are ineffective, other potential causes of headaches should be investigated.
196
What is the Sphenopalatine Ganglion Block (SPG Block) used for?
SPG Block is a simpler, low-risk treatment alternative for severe headaches, quickly reducing symptoms.
197
Describe the procedure for performing a Sphenopalatine Ganglion Block.
SPG Block involves inserting a cotton swab soaked with LA into the nose towards the back throat wall for 5 to 10 minutes with the patient's head tilted back.
198
When might complications be more likely during anesthesia procedures?
Complications are more likely if paresthesia was encountered during placement, with deficits following the affected area.
199
What technique poses a lower risk compared to others during anesthesia procedures?
The Epidural Catheter technique poses a much lower risk of complications during anesthesia procedures.
200
When is redirection of the needle indicated during anesthesia procedures?
Redirection of the needle is indicated when paresthesia is elicited during anesthesia procedures.
201
Why is documentation crucial in anesthesia procedures?
Documentation is crucial to track procedures, responses, and any complications that arise during anesthesia.
202
What should be done if spinal anesthesia has not set up after 15 - 20 minutes?
If spinal anesthesia has not taken effect within 15 - 20 minutes, it may be necessary to redo the block.
203
How should a patchy block be managed during anesthesia procedures?
Patchy blocks should be managed carefully to avoid neurotoxicity risks and adverse effects on the patient.
204
What should be avoided to prevent neurotoxicity in anesthesia procedures?
Avoid repeating procedures unnecessarily as it may increase the risk of neurotoxicity in patients.
205
What should be considered if a unilateral block is ineffective during anesthesia procedures?
If a unilateral block is ineffective, adjusting the position or considering IV sedation or general anesthesia may be necessary.
206
How can failure to adhere to strict cleanliness procedures lead to infections after spinal procedures?
Failure to follow cleanliness protocols can allow germs to enter the spine area during the procedure.
207
What role can the presence of bacteria in the patient's bloodstream play in causing spine infections during procedures?
Bacteria in the bloodstream can cause spine infections if introduced during the procedure.
208
Where is Streptococcus viridans typically found, and why is it important to wear a mask and practice handwashing?
Streptococcus viridans is found in the mouth and on hands; wearing masks and handwashing are vital to prevent bacterial spread.
209
What are the options for skin preparation before spinal procedures, and why is proper drying time crucial?
Skin preparation options include iodine, alcohol, and chlorhexidine; proper drying prevents arachnoiditis, and improper use of chlorhexidine can be neurotoxic.
210
Which combination is highly effective in preventing bacterial meningitis if used correctly before spinal procedures?
Alcohol and chlorhexidine, as recommended by Miller, are highly effective in preventing bacterial meningitis when used properly.
211
Which nerves are mainly affected in spinal procedures, and what additional nerves can be involved?
Cauda equina (L1 - S4) nerves are primarily affected, along with coccygeal nerves in spinal procedures.
212
What causes neurotoxicity in nerve complications during spinal procedures?
Neurotoxicity in nerve complications arises from high levels of local anesthetic drugs affecting nerve function.
213
What factors increase the risk of nerve complications, and how do high concentration local anesthetics contribute to this?
High concentration local anesthetics like 5% lidocaine and microcatheters increase the risk of nerve damage in spinal procedures.
214
What are the typical signs and symptoms of nerve complications in spinal procedures?
Signs include bowel/bladder dysfunction, sensory deficits, back pain, saddle anesthesia, sexual dysfunction, weakness, paralysis, and potential progression to paraplegia.
215
How should nerve complications in spinal procedures be treated in cases of compression as a contributing factor?
Immediate laminectomy within 6 hours is recommended for compression (e.g., disc, hematoma) contributing to nerve complications.
216
What complications can result from improper positioning during medical procedures?
Nerve stretching, such as the sciatic nerve, leading to temporary symptoms and myofascial strain/spasms.
217
How can Lidocaine 5% affect the incidence of complications during medical procedures?
Higher incidence of complications, approximately 19% when using Lidocaine 5%.
218
Which surgical positions can increase the risks of complications?
Surgical positions like the lithotomy position (hip or knee flex) can increase the risks.
219
What types of surgeries are associated with higher risks of complications?
Outpatient surgeries and knee arthroscopy are associated with higher risks of complications.
220
How do patients typically experience pain related to complications during medical procedures?
Severe radicular pain in the back and buttocks that radiates down both legs, typically within 6 to 36 hours after surgery.
221
What is the usual duration of pain experienced by patients after surgery complications?
Pain lasts from 1 to 7 days, resolving in 90% of cases within a week.
222
What medications are used for pain relief in cases of complications?
Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and opioid painkillers can help manage the pain.
223
How should catheter removal be conducted to prevent shearing of the catheter?
Always withdraw the needle and the catheter together to prevent catheter shearing.
224
What should be done if resistance is encountered during catheter removal?
Place the patient in the same position as during insertion or lateral decubitus, apply gentle, continuous pulling, and securely tape the catheter to the skin for removal.
225
What action should be taken if a piece of the catheter breaks off inside the patient?
Inform the patient about the breakage, monitor for symptoms, and consider surgical intervention if neurological symptoms develop.
226
What is the cause of blood in the needle during an epidural procedure?
The needle is positioned too laterally.
227
How can the issue of blood in the needle be resolved?
Adjust the needle towards the midline.
228
How should blood in the catheter be handled?
Slightly pull back the catheter, flush with saline, and repeat until no more blood is drawn or further adjustment is unsafe.
229
What is advised to prevent epidural vein cannulation?
Inject fluid in the epidural space before catheter placement.
230
What are the risk factors for epidural vein cannulation?
Multiple attempts, pregnancy, stiffer catheters, trauma during block procedure.
231
What are common causes of complications in epidural procedures?
Catheter inserted too far, tip proximity to nerve.
232
How can complications in epidural procedures be addressed if the catheter is inserted too far?
Adjust the catheter by pulling back slightly (1-2 cm) while leaving 3 cm in the epidural space.
233
What position can be used to reposition the patient in case of complications during an epidural procedure?
Lateral decubitus position, placing the patient on the non-numb side facing downwards.
234
What can be done if additional anesthetic is required to manage complications in an epidural procedure?
Inject diluted local anesthetic to balance the block.
235
When should catheter replacement be considered in managing complications during an epidural procedure?
If adjustments and additional anesthetic prove ineffective.
236
What causes lidocaine toxicity symptoms in epidural procedures?
Inadvertent injection of lidocaine.
237
What are the common symptoms of lidocaine toxicity during an epidural procedure?
Seizure, with cardiac arrest potentially preceding a seizure in cases involving bupivacaine.
238
Where is the prevalence of LAST (Local Anesthetic Systemic Toxicity) more common?
More prevalent in peripheral nerve blocks than in epidurals.
239
How does hypercarbia increase the risk of CNS toxicity in local anesthetics?
It increases cerebral perfusion, enhancing drug delivery, and decreases protein binding, allowing more free local anesthetic to enter the brain.
240
Why does hyperkalemia contribute to CNS toxicity with local anesthetics?
Hyperkalemia makes neurons more excitable and prone to depolarization, increasing the risk of CNS toxicity.
241
How does metabolic acidosis impact CNS toxicity related to local anesthetics?
Metabolic acidosis lowers the seizure threshold, increases drug retention in the brain (ion trapping), and exacerbates the risk of toxicity.
242
In what way does hypocarbia help reduce the risk of CNS toxicity from local anesthetics?
Hypocarbia reduces cerebral perfusion, decreasing drug delivery to the brain and lowering the risk of toxicity.
243
How does hypokalemia affect the risk of CNS toxicity associated with local anesthetics?
Hypokalemia makes neurons less excitable, requiring stronger stimuli for depolarization and reducing the risk of toxicity.
244
What role do CNS depressants like benzodiazepines and barbiturates play in CNS toxicity from local anesthetics?
CNS depressants elevate the seizure threshold, providing protection against CNS toxicity caused by local anesthetics.
245
How do local anesthetics impact heart functions leading to cardiovascular toxicity?
Local anesthetics reduce heart automaticity, conduction velocity, action potential duration, and effective refractory period, influencing myocardial depression.
246
What are the key factors determining the extent of cardiotoxicity from local anesthetics?
Factors include LA affinity to voltage-sodium channels, rate of dissociation during diastole, and specifics like high affinity and slow dissociation rate of bupivacaine.
247
Why does bupivacaine pose a higher risk of cardiac morbidity compared to other local anesthetics?
Bupivacaine's high affinity to voltage-sodium channels and slow dissociation rate during diastole contribute to its high cardiac morbidity risk.
248
How do different local anesthetics rank in terms of difficulty for cardiac resuscitation?
In terms of cardiac resuscitation difficulty ranking, it goes: Bupivacaine > levobupivacaine > ropivacaine > lidocaine.
249
How should airway be managed effectively?
Administer 100% oxygen to manage the airway effectively.
250
What medication is recommended for controlling seizures?
Benzodiazepines are recommended for controlling seizures.
251
Why should Propofol be avoided for seizure treatment?
Propofol should be avoided due to its potential negative effects on the heart in high doses and its inability to replace lipid therapy.
252
What precaution should be taken when using Epinephrine in Modified ACLS?
Exercise caution with Epinephrine as it can complicate resuscitation in Local Anesthetic Systemic Toxicity (LAST) cases and reduce the efficacy of lipid therapy.
253
How should Epinephrine doses be administered in Modified ACLS?
Administer doses less than 1 mcg/kg in Modified ACLS.
254
What medication is recommended for treating ventricular arrhythmias in Modified ACLS?
Amiodarone is recommended for treating ventricular arrhythmias in Modified ACLS.
255
What is the 'Lipid sink' proposed mechanism of action of Amiodarone?
The 'Lipid sink' mechanism sequesters and reduces local anesthetic plasma concentration.
256
How does Amiodarone affect myocardial fatty acid metabolism according to proposed mechanisms of action?
Amiodarone enhances myocardial fatty acid metabolism, increasing heart energy utilization.
257
How does Amiodarone impact heart muscle calcium levels in proposed mechanisms of action?
Amiodarone raises heart muscle calcium levels by enhancing calcium influx and intracellular calcium concentration.
258
What is the 'Membrane effect' of Amiodarone in proposed mechanisms of action?
The 'Membrane effect' impairs local anesthetic binding to voltage-sodium channels.
259
What action should be taken if a patient remains unresponsive to modified ACLS and lipid therapy?
If the patient remains unresponsive, prepare for cardiopulmonary bypass.
260
How should Lipid Emulsion Therapy be initiated for patients over 70 kg?
Initiate with a 100 mL bolus over 2-3 minutes, followed by a 250 mL infusion over 15-20 minutes for patients over 70 kg.
261
How should Lipid Emulsion Therapy be initiated for patients under 70 kg?
Begin with a 1.5 mL/kg bolus over 2-3 minutes, followed by a 0.25 mL/kg/min infusion for patients under 70 kg.
262
How long should the Lipid Emulsion Therapy infusion be maintained?
Maintain the infusion until 15 minutes after stability is restored.
263
What is the maximum dosage limit for Lipid Emulsion Therapy?
The maximum dosage limit for Lipid Emulsion Therapy is 12 mL/kg.
264
What did an article from 2002 document regarding patients with lumbar tattoos and epidurals?
Documented three cases where patients with lumbar tattoos underwent epidurals without complications.
265
What concern exists regarding the risk associated with performing an epidural on patients with lumbar tattoos?
There is a concern that tattoo ink could be carried into the spine during an epidural, causing chemical arachnoiditis.
266
What is the potential consequence of tattoo ink entering the spine during an epidural?
It could lead to inflammation known as chemical arachnoiditis.
267
Despite the 2002 report, what have subsequent cases indicated about epidurals on patients with lumbar tattoos?
Subsequent cases have shown that epidurals on such patients do not typically result in neurological problems.
268
What is the recommended approach regarding needle placement during an epidural on a patient with a lumbar tattoo?
It is advisable to try to avoid inserting the needle through tattooed skin to minimize risks.
269
How can healthcare providers prevent complications related to skin integrity during an epidural on a patient with a lumbar tattoo?
Providers should avoid 'nicking' the skin to maintain skin integrity and prevent potential issues.
270
In terms of timing, when is it considered safest to perform an epidural on a patient with a lumbar tattoo?
For safety reasons, it is recommended to perform an epidural within 5 months of the tattoo application.
271
How should the epidural tip be pointed during needle placement?
Point the epidural tip upwards (opening cephalad).
272
What is the purpose of withdrawing the stylet after placing the needle in the interspinous ligament?
To achieve 'Loss of Resistance' (LOR).
273
What are the options for achieving Loss of Resistance (LOR) during needle placement for an epidural procedure?
Air, Saline, or both can be used to achieve Loss of Resistance.
274
How should the needle be advanced to identify the epidural space during an epidural procedure?
Advance the needle until Loss of Resistance (LOR), noting depth to the epidural space.
275
What should be done after identifying the epidural space to insert the catheter?
Thread the catheter and advance it 3 - 5 cm into the epidural space while withdrawing the needle.
276
How should the catheter be secured post-insertion during an epidural procedure?
Secure the catheter with dressing, noting the length at the skin.
277
What numbers should be recorded for catheter management following an epidural procedure?
Depth to epidural space, Catheter marking at the skin, Catheter depth in the epidural space.
278
How can proper blockade establishment be ensured during an epidural procedure?
Establish a segmental blockade with appropriate epidural dosing.
279
Why is it important to avoid advancing the needle without checking for resistance during an epidural procedure?
To maintain good needle control and avoid complications.
280
What technique involves placing a saline drop at the needle hub to identify the epidural space without a syringe?
Hanging drop method.
281
How is the epidural space identified using the Hanging Drop Method for Loss of Resistance (LOR)?
Epidural space is identified when the saline drop is sucked into the needle due to negative pressure.
282
What is the purpose of a test dose during anesthesia administration?
To identify unintentional IV or SAB placement.
283
What is the composition of the test dose used for anesthesia administration?
3 mL of 1.5% lidocaine mixed with epinephrine (1:200,000).
284
How can accidental IV placement be identified during a test dose?
A jump in heart rate by 20% or more indicates intravascular injection, requiring catheter replacement.
285
What symptoms indicate accidental IV placement during a test dose?
Ringing in ears (tinnitus), metallic taste in mouth, numbness around the mouth.
286
How can accidental spinal injection be identified during a test dose?
Dense motor block within 5 minutes of test dose administration, prompting consideration of catheter replacement.
287
What special consideration should be taken when administering a test dose to pregnant women?
Administer the test dose after a contraction ends for clearer results.
288
How can needle placement in a blood vessel be indicated in patients on heart medications during a test dose?
Significant increase in blood pressure (>20 mm Hg) may indicate needle placement in a blood vessel.
289
What are the two ways to maintain an epidural according to dosing regimen?
Bolus dose and infusion.
290
How should the initial dose for an epidural be administered?
Administer 1-2 mL per segment of the spine to be anesthetized in 5 mL increments.
291
When should a top-up dose be administered during epidural anesthesia?
Before two-segment regression to maintain adequate anesthesia.
292
How much of the initial loading dose can be given after two-segment regression during epidural anesthesia?
1/2 or 3/4 of the initial loading dose can be given to sustain the block.
293
What are the best practices for epidural anesthesia administration?
Accurate dermatome assessment, aspirate for blood or CSF, inject slowly in 5 mL increments, monitor closely for 30 minutes for hypotension or unexpected dermatome spread.
294
Scenario: If a lumbar epidural started at L4-L5, calculate the required mL for T10 surgery.
6-7 mL would be required for T10 surgery after a lumbar epidural started at L4-L5.
295
What is the recommended top-up time for Lidocaine local anesthetic?
60 minutes from the initial dose.
296
How long after the initial dose is the recommended top-up time for 2-Chloroprocaine local anesthetic?
45 minutes.
297
When should Mepivacaine local anesthetic be topped up according to recommendations?
After 60 minutes from the initial dose.
298
What is the suggested top-up time for Bupivacaine and Ropivacaine local anesthetics?
120 minutes from the initial dose.
