Regional, Nerve Injury, Positioning

Question 1

List four variations of head-elevated surgical positions.

Answer 1

sitting (including lounge chair/beach chair)
supine with head tilted up
lateral, tilted head up (aka park bench)
prone, tilted head up

Question 2

Venous air embolism is the most feared complication of head up surgical positions. Edema of the face, neck, and tongue and head up positions may compromise the airway. What is the cause of edema in these areas and a head up position?

Answer 2

Due to venous and lymphatic obstruction caused by prolonged market neck flexion.

Question 3

What precautions should be taken to minimize the occurrence of face, neck, and tongue edema in the head up positions?

Answer 3

Avoid placing the patient’s chin against the chest - do not force the chin into the suprasternal notch - and use an oral airway to protect the endotracheal tube.

Question 4

Most frequent complication of sitting position?

Answer 4

hypotension

Question 5

Best position for patient in recovery room?

Answer 5

Side

Question 6

Most frequent nerve injury in anesthetized patients?

Answer 6

ulnar

Question 7

Nerves injured bu traumatic insertion of LMA or prolonged inflation of LMA?

Answer 7

SLN and/or RLN

Question 8

Possible injuries with fracture table:

Answer 8

pressure on pelvis and damage to genitalia and pudendal nerves, loss of penile sensation, brachial plexus damage (from extended arm or arm across chest) or lower extremity compartment syndrome.

Question 9

What is the result of blocking each of the nerve fiber types?
B, C, A-delta, A-gamma, A-beta, A-alpha

Answer 9

B fibers: ventilation with hypotension
C and A-delta: loss of pain and temperature
A-gama: muscle tone
A-beta: motor function and proprioception
A-alpha: motor function and proprioception

Question 10

What reflex best explains bradycardia during spinal anesthesia?

Answer 10

Bezold Jarish

Question 11

Of the local anesthetics administered intrathecally, which produces the most profound motor block?

Answer 11

Tetracaine

Question 12

What is the specific gravity of cerebrospinal fluid?

Answer 12

The specific gravity of CSF is 1.003 to 1.008.

Question 13

An epidural is administered- what is the first sign it is working?

Answer 13

Sensory analgesia is usually the first indication of successful epidural blockade. Sensory block is tested by pinprick sensation. Pinprick assesses analgesia.

Question 14

For epidural anesthesia clinically useful doses of local anesthetics are based on volumes that permit and even filling of the anterior and posterior epidural spaces at the level of insertion. What is the suggested volume per spinal nerve segment at cervical and thoracic levels to provide epidural blockade?

Answer 14

The suggested volume of local anesthetic for epidural anesthesia at cervical and thoracic level is 0.7-1 mL per spinal segment to be anesthetized

Question 15

Which four local anesthetics and concentration provide potent sensory analgesia and minimal motor block when administered epidurally?

Answer 15

Bupivacaine 0.5%
ropivacaine 0.5%
levobupivacaine 0.5%
plain lidocaine 2%

Question 16

How much local anesthetic is required for a fascia iliaca block?

Answer 16

Since the fascia iliaca block depends on the spread of local anesthetic along a connective tissue plane, it is a large volume block. Approximately 30 to 40 mL’s of injectate is necessary to accomplish a fascia iliac a block.
(0.5 to 1 mg/kg for pediatric patients)

Question 17

Describe the anatomy of the fascia iliaca block.

Answer 17

The three distal nerves of the lumbar plexus, the femoral, lateral femoral cutaneous, and obturator nerves, all emerge from the psoas muscle and run along the inner surface of the fascia iliaca. A fascia iliaca compartment block delivers local anesthetic between the fascia iliaca and iliacus muscles where it spreads to bathe the three nerves.

Question 18

What are the indications for a fascia iliaca block?

Answer 18

The fashion iliaca block provides analgesia of the femoral, lateral femoral cutaneous, and obturator nerves and therefore is useful for anterior thigh and knee surgery, and to provide analgesia following hip and knee procedures. The fascia iliaca block may be effective in more than 90% of children, compared with 20% effectiveness of the 3-in-1 technique.

Question 19

What is a fascia iliaca block?

Answer 19

Fascia iliaca block is a low-tech alternative to femoral or a lumbar plexus block. The mechanism behind this block is that the femoral and lateral femoral cutaneous nerves lie under the iliacus fascia. Therefore, a sufficient volume of local anesthetic deposited beneath the fascia iliaca has the potential to spread underneath the fascia and reach these nerves.

Question 20

You have just performed intercostal nerve blocks at 5 levels to provide analgesia for fractured ribs. The patient becomes hypotensive, bradycardic, and has a seizure. Describe seven actions to manage the situation.

Answer 20

The patient with hypotension, bradycardia, and seizures following intercostal nerve blocks has local anesthetic systemic toxicity- most likely due to an intravascular injection of local anesthetic. 1. get help 2. airway management- ventilate with 100% oxygen 3. seizure suppression- benzodiazepine’s are preferred. 4. BLS/ACLS with medication adjustments. 5. Infuse 20% lipid emulsion. 6. Alert the nearest facility having cardiopulmonary bypass capability. 7. Post LAST events at www.lipidrescueperiod.org

Question 21

Describe the recommended lipid emulsion dosing for treatment of local anesthetic systemic toxicity.

Answer 21

Intravenous bolus of 1.5 ml/kg (LBW) of 20% lipid emulsion such as intralipid 20%, over one minute.
Continuous infusion of 0.25 ml/kg/min for at least 10 minutes after cardiac function returns.
If cardiovascular instability continues, repeat bolus once or twice and consider increasing the infusion to 0.5 ml/kg/min.
Recommended upper limit is 10 ml/kg lipid emulsion over the first 30 minutes.

Question 22

What are the specific BLS/ACLS adjustments in local anesthetic toxicity?

Answer 22

reduce individual epinephrine doses to less than 1 mck/kg
avoid vasopressin
avoid calcium channel blockers
avoid beta adrenergic antagonists (beta blockers)
avoid local anesthetics!!!
amiodarone is preferred for ventricular dysrhythmias
propofol (for seizures) should not be used when there are signs or expectation of cardiovascular instability

Question 23

Six mechanistic actions may contribute to lipid resuscitation during the management of local anesthetic systemic toxicity. List the six mechanisms of action of lipid emulsion rescue.

Answer 23

1. Capture of local anesthetic in the blood- lipid sink effect
2. increased fatty acid uptake by mitochondria- metabolic effect
3. interference with local anesthetic binding of sodium channels- membrane effect
4. activation of Akt cascade leading to inhibition of GSK-3 which is glycogen synthase kinase- cytoprotective effect
5. promotion of calcium entry via voltage dependent calcium channels- inotropic effect
6. accelerated shunting- pharmacokinetic effects

Question 24

What is the incidence of post dural puncture headache with spinal anesthesia?

Answer 24

The incidence of post dural puncture headache with spinal anesthesia is up to 25%