Ocular and Bier Blocks

Question 1

What is a Bier block?

Answer 1

A double tourniquet IV regional block.

Question 2

Tools required for Bier Block?

Answer 2

Lidocaine 0.5 - 1%
IVs x 2 -> 1 surgical side and 1 on other side for sedation
Tourniquet x 2 (blue/red and know which cuff is at which location)

Question 3

mL of lidocaine 0.5% Bier Block

Answer 3

30 - 40 mL

Question 4

mL of lidocaine 1% Bier Block

Answer 4

12 - 15 mL

Question 5

First step of Bier Block

Answer 5

Elevate and wrap arm with esmarch to exsanguinate extremity

Question 6

Second step of Bier Block

Answer 6

Test tourniquet cuffs then inflate proximal tourniquet 50 -100 mmHg above MAP keeping distal tourniquet deflated.

Question 7

Third Step of Bier Block

Answer 7

Unwrap arm and inject 40 mL of Lidocaine 0.5% max dose of 3 mg/kg

Question 8

What is onset of Bier Block?

Answer 8

Immediate

Question 9

Fourth Step of Bier Block

Answer 9

Inflate distal cuff after 30 minutes and deflate proximal cuff. DO NOT DEFLATE CUFF IF SURGERY ENDS EARLIER THAN 20 MINUTES.

Question 10

There is no postoperative analgesia in Bier Blocks. T/F

Answer 10

True

Question 11

There is a motor block with Bier Blocks. T/F

Answer 11

False

Question 12

What provides innervation to lacrimal gland and posterior eye?

Answer 12

Ciliary Ganglion

Question 13

What nerve provides sensory afferent information in the eye?

Answer 13

Trigeminal nerve

Question 14

What muscle turns the eye down and out?

Answer 14

Superior Oblique

Question 15

What muscle turns the eye up and in?

Answer 15

Superior Rectus

Question 16

What muscle turns the eye in towards the nose?

Answer 16

Medial (Internal) Rectus

Question 17

What muscle is responsible for cross eyed or downward and inward?

Answer 17

Inferior Rectus

Question 18

What muscle turns the eye outward?

Answer 18

Lateral (External) Rectus

Question 19

What muscle turns the eye up and outward?

Answer 19

Inferior Oblique

Question 20

What nerve provides sensory input to the brain for what the eye is seeing?

Answer 20

Optic Nerve

Question 21

What reflex is activated by posterior globe pressure, muscle stretch, or surgical manipulation of the eye?

Answer 21

The oculocardiac reflex

Question 22

What cranial nerves pathways are responsible for stimulation and response of the oculocardiac reflex?

Answer 22

CN V Trigeminal Afferent

CN X Vagus Efferent

Question 23

What are the symptoms of the oculocardiac reflex?

Answer 23

Profound bradycardia and slowing of the impulse conduction through the AV node

Question 24

What is treatment of oculocardiac reflex?

Answer 24

STOP STIMULATION
Ensure adequate oxygenation and ventilation
Atropine IVP 0.01-0.02 mg/kg but pretreatment does not always prevent
Local anesthetic infiltration

Question 25

Best way to PREVENT oculocardiac reflex stimulation?

Answer 25

Retrobulbar or peribulbar blocks

Question 26

Patient cannot go into full cardiac arrest with oculocardiac reflex. T/F

Answer 26

False patient may need CPR

Question 27

How many mL of Local anesthetic for Retrobulbar block?

Answer 27

5 mL

Question 28

What nerve is anesthetized to prevent oculocardiac reflex?

Answer 28

Trigeminal CN V Afferent pathway

Question 29

When do you angle the needle during the retrobulbar block and in what direction?

Answer 29

Once past the axis of the globe and angle it superiorly and medially

Question 30

How many mL of LA for Peribulbar blocks?

Answer 30

10 mL = 2 x 5 mL

Question 31

Which is the deeper eye block? Peribulbar or retrobulbar?

Answer 31

Retrobulbar block

Question 32

Which is the safer eye block? Peribulbar or Retrobulbar

Answer 32

Peribulbular

Question 33

Where does the Afferent pathway send information before efferent pathway?

Answer 33

Medulla oblongata

Question 34

How can an eye block lead to respiratory arrest?

Answer 34

By inadvertent injection into the CSF which will cause a high neuroaxial blockade requiring intubation

Question 35

How can an eye block cause seizures?

Answer 35

By inadvertent intra-arterial injection of local anesthetic

Question 36

Most common complication in eye blocks?

Answer 36

Oculocardiac reflex