Mod10: Anesthesia for Orthopedic Surgery - Fracture Tables - Tourniquet

Question 1

_{Anesthesia for Orthopedic Surgery}

Consideration regarding Fracture Tables:

Answer 1

Team approach (as always) to positioning on this table

One person adjusts the traction that is applied to the fractured limb

Usually RN, has to be qualified to adjust;

_{ran into an issue once where an X-ray tech got in trouble for adjusting the traction (just trying to be nice) but something malfunctioned}

_{Barash p. 1449}

Question 2

_{Anesthesia for Orthopedic Surgery}

Benefits of Fracture Tables:

Answer 2

Can apply and maintain appropriate traction

Allows for manipulation in a closed reduction and fixation

Radiography can access the fracture site in multiple planes

Question 3

_{Anesthesia for Orthopedic Surgery - Fracture Tables}

Considerations for perineal post:

Answer 3

Be sure that the circulator pads the perineal post before the patient’s pelvis is positioned

The post is a vertical pole at the perineum that serves to keep the pelvis in position

Correct position is up against the pelvis between the genitalia and the non-fractured leg

Extreme pressure can be placed on the pelvis and the genitalia AND pudendal nerves can also be injured if not properly positioned and padded

Arm that is ipsilateral to the fx’d hip is placed on arm board or sling (across chest) to keep it from obstructing fluoro

Question 4

_{Anesthesia for Orthopedic Surgery - Fracture Tables}

Considerations for Jackson Orthopedic Table:

Answer 4

Make sure bed is in locked position (won’t flip 180 degrees), but also have locks on each separate wheel.

Difficult to intubate on this bed.

Have to stand on the side or get a step stool to reach over.

If difficulty expected, have a glidescope or C-Mac available and consider intubating on stretcher and moving to table after.

Question 5

_{Anesthesia for Orthopedic Surgery - Fracture Tables}

Considerations for Wilson Frame Table:

Answer 5

Used with Prone position

if turn neck laterally, can get overstretching of brachial plexus.

Neutral neck probably more safe.

Usually use prone face pillow, has cut out holes for eyes, nose, mouth.

Check frequently to ensure no pressure to eyes, nose, chin, ears.

When tape ETT, make sure tape on side where slit is pre-cut.

Make sure neck is neutral, not extended or flexed.

May have to have surgical team reposition.

May have to use towels beneath headrest to help reach appropriate height.

Get it right from the beginning. It’s the only chance you have to gain everyone’s cooperation.

Make sure abdomen not compressed => can push cephalad, decreasing FRC, decreasing VR

Question 6

_{Anesthesia for Orthopedic Surgery}

Position for Lumbar Spine procedure:

Answer 6

See picture

Question 7

_{Anesthesia for Orthopedic Surgery}

Considerations for Beach Chair Position

Answer 7

Shoulder surgery can be sitting/beach chair or, occasionally lateral decubitus,

Interscalene blocks are well suited for shoulder procedures, for intraop and post-op pain

Will find you won’t require as much INH agent and narcotics if you have adequate block

Goggles over eyes.

Pad straps beneath forehead and chin.

Make sure arm that is contralateral to the operative shoulder is in good anatomic alignment.

Check tube, position, etc. under the drapes frequently

Question 8

_{Anesthesia for Orthopedic Surgery}

MAP difference betwen arm and brain in

^{Beach Chair Position}

Answer 8

BP decreases 2 mmHg for every 2.5 cm height above the point of measurement

So blood pressure within the brain of a reclining or sitting patient under anesthesia is about 12-16 mmHg lower than that measured at the upper arm.

^{(Essentials of Cardiac Anesthesia for no—cardiac surgery)}

According to Storm anesthesia, for every 1 cm rise => 0.75 mmHg drop in in MAP

(So if 20 cm difference: for first conversion => BP would be 20 mmHg lower; for second conversion, MAP would be 18.75 mmHg lower)

According to the Anesthesia Patient Safety Foundation, there is a 0.77 mmHg decrease in MAP for every cm increase in distance/height (1 mmHg for each 1.25 cm)

Approximate distance between brain and site of BP cuff on arm is 10-30 cm (depends on size of patient and angle of sitting position)

So MAP will be approximately 8-24 mmHg lower at the brain than the MAP measured on the arm/from the brachial artery

Decreased VR and preload

Question 9

_{Anesthesia for Orthopedic Surgery}

How to maintain adequate cerebral perfusion in

^{<strong>Beach Chair Position?</strong>}

Answer 9

Risk for decreased CPP (evidenced by cases of blindness, CVA, brain death, decreased tissue oxygenation)

This makes adequate/accurate BP monitoring essential

Place BP cuff on upper extremity

measuring the BP on LE can result in readings that are 40 mmHg higher than a brachial reading

If surgeon requests induced hypotension, place an arterial line

Can place the transducer at the level of heart but it is BEST to place it level with the external meatus of the ear (level with brainstem)

Question 10

_{Orthopedic Surgery - Lateral Position for Hip Surgery}

What should you do when moving a patient from supine to Lateral Position?

Answer 10

Check and document prior Positioning

Maintain head, neck and shoulders in neutral position

Disconnect from circuit and hold the ETT

ALWAYS Make sure the teams tells you when they want to readjust the patient => always secure the ETT (or LMA)
_{<em>Barash p. 1449</em>}

Question 11

_{Orthopedic Surgery - Lateral Position for Hip Surgery}

What should you do once the patient is in Lateral position?

Answer 11

Dependent ear flat, free of pressure

Eyes, chin, nose free of pressure

Eyes taped prior to placing in lateral position; ideal to tape eyes during induction

Can remove a piece of the foam headrest if compressing an area.

I have to do this on a lot of prone cases

Chest (“axillary”) roll should never be placed in the axilla => should be 3-4 fingerbreadths below axilla

axillary roll used to avoid brachial plexus compression and compression of axillary vasculature

ALWAYS Make sure the teams tells you when they want to readjust the patient => always secure the ETT (or LMA)

Question 12

_{Orthopedic Surgery}

Hand table positioning:

Answer 12

Table 90 degrees, surgeon and resident or assistant sitting on each side of table

Pneumatic Tourniquet

Question 13

_{Orthopedic Surgery}

Anesthetic techniques for hand surgeries

Answer 13

One of most common anesthetics is for hand surgeries

Bier block can be used, but unless complicated case

usually a MAC or LMA case with surgeon injecting local

“Big MAC” during the injection of LA, then can lighten them up

Tourniquet is what usually causes discomfort following local, esp if longer surgery

Carpal Tunnel Release (far left) usually takes 30 mins or less, so want short-acting anesthesia. These can be done under MAC or GA with LMA

_{Picture on far right - Dr. Mirsad, Dr. Bindu repairing microscopic nerve injury 4.17.13}

Question 14

Orthopedic Surgery

Purpose of Pneumatic Tourniquet

Answer 14

To decrease blood loss and

Enhance operative conditions through the creation of a bloodless field

Question 15

Orthopedic Surgery

Proper cuff size Pneumatic Tourniquet

Answer 15

Proper cuff size, inflation pressure, and placement, as well as inflation time are essential to decreasing the potential for neuromuscular ischemia and injury

TQ width should be enough to allow for minimum of 3 inches of overlap, but it shouldn’t overlap more than 6 inches

The overlap point should be on the outside of the extremity to prevent compression of the nerve sheath

Question 16

_{Orthopedic Surgery}

Risks associated with using a Pneumatic Tourniquet (TQ) include:

Answer 16

Hemodynamic changes

Metabolic alterations

Pain

PE

Arterial thromboembolism

Question 17

_{Orthopedic Surgery}

Pneumatic Tourniquet Inflation Pressure

Answer 17

100 mmHg ABOVE patient’s baseline SBP for a LE

50 mmHg about baseline SBP for un UE

Question 18

_{Orthopedic Surgery - Pneumatic Tourniquet}

What should you document?

Answer 18

Site, pressure, inflation time and deflation time

Any notifications to the surgeon

Question 19

Orthopedic Surgery - Pneumatic Tourniquet

How long should be kept in place?

Answer 19

1 hour or less is ideal (not always realistic)

Max 2 hours

Question 20

_{Orthopedic Surgery - Pneumatic Tourniquet}

Prolonged inflation (>2h) could lead to:

Answer 20

Transient muscle dysfunction

possible permanent peripheral nerve injury and

even rhabdomyolysis.

Question 21

_{Orthopedic Surgery}

Characteristics and timing of Tourniquet Pain:

Answer 21

Ischemic pain similar to that caused by vascular occlusion and peripheral vascular disease

Begins after about 45 minutes to an hour after inflation (can be sooner OR later)

Starts as dull and aching => progresses to burning and can be SEVERE, excruciating

Signs of progressive SNS activation include marked HTN, tachycardia, diaphoresis, and tachypnea

Question 22

Orthopedic Surgery

Machanism of Tourniquet Pain:

Answer 22

Exact mechanism of pain is not fully understood

Precise neural and metabolic mechanisms unknown

But nerve fibers that transmit the impulses of tourniquet pain have been identified

C fibers – small, lack myelin and slow in conduction

=> responsible for burning, aching pain; resistant to LA or more difficult to anesthetize with LA’s

A-delta fibers – larger, myelinated, faster conduction

=> culprit of pinprick, tingling sensations (can persist after deflation)

Question 23

Orthopedic Surgery

Tourniquet Pain Treatment

Answer 23

Often resistant to analgesics, anesthetics, regardless of technique (this makes sense given the C fibers are difficult to target and anesthetize

IV regional > epidural > spinal > GA

They are more likely to experience TQ pain with IV regional than with GA

_{(Macksey, p. 48)}

Question 24

Orthopedic Surgery

For the prevention of LE TQ pain during orthopedic procedure, which LA is more effective?

Answer 24

Bupivacaine spinal anesthesia more effective than

Tetracaine spinal (Stoelting)

Question 25

Orthopedic Surgery

Severity of TQ pain multifactorial. It involves:

Answer 25

Anesthetic type

Extent of dermatomal spread with regional

LA type and dose (intensity of block)

Supplementation with adjuvants (e.g. opioids, ketorolac, dexmedetomidine) might be effective in some cases

Question 26

Orthopedic Surgery - Tourniquet pain

BUT…Don’t give too many narcotics. Why not?

Answer 26

Possibility that TQ may drop => apnea!

Some sources suggest beta blockers

Question 27

Orthopedic Surgery - Tourniquet pain

Definitive treatment:

Answer 27

Deflate the cuff

Question 28

Orthopedic Surgery - Tourniquet Deflation

Deflation of TQ cuff leads to

Answer 28

Metabolic and hemodynamic changes

Can be accompanied by a significant decrease in CVP and ABP

Rarely cardiac arrhythmias may occur

Washout of accumulated metabolic waste in ischemic extremity increases PaCO2, ETCO2, serum lactate and K+ levels.

Patients often become hypotensive, tachycardic, tachypneic, dysrhythmias

Question 29

Orthopedic Surgery - Tourniquet Deflation

How to prevent hemodynamic changes a/w TQ deflation?

Answer 29

Be sure to keep the patient euvolemic with adequate circulating volume while the TQ is inflated and

Preload the patient prior to deflating the TQ

Question 30

Orthopedic Surgery - Tourniquet complications

A TQ with an inflation pressure that is too high can cause:

Answer 30

Muscle weakness

Injury to blood vessels, nerves, muscles, or skin

Paralysis of the extremity could also occur

Question 31

Orthopedic Surgery - Tourniquet complications

LE exsanguination prior to TQ inflation

Answer 31

Shift of blood volume into central circulation

Usually not clinically significant…

BUT if BLE TQ’s => may result in increase in CVP and ABP that isn’t well tolerated by patients with stiff/non-compliant LV or diastolic dysfunction

Question 32

Orthopedic Surgery - Tourniquet complications

LE ischemia from the tourniquet can cause

Answer 32

Formation of a DVT => once tourniquet deflated

=> subclinical pulmonary emboli can be detected in the RA or RV by TEE

This is true even is cases as minor as a diagnostic knee scope

Although not common, there have been instances of massive pulmonary emboli during TKR.

Can occur:

During exsanguination

After inflation or Following deflation

Question 33

Orthopedic Surgery - Tourniquet complications

major causes of morbidity and mortality following orthopedic operations on pelvic and lower extremities are:

Answer 33

DVT and PE

Question 34

Orthopedic Surgery - Tourniquet complications

Reperfusion injury d/t:

Answer 34

Tissue damage caused when blood supply returns to tissue after period of ischemia,

leading to inflammation and oxidative damage

d/t induction of oxidative stress and formation of lipid peroxides

Propofol limits the superoxide formation and

some suggest using a Propofol anesthetic to decrease the potential for a reperfusion injury

Question 35

Orthopedic Surgery - Tourniquet complications

Tourniquet use in sickle cell pt’s:

Answer 35

Has been used safely

BUT…be sure to maintain adequate oxygenation,

normal temperature, and

normocarbia (or hypocarbia)

Question 36

_{Orthopedic Surgery - Pneumatic Tourniquet complications}

Bleeding during tourniquet inflation is commonly due to inadequate arterial occlusion.

A.True

B.False

Answer 36

A.True

B.False

Bleeding from surgical site during inflation RARELY due to inadequate occlusion of the major arterial inflow

Correct inadequate occlusion reapplying the cuff and proper degree of inflation

Bleeding is more commonly due to intramedullary blood flow in long bones.

Over-inflation does not resolve this problem!!!