Anesthesia for Orthopedics and Podiatry

Question 1

Purpose of the Pneumatic Tourniquet

Answer 1

Maintains a relatively bloodless field during intraoperative blood loss

Aids in the identification of vital structures

Expedites the procedure

Question 2

Components of the tourniquet

Answer 2

Inflatable cuff
Connective tubing
A pressure device
A timer

Question 3

Safety Measures for Preventing Tourniquet Complications

Answer 3

Tourniquet should be applied where the nerves are best protected in the underlying musculature

Test equipment for proper functioning before use

Tourniquet should not be used for > 2 hours

Use the widest cuff possible (use lower cuff pressure to occlude the
blood flow)

A minimum of 2 layers of padding should be placed around the extremity

Tourniquet size should be half the limb diameter and the cuff should overlap 3-6 inches

Tourniquet size should allow placement of 2 fingers between the tourniquet and the cast padding

When possible, extremity should be exsanguinated prior to tourniquet inflation

Only minimally effective pressure should be used for occluding blood flow:

Upper extremity: 70-90 mm Hg > SBP

Lower extremity: 2X the SBP

The pressure display must accurately reflect the pressure in the tourniquet bladder

Question 4

Use the ____ cuff possible (use ___ cuff pressure to occlude the blood flow)

Answer 4

widest, lower

Question 5

Tourniquet size should be ____ the limb diameter and the cuff should overlap ___to___ inches

Answer 5

half, 3-6 inches

Question 6

Only minimally effective pressure should be used for occluding blood flow:
Upper extremity: __to__ mm Hg > SBP
Lower extremity: ___ the SBP

Answer 6

Upper extremity: 70-90 mm Hg > SBP

Lower extremity: 2X the SBP

Question 7

Physiologic Changes Caused by Limb Tourniquets: neuro

Answer 7

Abolition of somatosensory evoked potentials and nerve conduction occurs within 30 minutes

> 60 minutes tourniquet time causes tourniquet pain and hypertension

> 2 hours tourniquet time may result in postoperative neurapraxia

Evidence of nerve injury may occur at the skin level underlying the edge of the tourniquet

Question 8

Physiologic Changes Caused by Limb Tourniquets: muscle

Answer 8

Cellular hypoxia develops within 2 minutes

Cellular creatinine level declines

Progressive cellular acidosis occurs

Endothelial capillary leak develops after 2 hours

Question 9

Systemic Effects of Tourniquet Inflation

Answer 9

Elevations in arterial and pulmonary artery pressure occur (this is usually slight to moderate if only one limb is occluded)

Question 10

Systemic Effects of Tourniquet Release

Answer 10

Transient decrease in core temperature

Transient metabolic acidosis

Transient decrease in central venous oxygen tension occurs, but systemic hypoxemia is unusual

Acid metabolites (i.e., thromboxane) are released into the central circulation

Transient fall in pulmonary and systemic arterial pressure occurs

Transient increase in end-tidal carbon dioxide occurs

Question 11

Non-Pneumatic Tourniquets

Answer 11

A silicone ring tourniquet (SRT) may be used for brief procedures

Consists of a silicone ring wrapped in a sleeve, with 2 pull handles connected by straps

At the end of surgery, the silicone ring tourniquet is removed by cutting the silicone ring

These tourniquets are not electronic. Therefore, tourniquet time must be closely monitored.

Question 12

Tourniquet Pain

Answer 12

Tourniquet pain occurs 45-60 minutes after tourniquet inflation

Once the pain begins, it is resistant to analgesics and anesthetic agents, regardless of anesthetic technique

Ischemic pain of associated with tourniquet application is similar to the pain of thrombotic vascular occlusion and peripheral vascular disease

Question 13

What are the symptoms of tourniquet pain?

Answer 13

Dull aching, which progresses to burning and excruciating pain that may require general anesthesia

Question 14

The specific neural and metabolic factors responsible for tourniquet pain are still unknown, but researchers have identified the nerve fibers responsible for transmitting the impulses:

Answer 14

Small and slow unmyelinated C fibers:
Responsible for burning and aching

Large, fast myelinated A-delta fibers:

Responsible for pinprick, tingling, and buzzing sensations

Question 15

Small and slow unmyelinated C fibers responsible for

Answer 15

burning and aching

Question 16

Large, fast myelinated A-delta fibers are responsible for

Answer 16

pinprick, tingling, and buzzing

Question 17

*True/False: Properly placed tourniquets inflated to appropriate pressures rarely cause injury

Answer 17

TRUE!

Question 18

Prevention of post-op parasthesias

Answer 18

Use of proper padding

Appropriate choice of tourniquet size

Following recommendations for appropriate tourniquet pressure and usage time minimizes the incidence of complications

Question 19

Goals of patient positioning

Answer 19

Optimal exposure of the surgical site

Protect all body systems

Enable appropriate monitoring throughout the procedure

Provide good access to the patient’s airway

Allow for comfort and warmth

Minimize or prevent physiologic functioning compromise

Protect all body systems

Maintain patient dignity

Question 20

How is arthroscopy managed?

Answer 20

Can be managed by any available anesthetic technique:

General anesthesia

Combined regional and general anesthesia

Local blockade with sedation

Question 21

Positioning for arthoscopy

Answer 21

Lower extremity arthroscopy:
Most often the supine position

Shoulder arthroscopy:
Lateral decubitus or “beach chair” position

Elbow arthroscopy:
Supine, lateral decubitus, or prone

Question 22

What are the complications of arthoscopy?

Answer 22

Subcutaneous emphysema

Pneumomediastinum

Tension pneumothorax

Fluid volume overload due to irrigation fluid

Question 23

What are the benefits of arthoscopy?

Answer 23

Minimally invasive, reduced blood loss, less post-op discomfort, reduced length of rehab

Question 24

Signs and Symptoms of Tension Pneumothorax

Answer 24

Sudden, inexplicable hypoxemia

Elevated central venous pressure (CVP)

Tachycardia

Absent breath sounds on the affected side

Cyanosis

Diaphoresis

Decreasing oxygenation

Tracheal shift (away from the pneumothorax)

Agitation (may be observed in patients receiving regional anesthesia)

Hypotension

Jugular vein distention

Increased airway pressure

Asymmetric chest wall movement

Percussive hyperresonance over the affected side

Extreme anxiety (may be observed in patients receiving regional anesthesia)

Question 25

Position related complications of beach chair

Answer 25

hypotension and bradycardia with interscalene blocks air embolism/pneumo DVT unilateral vision loss cerebral hypoperfusion cervical plexus and hypoglossal nerve neurapraxias

Question 26

Position related complications of lateral decubitus

Answer 26

temporary parasthesia neurapraxis of the dorsal digital nerve of the thumb and musculoscutaneous, ulnar, axillary nerves permanent neuropraxia post-op stroke DVT fluid-related airway compromise

Question 27

How to prevent position injuries with these..

Answer 27

beach chair - use level of brain systolic, attention to head positioning, prophylaxis for hypotensive bradycardic episodes lateral decub - 45 degrees of forward flexion with 90 degrees abduction 45 degrees forward flexion with 0 degrees abduction general anesthesia for longer cases place anterior inferior portal out of traction

Question 28

Arthroplasty terms

Answer 28

Total Arthroplasty: Replacement of all of the joint Hemiarthroplasty: Replacement of part of the joint Joint materials: Originally stainless steel Currently use nonferrous metal alloys (cobalt or titanium)

Question 29

What is the most common approach for hip surgery?

Answer 29

Posterior approach Requires a large incision extending from near the iliac crest across the joint to the midthigh level

Question 30

What is the purpose of the direct anterior approach for hip surgery?

Answer 30

Minimally invasive, muscle-sparing approach with shorter incision Benefits: Shorter hospital stay Faster postoperative recovery

Question 31

What is the positioning for the two methods of hip surgery?

Answer 31

Posterior approach: Lateral decubitus Anterior approach: Supine

Question 32

Are hip surgery patients at an increased risk for VTE, DVT, and P.E's?

Answer 32

Yes. Treatment up to 35 days Prevention of VTE: Anticoagulation therapy (i.e, LMWH) Intermittent pneumatic compression device (IPCD) for 10-14 days

Question 33

What is the prevention for DVT/PE with hip surgery?

Answer 33

Anticoagulation therapy (i.e, LMWH) Intermittent pneumatic compression device (IPCD) for 10-14 days Treatment up to 35 days

Question 34

What facilitates the surgical process for hip arthroplasty?

Answer 34

The muscle relaxation produced by a subarachnoid block (SAB)

Question 35

What type of anesthesia is common for total hip arthroplasty?

Answer 35

Regional anesthesia is common

Question 36

What is bone cement implantation syndrome (BCIS)?

Answer 36

Hypoxia, hypotension, cardiac arrhythmias, increased pulmonary vascular resistance and cardiac arrest Methyl methacrylate (MMA) may be instilled into the femoral canal Usually occurs at the following stages of surgery: femoral canal reaming, acetabular or femoral cement implantation, insertion of prosthesis or joint reduction, and occasionally after tourniquet deflation

Question 37

*What is the first sign of clinically significant BCIS?

Answer 37

absence of EtCO₂ in a patient under general anesthesia

Question 38

What are the clinical features for BCIS in the awake patient under regional anesthesia?

Answer 38

dyspnea and altered sensorium

Question 39

What is the treatment for BCIS?

Answer 39

Increase FiO₂ to 100% Aggressive fluid resuscitation Treat hypotension with α-agonists

Question 40

What increases the risk of getting BCIS?

Answer 40

Preexisting cardiovascular disease Preexisting pulmonary hypertension American Society of Anesthesiologists (ASA) class III or higher New York Heart Association class 3 or 4 Canadian Heart Association class 3 or 4 Surgical technique Pathologic fracture Intertrochanteric fracture Long-stem arthroplasty

Question 41

Risk of BCIS increased by what during total knee arthroplasty?

Answer 41

Both FEMORAL and TIBIAL surfaces are covered with MMA cement The high-density polyethylene patellar component is cemented and seated with a vise-like clamp

Question 42

Are tourniquets used during total knee arthoplasty and ankle arthroplasty?

Answer 42

Yes DVT, PE and fat embolus are a risk of ankle arthroplasty thromboprophylaxis

Question 43

Most popular intraarticular procedures for ankle arthroplasty

Answer 43

Osteochondral lesion Ankle or subtalar debridement Subtalar fusion Partial talectomy

Question 44

Most common extraarticular procedures

Answer 44

Os trigonum excision Tenolysis of the flexor hallucis longus tendon Endoscopic partial calcanectomy

Question 45

Anesthetic Management of Knee and Ankle Arthroplasty

Answer 45

Regional or General anesthetic (or a combination) Regional anesthesia combining femoral and sciatic nerve blocks are sufficient for all surgeries below the knee that do not require a thigh tourniquet The femoral nerve innervates the medial leg to the medial malleolus The common peroneal and tibial nerve (branches of the sciatic nerve) innervate the rest of the leg below the knee, including the foot

Question 46

Regional anesthesia combining which nerve blocks are sufficient for all surgeries below the knee that do not require a thigh tourniquet?

Answer 46

Femoral and sciatic nerve blocks

Question 47

Upper Extremity Arthroplasty: Shoulder Arthroplasty

Answer 47

Reverse Total Shoulder Arthroplasty provides a better treatment option for more complex pathologies, rotator cuff tears, and revision of failed TSA

Question 48

Best for shoulders?

Answer 48

RTSA

Question 49

Indications for TSA/RTSA:

Answer 49

Posttraumatic brachial plexus injuries Paralysis of deltoid muscle and rotator cuff Chronic infection Failed revision arthroplasty Severe refractory instability Proximal humerus fracture Bone deficiency after resection of a tumor in the proximal aspect of the humerus

Question 50

What are the two goals of TSA/RTSA?

Answer 50

Pain reduction and Improved range of motion

Question 51

Positions for shoulders

Answer 51

beach chair and lateral decubitus

Question 52

Why are shoulder associated with more blood loss?

Answer 52

Because you can't use a pneumatic turniquet

Question 53

Elbow arthroplasty positions

Answer 53

supine, lateral, prone

Question 54

Indications for elbows

Answer 54

Rheumatoid arthritis Traumatic arthritis Ankylosis of the joint

Question 55

Goals for elbows

Answer 55

Pain reduction Improved joint function

Question 56

What type of anesthesia do you use for upper extremity arthroplasty?

Answer 56

Supraclavicular block or interscalene block Combined general/regional anesthesia commonly used

Question 57

Anesthetic considerations for upper extremity arthroplasty

Answer 57

Be vigilant re: the risk of extubation Surgical manipulation can increase risk of cervical injury Monitor patient’s eyes for pressure throughout the procedure - consider foam goggles

Question 58

Beach chair issues with upper extremity arthroplasty

Answer 58

Pulmonary function will resemble more “normal” function than lateral position Increased risk of venous air embolism *Reaming of the shaft of the humerus leads to risk of fat or bone marrow embolism Cerebral ischemia can occur with hypotension Significant hydrostatic gradient between the brain and the site of BP measurement **Approximately 2 mm Hg per 1 inch of height differential

Question 59

*What is the difference between arm cuff measurement and brain pressure with beach chair?

Answer 59

**Approximately 2 mm Hg per 1 inch of height differential

Question 60

What leads to risk of fat or bone marrow embolism in beach chair position with upper extremity athroscopy

Answer 60

*Reaming of the shaft of the humerus leads to risk of fat or bone marrow embolism

Question 61

Postoperative visual loss

Answer 61

A result of intraoperative cerebral ischemia due to hypotension

Question 62

What defines Hypotensive bradycardic episodes (HBEs)

Answer 62

Decrease in HR of at least 30 bpm within a 5-minute interval, any HR < 50 bpm and/or a decrease in systolic BP of more than 30 mm Hg in a 5-minute interval or any systolic BP < 90 mm Hg

Question 63

What is the most common mechanism of hypotensive bradycardic episodes?

Answer 63

The Bezold-Jarisch Reflex

Question 64

Hypotensive Bradycardic Episodes (HBEs) and the bezold-jarisch reflex

Answer 64

An inhibitory reflex mediated through cardiac sensory receptors with a vagal efferent limb. Clinically, the Bezold-Jarisch reflex is an inhibitory reflex usually denoted as a cardioinhibitory reflex defined as bradycardia, vasodilation, and hypotension resulting from stimulation of cardiac receptors In the beach chair position, venous pooling in the lower extremities leads to an increase in sympathetic tone and ultimately a low-volume, hypercontractile ventricle Cardiac hypercontraction leads to activation of the Bezold-Jarisch reflex with an abrupt autonomic withdrawal of sympathetic response and activation of increased vagal tone The combination of venous pooling and paradoxical increased vagal tone results in sudden, profound bradycardia and hypotension that can be difficult to reverse rapidly

Question 65

*Prophylaxis of HBEs

Answer 65

Aggressive treatment of fluid deficits and blood loss Minimize venous pooling in the beach chair position with support stockings With regional anesthesia, avoid use of local anesthetics using epinephrine - Absorbed slowly, mimicking low-dose IV epinephrine administration - Increased cardiac contractility - Resulting in ventricular emptying - Increased heart rate (which reduces cardiac filling) - Increased peripheral vasodilation and pooling (decreased afterload) - Resulting in ventricular hypovolemia with hypercontraction Consider intraoperative β-blockade in select patients

Question 66

Most common position for spinals

Answer 66

prone

Question 67

Most Common Indications for spines:

Answer 67

Intervertebral disc herniation Spinal stenosis Scoliosis

Question 68

Laparoscopic approach Contraindications for spinal surgery:

Answer 68

Abdominal adhesions Abdominal trauma Severe cardiac or pulmonary disease (may not tolerate hypercarbia from insufflation) Thoracic approach contraindicated in patients that cannot tolerate one lung ventilation Patients requiring extensive instrumentation of the anterior spine

Question 69

Anesthetic Challenges for spinal surgery

Answer 69

Airway control Positioning Fluid and blood transfusion management Hemodynamic control Postoperative analgesia

Question 70

Advantages for laparoscopy for anterior spinal surgery

Answer 70

Slide 30. So many things. Shorter rehab, better view, decreased infection, better cosmetics, etc.

Question 71

Anesthesia for spines

Answer 71

General

Question 72

Patient Positioning for spines

Answer 72

Prevent eye injury/corneal abrasions Use rolls or positioning devices to prevent abdominal compression in the prone position to prevent: - Displacement of organs (including diaphragm) cephalad Reduced functional residual capacity (FRC) Reduced tidal volume (TV) Increased airway pressures Engorgement of the epidural venous network Contributes to increased blood loss

Question 73

Symptoms of aortic injury during a spine

Answer 73

Suspect with sudden, dramatic, unanticipated, sustained hypotension

Question 74

Main causes of post-op visual loss

Answer 74

Ischemic optic neuropathy Retinal vascular occlusion

Question 75

Spinal Surgery: Postoperative Visual Loss (POVL) risk factors

Answer 75

Male sex Obesity Use of Wilson frame Anesthesia duration > 6 hours Large blood loss Colloid as percent of nonblood fluids

Question 76

Spinal Surgery: Postoperative Visual Loss facts

Answer 76

Visual loss occurs 24 to 48 hours after surgery Usually bilateral Painless vision loss Afferent pupil defect or nonreactive pupil No light perception Decreased or absent color vision Elevated intraocular pressures (IOP) > 40 mm Hg

Question 77

Positioning to avoid visual loss during spines

Answer 77

Position patient’s head in a neutral position level with or above the heart Use a foam headrest Do NOT cover the eves with goggles when using a square foam headrest Perform and document eye checks every 20 minutes

Question 78

Recommendations from task force for visual loss

Answer 78

1. Consider informing patients who will undergo spine operations in the prone position anticipated to involve prolonged duration and/or substantial blood loss that they have a small but unpredictable risk of perioperative visual loss. 2. Continually monitor systemic blood pressure. 3. Colloids should be used along with crystalloids for maintaining euvolemia. 4. Hemoglobin or hematocrit values should be monitored periodically during surgery, but no optimal transfusion threshold to prevent perioperative visual loss has been identified. 5. The decision to use α-adrenergic agents should be made on a case-by-case basis. 6. Direct pressure on the eye should be avoided to prevent central retinal artery occlusion. 7. Position the head in a neutral position with the face down and the head level with or higher than the heart to minimize venous outflow obstruction. 8. Consider staging very prolonged procedures in high-risk patients with careful consideration of the risk: benefit ratio. 9. Assess vision when the patient becomes alert. 10. An urgent ophthalmologic consultation should be obtained if there is concern for postoperative visual loss. 11. Consider optimizing hemoglobin, hematocrit, hemodynamic status, and arterial oxygenation. 12. Consider magnetic resonance imaging to rule out intracranial causes of visual loss. 13. Antiplatelet agents, steroids, or intraocular pressure–lowering agents have not been shown to be effective for treatment of perioperative ION.

Question 79

Foot and Ankle Surgery

Answer 79

Most common ankle procedures: Repair of ankle fracture Ankle fusion Achilles tendon repair Most common foot procedures: Bunionectomy Hammertoe correction Plantar fasciotomy Anesthetic Management: Regional anesthesia MAC anesthesia General anesthesia

Question 80

Forearm and Hand Surgery

Answer 80

Indications: Fractures Nerve compression (carpal tunnel release) Anesthetic Management: Full stomach? (traumatic injury) Regional anesthesia IV regional (Bier block) Brachial plexus block Tourniquet pain with prolonged procedure and regional anesthesia MAC anesthesia General anesthesia

Question 81

Rheumatoid Arthritis (RA):

Answer 81

The most prevalent chronic systemic inflammatory disease Autoimmune disease Signs and symptoms: Joint swelling Joint tenderness Destruction of synovial joints Anesthetic concerns: Airway! - Effects on cervical spine, temporomandibular joint, larynx, and pulmonary system - Limited ROM *Cricoarytenoid joints are common sites for rheumatoid nodule deposition

Question 82

Ankylosing Spondylitis (AS):

Answer 82

Chronic inflammatory process Primary target: Spinal column and surrounding tissues Additional effects: - Cardiac valve dysfunction - Conduction delays - Bundle branch blocks - Restrictive lung disease Anesthetic Management: Airway! - Position patient so no neurologic symptoms are present prior to induction of anesthesia - Cervical spine in neutral position Regional anesthesia is a safe approach