Orthopedics Flashcards
What is “Orthopedics”
A branch of medicine concerned with the correction or prevention of deformities, disorders, or injuries of the skeleton and associated structures (tendons and ligaments)
List many problems that can occur during orthopedic surgery
-Airway problems
-Positioning problems
-Blood loss (now reduced d/t TXA)
-Paraplegia during scoliosis surgery
-Perioperative Vision Loss
-Thromboembolism
-Fat embolism
-Bone Cement Implantation Syndrome (BCIS)
-Anticoagulation therapy (bleeding?)
-Tourniquet problems / Neuropraxia
-Postoperative Delirium and confusion
-Surgical site infection
What sort of questions might you ask yourself when creating an anesthetic plan for an orthopedic case?
What type of surgery?
How long will the procedure take?
What comorbidities are present?
Does the patient have preferences (regional/general)
Does the patient’s airway present any challenges?
What position with the patient be in for the surgery?
What are some comorbidities and presurgical conditions requiring patients to seek orthopedic surgery?
Osteoarthritis (OA)
Rheumatoid Arthritis (RA)
Lupus
Ankylosing Spondylitis (AS): primarily affects the vertebral column and sacroiliac joints.
What is the most common type of arthritis and leading cause of joint replacement (99%)?
Osteoarthritis
Which population has the higher prevalence of osteoarthritis?
Women over the age of 60
Osteoarthritis is sometimes also called?
Degenerative Joint Disease
Osteoarthritis is commonly caused by:
-chronic wear and tear on joints
-high intensity sports
-previous injury: bone on cartilage
-obesity: extra stress on joints
-genetics: affects severity of OA of the spine and hip
What is the etiology of rheumatoid arthritis? What percent of men and women will develop RA?
Inflammatory autoimmune rheumatic disease
4% of women, 2% of men
when do symptoms of rheumatoid arthritis usually appear/start?
Over the age of 60
what are characteristics of rheumatoid arthritis
Joint swelling, joint tenderness, destruction of synovial joint
what genetic and environment factors influence the development of rheumatoid arthritis?
Smokers: with a greater than 20 pack/year history
Obesity
Periodontitis and Viral Infections
Is there a cure for rheumatoid arthritis?
No cure, symptom management only
What are rheumatoid nodules?
firm, round or oval lumps that commonly appear in people with rheumatoid arthritis (RA).
core of dead tissue with fibrin, a protein involved in clotting.
What causes rheumatoid nodules?
Chronic synovitis — persistent inflammation of the synovial lining of joints.
Rheumatoid nodules often form on places of chronic pressure such as elbows and fingers, however, they can develop other places that have more anesthetic, implications, such as:
Cervical spine - decreased ROM
TMJ - limits mouth opening
Larynx - fixation of vocal cords in adduction
Pulmonary - SOB
What is the most common cause of death in patient with rheumatoid arthritis?
D/t cardiovascular disease
Which form of arthritis is the most debilitating disease a.k.a. systemic effects?
Rheumatoid arthritis
What are the characteristics of ankylosing spondylitis?
Bamboo spine – on x-ray
Fixed neck flexion
Inflammatory back pain
Osteoporosis
What population is ankylosing spondylitis more common in?
Men
What cardiac conditions have been correlated to ankylosing spondylitis?
Aortic insufficiency (regurg)
Arrhythmias - AV Block
What respiratory conditions have been correlated to ankylosing spondylitis?
Restrictive lung disease
OSA
Spontaneous pneumothorax
Patient with ankylosing spondylitis often have normal PFT’s, why?
Due to diaphragm and abdominal muscle compensation
True or false: ankylosing spondylitis belongs to the family of inflammatory auto immune, rheumatic disease diseases.
True
What are some airway management techniques for patients with rheumatoid arthritis?
-Consider the patient has a difficult airway
-Proper positioning is important d/t decreased cervical mobility
-Consider regional technique versus General Anesthesia
-Subarachnoid Block (spinal) difficult, d/t higher than normal spread
-Awake Fiberoptic/Glidescope
-Use smaller ETT
RA patients take _______, _____________, or _______________ need careful assessment of the airway, including cervical spine x-rays
steroids, immune therapy, or methotrexate
The primary concern when caring for a patient with either RA or AS is the?
Patient’s Airway
Orthopedic procedures in children are usually for?
Accidents and Congenital conditions
Orthopedic procedures in your adults are usually for?
Shoulder
Sports related
Orthopedic procedures in older adults and the elderly are usually for?
Hip and Knee
What medications or lab values should be evaluated before ortho surgery?
-Current anticoagulation status
-MRSA Screening
-Total Joints: baseline lab values: CBC, Type and Screen (hips usually), and Urinalysis
When should antibiotics be administered during ortho surgery? And when should they be redosed?
Administered within 1 hour of incision
Re-dosed every 4 hours
What is the normal preoperative antibiotic and dose used for prophylactic coverage? When should you increase the dose?
Ancef (Cefazolin) 2 gram IV
if pt is >120kg, administer 3 grams
If patient has an allergy to cephalosporins, what antibiotic is commonly used as an alternative in orthopedic surgery?
Vancomycin
(clindamycin in other specialties)
If a patient has a penicillin allergy from childhood and reaction is either unknown, rash, or something vague how could you change your preop abx administration to monitor for penicillin/cephalosporin cross sensitivity.
you could do the Ancef in a 100 ML bag and give it slowly instead of through a syringe fast.
If you administer the preop abx, but delays occur and it is now more than a hour since administration, what should you do?
You have to redose the Abx
What is the goal of the Surgical Care Improvement Program (SCIP) - Now call ORYX Performance Measures
To improve surgical care by defining common measures that can be taken and provide appropriate guidelines to decrease surgical site infections.
What are the common variables the Joint Commission measures/recommends to decrease surgical site infections?
- Temperature Monitoring: >36 celcius
- Abx Admin within 1 hour of incision
- Continue Beta Blockers on day of surgery
What is “Enhanced Recovery After Surgery” ERAS Protocols?
Encompass a comprehensive range of perioperative therapies aimed at facilitating, the healing process following surgical procedures.
-enhance overall health outcomes
-mitigate medical expenses through reduction in hospital length of stay
-aim to decrease postoperative death rates
How do you calculate minimally accepted blood loss value? How do you calculate estimated blood loss value?
What are some ERAS society recommendations for preoperative care of hip and knee replacement patients?
-preop fasting
-standard anesthesia protocol: general &/or neuraxial techniques
-screen for PONV risk and give prophylaxis
Use of local anesthetics for infiltration, analgesia, and nerve blocks!
-prevention of perioperative blood loss: txa
-perioperative oral analgesia: Tylenol and NSAIDs
-maintain normothermia
-antimicrobial prophylaxis
-period operative fluid management
True or false: nerve block techniques have not shown clinical superiority over local infiltration analgesia.
True
True or False: Local infiltration analgesia for knee replacement has a high recommendation grade. red item Torabi
TRUE red item Torabi
Benefits to the use of a pneumatic tourniquet?
Reduces intraoperative blood loss
Aides in the identification of vital structures
Expedite the procedure
What is an example of a non-pneumatic tourniquet? When is it used and how does it compare to pneumatic tourniquets?
Silicone ring tourniquet (SRT)
Used for brief procedures
Application time is more rapid
Tourniquet pain and blood loss are the same
No device attached to monitor the time
When should tourniquet application occur?
Applied after anesthesia
(could theoretically be done before but NOT while inducing and intubating patient)
Inflation pressure of tourniquet is determined by:
Patient’s blood pressure and shape/size of extremity
what is the maximum time a pneumatic tourniquet can be inflated?
Max of two hours is considered safe
Pneumatic tourniquet application leads to interruption of blood supply to distal extremity, which leads to?
Tissue hypoxia, and acidosis
The degree of hypoxia/acidosis is influenced by duration of tourniquet time
Can a patient who received a spinal still feel tourniquet pain/pressure?
Yes, so a low-dose prop drip might help
When using a pneumatic tourniquet nerve conduction is abolished after ___________ minutes. And tourniquet pain starts around _______________ after application.
30 minutes
45-60 minutes after application
Postop neuropraxia (temporary nerve injury) can occur after how many hours after pneumatic tourniquet application?
Can occur after 2 hours
Enothelial capillary leak can develop how many hours after pneumatic tourniquet application?
Can occur after 2 hours
Upper extremity tourniquet pressure should be how much greater than a patient’s SBP?
70-90mmHg > SBP
(usually 250mmHg for arm)
Lower extremity tourniquet pressure should be how much greater than a patient’s SBP?
Twice the patients SBP
(needs to be at least 300mmHg)
What will be released when the tourniquet is deflated? What can this cause?
Anaerobic metabolites into systemic circulation
Hypotension, metabolic acidosis, hyperkalemia, myoglobinuria, and possible renal failure. Cardiac Arrest worst case scenario.
What happens to etCO2 when tourniquet is deflated?
Initial increase peaking at 1-3 minutes, returns to baseline 10-13min
What happens to cerebral blood flow when tourniquet is released?
Increased d/t increased etCO2. Goal to maintain normocapnia.
How does blood clotting change after tourniquet removal?
Increase fibrinolytic activity. increased bleeding for about 15 min.
After tourniquet release, how long does it take for metabolic changes to normalize?
~30min
How does body temperature after tourniquet release?
transient decrease in temperature, redistribution of core temp.
When does tourniquet pain usually occur?
45-60min after inflation
What kind of pain does tourniquet pain resemble?
Thrombotic vascular occlusion and peripheral vascular disease.
Tourniquet pain starts as dull and aching and progresses to?
Burning and excruciating pain that may require general anesthesia.
The burning and aching pain from tourniquet is from what fibers?
Slow-conducting, unmyelinated C fibers
The pin prick, tingling and buzzing sensations patients feel from pneumatic tourniquet are from what fibers?
Faster myelinated A-Delta fibers
Systemic Effects of Tourniquet Release (6)
-transient decrease in core temperature
-transient metabolic acidosis
-transient decrease in central Venus oxygen tension, but systemic hypoxia is unusual
-acid metabolites, such as Thromboxane A2 are released.
-transient fall and pulmonary and systemic arterial pressures
-transient increase in etCO2
Muscle changes that occur distal to pneumatic tourniquet (4)
Cellular hypoxia develops within two minutes
Cellular creatinine value declines
Progressive cellular acidosis
Endothelial capillary leak develops after two hours
Which local anesthetic may offer an advantage to lowering the incidence of tourniquet pain? Why?
Bupivacaine due to becoming enhanced by an increase in the rate of nerve stimulation
Which fibers may be more difficult to anesthetize due to tourniquet pain? red item Torabi
C fibers may be more difficult to anesthetize than A-Delta fibers and tourniquet pain therefore seems more consistent with pain sensation carried by C fibers
[🧬 Reason: Ischemia + C Fiber Physiology
C fibers are more sensitive to ischemia and metabolic stress than A-delta fibers.
Over time, ischemia irritates and excites C fibers, even if they were previously anesthetized.
This is why tourniquet pain often has that burning, aching quality — it’s C-fiber dominant.]
As the concentration of local anesthetic decreases, the activation of ___ fiber increase increases, but the _____ fiber activation is still suppressed
C
A-Delta
Nerve injury occurs at what area of the skin from pneumatic tourniquet?
skin level at edge of tourniquet
pneumatic tourniquet nerve damage is due to?
Rupture of the Schwann cell basement membrane
What are some steps to prevent postoperative tourniquet paresthesia?
Proper padding
Correct tourniquet size
Limit time to two hours
which patients should receive extra caution when using a pneumatic tourniquet?
Patient with fractures
Elderly
And patient with a history of risk factors for emboli formation
What are some responsibilities of the anesthetist to reduce the chance of pneumatic tourniquet injury?
Proper cuff size and application (OR Nurse apply)
Minimal effective pressure
Tourniquet set at appropriate pressure
Informed surgeon when tourniquet time >2hr
Over 2 hours, deflate for five minutes for reperfusion
what is a severe adverse condition that can occur from prolonged pneumatic tourniquet time?
Compartment syndrome
Compartment syndrome can develop due to prolong tourniquet time from?
Increased capillary permeability
Prolongation of clotting
What are some signs of compartment syndrome?
Tense skin
Swelling
Weakness
Parasthesia
Absent pulse - reversible paralysis
For a patient undergoing a procedure using a pneumatic tourniquet, If hemodynamics won’t be easily controlled what should you try?
Try decreasing tourniquet pressure
who is ultimately responsible for proper positioning of the patient on the operating table?
The anesthetist
What orthopedic procedures commonly require the patient in prone position?
Lumbar surgery (spine)
Podiatry cases
What orthopedic procedures commonly require the patient in lateral position?
Hip and shoulder
What orthopedic procedures commonly require the patient in beach chair position?
Shoulder surgery
What orthopedic procedures commonly require the patient in supine position?
Hand, arm, knee, foot/ankle, anterior hip
What orthopedic procedures commonly require the patient to be on a fracture table?
IM nailing (hip)
In the upright sitting/standing position, what is the distribution of ventilation and perfusion in the three lung zones? red Torabi item
Zone 1: Apex of Lung. Lowest blood flow, most ventilation.
Zone 2: Moderate blood flow, ventilation and perfusion are relatively well matched.
Zone 3: Highest blood flow, reduced ventilation
What nerve is most likely to be injured by a fracture of the proximal humerus?
Axillary, median, radial, or ulnar
Axillary
What method best diagnosis an extremity compartment syndrome?
A. needle measurement of compartment, pressure.
B. serum creatine phosphokinase level.
C. Doppler detection of extremity pulses.
D. extremity diastolic pressure.
A. needle measurement of compartment, pressure.
> 30mmHg
What are the 6Ps of compartment syndrome?
Pain out of proportion to injury
Paraesthesia
Pain on passive movement
Palpation of a tense hard compartment
Paralysis
Pulselessness
What type of anesthesia should be used with caution in patient with increased risk of developing compartment syndrome such as those with traumatic fractures? Why?
Regional anesthesia should be used with caution to avoid prolonged motor and sensory blocks use of intra-compartmental pressure monitoring is indicated during the postoperative period as patient may have prolonged motor and sensory anesthetic deficits
Which procedure is most associated with bone cement implantation syndrome?
A knee arthroplasty
B hip arthroplasty
C vertebroplasty
D ankle arthroplasty
B. hip arthroplasty
All can be associated, but hip is the most associated
What is the difference between arthroscopy vs arthroplasty?
Arthroscopy: scope inserted into joints for diagnosis or treatment
Arthroplasty: open surgical
procedure to restore the joint
What areas of the body are Arthroscopy done?
Shoulder
Knee
Elbow
Wrist
Hip
Ankle
Phalangeal Joints in Foot
Irrigation fluid for arthroscopy produces almost ______mmHg of pressure entering the joint space?
90mmHg
Absorption of excessive extravasated fluid from arthroscopy may lead to the development of?
signs and symptoms of congestive heart failure, pulmonary edema, volume overload, or hyponatremia (if a ‘‘salt-poor’’ fluid is used).
What are some Complications Associated with Arthroscopic Procedures?
■ Subcutaneous emphysema
■ Pneumomediastinum
■ Tension pneumothorax
■ Complications related to patient positioning ■ Irrigation fluid overload
What is the immediate tx for tension pneumo
14-18g IV angiocatch into 2-3 intercostal space anteriorly mid-clavicular.
Insert need at 90-degree angle
Followed by chest tube insertion
Benefits of Beach Chair Position
- Improved Visualization for surgeon
- Decreases distortion of the anatomy
- Minimizes potential for brachial
plexus injury (compared to lateral
position)
The beach chair position is often used for shoulder surgery.This position can cause:
venous pooling, reduced cardiac output, hypotension, and reduced cerebral perfusion.
Risks associated with Beach Chair Position
- Cerebral Hypoperfusion
- POVL
- Deterioration of cognitive
function - Memory Deficit
- Seizures
- Cerebral death/TIA/Stroke
Hemodynamic changes in beach chair position
MAP,
Pulmonary artery occlusion pressure,
Stroke Volume,
Cardiac Output (decreases 20%) and
PaO2 all decrease
How does the PAO2-PaO2 gradient change in beach chair position?
*Alveolar-arterial oxygen gradient (PAO2-PaO2), pulmonary vascular resistance, and total peripheral resistance increase.
How does cerebral perfusion pressure change in the beach chair position?
Decreases by 15%
What rate in mL/min and % CO go to the brain? (Red item Torabi)
750-900mL/min
15% of resting CO
Normal blood flow to brain tissue per minute
57mL/100grams of brain tissue
What is cerebral perfusion pressure?
The difference between mean arterial
pressure and intracranial pressure (or
central venous pressure, whichever is
greater).
CPP=MAP-ICP (or CVP)
What is normal Cerebral Perfusion Pressure?
~60-80mmHg
What is the calculation for MAP?
[SBP + 2DBP] / 3
What cerebral perfusion pressure suggests ischemia? What suggests irreversible brain damage?
30-40mmHg
<25 mmHg
Cerebral blood flow is autoregulated when MAP is between?
50-60 and 150mmHg
How does the autoregulation of Cerebral Blood Flow change in poorly controlled hypertensive patients?
Autoregulation of CBF is shifted to the right, requiring higher CPP/MAP to ensure adequate cerebral perfusion.
If patient is in beach chair position, and their MAP at the arm 65 what is the CPP?
50mmHg
Where should your a-line transducer be when patient is in beach chair?
At the external auditory meatus. Best represents the location of the base of the brain and circle of willis.
Pearls for Beach Chair
- Maintain normocarbia: (↓ETCO2 reduces CBF). Keep ETCO2 at higher levels,
do not hyperventilate. - Keep MAP ~60-150 mm/Hg; higher MAP if pt. has HTN
- Aline transducer at tragus/external auditory meatus
- Deduct 15mm/Hg from arm
MAP, Avoid BP cuff in lower
extremity
What is the conversion factor for blood pressure changes in beach chair?
1 cm rise = 0.75 mmHg drop in map
Normal cerebral oximetry values (NIRS)
60-80
What sort of cases should utilize cerebral oximetry?
CV surgery, vascular surgery, beach chair positions
What classifies a hypotensive bradycardic episode? red item torabi
Decrease in heart rate of at least 30bpm within a 5-minute interval
Any heart rate < 50 bpm and/or a decrease in SBP of more than 30 mmHg(ex: 120-40=80) within a 5-minute interval or a SBP < 90 mmHg.
What is the proposed mechanism of a hypotensive bradycardic episode?
Activation of Bezold-Jarisch reflex
What is one procedure and one block associated with hypotensive bradycardic episodes?
Common and shoulder arthroscopy – 30%
Interscalene block: LA with epinephrine
When activated, the bezold-jarisch reflex results in a triad of what symptoms?
Bradycardia
Hypotension
Peripheral vasodilation
What is the mechanism of the bezold-jarisch reflex?
This cardio inhibitory reflex occurs in the sitting position & after ISB with epi (15-30%)
► The ↓ venous return results from pooling of blood in the lower extremities
► Stretch receptors located in the ventricles are triggered resulting in decreased sympathetic tone and increased vagal tone.
How should you treat the bezold-jarisch reflex?
o Treat fluid deficits and blood loss
o Use support stockings to minimize venous pooling
o Avoid use of local anesthetics with epi
o Treat with ephedrine or epi
To prevent compression of the dependent brachial plexus an axillary roll is placed. Where do you place it? red item torabi
The roll is actually a “chest roll” and should
never be placed in the axilla. Place caudal to the axilla and avoids compression of axillary nerves.
What surgeries do you usually do both neuraxial and peripheral nerve blocks?
Total Knee Arthroplasty
Total Hip Arthroplasty
What dermatome level should the spinal reach for a hip surgery?
T10 - umbilicus
For longer cases will need to be higher bc it’ll wear off before case is done.
What dermatome level should a spinal reach for a thigh or lower leg amputation surgery?
L1 (inguinal ligament)
Advantages of regional anesthesia in orthopedics
■ Decreases incidence of deep vein thrombosis (DVT), pulmonary
embolism (PE), blood loss, respiratory complications
■ Improved analgesia
■ May block the progression of severe acute postoperative pain into a
chronic pain syndrome
■ Avoids manipulation of the airway
■ Enhanced Rehabilitation
■ Decreased N & V
■ Less cardiac complications
What peripheral nerve blocks can be done for knee orthopedic surgery?
-Adductor Canal Block,
-I-PAC (Infiltration between the Popliteal –Artery and Capsule of the Knee)
-Femoral
What peripheral nerve blocks can be done for hip orthopedic surgery?
Fascia Iliaca Compartment Block,
Femoral Nerve,
PENG block (preserves quad fxn)
What peripheral nerve blocks can be done for ankle orthopedic surgery?
Popliteal Block
What peripheral nerve blocks can be done for shoulder orthopedic surgery?
Interscalene or Supraclavicular Block
What peripheral nerve blocks can be done for forearm or hand orthopedic surgery?
Axillary Block
What body parts can undergo arthroplasty?
Hip
Knee
Ankle
Shoulder
What are some complications from arthroplasty?
Bone cement
Fat embolism
Air embolism
Thromboembolism
Bone marrow embolism
Which patient population is associated with an increased risk for needing a hip revision?
Younger aged males
Which patient population is associated with an increased risk of post-surgical mortality, following hip arthroplasty?
Older age males
Do age sex influence level of post surgical pain?
No
What percent of patients who need a hip replacement are obese?
50%
What are the two surgical approaches to a total hip replacement and what surgical positions must they be in?
Anterior approach – supine position
Posterior approach – lateral position
What approach is most common for total hip replacements? Where is the incision made?
Most common is posterior with a large incision from iliac crest to mid thigh
Do you use a tourniquet for hip replacement?
Nope
What are some features of a direct anterior total hip replacement approach?
- Minimally invasive alternative
- Muscle sparing procedure, shorter incision
- Shorter hospitalization, faster postop recovery
- Technically more challenging, incise through
several muscle layers - Need muscle relaxation?
(-Avoid Nitrous Oxide?)
What is your overall anesthetic plan for a total hip arthroplasty?
- Spinal block, Fascia Iliaca Block, Propofol gtt
- General Anesthesia (ETT vs LMA)
- Avoid Nitrous Oxide
- Ancef 2gm IVPB (within 1 hour incision)
Intraoperative blood loss during a total hip arthroplasty may exceed 1 L. what medication can help reduce blood loss and what is its MOA?
Transexamic Acid (TXA) 1-2g IV or Topical
Synthetic plasminogen-activator
* Decreases blood loss through inhibition fibrinolysis and clot degradation.
Impedes the binding of plasminogen to plasmin. So it’s stabilizers clotting by preventing clot breakdown.
How should you administer TXA?
1 g before incision, 1 g at end of procedure per surgeon order - knee or hip.
10-15 mg/kg should not exceed 100mg/min
Infuse over 15 minutes. Can cause hypotension.
In patient with renal impairment, how should TXA dose be adjusted?
↓ dose in patients with renal impairment (500mgIV)
Contraindications for TXA use
- Hypersensitivity to TXA
- Coronary or vascular stent placed within past 6 mos.
- DVT,PE
- MI, stroke within last 6 months
- Subarachnoid hemorrhage
- Bleeding disorders
- Hypercoagulable state
- Retinal vein or artery occlusion
What regional blocks are approved for the use of Exparel?
ISB
Adductor Canal
Popliteal
What Regional Field blocks are approved for the use of Exparel?
Field Blocks (PECS, TAP, ESP, PENG)
The maximum dosage of EXPAREL should not
exceed?
266mg
Intra-articular infusions of local anesthetics
following Arthroscopic and other surgical
procedures is a ? red item torabi
unapproved use!
EXPAREL should not be admixed with local
anesthetics other than?
Bupivacaine
How many hours does Exparel last for?
up to 72hrs
Standard Vial Concentration of Exparel?
20 mL single use vial, 1.3%
(13.3mg/mL)
What is Zynrelef?
ZYNRELEF combines bupivacaine, an amide-type local anesthetic, with a low dose of meloxicam, a nonsteroidal anti-inflammatory drug, in a proprietary Biochronomer® extended- release polymer that provides controlled diffusion of both ingredients simultaneously for 72 hours at the surgical site
Intraoperative use of cell saver has been shown to decrease the need for transfusion by?
31%
Strategies for reducing blood loss
(1) use of the cell saver, desirable for Jehovah Witness
(2) autologous blood transfusion
used in procedures with expected large blood loss. perfusionist spins blood down
What is bine cement? How does it work?
Methyl methacrylate (MMA)
-Strongly binds the prosthetic device to the patient’s bone.
-Mixing the powder with a liquid causes an exothermic reaction resulting in hardening of the cement and expansion against the prosthetic components.
How can bone cement syndrome develop? What can it produce?
Bone cement can cause Intramedullary hypertension (>500 mm Hg) occurs when the bone cement is applied to the prosthesis.
This intramedullary hypertension can force debris into the patient’s circulation causing serious complications.
Systemic absorption of residual methyl methacrylate monomer can produce vasodilation and a decrease in systemic vascular resistance.
(intramedullary - pressure in bone marrow)
Bone cement in plantation syndrome is most commonly associated with what procedure?
Total hip arthroplasty
What is usually the first indication of bone cement syndrome under general anesthesia? What are some other signs/ symptoms?
- Abrupt decrease in End tidal CO2 (1st indication under GA)
- Hypoxia (increased pulmonary shunt)
- Systemic Hypotension
- Arrhythmias (including heart block and sinus arrest)
- Pulmonary hypertension (increased pulmonary vascular resistance)
- Decreased cardiac output
- Mental status change (LOC) in patients with regionalanesthesia
- Dyspnea, altered sensorium in awake pt.
- Right ventricular failure and cardiac arrest
- Etiology: Embolus mediated
What is the occurrence of bone cement implantation syndrome? What stages does it occur in?
Occur in 2-17% of surgeries
■ Occurs in stages:
► femoral canal reaming
► acetabular or femoral cement implantation ► insertion of prosthesis or joint reduction
► after limb tourniquet deflation
Factors for bone cement, implantation syndrome
■ Preexisting pulmonary HTN
■ Preexisting CV disease
■ ASA class III or higher
■ New York Heart Association Class 3-4
■ Surgical technique
■ Pathologic fracture
■ Intertrochanteric fracture
■ Long-stem arthroplasty
Prior to cementing, how should you optimize your patient?
Optimize blood pressure
100% FiO2
Lavage before implantation
if you suspect your patient has bone cement implantation syndrome how do you treat?
► ↑ FiO2 (100%) if not already done
► Treat CV collapse as right sided heart
failure
► Aggressive fluid resuscitation
► Treat hypotension
What is fat embolism syndrome? (FES)
- Occurs with long/pelvic
bones surgery (hip) - Fat globules are released and enter circulation via tears in vessels
- Emboli travels to the right side of
heart and lung→ pulmonary
hypertension
How does fat embolism syndrome manifest?
Manifestation of FES can be gradual. It classically presents ~ 72 h following long-bone or pelvic fracture, leading to acute respiratory distress and cardiac arrest.
Mortality rate:10-20%
What is the classical triad of clinical manifestations in fat embolism syndrome?
- Classical Triad: dyspnea, confusion, and
petechiae - A petechial rash (conjunctiva, oral mucosa, and skin folds of the neck and axillae)
- Respiratory manifestations: mild hypoxemia , pulmonary edema, bilateral alveolar infiltrates. (fat droplets act as emboli)
- Neurologic manifestations:
✓ Drowsiness, confusion, obtundation and coma
Anesthetic management of fat embolism syndrome?
■ Flood surgical site
■ Supportive medical care
✓ Adequate oxygenation
and ventilation
✓ Vasopressors
■ Surgical care
Prophylactic placement of IVC
filters
■ Monitoring
Continuous pulse oximetry monitoring
Risk factors for thromboembolism
- Obesity
- Advanced age (> 60)
- Procedures lasting more than 30 min
- Use of a tourniquet
- Lower extremity fracture
- Immobilization for more than 4 days
What orthopedic procedures have the greatest risk for thromboembolism?
hip surgery and knee replacement,
major operations for lower extremity, trauma
Without prophylaxis, venous thrombosis develops in what percent of orthopedic patients?
40-80%
What is Virchow’s Triad?
Venous Statsis
Endothelial Injury
Hypercoaguable State
Why does orthopedic surgery have a high risk of VTE?
1) Use of tourniquet, immobilization
and bed rest cause venous blood
stasis
2) Surgical manipulations of the limb
cause endothelial vascular injuries
3) Trauma increases thromboplastin
agents
4) Use of polymethylmethacrylate
(PMMA) bone cement
What are some thromboprophylaxis options?
Low molecular weight heparin (for TKA,THA)
► Fondaparinux, Dabigatran, Apixaban, Rivaroxaban
► Low dose unfractionated heparin
► Adjusted-dose vitamin K antagonist
► Aspirin
► Intermittent pneumatic compression device x 10-14 days
► Thromboprophylaxis up to 35 days is preferred
When should low molecular weight heparin be discontinued before neuraxial anesthesia?
12 hours before
When should Plavix and warfarin be stopped before surgery?
Plavix – seven days
Warfarin – 4–5 days
Single dosing low molecular weight heparin should start how many hours after postop?
Four hours
How long after a daily dose of anticoagulation such as low molecular weight heparin should an epidural catheter not be inserted or pulled?
12 hours after last dose with a four hour delay before the next dose
A thigh tourniquet is applied with pressures usually set between?
250-300mmHg
Indications for total shoulder arthroplasty
► Post-traumatic brachial plexusinjuries
► Paralysis of deltoid muscle and rotator cuff ► Chronic infection
► Failed revision arthroplasty
► Severe instability
► Proximal humerus fracture
► Bone deficiency after resection of tumor
What is a common reason for ankle arthroplasty? Is a tourniquet required.?
Arthritis and tourniquet required
General anesthesia, spinal, block or all options
What are some minimally, invasive spinal surgeries?
Minimally invasive techniques
► Endoscopic lumbar discectomy
► Vertebroplasty
► Kyphoplasty
► Cervical discectomy
► Foraminectomy
* Performed in interventional radiology,
LA with IV sedation
* GA for difficult procedures
What is the benefit of a Jackson table?
Minimize intro, abdominal pressure and blood loss, has an open area for stomach to hang
For a case using a Andrew’s Frame, how are the our patients positioned? What is a consequence of this?
Modified knee-chest position.
Legs are below the level of the heart, venous return is decreased and severe hypotension can result. Blood pools in legs.
The use of the Wilson frame has been associated with?
Ischemic optic neuropathy
The patient’s face is below the level of the heart which can result in venous congestion and edema
What are some cardio pulmonary complications of prone position?
Pressure on abdomen compresses
inferior vena cava and femoral veins = ↑blood loss (goal is to minimize intra-abdominal pressure)
What are some respiratory complications of prone position?
Compression of abdomen displaces organs
and diaphragm cephalad= ↓ FRC, TV and ↑ airway pressure
What are some neurologic complications of prone position? Torabi Red
Neck rotation can result in decreased
cerebral perfusion
❑ Peripheral Neuropathies: Brachial plexus
❑ Eye and tongue swelling
❑ POVL: Post op vision loss
What is thoracic outlet syndrome?
■ Compression of brachial plexus
■ Swelling and coldness in arm/hand
■ Hypoxemia noted via pulse oximetry
■ No SSEPs in affected arm
■ Occurs in prone position
What are some risk factors for postoperative vision loss?
Obese and male patients,
Wilson frame, long
procedures,
↑ blood loss,
lower % of colloid administration, intraoperative hypotension,
anemia,
sitting or prone position.
How/When does POVL usually present?
■ Usually bilateral (esp. after spine surgery)
■ Visual loss typically occurs ~ 1st 24-48 hours postoperatively
■ Painless visual loss
■ Afferent pupil defect, nonreactive pupil, no light perception
■ Color vision is decreased or absent
At what intraocular pressure is the risk of POVL increased?
IOC > 40mmHg
What are some preventative strategies against POVL?
■ Position patients head at or above the heart ■ Not advisable to cover eyes with goggles when foam headrest is used
■ Document eye checks every 20 minutes
■ Horseshoe headrest should not be used
Risk factors for ischemic optic neuropathy associated with spine surgery?
-male sex
-obesity
-Wilson frame
-anesthesia, duration greater than six hours
-large blood loss
-colloid as percent of non-blood fluids
What are some foot and ankle surgeries? What sort of anesthesia is used? How long do they usually take?
- Bunionectomy * Hammertoe * Plantar Fasciotomy * Ankle fractures
- Anesthesia: Regional, IV sedation, SAB
- Usually 2 hours or less
