Orthopedic Anesthesia: Unit 1 Module 1-2 Flashcards
What are the two biggest factors associated with development of osteoporosis?
- Elderly age
- Menopause
What hormonal changes are characteristic of osteoporosis?
- ↑ PTH
- ↓ Vit D
- ↓ HGH
- ↓ Insulin-like growth factors
What are the four most common meds used to treat osteoporosis?
dronate drugs
- Fosamax (Alendronate)
- Actonel (Risedronate)
- Boniva (Ibandronic Acid)
- Reclast (Zoledronate)
Differentiate between Bouchard’s nodes and Heberden’s nodes.
- Bouchard’s = proximal interphalangeal joints
- Heberden’s = distal interphalangeal joints
What drug is the most common chondroprotective agent that helps protect the articular joint?
Glucosamine
What anesthetic considerations should be given to glucosamine?
Glucosamine needs to be stopped two weeks prior to surgery due to PLT aggregation inhibition.
Arthritis characterized by morning stiffness that improves throughout the day is….
Rheumatoid arthritis
Arthritis that is characterized by worsening symptoms throughout the course of the day is…
Osteoarthritis
What labs are typically elevated in a patient with rheumatoid arthritis?
- ↑ Rheumatoid factor (RF)
- ↑ Anti-immunoglobulin antibody
- ↑ C-reactive protein (CRP)
- ↑ Erythrocyte Sedimentation Rate (ESR)
What common dose of stress dose glucocorticoid is used for RA patients?
50mg hydrocortisone (Solu-cortef)
What two TNFα inhibitors are commonly used to treat RA?
- Infliximab
- Etanercept
Which of the following drugs treat RA?
- Methotrexate
- Hydroxychloroquine
- Sulfasalazine
- Leflunomide
Trick question. All of them do
- Methotrexate
- Hydroxychloroquine
- Sulfasalazine
- Leflunomide
What airway concerns should be considered with RA patients?
- Limited TMJ movement
- Narrowed glottic opening
- Cricoarytenoid arthritis
Where is the most instability typically located in the cervical spine of RA patients?
Atlantoaxial Junction
(be careful not to displace the odontoid process and impinge on the c-spine or vertebral arteries)
What are the signs and symptoms of atlantoaxial subluxation?
- Headache
- Neck pain
- Extremity paresthesias (especially with movement)
- Bowel/bladder dysfunction
What are the signs/symptoms of vertebral artery occlusion?
- N/V
- Dysphagia
- Blurred Vision
- Transient LOC changes
What ocular syndrome is typical of RA patients?
Sjogren’s syndrome
(Dry eyes and mouth)
What pulmonary issues are associated with RA?
- Interstitial fibrosis
- Restricted ventilation
What type of ventilatory settings would be utilized for an RA patient exhibiting a restrictive ventilatory pattern?
Pressure Control @ 5mL/kg
What artery is typically injured due to pelvic fractures? Where is the bleeding located in this instance?
Iliac artery → retroperitoneal space bleeding
What is the typical worst complication of long bone fractures?
Bone marrow fat embolism
What technique is used for intubation of a patient who has c-spine concerns?
MILS
Manual In-Line Stabilization
Describe the MILS technique
What is the mechanism of action of warfarin?
Warfarin inhibits Vitamin K epoxide reductase and limits the availability of Vitamin K throughout the body
What is the mechanism of action of LMWH?
LMWH binds to antithrombin thus → no thrombin → no fibrinogen forming into fibrin
What are some typical triggers for delirium? (11)
- Hypoxemia
- Hypotension
- Hypercarbia
- Sleep Deprivation
- Hypervolemia
- Infection
- Electrolyte abnormalities
- Pain
- Benzos
- Anticholinergics
- Circadian Rhythm disruption
FEV₁ decreases by ___% for each decade of life.
10%
What occurs with closing volume as we age?
Closing volume increases.
What is the goal of regional anesthesia vs general anesthesia?
Avoid:
- DVT
- PE
- EBL
- Respiratory complications
- Death
With placement of what device is fat embolism syndrome most likely to occur?
Femoral Medullary Canal Rod
What is the s/s Triad of fat embolism syndrome?
When do s/s typically present?
- Dyspnea
- Confusion
- Petechiae
Typically presents in 12 - 72 hrs
What lab findings are noted with fat embolism syndrome?
- Fat macroglobulinemia
- Anemia
- Thrombocytopenia
- ↑ ESR
What is ESR? What are normal values for males and females?
- Erythrocyte Sedimentation Rate
- Male: 0 - 22 mm/hr
- Female: 0 - 29 mm/hr
What minor s/s can be construed to characterize fat embolization syndrome?
- Fever
- ↑HR
- Jaundice
- Renal Changes
What are the anesthetic management techniques for fat embolization syndrome?
Supportive Therapy
- 100% FiO₂
- No N₂O
- IV Heparin
- CV & Resp support
What factors contribute to the development of DVT’s? (7)
- Lack of Prophylaxis
- Obesity
- > 60yrs old
- > 30min procedure
- Tourniquet use
- > 4 days immobilization
- > Lower extremity fracture
Which three surgery types present the greatest risk for DVT formation?
- Hip surgery
- TKA
- Lower extremity trauma
When does LMWH need to be initiated?
12 hours preop
or
12 hours postop
Can neuraxial anesthesia be done after LMWH 40 mg (qD) has been given?
Yes, if 12 hours after the dose.
Delay next dose 4 hours.
Can an epidural be placed in a patient on LMWH anticoagulation therapy twice daily?
No. Neuraxial catheter NOT okay
Neuraxial catheters must be removed ___ hours before the intiation of LMWH therapy (twice daily dose).
2 hours
Can a patient have neuraxial anesthesia if on warfarin?
Only if the INR is ≤ 1.5
When can you give the next dose of warfarin after DCing neuraxial catheter?
2 hrs
When can you give the next dose of heparin after DCing neuraxial catheter?
1 hr
When can you give the next dose of Fondaparinux (Arixtra) 2.5 mg or 5-10 mg SQ qd after DCing neuraxial catheter?
6-12 hrs
When can you give the next dose of Enoxaparin (Lovenox)
1 mg/kg SQ bid
or 1.5mg/kg SQ qd (full dose)
after DCing neuraxial catheter?
24 hrs
When can you give the next dose of Lovenox (40 mg SQ qd) after DCing neuraxial catheter?
6-8 hrs
indwelling catheters are contraindicated with antithrombotic agents except 1 traditional anticoagulant
heparin
antithrombotic agents are contraindicated with indwelling catheters when taking
OTHER TRADITIONAL ANTICOUGULANTS:
-warfarin, fondaparinux lovenox
DIRECT THROMBIN INHIBITORS:
-Argatroban, Bivalirudin (ANGIOMAX), Lepirudin (Refludan), Dabigatran (Pradaxa)
oral antiplatelet agents
GP IIB/IIIA inhibiors
Thrombolytic agents
Apixaban (Eliquis)
A spinal injection or catheter placement can be done after taking warfarin if….
INR < 1.5
A spinal injection or catheter placement can be done after taking Heparin full dose IV if….
aPTT < 40 after holding medication for 2 hrs
A spinal injection or catheter placement can be done after taking Heparin minidose (5000 u) SQ BID if….
No contraindication
A spinal injection or catheter placement can be done after taking heparin (minidose 5000 u SQ TID) if….
aPTT < 40 or 6 hrs after the last dose
A spinal injection or catheter placement can be done after taking heparin full dose (>5000 u SQ BID or TID) if….
aPTT < 40 or 6 hrs after the last dose
A spinal injection or catheter placement can be done after taking Fondaparinux (Arixtra) <2.5 mg SQ qd (prophylaxis) if….
36-42 hours
A spinal injection or catheter placement can be done after taking Fondaparinux (Arixtra) 5-10 mg SQ qd (full dose) if…
contraindicated
A spinal injection or catheter placement can be done after taking Enoxaparin (Lovenox)
1 mg/kg SQ bid or
1.5mg/kg SQ qd (full dose)
if…
after 24 hrs
A spinal injection or catheter placement can be done after taking Lovenox 40 mg SQ qd (prophylaxis)
12 hrs
Flip card for Anticoagulation guidelines for Neuraxial procedures.
Flip card for additional Anticoagulation guidelines for Neuraxial procedures.
What advantages does neuraxial anesthesia present in the prevention of DVT’s?
- ↑ extremity venous blood flow (sympathectomy).
- LA systemic anti-inflammatory properties.
- ↓ PLT reactivity
What is the maximum dose of TXA? (Tranexamic Acid)
2.5 g
What is typical dosing of TXA?
10 , 15, or 30 mg/kg
1000mg is typical
Tourniquet pain typically begins ___ minutes after application.
45 min
The width of a tourniquet must be greater than ____ its diameter.
½
How long can tourniquets be placed on an extremity?
- 2 hours is typically not exceeded
- 3 hours is max.
What mmHg is typically used for thigh tourniquets?
300 mmHg
(or 100 mmHg > SBP)
What mmHg is typically used for arm tourniquets?
250 mmHg
(or 50 mmHg > SBP)
When utilizing a double tourniquet, it is important to remember to…
inflate proximal → deflate distal
What occurs with tourniquet deflation?
- Transient lactic acidosis
- Transient Hypercarbia
- ↑ HR
- ↓ pain
- ↓ CVP, BP, & temp
-increased minute ventilation
-metabolic acidosis
-hyperkalemia
Prolonged inflation of tourniquet > 2 hrs can lead to …
nerve injury
-risk of ischemia & rhabdomyolysis
-mechanical trauma
** minimize risk by deflating the tourniquet 20-30 mins to allow for reperfusion
What are some important points of assessment necessary for upper body procedures preoperatively?
- Baseline vitals: BP and HR
- Airway
- Pre-existing nerve conduction issues
- Examine pupils
Most common reasons for shoulder surgery (4)
- Rotator Cuff Tear
- Subacromial Impingement
- Glenohumeral Instability
- Labral Tear
two most common positions for shoulder surgery
beach chair and lateral decubitus
What are the cardiac consequences of sitting/Beach Chair position?
- ↓ CO & BP
- ↑ HR & SVR
Due to pooling of blood in lower body.
What are the respiratory consequences of sitting/Beach Chair position?
- ↑ FRC & lung volumes
What are the neurologic consequences of sitting/Beach Chair position?
↓ CBF
How is venous air embolism prevented in a beach chair patient?
↑ CVP (above 0) to prevent a “suction” effect
VAE: air enters the right ventricle interfering iwth blood fow into the pulmonary artery causing pulmonary ____ & reflex ____
pulmonary edema and reflex bronchoconstriction
VAE: air may reach the cerebral and coronary circulation via a patent ___ ____
foramen ovale
In what percent of the population is a patent foramen ovale present?
20 - 30 %
How does one treat venous air embolism?
Besides prevention…
- Inform surgeon → irrigation & occlusive dressing
- DC N₂O if being used
- Bilateral compression of jugular veins (prevent neuro consequences)
- Place patient in head down position to trap in right atrium
- Withdraw air through right atrial catheter
- CV collapse will need tx with pressor
- & Resp support
The ultrasound transducer is being utilized to located venous air embolism in a patient. Where do you place the probe?
2ⁿᵈ - 3rd ICS right of sternum
Over the Right Atrium
Though ultrasound over the right atrium is the most sensitive indicator of VAE (venous air embolism), the most definitive is….
TEE
The characteristic sound of a VAE is a _____________ murmur.
“Mill-Wheel” murmur
What would be an indicator of a sudden decreased perfusion to the lungs?
↓ EtCO₂
________ of the neck in a sitting position patient can accidentally extubate them.
Hyperextension
In a sitting position patient, where would one zero their art line?
Tragus of the ear
Establishes knowledge of brain BP & thus perfusion.
What are ocular conditions do we want to avoid due to the hypotension inherent to the sitting position?
- Retinal Ischemia
- Ischemia Optic Neuropathy
Also avoid corneal abrasion.
There is a 40cm distance from the patients heart to their brain. The patient’s BP measured on the arm is 120/70. What is the estimated BP in the brain?
40cm x 0.77mmHg = 30.8mmHg
120 - 30.8 = 89.2mmHg
70 - 30.8 = 39.2mmHg
The patient’s brain BP is 89/39 Thus indicating hypotension and necessary correction.
A standing patient’s NIBP on the arm is 134/92. The distance between the patient’s knee and the NIBP cuff is 120cm. What is the BP in the patient’s knee?
120 x 0.77 = 92.4
134 + 92
92 + 92
Patient’s “knee” BP standing up is 226/184
What is the Bezold-Jarisch reflex?
Cardiac inhibitory reflex resulting in signification HoTN & ↓HR.
r/T venous pooling (decreased preload) & hypercontractile ventricle
- can prevent by giving zofran upfront
What are possible complications of a brachial plexus block?
- Respiratory depression
- Horner Syndrome (SE)
- Hoarseness
- Dysphagia –> aspiration
Why can respiratory depression occur with brachial plexus blocks?
Hemidiaphragmatic Paresis from Phrenic nerve blockade.
What is the triad of Horner Syndrome?
- Ptosis
- Miosis
- Anhydrosis
Postop concerns for shoulder surgery (3)
assess for nerve injury
pain management (opioid/regional)
delirium/confusion (elderly)
What commonly regional blocks do elbow surgeries require?
infraclavicular and axillary
** The brachial plexus block might not cover the elbow
What are the cardiac consequences of a lateral decubitus position? (2)
*Cardiac output remains unchanged unless venous return is obstructed (e.g. kidney rest).
*Arterial BP may fall as a result of decreased vascular resistance (right side > left side).
What are the respiratory consequences of a vented pt in lateral decubitus position?
(VQ mismatch)
- ↓ ventilation of dependent lung.
- ↑ perfusion of dependent lung.
- further decreases in dependent lung ventilation with paralysis and open chest
During mechanical ventilation in left lateral decubitus patient, which lung is overventilated?
Right lung (nondependent lung)
During mechanical ventilation in left lateral decubitus patient, which lung more perfused?
Left lung (dependent lung)
What are the respiratory consequences of pt in lateral decubitus position who is spontaneously breathing?
increased ventilation of dependent lung (no V/Q mismathc)
Where is an axillary roll placed on a lateral decubitus patient?
Caudad to the axilla to avoid compression of the neurovascular bundle.
** axillary roll displaces the head of the humerus against the brachial plexus (stretch and compression)
How is the upper arm placed during lateral decubitus?
the upper arm can rest on pillows or be placed in a padded support bar ( Allen arm rest), making sure not to stretch the brachial plexus
how should the neck be in lateral decubitus?
keep the neck in normal alignment via shea, pillow, or donut
** check that there is no pressure on the dependent eye and that the dependent ear is flat against the head.
How should the legs be positioned while in lateral decubitus?
-pillow placed btw the knees,
-dependent leg should be flexed slightly to pad bony prominences and lessen stretch on nerves.
** check breast and genitalia is free of pressure as well
When using an inflated bingbag during lateral decubitus, what effects does it have on respiration?
pushing abdominal contents cephalad –> decreased Vt & FRC and increases closing volume
Where should a pulse oximeter be placed in a lateral decubitus patient?
Dependent hand to ensure that there is no neurovascular compromise
Elbow surgeries need what additional block (in comparison to shoulder surgeries) ?
Musculocutaneous nerve
- most commonly missed
When a surgery requires a tourniquet what all do you need to document?
- inflation and delfation time
- total inflated time
- inflation pressure and any changes
Post op considerations for elbow surgery
-Pain management: (opioids/ NSAIDS/regional)
-immobility
Preop considerations for forearm to hand surgeries (4)
- preexisting nerve conduction issues
- fracture?
- Nerve impingement
- Traumatic amputation
- Typical assessment: head to tow or system to system
Positioning for forearm/hand surgeries
Supine w/ hand table
What blocks are used for forearm/hand surgeries
Axillary (supplement musculocutaneous nerve) & Bier block
Postop considerations for forearm/hand surgeries
pain management and immobilization
Is a patient with a hip fracture induced on the OR table or on the bed/stretcher?
Bed/Stretcher to avoid pain from movement to OR table.
Hip fracture mortality for
-initial hospitalization
-1 year
-initial hospitalization: about 10%
-1 year 25-30%
Why is the morality rate much higher at 1 year for hip fractures?
immobility and sedentary life style significanlty increases the risk of
-Cardiac and pulmonary conditions
-DVT
-Delirium
Preop: hip fracture (6)
Pain management
*Early surgery = lower pain
scores
Intravascular fluid status
Hgb & Hct
Central line & arterial line?
Baseline VS
*SpO2 on room air
Full stomach?
What is the position for hip fracture surgeries?
supine with fracture table
Postop consideration for hip fractures (4)
pain managment
mental status
blood transfusion
ICU admission?
What are the benefits of neuraxial anesthesia for hip fracture repairs?
- ↓ delirium
- ↓ DVT
- ↓ hospital stay
- Better pain control
Preop: total hip arthroplasty (4)
-mental status (confusion/delerium)
-Labs: H&H/anti-coagulation
-medications
-typical assessment
Etiology: total hip arthroplasty (8)
Osteoarthritis
Rheumatoid Arthritis
Degenerative Synovium or Cartilage Disease
Avascular Necrosis
Tumors
Congenital Deformity
Dislocation
Failed Reconstruction
What are the three life-threatening complications of total hip arthroplasty?
- BCIS: bone cement implantation syndrome
- Hemorrhage (Intra and postoperative)
- VTE
What is the position for THA?
Lateral decubitus
-operative side up, padding, axillary roll
What are the benefits of neuraxial anesthesia for Total hip arthroplasty?
-decreased EBL
-Decreased DVT and PE incidence
-Decreased incidence of postop delirium
*Most hips get a spinal with hydromorphone or doromorph
Is muscle relaxation required in THA?
Yes
What chemical is bone cement?
PolyMethylMethAcrylate (PMMA)
What does bone cement do when introduced to the intramedullary bone surface?
Release heat and pressurize (Intramedullary HTN >500mmHg!)
This can lead to possible embolization of fat, bone marrow, and cement.
If cement is systemically absorbed, what happens?
-vasodilation, decreased SVR –> HoTN
-Plt aggregation: r/t tissue thromboplastin release
-Microthrombus in lungs
-CV instability
Prevention of BCIS (5)
o Minimize hypotension & hypovolemia
o Maximize FiO2 (100%) & SpO2
o Vent hole in femur
o Lavage of femoral shaft
o Avoid bone cement
S/S of BCIS (5)
hypoxia
hypotension
arrhythmias
pulmonary HTN
Decreased CO
What is the anesthetic management of BCIS?
- ↑ FiO₂
-Maintain euvolemia
-Manage HoTN with vasopressors
What are the most common complications post THA? (5)
-Cardiac events
-PE
-Pneumonia
-Respiratory failure
-infection
Indications for hip arthroscopy (4)
Femoro-acetabular impingement
Acetabular labral tears
Loose bodies
Osteoarthritis
Positioning for hip arthroscopy
supine w/ weighted traction
other equipment
What are the 8 pressure points you worry about when pt is in the supine position?
-Toes
-heel
-thighs
-sacrum
-elbow
-humerous
-vertebrae
-occiput
What are the cardiac physiological changes when a pt is lying supine?
*equalization of pressures throughout the arterial system
*increased right-sided filling and cardiac output
*decreased heart rate and peripheral vascular resistance (PVR)
What respiratory physiological changes occur in supine ?
*Gravity increases perfusion of dependent (posterior) lung segments
*abdominal viscera displace diaphragm cephalad
*FRC decreases (~800 mL) and may increase/fall below CV (closing volume) in older patients
*further exacerbated by an enlarged abdomen such as with obesity, pregnancy, or ascites.
In a supine position, spontaneous ventilation favors _______ lung segments, whilst closing volume favors ________ lung segments.
Dependent ; independent
The most common postoperative peripheral neuropathy is:
a. Ulnar neuropathy
b. Brachial plexus injury
c. Median nerve injury
d. Sciatic nerve compression
a. Ulnar Neuropathy
Where are the two major sites of injury in ulnar nerve injury?
Elbow at the condylar groove and cubital tunnel.
How is the condylar groove formed?
*the medial epicondyle of the humerus
*the olecranon process of the ulna.
*The ulnar nerve is shallow at this point pre-disposing to compression injury, especially in males where there is less protective adipose tissue
How is ulnar nerve injury avoided?
Supinate hands (palms up!)
Preop hip dislocation (4)
NPO status
Comorbidities
Intravenous fluid status
Require closed reduction
What common drugs are often used for “conscious sedation” of a hip dislocation?
Ketamine/Propofol Mix
Succinylcholine
Postop management of hip dislocation
Pain management
mental status
- may be admitted for observation
Positioning for knee arthroscopy
supine with knee flexed
is neuraxial anesthesia common for knee arthroscopy?
No, it is a quick procedure and neuraxial can delay discharge
usually sedation with extraarticular and intraarticular injections
Post op pain management is typically what for knee arthroscopy?
peripheral nerve block or injections by the surgeon
Preop: Total knee arthoplasty
Mental status
*Confusion/delirium
Labs
*Hgb & Hct
*Coagulation
Medications
Typical assessment
Anesthesia management: TKA
-position
-general
-Neuraxial
-Peripheral nerve block (2)
-tourniquet applied:
-position: supine
-general
-Neuraxial: preferred * spinal
-Peripheral nerve block (2)
-femoral & sciatic
-tourniquet applied:
-blood loss begins w/d
deflation
-risk of peroneal nerve palsy
What are the possible complications of tourniquet placement for knee surgeries?
- Blood loss on deflation (note for 24hrs)
- Peroneal Nerve Palsy
What are the 4 artificial components to a TKA (Total Knee Arthroplasty) ?
- Tibial Component
- Femoral Component
- Patellar Component
- Plastic Spacer
There is significant post op pain after a TKA. What are some pain management considerations?
indwelling epidural catheter
continuous peripheral nerve block
What three conditions (that anesthesia can control) are most often associated with wound infections?
- Peri-operative glucose control
- Post-op hypoxia
- Post-op hypothermia
What are techniques that can be implemented to decreased risk of wound infections in the OR? (4)
-Decrease traffic in and out of the OR
-prep & drape
-preop abx
-use of hoods
Preop: amputation
comorbidities:
-diabetics: FBS
-pressure ulcers
Full sensory assessment
psychological support
positioning for amputation
supine
** make sure there is appropriate padding for obese and cachectic pts
is general or neuraxial anesthesia preferred for amputation?
neuraxial dt decreased incidence of delirium and potentially less phantom pain
When can phantom pain occur after amputation
a few days of surgery
** can feel like shooting, stabbing, squeezing, burning, or throbbing pain (C-fibers and A-delta fibers)
what are some triggers for phantom pain?
weather changes
emotional stress
pressure on the remaining area
What are some causes of phantom pain? (5)
Remapping of circuitry
Damaged nerve endings
Scar tissue
Physical memory
Pain prior to amputation
TX of phantom pain
biofeedback
relaxation
massage
TENS unit
medication
What medication classes can be used to treat phantom pain from amputation?
- Neuroleptics
- Antidepressants
- Na⁺ channel blockers
What position is the pt in for an achilles tendon repair?
lateral or prone
** all other ankle/foot procedures are usually done supine
Ankle and foot procedures can be done with three different anesthetic approaches. What are they
General, neuraxial or regional
What are the 5 nerves that innervate the foot?
Posterior tibial nerve
Saphenous nerve
Deep peroneal nerve
Superficial peroneal nerve
Sural nerve
What nerve innervates the plantar surface?
Posterior Tibial nerve
What nerve innervates the medial malleolus?
Saphenous nerve
What nerve innervates the interspace between the great & 2ⁿᵈ toes?
Deep Peroneal nerve
What nerve innervates the space between the dorsum of the foot and the 2ⁿᵈ - 5th toes?
Superficial peroneal nerve
What nerve innervates the lateral foot and lateral 5th toe?
Sural nerve
Postop management for foot/ankle surgery
pain management
immobilization
*typically outpatient surgery
