Orthopedics- Lower Flashcards
1
Q
What are some important things to consider regarding ortho procedures for the lower extremities?
A
- Goal is to have post-operative analgesia that allows for rapid post-op rehabilitation
- Reduce post-op morbidity and mortality d/t DVT and PE
- Total hip 42-57% DVT and 0.9-28% PE
- Total knee 41-85% DVT and 1.5-10% PE
- Hip fx 46-60% DVT and 3-11% PE
- Use LMWH and coumadin- anticoagulation sometimes started intra-op. Think about this when selecting neuraxial anesthesia!
- given 10 days for knees and up to 35 days post hip
2
Q
What is an arthroplasty of the hip?
A
- Large incision from iliac crest to mid-thigh
- Muscle relaxation needed to access joint (spinal is ideal)
- Femoral head is dislocated from acetabulum
- Arthritic femoral head and portion of neck is excised
- Acetabulum and femoral canal reamed to accept cemented metal/plastic prosthesis
- fat and emboli can occur during this process
- Cup, ball and stem replace femur head
- blood loss 500-1,000 ml
- Hgb threshold for replacement <10 conservative or <8 studies show no difference in outcomes
3
Q
Anesthesia management for hip arthroplasty:
pre-op
monitoring
positioning
A
- Pre-op
- D/C anti-inflammatory meds at least 1 week prior
- assess cervical flexion and extension and TMJ
- Type & Cross
- Monitoring
- Elderly w/underlying disease
- Cardiac function is difficult to assess pre-op d/t decreased mobility
- A-line, CVP?
- Careful fluid managment
- Look for signs of emboli
- hypoxia
- Positioning
- Lateral decub
- V/Q mismatch
- neurovascular complications
- keep head and shoulders neutral
- dependent arm abducted on padded arm rest
- axillary artery- use roll
- femoral nerve injury
- Lateral decub
4
Q
Anesthetic for Hip Arthroplast
GA
A
- Can do GA,
- good for muscle relaxation but need post-op pain management
- consider with PCA or combined regional
- Pt may be difficult to position
- ASA status and co-existing disease may be an issue
- Best choice if pt is already anti-coagulated
- good for muscle relaxation but need post-op pain management
5
Q
Anesthetic for Hip Arthroplasty:
Regional
A
- **Regional is anesthetic of choice!
- Neuraxial
- SAB (hypo or isobaric) or epidural
- lumbar plexus block or psoas compartment block
- Femoral nerve block- weakness of quadraceps increases post-operative falls
- Neuraxial
- Adequate IV hydtration to avoid hypotension with sympathectomy
- Considerations:
- pt may be difficult to position
- case length may predispose patient to discomfort
- regional provides post-op pain control
- airway access in lateral decub
6
Q
How can you prevent blood loss during a hip arthroplasty?
A
- deliberate hypotension
- Diltiazem
- nitroprusside
- nitroglycerin
- beta blockers
- regional anesthesia
- Autologous donation
- Cell saver
- Tranexamic acid (TXA)
7
Q
What might a surgeon inject into the periarticular space?
A
- A “surgeon’s Cocktail”
- LA
- epinephrine
- an NSAID
- an opioid
- a corticostaroid
- antibiotic
8
Q
What are the stats on DVTs with Hip arthroplasty?
A
- Morbidity from DVT >50% without prophylaxis
- Morbidity from DVT is 10-20% with anticoagulant and compression device
9
Q
What is Tranexamic acid?
How is it dosed?
Pharmacokinetics?
FDA approval?
A
- Antifinbrinolytic that inhibits conversion of plasminogen to plasmin
- reduces blood loss 29-54%
- Dosing may depend of fibrinolytic response according to the type of surgery
- Optimal dosing is procedure specific
- best given pre-operatively
- Pharmacokinetics:
- low PB (3%)
- Volume of distribution 9-12L
- 5% metabolized by liver
- 95% eliminated unchanged in kidney
- elimiation 1/2 life 2 hours
- FDA approved for hemopheliacs having teeth removed and women with heavy menses
- Still used extensively
10
Q
What is methyl Mehtacrylate?
What are some physiologic changes you may see?
A
- Cement used to bind prosthetic to bone
- cement mixing causes exothermic reaction and expands, causing pressure against bone surface
- this pressure (intramedullary hypertension) pushes fat, air, and marrow into the femoral venous channels
- Physiologic changes seen in 2-17% called bone cement implant syndrome (BCIS)
- decreased SVR
- hypotension
- hypoxia
- arrhythmias
- increased PVR
- loss of consciousness
- cardiac arrest
11
Q
What is the first sign of BCIS?
Treatment?
A
- First sign:
- GA- drop in ETCO2
- Regional- dyspnea or altered sensorium
- Treatment:
- 100% O2
- aggressive fluids
- correct hypotension with alpha agonists
- Before cement:
- 100% O2
- optimize BP- have fluids on pressure bags
- Avoid nitrous!
- document cement timing on record
12
Q
What can post-cement hypotension result in?
When is it common?
What are some possible explanations?
A
- Profound post-cement hypotension can result in cardiac arrest and death
- Uncommon in elective primary total hip replacement but not uncommon in high risk pts
- Possible explanations:
- caused by direct vasodilation or cardiac depression from methylmethacrylate
- Caused by the forced entry of air, fat, or bone marrow into the venous system causing a PE
13
Q
What is the other post-cementing concern?
When can it occur?
Treatment?
A
- Hypoxia
- can occur immediately after insertion or up to 5 days post-op
- In the event of hypoxemia:
- 100% FiO2
- rule out atelectasis of dependent lung, hypoventilation, fluid overload
- Post operative management
- Nasal O2
- pulse oximetry for several days
- manage fluids/diuresis
14
Q
What is fat embolism syndrome?
Treatment?
A
- Most common 72 hours post-op in long bone fracture/surgery
- Symptoms:
- dyspnea
- confusion
- petechial rash on chest
- decreased arterial oxygenation
- EKG changes/tachycardia
- diffuse alveolar infiltrates
- pulmonary edema
- sudden drop in ETCO2
- Treatment:
- possibly early corticosteroid treatment
- otherwise supportive
15
Q
What are the risk factors for venous thromboembolus?
A
- high BMI
- COPD
- anemia
- presence of pre-op DVT
16
Q
What can be done to prevend venous thromboembolus?
A
- D/C procoagulant medication
- autologous blood donation
- hypotensive anesthesia
- Regional anesthesia
- IV heparin during surgery
- aspiration of intramedullary contents
- pneumatic compression
- knee high elastic stockings
- early mobilization
- chemoprophylaxis
17
Q
What does the average femur neck fx patient look like?
What is the fracture table like?
A
- 80 years old, most are women with multiple medical problems
- In- hospital morbidity is 3% and 1 year after 20% have died
- ASA status and age influence mortality
- present with dementia
- Fracture table:
- must pad perineal post
- arm ipsilateral to hip fx on arm board or sling and avoid xray obstruction
18
Q
What does the ORIF of a femur look like
A
- There will be reaming and an implant
- lots of blood loss
- Regional vs GA
- regional (SAB or epidural) reduces perioperative risk of death, pulm complications and DVT by 30-50%
- most common intraop cause of death are MI or PE
19
Q
Knee arthroscopy:
Indication
position
What can be done in conjunction with an arthroscopy?
A
- Indication- diagnose and treat intra-articular problems
- torn meniscus/ACL
- loose bodies
- arthritis
- infections
- Position- supine with foot of OR table lowered for access
- Multiple entry points at knee for scope. Extra incisions may be required for meniscus repairs
- Debridement and meniscectomy can be done in conjunction with arthroscopy
- irrigation fluid 3-5L
- be cautious with CHF
20
Q
Anesthetic considerations for knee arthroscopy?
A
- minimal EBL
- tourniquet not often used
- out patient
- receive abx
- consider general vs regional
- cleaning out of knees dont have much pain
- ACL surgeries are painful
- usually regional for post op pain and GA during operation
21
Q
How is an arhtroplasty of the knee done?
A
- Femur patella and tibia are exposed
- cartilage and bone excised with saw
- new components cemented into place
- tourniquet used
- may have 2 units blood loss without tournequet
- good amount of blood loss after tournequet is removed
- positioning supine
22
Q
What are some considerations for arthroplasty of knee?
A
- Pts often have:
- severe RA
- degenerative OA
- obesity
- other significant co-morbidities
- procedure is 1-3 hours
- post op pain- regional is great option
- morbidity:
- DVT
- Risk of post-op dislocation <35%
- PE 1-7%
23
Q
Optimal analgesia for total knee
A
- Regional-neuraxial and peripheral blocks
- femoral nerve
- saphenous/adductor canal block
- lumbar plexus
- sciatic with femoral
- selective tibial
- obturator
- Tourniquet usually 100 mmHg above SBP
- must block all 4 nerves for tourniquet pain
- femoral
- lateral femoral cutaneous
- obturator
- sciatic
- must block all 4 nerves for tourniquet pain
- Spinal
- hyperbaric (more sensory than needed)
- isobaric
- Epidural with continuous catheter
- PNB- Femoral 3 in one or psoas
24
Q
Foot and Ankle surgery:
position
anesthetic
A
- Position:
- supine or prone (for calcaneous)
- Regional vs GA
- selection of regional technique dependent on use of calf or thigh tourniquet, degree of wt bearing and ambulation post op
- Thigh tourniquet >15-20 min requires GA or neuraxial
- If no thigh tourniquet:
- combined sciatic and femoral
25
Q
General info about above knee amputations:
coexisting disease
surgical procedure
anesthetic management
post-op
A
- Co-existing disease
- DM
- PVD
- CV disease
- trauma
- Surgical procedure
- leg completely excised at distal one third of femur
- supine position
- tourniquet used- no major blood loss
- Anesthetic:
- Regional- epidural + adjuncts (clonidine)
- GA- multimodal (ketamine infusions/opioids)
- Post-op
- epidural- Bupivicaine 0.125-0.25% + Fentanyl 2 mcg/ml
- psych considerations
26
Q
Lower extremity amputations:
surgical description
anesthetic considerations
A
- Surgical description
- AKA: distal 1/3 portion of femur removed, stu,p fashioned with flap for prosthetic
- traumatic AKA- stump not fashioned, return to OR every 1-3 days
- BKA: mid leg portion removed
- AKA: distal 1/3 portion of femur removed, stu,p fashioned with flap for prosthetic
- Anesthetic considerations
- Gangeree, sptic, chronic disease, trauma
- 250 ml EBL
- mortality 10-20%
- morbidity: phandom limb (most common), infection, PNA, MI, Emboli, CVA
27
Q
What is the Psoas block?
A
- Femoral, lateral cutaneous block, obturator nerve
- motor and sensory to hip, anterior thigh, knee
- sensory to medial upper and lower leg and ankle
28
Q
Sciatic nerve
roots
location
motor
sensory
A
- Nerve roots L4-5 + S1-3
- exits the pelvis at greater sciatic foramen
- travels under gluteus maximus
- separates mid thigh into tibial and common peroneal nerves
- Motor: posteror thigh, leg, and foot
- Sensory: skin of posterior thigh/knee, lateral leg and foot
29
Q
Sciatic nerve block:
indications
advantage
disadvantage
A
- Indications:
- anesthesia/analgesia to posterior distal thigh, posterior knee, lower leg/ankle/ foot
- Advantage:
- complete block of leg when combined with femoral nerve block
- Disadvantages:
- Deep nerve structure, difficult to identify
- motor blockade can limit postop mobility and physical therapy
30
Q
Blocking the _______ nerve causes foot drop.
A
Common peroneal
31
Q
Femoral nerve block:
motor innervation
sensory innervation
indications
A
- Motor to quads and sartorious
- Sensory to anterior thigh, anterior/medial knee, medial lower leg and ankle
- Indications:
- surgery to anterior thigh
- quadriceps muscle bx or quad tendon repair
- knee arthroscopy/ACL, AKA. BKA or TKR
- complete block of lower extremity when combined with sciatic nerve block
32
Q
Popliteal nerve block
What nerves?
indications?
advantages?
A
- Tibial and common peroneal
- indicated for ankle and foot surgery
- Advantages:
- spares posterior thigh muscles
- facilitates early physical therapy and ambulation
33
Q
Adductor canal block
nerve?
indications
advantages
A
- Saphenous nerve (branch of femoral)
- anterior, medial knee sensory
- medial lower leg and ankle sensory
- indications:
- Knee analgesia (TKA, ACL, foot/ankle)
- Advantage
- spares quadricep motor
- allows for early ambulation
34
Q
What is the iPACK block?
A
- blocks pain at posterior compartment of knee by anesthetizing the perforating branches of the sciatic nerve to periosteium without causing foot drop
- useful in ACL repair or patella tendon harvest or Total knees
- Common peroneal nerve palsy (CPNP) occurs 0.3-0.4% after TKA
35
Q
Ankle block
nerves
needle/volume
epi?
A
- nerves:
- posterial tibial
- deep peroneal
- saphenous nerve
- superficial peroneal
- sural nerve
- 22G B-bevel 38 mm needle
- 5-7 ml pernerve
- NO EPI
36
Q
Guidelines for neuraxial anesthesia and anticoagulants:
LMWH
Sub Q heparin
IV heparin
A
- LMWH
- 12 hours after prophylactic dose
- 24 hours after treatment dose
- catheters removed at least 2 hours before starting BID dosing
- Catheters can remain for once/day dosing, but when removed should come out 10 hours after previous dose
- Subcutaneous heparin
- 10,000 u/day or less, no contraindications
- >10,000 u/day, use caution
- check platelet count if on heparin more than 4 days
- IV Heparin
- stop 2-4 hours prior to catheter removal
- wait 1 hour after neuraxial block or catheter removal before administering
37
Q
ERAS in joint arthroplasty
pre-op education
intraoperative techniques
A
- Pre-op education
- nutrition
- carb loading, liberal fasting rules
- optimization of anemia
- active prewarming of OR
- preemptive oral analgesia
- nutrition
- Intraoperative anesthetic techniques
- regional
- short acting sedatives
- goal-directed fluid therapy
- normothermia
- blood conservation
- antibiotic prophylaxis
- postoperative analgesia
38
Q
Post operative ERAS
A
- multimodal opioid sparing analgesia
- regional, NSAIDS, acetaminophen
- PONV prophylaxis
- early mobilization
- early po intake
39
Q
What is included in multi-modal analgesia in orthopedic surgery?
A
- acetaminophen
- NSAIDS
- gabapentin
- methadone or tramadol
- ketamine
- lidocaine
- dexmedetomidine
- beta blockers
