Orthopedic Anesthesia 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?
50-100mg hydrocortisone (Solu-cortef)
(Also Decadron)
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 (hoarseness)
- Cricoarytenoid arthritis
Where is the most instability typically located in the cervical spine of RA patients?
Atlantoaxial Junction (C-spine)
(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 intervention could be done if atlantoaxial subluxation does occur?
Eval C-Spine and CXRs
RA
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 issues with the following body systems are an anesthesia concern in RA patients?
Vascular:
Cardiac:
Renal:
GI:
Vascular: Vasculitis
Cardiac: Pericarditis, Tamponade
Renal: Insufficiency
GI: Gastric Ulcers (NSAID use)
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
Thromboembolic hypoxic resp. failure
How much cricoid pressure shoud we provide for trauma intubations?
10 lbs
aka Sellick Maneuver
What is the correct dose of Roc for a truama intubation?
1.2 mg/kg (RSI)
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?
- Hypoxemia
- Hypotension
- Hypercarbia
- Sleep Deprivation
- Hypervolemia
- Infection
- Electrolyte abnormalities
- Pain
- Benzos
- Anticholinergics
- Circadian Rhythm disruption
SHIP BEACHHH
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
- Blood Loss
- Respiratory complications
- Death
With placement of what device is fat embolism syndrome most likely to occur?
Femoral Medullary Canal Rod
How likely is FES?
Mortality?
<1%
10-20%
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
Based on the patho of FES, where are the fat emboli and bone marrow particulates specifically obstructing?
End organ capillaries
Pulmonary Complications d/t FES:
Pulm Endothelial Cell injury
Pulm Edema
Mild Hypoxemia
Alveolar Infiltrates
ARDS (<10%)
Where can a petechial rash develop with FES?
- conjuctiva
- Oral mucosa
- skin folds of chest
- neck
- axilla
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?
- 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 has been given?
Yes, if 10 - 12 hours after the dose.
Delay next dose 4 hours.
Can an epidural be placed in a patient on LMWH anticoagulation therapy?
No. No indwelling catheters
Neuraxial catheters must be removed ___ hours before the intiation of LMWH therapy.
2 hours
Can a patient have neuraxial anesthesia if on warfarin?
Only if the INR is ≤ 1.5
How long must we wait to perform a spinal injection after the last dose of:
Full dose SQ Heparin:
5-10 mg Fondaparinux:
40 mg SQ Lovenox:
Full dose SQ Heparin: When aPTT is <40 or 6 hrs
5-10 mg Fondaparinux: Contraindicated (36 hrs for 2.5 mg)
40 mg SQ Lovenox: 12 hrs
How long must we wait to perform a spinal injection after the last dose of:
Dabigatran:
ASA:
Plavix:
Prasugrel:
Ticlopidine:
Dabigatran: 7 days
ASA: No wait time
Plavix: 7 days
Prasugrel: 7 days
Ticlopidine: 14 days
How long must we wait to perform a spinal injection after the last dose of:
Tirofiban:
Eptifibatide:
Abciximab:
TPA full dose:
Tirofiban: 8 hrs
Eptifibatide: 8 hrs
Abciximab: 48 hours
TPA full dose: 10 days
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 type of procedures were mentioned in lecture in which TXA is frequently used?
Total Knee and Total Hip
What is typical dosing of TXA?
10 - 30 mg/kg
1000mg is typical
Tourniquet pain typically begins ___ minutes after application.
45 min
C Fibers start to fire (slow)
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
*Bier Block
What occurs with tourniquet deflation?
- Transient lactic acidosis
- Transient Hypercarbia (thus V̇T)
- ↑ HR
- ↓ pain
- ↓ CVP, BP, & temp
What are some important points of assessment necessary for upper body procedures preoperatively?
- Baseline vitals
- Airway
- Pre-existing nerve conduction issues
- Examine pupils
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
Describe the process of venous air embolism from entrance into the system down to death.
- Surgical site higher than the heart = air will enter the RV
- Blood from the pulm. artery is interfered with, therefore pulmonary edema and reflex bronchoconstriction can occur
- Air could reach cerebral circulation via foramen ovale
- Death via CV Collapse and arterial hypoxemia
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 support with pressors
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.
How can we mitigate the effects of the Bezold-Jarisch reflex?
Increase Preload
Preemptive Zofran I guess..?
What are possible complications of a brachial plexus block?
- Respiratory depression
- Horner Syndrome
- Hoarseness
- Dysphagia
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
Why might we see a decrease in CO with patients in Lateral Decubitis position?
Obstructed venous return d/t the use of a kidney rest
What are the respiratory consequences of a lateral decubitus position?
(VQ mismatch)
- ↓ ventilation of dependent lung.
- ↑ perfusion of dependent lung.
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)
Where is an axillary roll placed on a lateral decubitus patient?
Caudad to the axilla to avoid compression of the neurovascular bundle.
Where should a pulse oximeter be placed in a lateral decubitus patient?
Dependent hand to ensure that there is no neurovascular compromise
What can be used to avoid brachial plexus stretching in upper arm procedures while in lat. decubitus.
Allen’s Arm rest
Elbow surgeries need what additional block (in comparison to shoulder surgeries) ?
Musculocutaneous nerve
Regional methods for forearm to hand procedures?
- Axillary Block
- Bier Block
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.
What are the benefits of neuraxial anesthesia for hip fracture repairs?
- ↓ delirium
- ↓ DVT
- ↓ hospital stay
- Better pain control
What are the three life-threatening complications of total hip arthroplasty?
- BCIS
- Hemorrhage
- VTE
What chemical is bone cement?
PolyMethylMethAcrylate
What does bone cement do when introduced to the intramedullary bone surface?
Release heat and pressurize (500mmHg!)
Possible embolization of fat, bone marrow, and cement.
Does the use of PMMA cause:
Increased or Decreased SVR?
Coagulation or Anticoagulation?
Decreased SVR
Coagulation (PLT Aggregation from thromboplastin release)
What is the anesthetic management of BCIS?
What about things the surgeon can do?
- Combat ↓BP and ↓Volume
- ↑ FiO₂ & SpO₂
Surgeon:
- Vent Hole in femur
- Lavage of femoral shaft
What are the s/s of BCIS?
- Hypoxia
- Hypotension
- Arrythmias
- pHTN
- ↓CO
Indications for a Hip Arthroscopy:
- Femoro-acetabular impingement
- Acetabular labral tears
- Loose bodies (fragments)
- Osteoarthritis
Per Dr. Castillo, what are the pressure points we should know in the supine position?
- Toes (from the bed sheets)
- Heel
- Thighs
- Sacrum
- Elbow
- Humerous
- Vertebrae
- Occiput
Cardiac changes that are possible in the supine position:
- increased CO, Right-sided filling pressures
- Bradycardia
- Decreased PVR
In a supine position, spontaneous ventilation favors _______ lung segments, whilst closing volume favors ________ lung segments.
Dependent ; independent
In the supine position, where does the diaphragm shift towards?
Cephalad
FRC might ___ in older patients.
It may be drastically changed however, in these 3 patient populations.
DECREASE (below closing volume)
- Pregnant
- Obese
- Ascites
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 ulnar nerve nerve injury avoided?
Supinate hands (palms up!)
What common drugs are often used for “conscious sedation” of a hip dislocation?
Ketamine/Propofol Mix
Succinylcholine
What are the possible complications of tourniquet placement for knee surgeries?
- Blood loss on deflation (note for 24hrs)
- Peroneal Nerve Palsy
What are the steps to a TKA (Total Knee Arthroplasty) ?
- Tibial Component
- Femoral Component
- Patellar Component
- Plastic Spacer
What three conditions (that anesthesia can control) are most often associated with infection of knee replacements?
- Peri-operative glucose control
- Post-op hypoxia
- Post-op hypothermia
Non-pharmacologic tx for phantom pain:
- Biofeedback
- Massage
- Relaxation
- TENS unit
What medication classes can be used to treat phantom pain from amputation?
- Neuroleptics
- Antidepressants
- Na⁺ channel blockers
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 saphenous nerve
What nerve innervates the lateral foot and lateral 5th toe?
Sural nerve
