Exam 1: Orthopedic Anesthesia Flashcards
What are the two biggest factors associated with development of osteoporosis?
- Elderly age
- Menopause/post-menopause
What hormonal changes are characteristic of osteoporosis?
- ↑ PTH
- ↓ Vit D
- ↓ HGH
- ↓ Insulin-like growth factors
I Prefer High D’s
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
Medical management for Osteoarthritis
- NSAIDS: meloxicam
- COX2 inhibitor: celebrex
- Topical treatment (voltarin is now a over the counter drug)
- Intra-articular therpy (steroid injection)
- Chondroprotective agents
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.
What arthritis is 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)
C? Reggie Acts Entitled
What common dose of stress dose glucocorticoid is used for RA patients?
50 - 100mg hydrocortisone (Solu-cortef) or dexamethasone
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 i.e the dens 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
NHEBs
What are the signs/symptoms of vertebral artery occlusion?
- N/V
- Dysphagia
- Blurred Vision
- Transient LOC changes
Naked Dicks Be Loose
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
Additional anesthesia concerns for RA:
- vascular
- cardiac
- GI
- Renal
- Vasculiltis
- Pericarditis or cardiac tamponade
- Gastric ulcers
- Renal insufficiency
Preop eval for RA
- Joint involvment
- neuro assessment (where is the numbeness and tingling)
- pain level at BL
- surgical positioning and mobility
- consider the type of anesthetic (regional and pt comfort, ability to remain still for procedure, post ROM)
always establish the baseline in preop
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
ABCD’s of trauma anesthesia (how to do a trauma RSI)
- MILS
- preoxygenate (100% 10-15L/min for 3 mins minimum) can preoxygenate before putting on monitors in this case
- cricoid pressure sellick maneuver/BURP (10lbs of pressure
- induction with medications (ketamine or etomidate then muscle relaxation)
- apenic ventilation (careful with modified RSI)
- DL or LMA after 3 attempts
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 (Castillo says debatable)
- Anticholinergics
- Circadian Rhythm disruption
Pre-op eval of lungs
- age related:
- decreased PaO2
- increased closing volume
- FEV1 decreases
- Obesity
- OSA (stop-bang questionnaire)
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 (IM nail/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
C? Dis Persnickety
What lab findings are noted with fat embolism syndrome?
- Fat macroglobulinemia
- Anemia
- Thrombocytopenia
- ↑ ESR
Ees FAT
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
Jill Has Fewer Rashes
What are the anesthetic management techniques for fat embolization syndrome?
Supportive Therapy early recognition
- stabilization of fracture
- 100% FiO₂
- No N₂O
- IV Heparin
- Aggressive and early CV & Resp support (could pregress to ARDS yikes)
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
Castillo hinted this would be on the test
Can neuraxial anesthesia be done after LMWH has been given?
Yes, if 10 - 12 hours after the dose.
Delay next dose 4 hours and remove catheter 2+ hours before next dose
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
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 - 30 mg/kg
1000mg is typical
adminstered before incision (think about single dose vs repeated dose)
Tourniquet pain typically begins ___ minutes after application.
45 min
The width of a tourniquet must be greater than ____ its diameter.
½
apply over padding and exanguinate the limb before inflation
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 cuff first → deflate distal cuff first
Primero Proximao
Duo distal
What occurs with tourniquet deflation?
- Transient lactic acidosis
- Transient Hypercarbia (thus increase V̇T)
- ↑ HR
- ↓ pain
- ↓ CVP, BP, & temp
Hyper LA Hides Panicked BalTiCs
Lecture 2 start
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
If the surgical site is higher than the heart, its possible to entrain air into the open vessels and cause an air embolism
Treatment for Venous air embolism
- Tell surgeon so they prevent further entraning of air
- apply occlusive dressing
- D/C N2O
- Bilateral compression of jugular veins
- Tburg position to trap air in R atrial apex (prevents enterance to pulm. art.
- withdraw air from central line if its already there (dont place a new one)
- CV collapse will need pressors
The doppler US transducer can be used to indicate a VAE in a sitting pt, where do you place the probe on the chest?
- over RA
at the 2nd or 3rd intercostal space to the right of the sternum (most sensative non-invasive indicator of VAE)
Most definative is still a TEE
What is the characteristic sound of a VAE, and most characteristic monitor change?
- sound = mill-wheel murmur
- Monitor change = sudden decrease in EtCO2 (decreased perfusion to lungs)
In what percent of the population is a patent foramen ovale present?
20 - 30 %
____ 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.
this is at the level of that damn Willis Suurkle
Sometimes the hammer-dudes want us to lower the BP so they can see the surgical site better, 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?
Castillo’s way: 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.
Easier way: just remember 7.410pH i.e. for every 10cm change from the heart, the pressure changed by 7.4mmHg
40cm away = 4 x 7.4 = 29.6
120-29.6 ~90
70-29.6 ~ 40
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.
The Bezold–Jarisch reflex is an alternate explanation for the bradycardia that often accompanies hypotension after neuraxial anesthesia. This reflex is mediated by 5HT-3 serotonin receptors located in the vagus nerve and in ventricular myocardium. Activation of these receptors in response to systemic
hypotension increases efferent vagal signaling, producing bradycardia, reduced cardiac output, and worsened hypotension.
Several groups have studied the effects of HT-3 receptor antagonists like ondansetron on the hemodynamic effects of neuraxial anesthesia. Meta-analysis of these results suggests that ondansetron may halve the risk of subarachnoid anesthesia-induced hypotension
How do we avoid the Benzold-Jarisch?
Increase preload and give zofran upfront
What are possible complications of a brachial plexus block?
- Respiratory depression
- Horner Syndrome
- Hoarseness
- Dysphagia
Reggie Horner, Horse Doctor
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
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. (Displaces the humeral head away from the brachial plexus)
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
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 (bone cement implantation syndrome)
- 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.
What is the anesthetic management of BCIS?
- Combat ↓BP and ↓Volume
- ↑ FiO₂ & SpO₂
What are the s/s of BCIS?
- Hypoxia
- Hypotension
- Arrythmias
- pHTN
- ↓CO
High High CO And Puffs
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 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
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 Peroneal nerve
What nerve innervates the lateral foot and lateral 5th toe?
Sural nerve
