Ortho - Exam 7 Flashcards
Benefits of tourniquet use:
-bloodless field for extremity surgery
-minimize blood loss
-identification of structures
-expedites procedure
Methods to prevent tourniquet complications:
-put on area where nerves are best protected in underlying muscle
-test equipment before use
-use for no longer than 2 hrs
-WIDEST cuff possible (occlude blood with less pressure needed)
-minimum of 2 layers of padding around extremity
-best skin protection is seen with elastic stockinette
-should allow for 2 fingers between padding and cuff
-extremity should be exsanguinated before cuff inflation (often w Esmarch bandage)
-minimal effective pressure should be used
-UE: 70-90mmHg more than pt’s SBP
-LE: 2x pt’s SBP
-Bier block: minimum of 250mmHg (unless placing on pt’s upper leg)
-Bier block (upper leg): 2x pt’s SBP (less than 300mmHg tho)
Tourniquets are typically applied _ (before/after) initiation of anesthesia.
after
T/F Time of tourniquet inflation only needs to be documented in the OR record.
False,
anesthesia record as well
Built in timer on tourniquets are generally set at _ mins
60
Max time for tourniquet inflation on an extremity is _ hrs.
2
Deflation of the tourniquet can result in release of metabolic waste into the plasma, potentially causing:
MYONEPHROPATHIC METABOLIC SYNDROME
-metabolic acidosis (transient)
-acid metabolites released (thromboxane)
-hyperkalemia
-myoglobinemia
-myoglobinuria
-renal failure
-changes in hemodynamics and pulse ox (transient)
-decrease in core temp (transient)
-decrease in pulm and arterial pressures (transient)
-decrease in central venous O2 tension (transient, shouldn’t cause systemic hypoxemia)
-INCREASE of EtCO2 (transient)
Systemic changes seen with tourniquet use
-Neuro
-abolition of SSEPs and nerve conduction in 30min
->60 min causes tourniquet pain and HTN
->2hr can cause postop neuropraxia
-nerve injury at level of skin under tourniquet
Systemic changes seen with tourniquet use
-Muscle
-cell hypoxia within 2 min
-cellular creatinine value decreases
-progressive acidosis
->2hr causes endothelial capillary leak
Systemic changes seen with tourniquet use
-Inflation
INCREASE in arterial and pulm artery pressures (minor if only one limb occluded)
T/F Silicon ring tourniquets are best used for longer cases.
false
-brief cases
How is a silicon ring tourniquet removed after a procedure is done?
it is cut off
Which kind of tourniquet is more rapidly applied, silicon ring or pneumatic?
silicon ring tourniquets
What do silicon ring tourniquets lack that pose a patient risk if operator is not paying attention?
lack of a timer
Ischemic pain from tourniquet use is similar to pain from a _ _ occlusion or _ _ disease
thrombotic vascular occlusion
peripheral vascular disease
About _ - _ min after tourniquet pressurization, pts describe a dull ache that progresses to a burning, excruciating pain that often requires GA.
45-60min
-even with GA pain may cause BP and HR to rise to a point of needing meds to fix it
_ fibers are more difficult to anesthetize than _ fibers and so tourniquet pain is more aligned with pain sensations from _ fiber stimulation
C fibers
A delta fibers
C fiber
As LA wears off, activation of _ fibers increases while the _ fibers may remain suppressed.
C fibers
A delta Fibers
Burning and aching pain from tourniquet corresponds with the stimulation of small, slower conducting _ (myelinated/unmyelinated) _ fibers
unmyelinated C fibers
Pinprick, tingling sensation qith tourniquet application even after deflation correspond with stimulation of larger, faster _ (myelinated/unmyelinated) _ fibers
myelinated A delta fiber
Potency of bupivacaine is _ (increased/decreased) by increased stimulation of nerves.
increased
-helps with better coverage for lowering tourniquet pain
T/F Blockage at the thoracic sensory level is more important than the bloackade of sacral roots in preventing tourniquet pain
false
-blocking sacral roots > blocking thoracic sensory level
-this is bc pain is from ischemia of the WHOLE leg as well as skin under tourniquet
Postop paresthesia risks from tourniquet use:
-deformation of underlying nerves (myeline stretching too far)
-rupture of Schwaan cell membranes
-avoid this with proper padding and adhering to proper cuff size, pressure, and time constraints
How are the majority of orthopedic operations classified with 30- day cardiac death/myocardial infarction
intermediate risk, 1-5%
after what age is there an increased cardiac risk relating to surgery?
80 y/o. the risk decreases after 2 weeks, though.
What is the Gupta score and what are its main factors?
It is a perioperative risk index measuring the facotrs that are associated with cardiac risk after surgery. Dependent functional status, age, abnormal creatine, and type of surgery are the main factors.
What is the geriatric sensitive perioperative cardiac risk index and what are its 7 variables.
Developed because there are a bunch of old people and there we a need to better index their cardiac risk. The book says there are 7, but then only lists 6.
Stroke history, ASA class, type of surgery, functional status, creatinine, history of heart failure, and diabetes mellitus status
Why is the development of high sensitivity cardiac troponin assays important?
They can detect patients at risk beyond established risk scores and they allow for detection of acute cardiomyocyte injury during the perioperative period
How is perioperative myocardial injury defined?
increase in high sensitivity cardiac troponin of 14ng/L or > from pre-post operative measurements in high risk patients 65y/o or > or in patients 45 years or > with hx of pre existing CAD, PAD, or stroke
What is the most important cardiac risk factor in orthopedic patients?
Conary artery disease
Pulmonary hypertension is hemodynamically defined as a resting mean pulmonary arterial pressure of ____mmHg or greater
25
What are the 5 classified groups of pulmonary hypertension?
- Pts with primary pulmonary arterial hypertension
- Pts with pulmonary hypertension d/t left heart disease
- Pts with pulmonary hypertension due to chronic lung disease and/or hypoxia
- pts with chronic thromboemolic pulmonary hypertension
- pts with unclear, mixed, or multifactorial reasons for pulmonary hypertension.
What increases the morbidity and mortality in patients with pulmonary hypertension undergoing noncardiac surgery?
Major/emergency surgery, long procedure (>3hr), high ASA calss score, concomitant cardiovascular disease, poor exercise tolerance, higher preoperative pulmonary artery pressure, and the diagnosis of primary arterial hypertension.
What should an examination of a patient with pulmonary hypertension focus on?
The nature of symptom progression, exercise tolerance, signs of right ventricle failure, heart rate, blood pressure, ECG, chest CT, BNP, and high-sensitivity cardiac troponins
What are the non-cardiac risk in orthopedic populations?
Preop mental status, level of dependency, anemia, extreme low or high body weight, pulmonary risk factors, and immune status
What is the most common surgical complication in older adults?
Postop delerium
Main risk factors for postop delerium are
> 65 y/o, older chronic cognitive decline/dementia, poor vision/hearing, severe illness, and presence of infection
After age, the most important risk factors for OA are
obesity and joint trauma/malalignment
What type of vision loss is most common in the prone position?
Ischemic optic neuropathy
Osteoarthritis occurs when there is a loss of _____ cartilage and associated inflammation
Articular
T/F: there are systemic manifestations involved in osteoarthritis
False
Heberden nodes: spurring and swelling of ____ joints
distal
Bouchard nodes: spurring and swelling of _____ joints
Proximal
What type of block should be used for forearm surgery with significant ipsilateral shoulder arthritis
Interscaline Block
What is the difference between OA and RA?
Rheumatoid arthritis is autoimmune in nature and affects multiple organ systems. Joint pain is worse with periods of rest and improve with activity
OA does not have systemic manifestations involved. Joint pain worsens with activity
What test is used to diagnose RA?
Pain and stiffness in multiple joints, there is no single test used.
Rheumatoid factor and anti-immunoglobulin antibodies are often elevated
What are airway considerations r/t RA?
Limited TMJ movement (synovitis): may limit mandibular motion and mouth opening
Narrow Glottic opening: arthritic damage to cricoid arytenoid joints may decrease vocal cord movement (hoarseness/stridor), difficult ETT passage
If a RA pt has cervical involvement, how should you intubate them?
Using a glidescope
if a RA pt has cervical instability, how should you intubate them?
Awake fiberoptic intubation. If distance from anterior arch of atlas to odontoid process exceeds 3mm, perform awake fiberoptic with C collar
Ankylosing spondylitis is a chronic inflammatory disease that results in
fusion of axial skeleton
what are the benefits of Regional?
Less risk of DVT/PE
Decreased blood loss
Less respiratory issues
No need for airway manipulation
Better postop pain mgmt
Less N/v
Excellent skeletal muscle relaxation
What “risk” surgery is orthopedic surgery?
intermediate
Which procedures are high risk for fat embolism?
long bone cases messing with fem and medullary canal
Mechanical theory for FES:
embolization of fat and marrow occlude capillaries of end organs entering circulation thru torn vessels
Biochemical theory of FES:
fat emboli lodged in microvasculature is metabolized into FFA which causes systemic inflammatory response causing endothelial damage and ARDS
Triad of FES symptoms
Hypoxemia
Neuro changes
Petechial Rash
(in this order!)
-CNS s/s can develop before resp bc of shunts
FES s/s
tachypnea
dyspnea
hypoxia
-resp ALKALOSIS
BL infiltrates on CXR
ARDS like symptoms
NON DEPENDENT petechial rash (thorax, head/neck, axilla, conjuctiva)
neuro changes
fever
fat in urine
cardiac depression
anemia/thrombocytopenia
coag issues
Difference between PE and FES:
PE:
-no neuro changes
-ARF and R sd HF s/s
-no rash
Difference between Air embolism and FES:
Air:
-IMMEDIATE onset of resp and neuro changes
-ARF s/s
-rarely a rash
Difference between amniotic embolism and FES:
Amniotic
-pt must be pregnant
-seizures, not AMS
-no rash
-CV collapse
Onset of FES:
12-72 hr delay usually
onset is immediate if fulminant
FES tx:
-supportive
-early resusc
-minimize stress response for pt (HoTN, hypoxemia, perfusion)
-intubate before resp failure occurs
-s/s resolve in 3-7 days
-corticosteroids controversial but may help emergently
Most common s/s in FES:
respiratory
-dyspnea
-tachypnea
-hypoxia
Should beta blockers be started in elderly pts before ortho cases and if so, what is target HR?
yes if they’re high risk
80 is target
Best marker for MI, troponin I or CKMB?
Trop I
TXA
-class
-MOA
Class: antifibrinolytic
MOA:
-bind reversibly to PLASMINOGEN at its lysin binding site to inhibit association with fibrin
-inhibit proteolytic activity of PLASMIN
Which patients should avoid TXA?
-hx arterial/ venous thromboembolic disease
-recent cardiac stent
-hx severe ischemic heart disease (NYHA class III and IV)
-hx CVA
-renal impairment
-pregnancy
T/F A form of fat embolism exists in nearly ALL pts following long bone and pelvic fractures and knee/hip replacements.
true
-subclinical form
What would allow a fat embolism to migrate systemically?
PFO or pulmonary shunt
Best preventative method to avoid FES?
early reduction and immobilization of fracture site
Bone cement implantation syndrome (BCIS) s/s
-marked intraop HoTN
-bronchoconstriction
-hypoxia
-abrupt drop in EtCO2 1st s/s in GA
-cardiac arrhythmias
-increased Pulm VR
-RV failure
-arrest
-awake pt: dyspnea altered sensorium
Risk factors for BCIS:
-metastatic disease
-ASA 3+
-previously not instrumented fem canal
-long stem prosthetic (THA>TKA)
-revisions
-THA for a pathologic fracture
-preexisting pulm HTN and RV failure
-large amount of cement use
Mechanisms of BCIS:
-embolization of bone marrow debris to pulm circulation from pressurization of medullary canal
-toxic effects of circulating methyl methacrylate monomer
-release of cytokines and cyclooxygenase during reaming of canal (inducing vasoconstriction and microemboli)
Tx for BCIS
supportive
-may need potent vasopressors/inotropes
-fluids
-mech vent
BCIS prevention/intraop mgmt
-vigorous lavage of canal and drilling vent holes in long bones before insertion (but holes can cause extravasation)
-art line , central line if high risk
-noncement prosthetics
SSEPs monitor the _ portion of the spinal cord.
- Impulses from the periphery (cell bodies in _ root ganglia) ascend via the _ column to synapse in the _.
- Secondary fibers decussate and ascend to the _ _
- Tertiary fibers ascend from the _ to the primary _ _ (postcentral gyrus).
posterior (sensory)
- dorsal, dorsal
- contralateral thalamus
- thalamus, sensory cortex
MEPs monitor the _ portion of the spinal cord.
1.
anterior (motor)
-impulses brain -> periphery
EMG monitors nerve root injury during:
pedicle screw placement
N20 reduces _, while IA increase _
N2O decreases AMPLITUDE
IA increases LATENCY
Cardiac considerations for RA
Pericarditis: characterized by symptoms of RHF (get 2D)
Cardiac tamponade: JVD, narrow pulse pressure, muffled heart sounds
Premature atherosclerosis: leads to 2x more MI/CHF
What is the most common type of arthritis and how is it defined? Who is most prone?
Osteoarthritis, loss of articular cartilage with NO systemic manifestation
Aging! Slightly more women than men
Heberen nodes are swelling of ______ joints, whereas Bouchard nodes are swelling of _______ joints?
Heberen: distal
Bouchard: proximal
If someone is having forearm surgery but has arthritis in their other shoulder, which type of block is most apporpriate?
a. Brachial Plexus
b. Interscalene
B Interscalene
What is rheumatoid arthritis and in which gender is it most prevalant? What does it involve?
Chronic, autoimmune inflammatory disease with systemic manifestations, and in women!
Persistent synovial fluid inflammation and loss of joint integrity
Rheum A
-s/s
-Morning symptoms lasting an hour after moving
-progressing over weeks to months to multiple joints
-Warm, boggy, tender joints with nodules
-Lymph node enlargement
Meds used to treat RA and side effects
NSAIDS or Glucocorticoids
Hyperglycemia, cataracts, osteoporosis
What is atlantoaxial instability and what are the anesthetic implications
Cervical arthritis (C1 and C2)
Flexion of the head can push odontoid process into cspine causing compression of medulla and vertebral arteries, leading to quadriparesis, spinal shock, and death
If distance from and anterior arch of atlas to odontoid process is < 3mm, you should perform what kind of intubation?
Awake fiberoptic with C-collar
What are common cardiac issues (with symptoms) related to RA and associated test?
Pericaridits: friction rub, chest pain, dyspnea, fever, pulsus paradoxus
2D echo
Sjorgen’s Syndrome is:
dry eyes and corneal lesions associated with RA
Treat with tears/ eye lube
What is a pulmonary issue associated with RA and what are the symptoms?
Diffuse interstitial fibrosis (restrictive)
Dyspnea and chronic cough
Achondroplasia and most serious associated complication?
Most common cause of dwarfism
narrowed cervical canal or foramen magnum stenosis - awake fiberoptic!
What is the most common CV complication associated with achondroplasia and what conditions should be avoided intra-operatively to prevent it?
Pulmonary HTN leading to cor pulmonale
Avoid hypoxemia and acidosis
What are the symptoms of post-thrombotic syndrome?
Hypoxemia, pulmonary HTN, recurrent DVTs
Long term treatment of DVT?
Warfarin with INR target of 2.5
(blocks vitamin k dependent coagulation factors)
Contraindication to regional anesthesia
full AC/ DAPT
Do aspirin and NSAIDS increase the risk for epidural hematoma with regional anesthesia?
no
ACL repairs are done with ____ to help prevent PDPH
pencil point needles
What is Transient Neurological Syndrome? What are the symptoms? With what method and medication is this most common?
How do you treat it?
Pain in gluteal region that can radiate down the legs within 24 hours after neuraxial anesthetic - can last 2-5 days and be mild to severe.
Most common with spinal with lidocaine
Treat with NSAIDs
Hip arthoscopy is done in which two positions and with what extra tool?
supine or lateral
-50-75lb of traction
What surgery has the greatest risk of death from PE?
hip fracture
What is the mortality rate for pelvic fractures and what is it often related to? What are the symptoms of this condition?
14% r/t retroperitoneal bleed
hypotension and increasing abdominal girth
Optimal repair for a pelvic fracture is ______?
1 wk of trauma
What is the preferred method of anesthesia for pelvic fracture? What nerve injury are you looking to prevent by adding neuromonitoring?
GA + epidural postop
sciatic n injury
Pelvic fracture repair comes with a high risk of _____, and therefore the placement of _______ before surgery may be indicated?
PE/DVT
IVC filter
What are signs and symptoms of BCIS? Which will come first?
Abrupt decrease in ETCO2 (first)
Hypoxia
Hypotension
Altered mental status
Are hips or knees at greater risk for BCIS?
hips
Most common complications of hip or knee scopes?
cardiac events, PE, PNA, infection
In lateral decubitus, what is a major positioning concern? How do you prevent it?
excessive pressure on axillary artery and brachial plexus by the dependent shoulder
Placing a roll or bad under the upper thorax
What is the ideal anesthetic for a hip or knee scope?
SAB with controlled HoTN (MAP 50-60)
When a total hip is done via the anterior approach, what nerve is at risk and what are the symptoms of injury?
Lateral femoral
Loss of sensations of the upper and lateral thigh
Blood loss continues for _________ after deflation of tourniquet
24h
What nerve injury can occur with extensive tourniquet use? How can this be prevented?
peroneal n palsy >120 min
deflate for 30 min, allow for reperfusion
Where on the tourniquet cuff is nerve damage maximal?
Distal and proximal ends
What hemodynamic pressures will increase 30-60min after tourniquet inflation? In what patients is this more pronounced?
MAP and PAP
In patients undergoing balanced anesthesia that does NOT include IA
Most common nerve injuries related to upper and lower tourniquet use?
Upper: radial
Lower: peroneal
What kind of blockade can be used for foot and ankle surgery (or any surgery below the knee)?
Sciatic and femoral nerve block
What is a common complication of foot and ankle surgery and in what type of injury is it most common? What is the normal presenting symptom?
Compartment syndrome, fracture of tibia
Presents with pain out of proportion to the clinical situation
How can nerve block impact our ability to diagnose compartment syndrome?
Long acting PNBs may mask the signs of it
5 terminal nerve blocks for anesthesia to foot
- deep peroneal
- Sural
- superficial saphenous
- saphenous
- Posterior tibial
Brachial plexus (blocked for upper extremity surgery) is at the ________ nerve roots?
C5-T1
Where is an interscalene block initiated and what is a major complication?
between scalene muscle at level of cricothyroid notch (C6)
CNS toxicity
What is a complication of an interscalene block related to the diaphragm?
Ipsilateral phrenic nerve blockade causing hemidiaphragmatic paresis - 25% reduction in pulmonary function
Describe the pathophysiology of HBE’s
Bezold-Jarisch Reflex: LV receptor senses low volume (beach chair position), an efferent signal causes decreased sympathetic flow (hypotension drop of SBP 30mmhg or SBP <90 in5 min) and increased vagal output (bradycardia (<60 within 5 min)
What meds can be used for prophylaxis of HBE’s
Beta blockers, anxiolytics, and IVF
Epi makes it worse!
For spinal surgery, what conditions require awake fiberoptic and what conditions require glidescope?
Cervical spinal instability: awake fiberoptic
Reduced mobility but stable spine: glidescope
Why is there potential for high EBL in spinal surgeries?
proximity to major vessels
Risks for airway complications with spinal surgery?
length of surgery
IVF used
Obesity
Revision
4 or more levels fused
Fusion of C2
What are some techniques to prevent EBL in spinal surgery?
Proper positioning
Surgical hemostasis
Controlled hypotension
Reinfusion of salvaged blood
Clot promoting drugs
A young, healthy patient getting scoliosis repair can tolerate a MAP of _________? Which type of patients will require more blood pressure?
50-60
elderly, CV disease
How can you assess end organ perfusion during spinal surgery?
-invasive lines
-UOP 0.5-1mL/kg
-ABG monitor for met. acid
If you see an increase in HR during anesthesia with permissive hypotension, what are some things to think about?
Anemia, hypovolemia, or light anesthesia - but wouldn’t see this if on a beta blocker
Most idiopathic scoliosis curves are ______ sided?
Surgical intervention occurs with curves > _____ degrees?
right
40*
Which has more surgical site infections, knees or hips?
knees
______degree spinal curvature causes significant decrease in lung volumes and potential restrictive lung disease?
65*
In scoliosis surgery, vital capacity of <_____% of normal is predictive of requiring mechanical ventilation?
40*
What is a cardiovascular concern related to thoracic scoliosis surgery? What test should be done to assess for this?
-chronic hypoxemia and increased PVR can lead to cor pulmonale
-2DE done for RV hypertrophy and pulm HTN
What is the most feared complication in scoliosis surgery? What can be done to prevent this? What area of the body is this test limited to?
Postoperative neuro deficit
Wake up test to determine integrity of spinal cord
Test limited to lower extremities
What are some possible complications of performing the wake up test?
-accidental extubation
-air embolism during sleep inspiration
-dislodging instruments
What are some physiologic factors that decrease SSEPs and MEPs? How should you adjust MAC during this monitoring?
-HoTN
-hypothermia
-hypocarbia
-hypoxemia
-anemia
-use 0.5 MAC
What are some possible adverse effects of MEPs and who are the contraindicated in?
Cogitive defects, seizures, bite injuries, awareness, scalp burns, arrhythmias
Avoid in patients with seizures, vascular clips, and cochlear implants
How does N2O affect MEPs? What about inhaled anesthetics?
N2O - decreases AMPLITUDE
VA- increase LATENCY
How does propofol impact MEPs? What can be added to counteract this?
depresses MEPS, use ketamine too
Which drugs impact MEPs the LEAST?
-opioids
-midazolam
-ketamine
Most common cause of POVL?
ischemic optic neuropathy
Difference in presentation beween AION and PION?
AION-early
PION - late
Can ION occur without direct pressure on the eye?
yes
Which type of POVL is most often DIRECTLY related to improper head positioning?
CRAO
What are 2 common factors seen in most POVL cases?
-EBL >1L
-prone >6hr
What age groups are most at risk for POVL?
-<18y
->65y
Which anesthetic may be used for spinal surgery when MEP are monitored?
A. N2O
B. Rocuronium
C. 1 MAC Isoflurane
D. Fentanyl
D. Fentanyl
Tourniquet size should be how much of the limb diameter?
A.3/4
B. 2/3
C. 1/2
D. 1/4
C. 1/2
What is the leading cause of morbidity and mortality after orthopedic surgery?
A. PNA
B. MI
C. Infection
D. Thromboembolic complications
D. thromboembolic complications
Select the correct reason to perform a wakeup test during surgical instrumentation of the spine?
A.monitor evoked potentials
B. evaluate motor function
C. evaluate sensory function
D. evaluate consciousness
B. monitor motor function
What is the most frequeent surgical complication after a pelvic fracture?
A. cardiac arrhythmias
B. Sciatic n injury
C. Compartment syndrome
D. Retroperitoneal bleed
D. RP bleed
What is the max “safe” tourniquet time on a lower extremity?
A.60 min
B. 30 min
C. 120 min
D. 180 min
C 120 min
Which of the following MUST be present to diagnose fat embolism syndrome?
A. tachycardia
B. jaundice
C. fever
D. fat present in blood
D. fat present in blood
Which patient has the highest risk of death from a PE?
A. 80yo having hip fracture surgery
B. 65 yo having lumbar fusion
C. 32 yo having shoulder arthroscopy
D. 50 yo having TKA
A. 80 yo with hip fractrue surgery
Hypotensive-bradycardic episodes in the beach chair position are thought to be due to which reflex?
A. Bezold-Jarish Relfex
B. Vagal Reflex
C. Carotid - Sinus Pressure Reflex
D. Aortic Arch Pressure Reflex
A. Bezold-Jarish Reflex
Prophylaxis to prevent HBE includes all of the following except:
A. fluid bolus
B. Epi
C. Beta blocker
D. Anxiolytic
B. Epi
Which of the following agents will cause a significant increase in the latency and a reduction of the amplitude of SSEPs?
A.Low-dose propofol
B. Isoflurane
C. Fentanyl
B. Isoflurane
Methyl Methacrylate may cause all of the following except:
A. Increased preload
B. HoTN
C. Hypoxia
D. Arrest
A. Increased preload
When monitoring evoked potentials, volatile anesthetics cause a dose-dependent decrease in amplitude:
T or F
true
