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
