• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/117

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

117 Cards in this Set

  • Front
  • Back
Bones are highly vascularized, predisposing the pt to risk for ____.
hemorrhage
A very high risk complication of ortho surgery is...
fat embolism
____ and ____ must be secured and verified after all position changes.
monitors and airway devices
What are the key positioning points during ortho surgery?
- head level, not down tilting
- free chest, abdomen w rolls
- no direct eye pressure
- supine, lateral, prone, modified fowlers (Beach chair)
What is the target Hgb and HCT for ortho surgery?
- hgb > 9 mg/dl
- hct > 28%
During ortho surgery, the target BP is ___% of control, and fluid losses should be replaced _____.
75%, aggressively (Blood PRN)
Gel pads for chest/abdomen during positioning can be adjusted to allow for..
- chest excursion
- large abdomen
- pendulous boobies
Perfusion of the lung is dependent on _____. The ____ segments have the greatest amount of perfusion.
posture/positioning,
gravity-dependent
Describe VQ in the upright sitting position
- VQ mismatch
- most effective in middle lung fields (zone 2)
- blood flow greater in zone 3, gas distribution initially distributed in zone 1
- with inspiration, fall in pressure will draw the greatest gas volume to more dependent areas of the lungs
In some pts, changing from supine to prone positioning displaces the weight of the abdominal contents, resulting in...
reversal of blood flow distribution to the anterior segments -- difference in blood flow distribution is based on pressure affecting the capillaries
The pressure of the _______ can influence the resistance to blood flow through the capillaries.
surrounding tissues
Blood flow to areas of the lungs depends on...
pulmonary artery pressure, alveolar pressure, and pulmonary venous pressure
When standing, VQ match is best in zone __.
2
When supine, VQ match is best in zone ___.
3
Supine positioning leads to a ____ in FRC. Why?
reduction

800 mL, with abdominal contents pushing on diaphragm
General anesthesia decreases FRC as much as 400 mL due to...
diaphragmatic relaxation
Paralysis with mechanical ventilation directs more ventilation toward the _____ areas of the lung, to improve ____.
gravity-dependent, VQ match
How are ventilation, perfusion and lung volumes affected by the lateral decubitus position?
- upper lung is zone 1, best ventilation but worst blood flow
- lower dependent lung is zone 3, best blood flow least ventilation
- zone 2 is decreased
- decr vital capacity and TV
- mediastinum shifts toward dependent side, pushing on heart, decr venous return and CO, leads to hypotension
How are ventilation, perfusion and lung volumes affected by the prone position?
- must maintain venous return by freeing the abdomen and avoiding vena caval occlusion
- zone 2 decr VQ match, zone 3 incr VQ match
- requires greater positive pressure to ventilate
- c-spine alignment and avoid eye compression
What are the considerations for the sitting/beach chair position?
- airway is isolated (Can use ETT, LMA, or Spontaneous ventilation)
- incr hypotension
- pad pressure points, align head, protect eyes
What are the physiologic changes involved in moving a patient to the upright position?
- decr: MAP, CVP, PAWP, SV, CO, and PaO2
- incr: A-a gradient, pulm vasc resistance, total peripheral resistance
Under nonanesthetized conditions, the effects of uprighting a patient are compensated for by an increase in ______ by as much as 50-80%.
incr SVR
During the upright position, autonomic responses are blocked by ________, which further exacerbates and compromises CO.
vasodilating anesthetics
Blood pressure remains unchanged or incr slightly in nonanesthetized pts in the sitting position but decreases in the _____ state.
anesthetized
Cerebral perfusion pressure (CPP) ______ by approximately 15% in the sitting position in non-anesthetized patients and could further ______ under anesthesia because of _______ and _______.
decreases, decrease,
vasodilation and impaired venous return
Venous return from the cerebral circulation is usually _______ by inspiratory subatmospheric pressure during spontaneous ventilation, but this mechanism is nullified by ______.
increased, positive pressure ventilation
Obstruction of the _____ in the sitting position may also impede cerebral venous drainage, especially with unfavorable positions of the head and neck, such as _____ of the head.
internal jugular veins, flexion
Cerebral autoregulation maintains cerebral blood flow constantly between a MAP of ____.
50-150 mmHg
Poorly controlled HTN pts experience cerebral autoregulation shift to the ____, requiring ______ CPP/MAP to ensure adequate cerebral perfusion.
right, higher
What is a better lower limit for the MAP in pts with chronic HTN to maintain adequate cerebral autoregulation?
70-93 mmHg (mean 80 +/- 8)
Some ortho surgeons require deliberate _____ for shoulder surgery, eliminating any margin for error if BP falls further.
hypotension
In the supine position, BP in the arm and BP in the brain are...
essentially the same
In the beach chair position, BP will be _____ in the brain than at the heart or arm .The BP difference will be equal to the ______ between the heart/arm and the brain.
less, hydrostatic pressure gradient
What is the approximate difference in BP if the pt is positioned with the base of the brain approx 20 cm above the heart?
15 mmHg less in the brain

anesthetist must correct he BP readings at the arm to account for height of brain above arm!
If SBP is 80-100 with a MAP of 50-80, the MAP at the base of the brain will be approx _____ lower, and at the top of the cerebral cortex approx _____ lower. This may suggest hypoperfusion to the cortex!
15-20 mmHg lower at brainstem
another 9 mmHg lower at top of cortex
What is the critical variable in determining the diffence in BP at the cuff and in the brain?
vertical distance between external auditory meatus and BP cuff
Once you calculate the vertical distance between the external auditory meatus and the BP cuff, it should be converted to a ______ that must be incorporated into BP mgmt during the procedure.
hydrostatic pressure gradient
How is hydrostatic pressure gradient calculated?
0.77 mmHg decr for every 1 cm
OR
1 mmHg for every 1.25 cm
The distance between the brain and site fo BP cuff on arm in the seated position will be _____ Depending on angle of sitting position and height of pt.
10-30 cm
If the beach chair position is combined with the use of ______, cerebral perfusion will be severely compromised!
deliberate hypotension
What happens if the BP cuff must be placed on the leg during a seated position case?
even more exaggerated difference between cuff reading and cerebral perfusion pressure
Patients in the beach chair position are at risk for intraop. _____ if borderline low BPs, as measured in arm, are used without appreciating the effect on CPP and CBF.
stroke
Blood pressure values during seated position of less than ____% preop resting values should be treated aggressively to enhance the margin of safety.
80%
Deliberate _____ should be avoided in beach chair position cases.
hypotension
During supination, you should be careful not to flex the non-surgical leg greater than ____ degrees, and the arms should be ....
no greater than 90 degrees
tape arms across body w padding
What is the purpose of the axillary roll during lateral decub positioning?
avoids compression of the axillary artery and brachial plexus
What are the c-spine techniques during lateral decub positioning?
head and neck and thoracic spine should be in alignment
The torso can be positioned with ____ or ____ during lateral decub positioning.
bean bag or metal rod
During lateral decub positioning, it is important to monitor for pressure on the ____.
down ear
Increased pressure on the chest during pronation results in _____ chest wall compliance and lung expansion.
decreased
During pronation, there is a risk of ____ damage from excessive pressure or traction.
peripheral nerve damage
What must be specially protected from pressure during pronation?
eyes, ears, nose, breasts, genitalia
The _____ is a common table used for pronation and can be placed into 3 different shapes.
andrews table
This type of OR table is used for pronation and creates a nice little arch in the patients c-spine and hips.
jackson table
What are some considerations when choosing the anesthetic technique in an ortho case?
- proposed procedure and location
-length of procedure
- expected EBL
- postioning (prone, lateral, sitting)
- coexisting medical conditions (obesity, meds)
- pt preference or refusal of regional
- surgeon preference, anesthetist skill level
What are the advantages of regional in ortho?
- decr stress response
- avoids pulm irritation with COPD
- decr afterload, decr bleeding
- may prevent thromboembolism
What are the disadvantages of regional in ortho?
- must pre-hydrate
- sedation to keep comfy
- takes more time
- may not be do-able in dementia pts
- cant use if too anticoag
- may not be fully effective
What are some of the regional hemodynamic effects in ortho cases?
- decr MAP
- blood flow redistribution to larger caliber vessels
- locally reduced venous pressure w epidural
What are the advantages of general anesthesia with ortho cases?
- ease of administration
- pt comfort
- control ventilation
- no "Failed" generals
What are the disadvantages of general anesthesia in ortho cases?
- myocardial and resp depr
- not protective against thromboembolism
- airway control necessary
- prolonged effects in elderly
What are the advantages of tourniquet use in ortho cases?
- reduced blood loss
- bloodless surgical field (better operating conditions)
What nerve is the most often injured by use of a tourniquet?
radial nerve bc sits next to humerus and can easily be compressed
What are the disadvantages of tourniquet use during ortho cases?
- potential nerve damage due to direct compression between bone and tourniquet
- ischemia of tissues
- systemic metabolic acidosis
- skin damage due to excessive pressure
- hypo/hypertension
What are the guidelines of tourniquet placement during ortho anesthesia?
- cuff should overlap 3-6x over a width of 50% of the extremity
- must be padded
- placed by surgeon or OR nurse
- pressure must be from pneumatic source
- limited to 2 hr duration
What are the recommended tourniquet pressures for upper vs lower extremities?
- 75-100 mmHg above SBP for LE (350 mmHg)
- 50-75 mmHg above SBP for UE (250 mmHg)
After _____ minutes, the tourniquet should be let down for _____ minutes for reperfusion and to properly recover from inflation before putting tourniquet back up.
60-90 min, 10-15 min
While giving a tourniquet break, the surgeon can....
continue to operate or elevate the limb and apply pressure dressing to incision
Most of the time, surgeons do not want to let the tourniquet down until after the pressure dressing has been applied to....
decrease edema and bleeding
A _____ just distal to the cuff and padding will help protect it and the skin from betadine solution.
plastic drape
Describe tourniquet pain
- signs progressive from SNS activation
- onset 45-60 min after inflation for awake pts
- suggest ischemia of tissues and nerve fibers, destruction of muscle tissues
- dull, aching, burning, referred to above tourniquet
- pain despite effective SAB/CLE anesthesia
What may signal tourniquet pain under general anesthesia?
HTN, tachy
Tourniquet pain is difficult to treat...what do you do??
use narcotics
incr IA
may not improve s/s until tourniquet deflated
Why does tourniquet pain present the way it does?
transmission is via C fibers (may be more resistant to LA or recover faster than A delta fibers)
Although neither can truly ablate tourniquet pain, which works better? spinal or epidural?
spinal better
_____ neuraxial solutions provide a denser block than _____ solutions.
isobaric denser than hyperbaric
To treat sympathetic outflow during use of tourniquets in ortho cases, you can give what drugs?
hydralazine, nifedapine, labetalol
List the complications associated with tourniquet use
- accumulated metabolic wastes from ischemic limb causes transiet effects after release (incr ETCO2, incr O2 consumption, treat w incr ventilation, metabolic acidosis, decr core temp, decr MAP/CVP)
- pulmonary emboli d/t DVT
- skin injuries
- arterial spasm/vascular injury
- bleeding
- nerve injury (paresthesia/weakness)
- compartment syndrome
What are the "Evil humors" released from the extremity when tourniquet pressure is relieved?
- acids
- emboli of fat, air, cement
- CO2
- thromboxane
- myoglobin
- intracellular enzymes
- K
- all contribute to hypotension, incr ETCO2, decr core temp, tachy, ectopy, arrest
What might awake pts feel during tourniquet release?
dizzy, confusion, nausea, bradycardia, cold
What 3 things should you have ready when you drop a tourniquet?
fluids
pressors
O2
Compartment syndrome
- true ortho emergency
- occurs following trauma or surgery, often repetitive and/or extensive muscle use of extrem
- may be from casts/tight drsgs
- incr pressure in closed fascial compartment causing tissue ischemia
- can lead to nerve damage or muscle death
- progressive, unrelenting pain
- rapid onset, severe tenderness to site, pulse change is LATE sign
What is the treatment for compartment syndrome?
fasciotomy
cant use regional for this
What is polymethylmethacrylate? What's it used for?
- binds prosthetic w bone, bone cement
- cement mixing causes exothermic rxn ultimately expanding and causing pressure against bone surface (intermedullary pressure > 500 mmHg)
Intermedullary pressures push ________ into the femoral venous channels.
fat, air and marrow
What are some of the clinical manifestations after placement of bone cement?
hypoxia
hypotension
dysrhythmias
pulm HTN
decr CO
How are the adverse effects associated with bone cement placement treated?
100% O2
incr fluids
pressors PRN
DVT and PE are most common following what types of surgeries?
pelvis and lower extrem surgeries
DVT and PE occurs due to _____ and _____ state.
venous stasis, hypercoagulable state
What are the risk factors for DVT/PE development?
obesity
incr age
tourniquet use
long immobilization
What are some techniques to lower the risk of DVT/PE developmen after ortho surgery?
- anticoagulation post op
- SCDs
- early rehab
- use of regional anesthesia
Fat embolism syndrome
- presents within 72 hrs following long bone/pelvic fx.
- s/s: pulm edema, dyspnea, hypoxia, tachycardia, mental status change/agitation/ confusion, cerebral edema, petechiae on eyes/armpits/ chest, drop in ETCO2 and PaO2
What is the treatment for fat embolism syndrome?
- stabilization of fracture
- 100% Fi02, CPAP
- steroids if cerebral edema
What sign heralds onset of fat embolism syndrome?
early persistent tachycardia
How is temp affected during fat embolism syndrome?
high spiking temps
What is the pathophysiology behind fat embolism syndrome?
- large fat droplets released into venous system
- droplets deposited in pulm capillary beds, travel through AV shunts to brain
- microvascular lodging of droplets --> local ischemia and inflammation, release of inflammatory mediators, plt aggregation, vasoactive amines
- hormonal changes caused by trauma/sepsis --> systemic release of free fatty acids/ chylomicrons, c-reactive proteins
Fat embolism triad of S/S
dyspnea
confusion
petechiae
Arthroscopy
- used to examine interior of a joint
- minimal post op pain
- decr blood loss
- shortened length of stay/rehab
- can do it almost any joint (access ports, fluid infused, needle muscle relaxation)
- GA, LMA, ETT, SAB, other block w sedation (interscalene, axillary)
Arthroplasty
- joint replacement (hip, knee, shoulder, ankle most common)
Hemiarthroplasty
partial joint replacement
What are the complications associated with arthroplasty?
blood loss, pain, thromboembolism, nerve injury
What is the positioning for hip surgery?
lateral decub
What are the anesthetic technique options for arthroplasty?
GA, SAB, CLE
Total Hip Arthroplasty (THA)
- performed in latera lposition
- avg duration 1-4 hrs
- significant blood loss 1-6 units
- 2 IVs, T/C
- a-line, cvp
- consider cell saver use
- elderly population
Deliberate hypotension during hip surgery may reduce blood loss by...
30-60 %
ORIF
open reducation internal fixation
- common for severely displaced fractures
- requires screws, pins, external fixation
- greater postop pain
- GA, SAB, extremity block
What are the anesthetic considerations for spine surgery ?
- ortho/neuro surgeons
- positioned with a specialized "Rack", pronated
- hypothermia
- blood loss significant
- neuro monitoring
SSEP
somatosensory evoked potentials
- continuous assmt of spinal cord fcn
- monitor sensory system
- IA may cause latency response and decr amplitude, use <1 MAC
MEP
muscle evoked potentials
- motor responses fron transcranial stimulation
- monitors motor pathways
- NMBs affect response, ok to maintain 1-2 twitches on TOF
List the types of ortho surgeries on the upper extrem?
- carpal tunnel release, neuromas (local bier block)
- hand surgery (local/bier/axillary, GA)
- forearm to elbow (axillary block w musculocutaneous nerve block, GA, infraclavicular/supraclavicular block - risk of pneumothorax or ulnar sparing)
- upper arm (interscalene/ infraclavicular/ GA)
Anesthesia considerations for shoulder surgery
- usually performed in sitting position
- GA w or w/o regional (interscalene)
- painful
- brady/hypotension from vasovagal response
What rare complication is associated with shoulder surgery?
- fluid infused through shoulder ports can infiltrate tissues of neck and cause airway obstruction
List the types of ortho surgeries in the lower extrem?
- foot (SAB/epidural/ ankle block/ local w MAC)
- ankle (SAB, epidural, sciatic/saphenous nerve block)
- knee (SAB, epidural, formoral/lumbar plexus/ sciatic block)
- hip and femoral neck fx (GA prior to moving to OR table, SAB/CLE for cooperative pts)
Ortho preop assessment should include...
- comorbidities
- volume status (dehydration, blood loss)
- arthritis (rheumatoid, osteoarthritis)
- ankylosing spondylitis
- pain
Rheumatoid Arthritis
- immune-mediated condition affecting synovium (joints), chronic, progressive, inflammatory, systemic
- impaired immune system, risk of infection
- CV: pericardial thickening, valvular fibrosis, conduction defects
- pulmonary: effusions
- heme: anemia
- endo: adrenal insufficiency from steroids
- pharm: nsaids and ASA
- airway: potential atlantoaxial subluxation
- calcified arteries, ischemic heart disease, muscle wasting, fused joints
- difficulty positioning, difficult IV access
- multiple joints, symmetrical involvement
What are the airway concerns associated with RA pts?
- severe atlantoaxial subluxation
- may push odontoid (C2) into foramen magnum -- may reduce vertebral arterial blood flow, cord compression --> nerve damage or death
- cricoarytenoid arthritis: hoarseness, inspiratory stridor, narrow glottic opening, use smaller ETT, post extubation monitoring
Osteoarthritis
- degenerative disease
- articular surface wear and tear, one or more joints
- most commonly hip and knee
Ankylosing Spondylitis
- ossification of ligaments at bone attachment sites
- immobility and consolidation of joints, consider awake FOB
- affects c-spine, hips, shoulders, costovertebral joints
- impaired lung fcn (rigid rib cage, preO2)
- risk of spinal/cervical fx (Careful positioning, while pt still awake, difficulty placing regional)