A for orthopedics Flashcards
preoperative assessment
cardiovascular system: AHA recommendations for cardiac testing, mobility is an issue
respiratory system: decreases in SaO₂, increase in closing volume, hip fracture → decreased PaO₂
neurologic assessment: delirium and POCD-assess mental status
preoperative assessment: check coag status and baseline lab values, SSI- major concern with joint arthroplasty, large bore IVs
Surgical site infection
Major issue in orthopedic surgery
- destroys healing and repairs
- may lead to removal
- TKA has 2x infection rate of THA because of less soft tissue and muscle
thromboprophylaxis: highest risk of DVT
THA/TKA
hip/pelvic fx
surgical site infection prevention
- patient antibacterial soap
- laminar flow
- prophylactic abx
- meticulous skin prep
thromboprophylaxis: warfarin
INR > 2.5
orthopedic emergencies
dislocated hip
finger reimplantation
compartment syndrome
orthopedic emergencies: dislocated hip
general (usually)
NPO status
quick procedure
orthopedic emergencies: finger reimplantation
general with a block
VERY long procedure
NPO status
orthopedic emergencies: compartment syndrome
seen most often with tibial fx’s
treatment surgical decompression
advantages of regional anesthesia
- less risk of DVT/PE
- decreased blood loss
- less respiratory issues
- no need for airway manipulation
- better postop pain management → less incidence of chronic pain
- less N/V
- excellent skeletal muscle relaxation
common comorbidities in orthopedic surgery
osteoarthritis: loss of articular cartilage, no systemic manifestations, positioning concerns
rheumatoid arthritis: systemic disease, autoimmune disease
ankylosing spondylitis: fusion of axial skeleton, kyphosis, difficult airway & regional
rheumatoid arthritis
- possible difficult intubation
- acute pericarditis
- acute interstitial fibrosis
- Sjoren’s syndrome
RA: difficult intubation
- TMJ synovitis
- decreased glottic opening
- cervical spine immobility/pain
- Atlanta occipital subluxation
RA: acute pericarditis
- symptoms of right heart failure
- 2D echo to evaluate
- cancel case if acute – may need to be drained
RA: acute interstitial fibrosis
restrictive disease
dyspnea and chronic cough
RA: Sjoren’s disease
chronic dry eyes
use lubricant
orthopedic considerations
tourniquet
fat embolism
POVL
positoning
pneumatic tourniquet: preparation
- widest cuff possible
- 2 layers of padding
- 2 fingers between pad and cuff
- exsanguinate with esmarch (bandage)
pneumatic tourniquet: pressure/time
- pressure: usually 100 mmHg > SBP
- limit of 2 hours (some say 2.5-3 hrs)
- deflation: 10-30 mins for time> 2 hrs
pneumatic tourniquet: tourniquet pain
- occurs after 60 mins
- tachycardia and HTN
- only treatment → deflation
pneumatic tourniquet: complicaitons
local: nerve/muscle injury
systemic:
- cardiovascular: HTN & tachy
- cerebral: increased CBF
- hematologic: hypercoagulable & fibrinolytic
- metabolic: LA, hyperaklemia, hypoxic
- temperature: inflation vs. deflation
Myonephropathic metabolic syndrome
- upon deflation
- hypotension
- metabolic acidosis
- hyperkalemia
- myoglobinuria
- myoglobinemia
- possible renal failure
fat embolism: pathogenesis (mechanical theory)
- injury → vessels are torn. Fat emboli enter circulation through the torn vessels
- traveling fat → respiratory system. enters pulmonary capillaries and obstructs them
- arterial system → two mechanisms. microemboli, patent foramen ovale
- unanswered questions? → why the wait? Symptoms don’t appear 24-72 hrs. FES with no fracture?
fat embolism: pathogenesis (biochemical theory)
THE PRODUCTION OF TOXIC INTERMEDIATES (with pro-inflammatory effects) of circulating fat
- FFA
- cytokines
- C-reactive proteins
fat embolism: clinical presentation & differential diagnosis
- delayed presentation
- pulmonary features are the most common presenting features
differential diagnosis
- PE
- amniotic fluid embolus
- air embolus
FES typically manifests __ to __ hours after initial insult
24-72
FES: respiratory
- usually presenting symptom
- hypoxia, dyspnea and tachypnea
- ARDS-like syndrome develops
FES: petechial rash
- found on non-dependent areas of the body: head, neck, anterior chest, thorax, axilla, sub-conjunctiva
FES: classic triad
hypoxemia
neurologic abnormalities
petechial rash
FES: clinical/lab findings
- anemia/thrombocytopenia
- fever
- fat in urine
- coagulation disorders
- myocardial depression
differential diagnosis
PE
- same time frame
- no neurologic symptoms or rash
- PE will show up on CT
amniotic embolus
- pregnant?
- presents with CV collapse, respiratory failure, and seizures
Air embolus
- rash in unusual
- neurologic and respiratory symptoms will show immediately with AE
POVL: causes
central retinal artery occlusion
ischemic optic neuropathy
POVL: timing/presentation
24-48 hrs
bilateral
painless, loss of pupillary reflex
POVL: risk factors
obesity
Wilson frame use
length of surgery
blood loss
decreased use of colloids
positioning-prone
- induce on a stretcher
- head and neck supported & aligned with turn
- check breath sounds after turning
- arms < 90 degrees or tucked
- abdomen must be hanging freely
- avoid flexion/extension of neck
- head above heart level - increased ICP, increased IOP
- PSV vs. VCV
positioning-lateral
- dependent lung is under-ventilated and over-perfused
- axillary roll
- pulse ox on the dependent arm
- “bean bag”
- pad facial structures, breast, and genitalia
positioning-beach chair
- decreased BP & preload, from venous pooling
- adequately hydrate
- lighten anesthesia
- watch for inadvertent extubation
- support head, maintain a neutral position
- VAE
arthroscopy-lower extremity: outpatient
- most done outpatient
- GA usually done
- pain control
- (intraarticular injection/PNB)
arthroscopy-lower extremity: knee/hip & TNS
ACL repair - postop pain, muscle relaxation
Hip scope - positioning with traction
TNS
- transient neurologic symptoms
- seen after neuraxial
- common with lithotomy, knee scope, lidocaine
hip fracture: mortality
1 year = 30%
50% have postop confusion/delirium
hip fracture: timing of surgery
- earlier is better
- less pain
- less complication
- decreased LOS
- beware of good Hct!
pelvic fracture: mortality
3 month mortality = 14%
retroperitoneal bleeding
hip fracture: anesthesia
- fracture table
- aline?
- SAB - 4x greater risk for DVT with GA
pelvic fracture: timing of surgery
- earlier is better
- other injuries may delay surgery
- optimal time to repair = 1 week
pelvic fracture: anesthesia
- high risk of DVT &/or PE
- GA with an epidural for postop analgesia
- large bore IVs or possible central line
- possible neuromonitoring
hip/knee arthroplasty: most important risk factor for adverse events are
ADVANCING AGE
hip/knee arthroplasty: anesthesia
- SAB is an ideal anesthetic
- Hip: significant EBL
- TXA
- controlled hypotension
- preop preparation
hip/knee arthroplasty: common complications
cardiac events
PE
pneumonia
infection
hip/knee arthroplasty: methyl methacrylate
hypotension
BCIS (bone cement implantation syndrome)
treatment - supportive & O₂
GA with OET was found to be an independent risk for…
nonsurgical complications after a TKA
bone-cement implantation syndrome: when will it occur?
- femoral reaming
- acetabular/femoral cementing
- insertion of the prosthesis
- after TQT release (rare)
bone-cement implantation syndrome: signs/symptoms
- hypotension/hypoxia
- An abrupt decrease in ETCO₂ will be the first indication under anesthesia
- awake patient: dyspnea & altered sensorium
bone-cement implantation syndrome: mechanism
- embolization of bone marrow debris
- toxic effects of MMA
- release of cytokines
bone-cement implantation syndrome: risk factors
- pre-existing cardiac/pulmonary dx
- ASA 3 or higher
- long stem arthroplasty (THA > TKA)
- revision surgeries
TXA
- antifibrinolytic and plasminogen activator
- stops the conversion of plasminogen to plasmin
- stops the breakdown of fibrin clots
has decreased the rate of transfusion in THA/TKA to < 5%
dosing is still being investigated
foot/ankle surgery: common complications
- compartment syndrome: be careful with long-acting PNB - may mask signs of compartment syndrome
foot/ankle surgery: anesthesia
SAB or PNB need to block sciatic and femoral nerves (no thigh TQT)
shoulder surgery: Bezold-Jarish reflex
LV receptor senses low-volume → efferent signal → decrease sympathetic flow (hypotension) & increase vagal output (bradycardia
shoulder surgery: postioning
-beach chair/lateral
- VAE
- POVL
shoulder surgery: HBE (hypotensive bradycardic episode)
- get hypotensive and bradycardic when doing a shoulder scope under an interscalene block
- bezold-jarish reflex
- may progress to cardiac arrest
shoulder surgery: anesthesia
- watch for hypotension
- cuff-location when sitting, not reading BP at circle of willis
spine surgery: positioning
prone
POVL potential
spine surgery: neuromonitors
- SSEP (somatosensory evoked potentials)
- MEP (motor evoked potentials)
- EMG (electromyography)
spine surgery: anesthesia
- cervical procedures - glide scope
- cervical instability - awake FOI
- anterior/posterior repairs
SSEP
- monitor the posterior (sensory) portion of the spinal cord
- impulse: periphery → brain
MEP
- monitors anterior (motor) portion of spinal cord
- impulse: brain → periphery
EMG
monitors nerve root injuries during pedicle screw placement
amplitude and latency
- IA - reduce latency
- nitrous: reduce amplitude
attenuate SSEP & MEP
- hypotension
- hypothermia
- hypocarbia
- anemia
- anesthetics
types of scoliosis
idiopathic
congenital
neuromuscular
scoliosis: large blood loss
- deliberate hypotension
- cell saver
- intraoperative normovolemic hemodilution
- TXA
- autologous blood
scoliosis: POVL/neuromonitoring
- POVL rare (0.1%)
- SSEM/MEP - usual
- “wake up” test
scoliosis: anesthesia
- large bore IVs
- arterial line
- TIVA?
- watch EBL
anesthetic implications: positioning
- prone
- POVL potential
- decreased abdominal pressure (may lead to increased EBL)
anesthetic implications: large EBL
- cell saver
- intraoperative nomovolemic hemodilution
- TXA
- autologous blood?
- aline- yes
anesthetic implications: complicaitons
- postoperative neurological deficit
- wake up test (if needed)
- inadvertent extubation
- air embolus
- dislodgment of instrumentation
major risk factors for delirium
alcohol use
preoperative dementia
cognitive imapirment
psychotropic medication
multiple comorbidities
perioperative triggers for dementia
- hypoexemia, hypotension, hypervolemia
- abnormal electrolytes
- infection
- sleep deprivation
- pain
- benzos
- anticholinergics
