anesthesia for orthopedic surgery Flashcards
(42 cards)
1
Q
what are common characteristics seen with orthopedic patients?
A
- many have arthritic joints/deformities
- many have limited ROM in neck
- require careful positioning
- may need help moving to OR table
- fracture patients may have full stomachs
- may have increased bleeding
- increased risk of fat emboli, DVT, and PE
- exposure to large amounts of radiation
- 80% young and healthy; 20% old w/ fall or bad arthritis (inactive)
2
Q
describe rheumatoid arthritis
A
- immune related, progressive inflammation of synovial joints (not just joint wear and tear)
- systemic manifestations
- multiple joint involvement, deformity
- chronic NSAID use (GI bleeding, renal toxicity, platelet dysfunction)
3
Q
what are issues seen r/t joint deformity?
A
- invasive lines and monitoring challenges
- immobility and decreased endurance of patients
- cervical and TMJ issues: check neck ROM, mouth opening
- atlantoaxial subluxation: C-spine films to evaluate and determine if fiberoptic intubation is indicated if greater than 5 mm instability exists
- cricoarytenoid arthritis: hoarseness, airway obstruction
4
Q
what are CV effects of rheumatoid arthritis?
A
- pericardial thickening and effusions
- myocarditis
- coronary arteritis
- conduction defects
- cardiac valve fibrosis (AR)
5
Q
what are pulmonary effects of rheumatoid arthritis?
A
- pleural effusions
- pulmonary nodules
- interstitial pulmonary fibrosis
6
Q
what are hematological effects of rheumatoid arthritis?
A
- anemia
- platelet dysfunction
- thrombocytopenia
7
Q
what are endocrine effects of rheumatoid arthritis?
A
- adrenal insufficiency (on steroid treatment)
- impaired immune system
8
Q
what are dermatologic effect of rheumatoid arthritis?
A
thin atrophic skin
9
Q
describe positioning for orthopedic cases
A
- usu. done after pt. is anesthetized
- usu. supine, sitting lateral decubitus or prone
- protect face from injury: eyes/nose, pad face
- sitting increases risk for air embolus: head and neck neutral position; avoid N2O
- arms over chest may impede ventilation
- sitting can reduce CPP
- stretch injuries
10
Q
describe used of regional anesthesia for orthopedic cases
A
- excellent advantages but can be unreliable
- supplement w/ IV opioids
- may use more for upper extremity surgery
- may be used in combo w/ GA for post op pain control
- reduced blood loss in some surgeries
- bier block commonly w/ wrist and hand surgeries
- neuraxial or peripheral nerve catheters allow continuous infusions in the post op period
11
Q
describe shoulder surgery
A
- lateral or “beach chair” position (lateral is best)
- open or arthroscopic (90%) technique
- positioning challenge: ears, eyes, boney areas
- may use LMA
- interscalene block combine w/ GA
- controlled hypotension (low 90s systolic allows surgeon to see shoulder joint)
- irrigation pressure during arthroscopic surgery must be higher than systemic pressure (too high can lead to injury)
- associated w/ nerve injury
- VAE possible in “beach chair” position
12
Q
how can CPP be estimated?
A
- level of the external auditory meatus and tragus correlates w/ the Circle of Willis, where CPP can be measuered
- lower pressure than level of heart d/t the vertical column and hydrostatic pressure difference
- *each 10 cm distance from heart equals 7.5 mmHg lower
13
Q
describe arthroscopic surgery
A
- knee, shoulder, elbow, wrist, hip , ankle
- less invasive w/ reduced blood loss
- bloodless surgical field
- minor incision w/ less post op pain
- reduced blood pressure on non tourniquet joints optimizes surgical field
- irrigation fluid 60-80 mmHg distends joint
- high pressure w/ long duration associated w/ sub q emphysema and tension pneumothorax
- keep systemic BP as low as possible to still maintain CPP so surgeons won’t have to increase their pressure
14
Q
describe spinal surgery
A
- most often to decompress cord or nerve root
- neuro and ortho surgeons perform
- multilevel instrumentation w/ plates, rods, and screws for spinal instability
- GA w/ or w/o paralysis
- if transthoracic, may need to deflate the lung
- airway challenges: prone position, cervical immobility
- can be done posterior or anterior approach
- may develop CSF leak requiring a vital capacity maneuver (VCM or valsalva)
15
Q
describe cervical spine surgery considerations
A
- prone, sitting, or supine position
- arthritic conditions may cause ROM issues (may require FO)
- major arteries and veins are near by (check distal pulses; can use ear probe oximeter)
- potential recurrent laryngeal nerve injury (some surgeons don’t allow muscle relaxant use)
- airway swelling could be post op issue
- identify and document preexisting neuro deficits
- prevent too much neck and head traction (pad)
- coughing or bucking must be prevented (LTA kit)
16
Q
what arthritic conditions may cause ROM issues?
A
- TMJ dysfunction: limited jaw opening
- atlantoaxial instability: limited neck ROM
- potential airway management challenge, may require F/O intubation
17
Q
describe lumbar spinal surgery
A
- can be minimally invasive or more extensive
- prone position using prone chest rolls
- brachial plexus at risk
- keep arms and shoulders less than 90 degrees
- abdominal compression
- impedes venous return
- diaphragm is cephalad, decreasing FRC and Vt
- biggest fear: eye injury or vision loss
- long procedures lead to large blood loss
18
Q
describe spinal fusion
A
- fusion of two or more vertebra are indicated
- bone grafting autologous or cadaveric
- artificial disk is inserted into space
- plates, rods, screws stabilize the two vertebra
- restores the correct distance b/w vertebra as a “cage” is constructed to hold the vertebra in place and prevent collapse
- risk hitting vertebrae, tear dura, or hit spinal cord
19
Q
what are anesthesia implications for spinal fusion?
A
- identify and document preexisting neuro deficits
- pressure off eyes, ears, nose, breast, genitalia
- blindness can occur
- ischemic nose or chin
- limited access to airway, monitoring leads
- longer procedures: warm patient, temp monitors
- greater blood loss: cell saver, typed and cross matched
- scoliosis pt. may have restrictive lung disease
- major vessels are in close proximity to spine
- monitor blood loss and temp*
20
Q
describe hip fracture
A
- typically elderly, frail, debilitated, dehydrated pts. w/ existing comorbid conditions
- supine position
- fracture table
- traction applied to fracture
- perineal post
- ipsilateral arm is placed on chest
- hypobaric and hyperbaric SAB can be used
- fat embolism common
21
Q
describe hip replacement
A
- typical pt. is elderly, likely arthritic history
- blood loss can be large (watch blood loss!)
- lateral decubitus position allowing greater ROM
- large incision
- prosthetic can be cemented or uncemented
- bilateral hip surgery contraindicated if declining pulmonary function occurs after first hip surgery (wait 6 mth.)
- axillary/chest roll
- up arm supported and stabilized
- down ear should be flat or no pressure
22
Q
what causes declines in pulmonary function during hip replacements?
A
when banging prosthetic in, micro emboli will scatter from hip bone and will see a drop in the O2 saturation as micro emboli reach lungs
23
Q
describe knee replacements
A
- usu. elderly, arthritic
- supine position
- tourniquet used
- more painful than hip
- high incidence of DVT
- many regional anesthetic options
- mostly older, at risk, out of shape population vs. young, active, in shape arthroscopic knee surgery
- prosthetics cemented to femur and tibia
24
Q
what regional anesthetic options are available for knee replacements?
A
- femoral 3 in 1 block (LFC, Obt, FN) combined w/ spinal
- femoral catheter used post op for pain control
25
describe closed reduction
- usu. very short procedures
- hips, shoulders, wrist, elbow, fingers (many times popped out of place)
- short acting paralysis usu. required (muscle tone may be working against surgeon popping back in )
- may be done w/ mask ventilation
- done many times w/ propofol bolus since short time (usu. minutes) are required for reduction success
26
describe methylmethacrylate cement
- used to bind prosthetic to bone
- exothermic reaction occurs which hardens cement and expands (causes lysis of blood cells and marrow)
- intermedullary hypertension: embolization of air, fat, marrow, and cement
- systemic absorption: decreased SVR d/t vasodilatory effects; release of tissue thromboplastin, platelet aggregation, microemboli formation
* *drop in O2 Sat
* *cant smell if pregnant
27
describe bone cement implantation syndrome
- emboli migrate to pulmonary system
- hypotension
- hypoxia
- reduced cardiac output
- dysrhythmias
- shunt
- pulmonary hypertension
- increase FiO2
- adequate hydration
28
describe the pneumatic tourniquet
- utilized to minimize blood loss and optimize surgical field
- exsanguination: esmarch bandage; distal to proximal
- cuff overlap should be 180 degrees from nerve bundle
- inflation pressure: determined by BP
* typically 100 torr lower ext. and 50 torr upper ext. over SBP
* venous tourniquet can occur
- neurological damage may occur if over 2 hours or if overlap is over nerve bundle
29
what are physiologic effects of tourniquet inflation?
- initial rise in SVR, CVP, PVR
- displaced blood volume (300-500 ml) w/ exsanguination
- prolonged inflation increased HR and BP (cant control)
30
what are physiologic effect of tourniquet deflation?
- metabolic acidosis: increased potassium and CO2 levels
- HR increase
- temp decrease (warm blood goes back to cool limb and cools rest of body
- hypotension (most common)
* sudden reduction in SVR and PVR
* wash out of ischemic metabolites (thromboxane)
* *during inflation, distal to TQ, anaerobic cellular respiration occurring creating lactic acid and CO2 which is washed back into system w/ deflation (acidosis, hypotension)
31
what are neurological effects of TQ?
- abolition of SSEP and nerve conduction within 30 min
- more than 60 min causes TQ pain and HTN
- more than 2 hrs can result in post op neuropraxia
- evidence of nerve injury may occur at the skin level underlying the TQ
32
what are muscle effects of TQ?
- cellular hypoxia within 2 min
- cellular creatinine value declines
- progressive cellular acidosis occurs
- endothelial capillary leak after 2 hrs.
33
describe TQ pain
- usu. an hour after inflation
- increase in HR and BP
- ischemia, nerve fiber compression
- burning, dull aching, throbbing pain (c fibers)
- IV analgesics minimally effective
- opioids added to local anesthetic have been shown to help
- deflation for 10-15 min can help
- quality/intensity of block vs. level of block
34
describe C fibers
- unmyelinated
- slow conducting
- burning, dull aching, throbbing pain w/ TQ inflation
35
describe A delta fibers
-pinprick, tingling pain after deflation
36
describe long bone fractures
- fracture of femur and tibia
- fat released into the circulation
- fat embolism syndrome (triad)
- DVT and PE can occur
- VAE can also occur
37
describe fat embolus
- common in fractures of femur and tibia (long bones)
- fat globules are released into the blood
- fat embolism syndrome triad occurs 12-24 hrs. later
- tachycardia and/or ST segment changes may occur
- fat in the urine and sputum, conjunctiva may be present
- coexisting lung disease at greater risk
38
what are the consequences of fat globules released in the blood?
- impaired pulmonary perfusion
- endothelial damage to pulmonary capillaries
- alveolar wall damage
- pulmonary congestion
39
what makes up the fat embolism syndrome triad?
- petechiae (axillary, subconjunctival)
- dyspnea
- confusion, mental changes
40
what is treatment for fat embolism syndrome?
- O2
- fluids
- steroids if indicated (fat emboli can cause inflammatory reaction in lungs)
- aggressive ventilation required
41
describe DVT and PE
- more common after total hip and total knee arthroscopy
- mechanisms: venous stasis, hypercoagulable state, platelet aggregation
- TQ greatly contributes to problem: venous stasis
- epidural or spinal reduces DVT (higher levels of plasminogen and plasminogen activators; hyperkinetic blood flow)
- may be attributed to allowing early ambulation
* utilization of anticoagulants
42
describe post op pain management
- NSAIDS (if not contraindicated) and IV opioids
- systemic opioids via PCA device (improved anesthesia, decreased total opioid consumption, increased pt. and nurse satisfaction)
- intra-articular injection: combo of opioids and LA
- continuous post op neuraxial and peripheral analgesia: better pain relief, faster ambulation and overall rehabilitation, better post op joint mobility
