Anesthesia for Orthopidic Surgery Flashcards
What are some special consideration in ortho surgery?
- Bone cement
- Pneumatic tourniquets
- Fat embolism syndrome
- Deep venous thrombosis
- Thromboembolism
Characteristics of bone cement:
- Exothermic reaction resulting in hardening
- Heat, expansion and hardening lead to intermedullary hypertension (>500 mm Hg)
- Residual mma monomer produces vasodilation, decrease in SVR
- Tissue thromboplastin release may cause platelet aggregation microthrombus (lungs) and CV instability
What symptoms correlate with bone cement implantation syndrome:
- Hypoxia (increased pulmonary shunt)
- Pulmonary HTN (increase PVR)
- Dysrthythmias (Heart blocks / Sinus arrest)
- Hypotension
- Decreased CO
- Embolization most frequent during prosthetic insertion
What are the strategies to limit MMA (Bone Cement) effects:
-Increase inspired O2 prior to MMA (bone cement)
-Maintain euvolemia
-Vasopressor as needed
SUGICAL METHODS
-venting distal femur
-high pressure lavage of femoral shaft
What kind of hemodynamic changes will be seen with pneumatic tourniquets?
- Increase B/P
- Increase HR
What are the problems with pneumatic tourniquets?
- hemodynamic changes
- Pain
- Metabolic changes
- Arterial thromboembolism
- Pulmonary embolism
- Muscle and nerve injury
- Limb cooling
Prolonged cuff time of __ to __ minutes associated with HTN, ________, ___________ stimulation (sweating).
45 to 60
tachycardia
sympathetic
What will the deflation of the Pneumatic cuff do to the hemodynamics?
- Decreases CVP
- Decreases MAP
T/F: The core temperature drops with the use of a pnuematic cuff.
TRUE
Pneumatic cuff pressure should be ____ torr above systolic pressure or the upper extremity should be ___ torr and the lower extremity ___ torr.
100
250
350
What kind of pain is associated with the tourniquet?
-Sever aching and burning (several minutes)
-Unmyelinated, slow conduction C fibers
Supplemental analgesia needed
T/F: Tourniquest pain is less common in general anesthesia then in regional anesthesia.
FALSE (…. less common in regional anesthesia then in general anesthesia.)
What metabolic changes are noticed with the tourniquet?
- Waste accumulation in the tissue
- Cuff deflation is rapid wash out which will increase PaCO2, ETCO2, serum lactate, and potassium.
- With deflation an increase in spontaneous breathes and possible disrhythmias
- Re-perfusion injuries from free radical formation
T/F: Tourniquet contraindicated in calcified artery.
TRUE
T/F: Tourniquet ischemia is NOT associated with upper/lower extremity that leads to a deep venous thrombosis.
FALSE (It is associated and is more common in the lower extremity)
Prolonged inflation of the tourniquet > _ hours leads to transient _______ and permanent _____ injury.
2
muscle
nerve
T/F: Rhabdomyolysis can be associated with prolonged tourniquet times.
TRUE
What is the triad of fat embolism syndrom:
- dyspnea
- confusion
- petechiae (pathognomonic)
Classic presentation of fat embolism syndrome with in __ hours of ____ bone or ______ fracture.
- 72
- long
- pelvic
What other modalities can cause fat embolism syndrome?
- CPR
- Liposuction
- IV lipids
How do fat emboli enter into circulation:
medullary vessel
Increased fatty acid levels toxic to capillary alveolar membrane releasing vasoactive ______ and ____________.
- amines
- prostaglandins
What type of coagulation effects will be seen with fat embolism syndrome.
- Thrombocytopenia
- Prolonged clotting time
What kind of pulmonary symptoms will be seen with fat embolism syndrom?
- Progressive pulmonary involvement from mild hypoxia and clear CSR to ARDS
- Under GETA see decline in ETCO2 and SpO2 and rise in PAP
People with risk factor of Deep vein thrombosis are:
- age > 60
- obesity
- Tourniquet
- lower extremity fracture
- immobilization > 4 days
- procedure > 30 minute
The highest risk for deep vein thrombosis are:
Knee replacement
Hip replacement
Placement of epidural needle or catheter (or removal) should not be undertaken within ____hours of a SQ minidose of heparin or within ______ hour of LMWH.
6-8
12-24
T/F: It is acceptable to place an epidural or needle in a fully anticoagulated patient.
FALSE (NEVER ACCEPTABLE)
What are the hallmark signs of a hematoma due to a epidural needle or catheter?
- back pain
- Lower extremity weakness
____ and _______ that limit range of motion of a joint may require anesthesia for manipulation to occur.
Scars
Adhesion
What does general anesthesia do for the management of joint manipulation?
The profound relaxation allows surgeon to distinguish anatomical limitations from patient guarding
The management of a closed reduction may include:
- surgery could either be short or long
- percutaneous pins
- Xray/fluoro
- Casting/splinting
What should be determined of the patient with a hip fracture?
Why did they fall?
- Accidental
- Neuro event
- Cardio vascular
- dementia
- dehydration/electrolyte
- ??Abuse??
Hip fracture mortality is __ % during initial hospitalization and __% within the ____year.
10
25
first
Other consideration of a hip surgery:
- Surgery within 48 hours of injury
- Time for medical evaluation and treatment of pathology
- Type and Cross
- evaluate hypoxia
What are some reasons to delay a hip surgery:
- Coagulopathy
- Uncompensated heart failure
What are some predictors of peri-op mortality for hip fractures:
- age > 85 years
- History of cancer
- Baseline/pre-op alteration in neuro status
- Post op chest infection
- Post op wound infection
What are the benefits of regional anesthesia vs. general:
- hypobaric technique can be utilized to keep patient off of fracture
- reduced blood loss
- Reduced DVT/PE
- Quicker return to baseline neuro
T/F: After two months no difference in mortality for regional vs general in hip repair.
True
Will lose benefit of regional in hip surgery if:
- patient oversedated
- patient becomes hypoxic
How can blood loss be determined by location of hip fracture?
- Greater blood loss occurs further distally from the hip.
- From greater to less blood loss: subtrochanteric and intertrochanteric > base of femora neck > transcervical and subcapital
What should be considered with hip fracture during general anesthesia:
-Bigger fracture (arterial line and size of IV)
-Use of short acting drugs
-Use lower solubility agents
-minimize postop cognitive impairment
{older patient less versed
{Maintain oxygenation
{Maintain hemoglobin
{Maintain normal capnea
What are the benefits of a arthroscopy:
- less estimated blood loss
- less postop pain
- less rehab time
What is a arthroplasty good for:
Surgical replacement of all joint components to achieve return of natural motion and function of the joint.
What are the goals of a arthroplasty:
- pain relief
- Deformity corrected
- stability of joint motion
What is the most common reason for a total hip arthroplasty (THA):
osteoartritis
What are the factors that cause osteoarthritis: (THA indciation)
repetitive motion, obesity, often others areas of involvment (other joints)
What are the factors that cause rheumatoid arthritis (RA): (THA indication)
immune mediated joint destruction with synovial inflammation systemic involvement with significant deformity atlantoaxis (C1-C2) subluxation and TMJ involvement use of steroids, anti-inflammatories, methotrexate
What are the factor that cause vascular necrosis (THA indication)
injury
drug use
Total hip arthroplasty (THA) intraop managment:
- Position: lateral decubitus
- Embolic event most frequent at insertion of femoral component
- Use of MMA
- Prophylaxis of DVT/PE
- Blood loss
- Heat loss
- Periop infection
- Postop pain control
What is the estimated blood loss of a total hip arthroplasty?
- 400 to 1200 mL
- Revision 2000 mL
What has the highest rate of DVT of all ortho procedures?
Total knee arthroplasty (TKA)
What is the estimated blood loss of total knee arthroplasty (TKA):
100 to 200 mL
What should be remembered for upper extremity surgery?
- Position is sitting (beach chair) or lateral decub (Maintain B/P MEAN)
- Interscalene block of brachial plexus helpful
- Cerebral oximetry
What anesthsia consdieration of upper extremity arthroplasty:
- surgical position
- no tourniquet (large blood loss)
- Potential pneumothorax
- potential injury to subclavian veins
- Potential in advertent extubation
- Potential for C spine injury
- Potential for VAE, fat or bone embolism
- Effect of MMA
What are the anesthesia consideration for a foot and ankle surgery:
- candidates for regional anesthesia
- nerve blocks with IV sedation
- Use of tourniquet
- LMA with local injection for postop pain control
What are anesthetic concern for re-implantation of a limb/digit?
- attnetion to positon
- maintain body temp
- regulation of fluids
- Optimal HCT 28-30%
- Avoid vasoconstrictors
- Dextran or heparin infusion intraop
What nerves consist of the interscalene block:
C5-T1
Where does injection take place in an interscalene block:
Between scalene muscle at level of cricothyroid (C6)
What are complications of Interscalene block:
- CNS and CV toxicity from carotid artery, vertebral artery, and jugular vein
- Respiration depression
- Pneumothorax
- Hoarseness,
- Dysphagia
- Horner’s syndrom
- Ipsilateral phrenic nerve block most patient with hemidiaphram paralysis, 25 % decrease pulmonary function. Some may not tolerate.
What are the S/S of local toxicity:
- Ringing/buzzing in ears
- Metallic taste or perioral numbness
- Dysphasia, confusion
- Orthostasis
- PVC’s
- Wide QRS/PEA/Asystole (BUPIVICAINE)
- Brady/AV blocks/asystole (lidocaine)
What is the procedure for lipid resuscitation of local anesthetic toxicity:
- Stop infusion of local anesthetic
- Bolus of 20% lipid solution at 1.5 mg/kg
- Infusion of 0.25 mg/kg/min of 20% Lipid solution
- Life support measures
