Anesthetic Considerations for Orthopedic Procedures Flashcards
What is a common complication associated with orthopedic surgeries?
Major blood loss
What comorbidities are commonly associated with patients undergoing an orthopedic procedure?
CAD
Rheumatoid arthritis with systemic pulmonary, cardiac and musculoskeletal involvement
Osteoarthritis
Mental status (large population are elderly)
What is Rheumatoid arthritis?
Chronic inflammatory disease affecting multiple joints and organ systems
What are the most common joints rheumatoid arthritis affects?
C-spine, hips, shoulders, knees elbows, wrists and metecarpophalangeal joints
What are systemic effect of rheumatoid arthritis?
Anemia, pericarditis, cardiac tamponade, myoocarditis and pulmonary interstitial fibrosis
What affect does RA have on the immune system?
It impairs the immune system
What complications can occur when trying to intubate a patient with RA?
Cervical cord compression or compression of vertebral arteries from subluxating C2 at the odontoid process when flexing the neck
Why are patient with RA difficult to ventilate?
Restrictive lung disease from pulmonary fibrosis
What is ankylosing spondylitis?
Abnormal immobility of joint caused by fibrous growth in joint
What are common characteristics of ankylosing spondylitis?
Ossification of ligaments at attachment to bone
Progressive ossification
Seronegative for rheumatoid factor –> may go undiagnosed
What characteristic of ankylosing spondylitis is of interest to the anesthetic provider?
Axial skeleton disk space “bamboo spine”
What population is ankylosing spondylitis more common in?
Caucasian Males
What are symptoms of ankylosing spondylitis?
Low back pain, sacroilitis, multiplane rigidity of spine, chest stiffness and uveitis
Why are patients with ankylosing spondylitis difficult to intubate?
Atlantoaxial instability and spine fractures during airway manipulation
Why are patients with ankylosing spondylitis difficult to ventilate?
Rigid chest
What is the purpose of using a tourniquet in orthopedic cases?
Allows a bloodless field and minimizes blood loss
What is the maximum a tourniquet should be inflated?
100mmHg greater than systolic BP
What is known to occur if a tourniquet is inflated for longer than two hours?
Inflation greater than 2hrs routinely leads to transient muscle dysfunction and may be associated with permanent peripheral nerve injury
When does tourniquet pain usually begin to appear?
30-45min after inflation
What type of nerve fibers are thought to transmit tourniquet pain?
Unmyelinated C fibers
What is the definitive treatment for tourniquet pain?
Tourniquet release
What position are patients typically placed in for shoulder surgeries?
Beach chair position, flexed at hips and knees, 10 to 20 degree reverse trendelenburg
What nerve is at risk of injury in the beach chair position?
Brachial plexus injury
What occult blood loss can occur with a hip fracture?
Extracapsular and Subcapsular
Which type of fracture to the hip is associated with a higher occult blood loss?
Extracapsular fracture: femoral neck, intratrochanteric and subtrochanteric
In what order does the most occult blood loss occur from injury to the hip?
Subtrochanteric > Intertrochanteric > base of femoral neck > transcervical > subcapital
What syndrome is highly associated with a hip fracture?
Fat Embolism Syndrome
What is the triad of symptoms seen with fat embolism syndrome?
Dyspnea
Confusion
Petechiae on chest, upper extremities, axilla & conjunctiva
When is fat embolism syndrome most likely to occur?
72hrs following long bone or pelvic fracture
What are the signs of fat embolism syndrome during general anesthesia?
Decreased EtCO2 and arterial saturation
What is the treatment for fat embolism syndrome?
Early fracture stabilization and supportive care
What position is a total hip replacement usually done in?
Lateral decubitus, higher degree of visibility and range of motion
What is the most common indication for a total hip arthroplasty?
Osteoarthritis (Degenerative joint disease)
What are the surgical steps to a total hip arthroplasty?
Dislocation and removal of femoral head
Reaming of acetabulum
Insertion of acetabular cup
Reaming of femur and insertion of femoral component
What are the three life threatening complications of a total hip arthroplasty?
Bone cement implantation syndrome
Perioperative hemorrhage (reaming and insertion)
Thromboembolism
What is bone cement implantation syndrome?
Hardening and expansion against components causes intramedullary HTN forcing embolization of fat, bone marrow, cement and air into femoral venous channels
What effect does residual methylmethacrylate monomer produce?
Vasodilation and decreased SVR
What can trigger platelet aggregation, and produce pulmonary microthrombi and CV stability in bone cement implantation syndrome?
Release of tissue thromboplastin
What are the clinical manifestation of bone cement implantation syndrome?
Hypoxia HoTN Dysrhythmias Pulmonary HTN Decreased CO
How can the anesthetic provider intervene if bone cement implantation syndrome is suspected?
Increased FiO2
Maintain euvolemia
Ask the surgeon to perform a high pressure lavage of femoral shaft to remove debris
What is a significant cause of morbidity and mortality in patients that undergo an orthopedic procedure?
Venous thrombosis
What can be done to prevent venous thrombosis in the post operative period?
Regional anesthesia
Intermittent leg compression devices
Low-dose anticoagulant prophylaxis
What can occur when the tourniquet is released after a total knee arthroplasty?
HoTN
Why might the surgeon request muscle relaxation to facilitate a closed reduction?
Once fractured, the muscles tend to spasm and pull fracture together to try to heal. Does not heal properly
What position are spine cases typically performed in?
Prone position
What are some considerations with the prone position?
Neck must be neutral Shoulders abducted less than 90 degrees Ischemia to ears, eyes, nose, forehead female breasts or male genitalia HoTN Ventilation difficulties
Why is it so important for a patient’s abdomen to be free from pressure while in the prone position?
If pressure on the abdomen it increases venous blood flow which increases after load causing an increase in blood loss
What complications are associated with spinal surgery?
Large blood loss
Vision loss
VAE
What two tests can be used for spinal cord monitoring?
Wake up test
SSEP, MEP monitoring
What can cause vision loss after a spinal procedure?
Optic neuropathy
Retinal artery occlusion
Cerebral ischemia
What changes are observed in SSEPs if spinal cord dysfunction occurs?
Changes in the latency and amplitude
How do volatiles affect SSEPs?
Decrease amplitude and increase latency
What anesthetics have no clinically relevant effect on SSEP signals?
Propofol, Ketamine and narcotics
What is the most reliable monitoring tool for spinal procedures?
The wake up test
When should volatiles be discontinued if planning to perform a wake up test?
An hour prior to wake up test
If paralytic is used, what should be done in order to prevent interference with the wake up test?
Maintain 2-3 twitches on TOF/no reversal, the patient must have sufficient toe movement
When is an anterior and posterior fusion performed on a patient with scoliosis?
If the curvature is greater than 90 degrees
When is controlled HoTN required during an anterior and posterior approach for scoliosis?
Posterior portion, MAP should be 60mmHg or more to prevent blindness or cord ischemia
Why does right ventricular hypertrophy and pulmonary HTN occur after an anterior and posterior approach for scoliosis?
Prolonged alveolar hypoxia due to hypoventilation and V/Q mismatch –> irreversible vasoconstriction and pulmonary HTN
What are some considerations for patients undergoing limb reimplantation?
Keep the patient warm
Euvolemic
Anemia if tolerated
DO NOT use pressirs
