Test 2: Orthopedics (pt 3/4) Flashcards
The surgical replacement of all (total arthroplasty) or part (hemiarthroplasty) of a joint to restore the natural motion and function of the joint, as well as restoring the controlling function of the surrounding soft tissues (i.e., muscles, ligaments, and tendons).
Arthroplasty
What are the goals of arthroplasty?
pain relief, stability of joint motion, and deformity correction.
What is the mean age of patients undergoing Total Hip Arthroplasty (THA)?
65 years old
What is the most common surgical approach used for THA?
Posterior approach - which requires a large incision extending from near the iliac crest across the joint to the midthigh level.
What is different about the direct anterior approach (DAA) compared to the posterior?
Minimally invasive alternative
What is the anesthetic plan for patients undergoing THA?
Regional Anesthesia
If pt refuses or C/I for spinal, use GA
What is the positioning for posterior THA? For Anterior THA?
Posterior - Lateral Decubitus
Anterior - Supine on special traction table
What do you give for the potential significant blood loss associated with THA?
Tranexamic Acid (TXA)
What is TXA?
A synthetic plasminogen-activator that helps to decrease blood loss through inhibition of fibrinolysis and clot degradation. The use of TXA has been shown to decrease perioperative blood loss and transfusion requirements in these patients, with minimal risk of complications, 1-2 grams administered perioperatively.
What is the official name of the bone cement?
methyl methacrylate (MMA)
Describe the Orthopedic Fracture table function and things to note.
-Used for orthopedic hip, femur fx surgery
-Allows manipulation of leg/hip joint exposure
-Caution with positioning/pressure points!!! Falls and risk of pressure ulcer (genitalia from center post)
What are the anesthetic techniques and positioning used for Total Knee Arthroplasty (TKA)?
-General, Regional, or combined RA/GA
-Supine
-Uses pneumatic tourniquet
-Significant blood loss: Use TXA
-Bone Cement implications
What are the anesthetic implications and positioning used for Ankle Arthroplasty?
-General, Regional, or Combo.
-Supine
-Requires tourniquet, usually has spinal or epidural
-RA that combines sciatic and femoral nerve blocks is sufficient for all surgical procedures below the knee that do not require a thigh tourniquet.
-VTE & bone cement risks
What are the anesthetic implications and positioning used for Shoulder Arthroplasty?
-General, Regional, or Combo
-Interscalene or Supraclavicular Block
-+/- Superficial cervical plexus
-Lateral decubitus or Beach Chair
-Bezold Jarisch reflex risk
-Risk for VAE
-Risk for POVL due to hypotensive technique
- Risk for intraop cerebral ischemia
-No tourniquet - so higher blood loss (give TXA 1-2 g periop)
-Bone cement risk
What are indications for shoulder arthroplasty?
posttraumatic brachial plexus injuries, paralysis of the deltoid muscle and rotator cuff, chronic infection, failed revision arthroplasty, severe refractory instability, proximal humerus fracture, and bone deficiency after resection of a tumor in the proximal aspect of the humerus.
What are complications of orthopedic trauma?
-Significant hemorrhage leading to shock
-Fat emboli
-Thromboembolic hypoxic resp failure
-High risk for compartment syndrome
-Pelvic Fx associated with massive hemorrhage
-Falls (43%) and MVCs (26%)
Treatment aims for orthopedic trauma?
-Early fixation with intramedullary nails allows ambulation within 24 hrs of surgery (reducing PPCs)
-Ideal time to repair open fx is within 12 hrs of injury (emergency surgery - risk for aspiration)
Mortality rates go as high as ____% with open pelvic fxs
70%
Why is mortality rate so high with pelvic Fx?
-Displaced bone may injury or sever arteries/veins/nerves, leading to massive hemorrhage
How do you treat hemorrhage associated with pelvic fx? (!!!!)
TXA 1-2 g periop and blood product transfusion
What is the treatment for pelvic fx?
Damage control resuscitative efforts and damage control surgical measures are critical in order to improve the outcome in such cases.
External fixation, angiographic embolization, and application of pelvic packing have been used with some success as elements of damage control surgery.
What is the anesthetist’s role in surgery for pelvic fx?
close monitoring of hemodynamic end-organ perfusion in addition to replacing blood loss using principles of damage control resuscitation.
What is the classic triad of Fat Embolic Syndrome (FES) symptoms?
Hypoxemia, Neurologic Impairment, and classic Petechial Rash (!!)
When does FES symptoms begin?
24-72 hrs after injury
Spinal cord terminates at what level in adults?
L1-2
What is the blood supply to the spinal cord?
1 Anterior Spinal artery that originates from 6-8 radicular arteries
-Artery of Adamkiewicz
2 Posterior Spinal arteries
An artery that supplies the anterior 2/3 of the spinal cord, found at T10-11. Disruption = paralysis
Artery of Adamkiewicz
What is the gold standard surgical approach for spinal stenosis?
Bony decompression by laminectomy
What is the common surgical technique for bony decompression by laminectomy?
the posterior approach consists of a midline incision and tissue dissection to expose the disc herniation or stenotic areas. Surgery is undertaken to relieve the pressure on the nerve root that is causing the pain.
Bony Decompression may lead to spinal instability. How is this managed?
Surgical lumbar interbody fusion (LIF) may be performed in addition to laminectomy.
Surgical lumbar interbody fusion (LIF) may also be used to treat what?
Spinal deformity and radiculopathy secondary to degenerative disc disease (DDD)
What is the surgical tx for DDD?
-Most often fusion
-Some younger pts undergo total disc replacement
Total disc replacement requires what approach?
Anterior Approach:
-Requires assistance of gen/vasc surgeon to aid in the displacement of organs and vasculature.
-A double-lumen tube may be used for lung isolation to facilitate surgical exposure if at thoracic levels
What may become difficult after Lumbar Interbody Fusion (LIF) due to hardware?
Regional Anesthesia
Lateral curvature of the spinal column by more than 10 degrees.
-80% of cases idiopathic
-Chronic pain, neurologic and cardiopulmonary compromise, and cosmetic concerns
Scoliosis
What are the non-idiopathic causes of scoliosis?
congenital skeletal abnormalities, neuromuscular disease, neurofibromatosis, or irritative phenomena resulting from spinal cord compression from a tumor.
Tx of Scoliosis depends on what?
Treatment pathways are determined by the severity and cause of the deformity, and may be nonsurgical or surgical.
Describe surgical intervention of scoliosis?
Primarily of fusion of multiple joint spaces, with or without anterior release, and may include extensive instrumentation (e.g., Harrington rods or other instrumentation).
-Scoliosis repair may require anterior or posterior approaches, or a combination of both.
-Any approach is a major surgical intervention, but the anterior approach is more technically involved. The anterior approach to the thoracic spine requires performing a thoracotomy (and possibly a double-lumen ETT)
What are the anesthesia implications with Scoliosis surgery?
-Hemodynamic control: IV access, ABP, blood products, hypotensive technique
-Chronic pain pts: multimodal
-Airway mgmt
-No NMB for neuromonitoring
What is the safest anesthetic approach for spinal surgery?
General Anesthesia
-Consider monitoring of evoked potentials throughout surgery (SSEP/MEPs)
What are anesthetic implications for spine surgery?
-Positioning (prone)
-If thoracic cavity, will need double-lumen tube
-Significant blood loss - need IV access, hemodynamic monitoring, blood products
-Blood conservation methods
-Temperature management
-Monitoring of SSEPs/MEPs: No Nitrous, no NMBs, 1/2 MAC anesthesia
What is the purpose of a double-lumen tube?
So the ipsilateral lung can be deflated to facilitate visualization of the thoracic spine.
What patients would need a fiberoptic or other assisted device intubation, either awake or after the induction of general anesthesia?
-Myelopathic
-C-Spine instability
-Pts with previous spinal fusion and limited neck extension
What are the blood conservation strategies?
-Pre-donation autologous blood
-Surgical site infiltration with epi solution
-Hypotensive anesthetic technique (still have to perfuse the brain though)
-Cell saver
-Antifibrinolytics (TXA 1-2g periop)
What are Evoked Potentials?
Eps are used to guide the surgical strategy and to act as a warning of neurologic deficits to prevent irreversible damage
How can injuries to neural structures arise?
Injuries to neural structures can arise from heat (electrocautery), mechanical stress (retraction), ischemia (ligation, edema, and vessel damage), and loss of functional integrity (transection). Also, can be affected by hypothermia, hypotension, positioning, and anemia.
What is the key to reducing serious neuro complications?
Early detection + Communication between anesthesia, surgeon, and neurophysiologist
Amplitude represents?
Amplitude represents the intensity of the evoked response
Latency is?
Latency is indicative of the time necessary for the evoked response to be measured in the brain.
A ___% decrease in amplitude or a ___% increase in latency is suggestive of the possibility of cerebral ischemia, and the surgical team should be made aware of this change.
50; 10
Used to monitor the integrity of the neural structures along both the peripheral and central somatosensory pathways of the brain and spinal cord.
-Posterior column and lateral sensory tract
Somato-Sensory evoked potentials
How are SSEPs usually induced?
Stimulation of a peripheral nerve, which contains both a sensory and motor component that combine to provide a mixed signal.
What procedures use SSEP monitoring?
Neurosurgical procedures (cerebral aneurysm & spine), Aortic cross-clamping, CEA with shunting
Almost all anesthetic agents ______ latency and or _______ amplitude, with the exception of _______, _________, and ____________.
Increase; decrease; Ketamine, etomidate, and opiates.
Which has a greater depressant effect of EP waveforms, inhalation or iv agents?
Inhalation > IV
What does N2O do to SSEPs?
Depressant effect, avoid use of N2O
What is the anesthetic technique for SSEP monitoring?
Narcotic based, TIVA, 1/2 mac inhalation
_____ & _____ increase cortical amplitudes and enhance SSEP waveforms?
Etomidate & Ketamine
Do NMBAs affect SSEP monitoring?
No, but can’t do MEPs if using NMBAs
Used to monitor the functional integrity of motor tracts, particularly in the corticospinal tract. Considered the gold standard for monitoring the motor pathways.
Motor evoked potentials (MEPs)
What is the indication for MEP monitoring?
Spine and intracranial surgery where the motor cortex or descending motor pathways are at risk.
What is the anesthetic technique for MEP monitoring?
Narcotic based, TIVA, 1/2 mac inhalation
-NO NITROUS (Depressant)
-NO NMBAs!!!!!
What do etomidate and ketamine do to MEP waveforms?
Increase cortical amplitudes and enhance MEP waveforms
Has the capability to stimulate a motor nerve and monitor the known innervated muscle groups, as well as passively “listen” to all muscle groups.
Electromyography (EMG)
What is an indication for EMG?
-Analysis of the Facial Nerve (Parotid Gland)
-Inspection or R/L Recurrent laryngeal nerves during thyroidectomy and other head/neck surgeries
What kind of tube is used for Anterior Cervical Disc Fusion (ACDF) surgery?
NIMS: Nerve-integrity monitoring endotracheal tube
What is the anesthetic technique for EMG?
Anything, just AVOID NMBAs!!!!
