Spinal Surgery pt2 Flashcards
What type of frame pictured below?
Wilson Frame
What are the respiratory effects of prone positioning?
↓ FRC
↓ compliance
Due to ↑ intrabdominal pressures → ↑ intrathoracic pressures.
Does venous return increase or decrease in prone positioning?
decrease
Which of the following positioning devices is the most stable?
Mayfield Tongs
What cardiac consequences are there to prone positioning?
Why?
- ↓ preload
- ↓ CO
- ↓ BP
Due to pooling of blood in extremities and compression of abdominal contents and muscles.
What neurological consequences occur due to prone positioning?
↓ cerebral venous drainage and ↓ CBF from extreme head rotation
What risk factors are there for increased blood loss during spinal surgery?
- Number of vertebrae
- > 50 yo
- Obesity
- Tumor surgery
- ↑ intrabdominal pressure
- Transpedicular osteotomy
When is autologous blood donation contraindicated in spinal surgery?
- Significant cardiac disease
- Infection
What is the push dose of Tranexamic acid (TXA)?
- 10 mg/kg IV (Max: 2.5 grams)
What is the infusion dose of TXA?
2 mg/kg/hr
DC at end of procedure
What is the push dose of aminocaproic acid (Amicar)?
Infusion dose?
Push dose: 100 mg/kg IV
Infusion: 10 - 15 mg/kg/hr
DC at end of procedure
Somatosensory Evoked Potentials (SSEPs) are associated with what spinal column and sensations?
Dorsal column pathways (sensory)
- Proprioception
- Vibration
assesses afferent pathways from periphery to the CNS
Motor Evoked Potentials (MEPs) are associated with what spinal column and sensations?
Anterior/ Motor Column of spinal cord
assesses efferent pathways from CNS to the periphery
During spinal surgery, electromyogram (EMG) is used to monitor for what during pedicle screw placement and nerve decompression?
Monitor for nerve root injury.
What is a Somatosensory Evoked Potentials (SSEP)?
Impulse from a peripheral nerve that is measured centrally (CNS).
What are Motor Evoked Potentials (MEPs)?
Impulse triggered in the brain (centrally) and monitored in specific muscle groups.
What are possible adverse effects associated with MEPs?
- Cognitive defects
- Seizures (can be triggered)
- Intraoperative awareness
- Scalp burns
- Cardiac arrythmias
- Bite injuries (bite block necessary)
In what patients should MEPs be avoided?
- Patients w/ active seizures (can be triggered)
- Patients w/ vascular clips in brain
- Patients w/ cochlear implants
metal components can heat up
Differentiate amplitude and latency in regards to neurophysiologic monitoring.
Amplitude: signal strength
Latency: time for signal to travel through spinal cord.
What physiologic factors commonly can affect amplitude and latency of neurophysiologic monitoring?
- Hypothermia
- Hypotension
- Hypocarbia
- Hypoxia
- Anemia
- VAAs
How do VAAs affect neurophysiologic agents?
Dose dependent
- ↓ amplitude
- ↑ latency
May consider TIVA alternative
Out of the following drugs, which affects our MEPs the most?
- Opioids
- Midazolam
- Ketamine
- Propofol
Propofol depresses MEPs.
The others have little effect on MEPs.
What muscle relaxant should be utilized when using MEPs?
No muscle relaxants after intubation.
What type of peripheral nerve block might be used for spinal surgery?
Erector Spinae block
During what surgery is venous air embolism at its greatest risk of happening?
Laminectomies
- Large amount of exposed bone
- Surgical site above the heart
What are some s/s of VAE?
- Unexplained ↓BP
- ↑ EtN₂
- ↓ EtCO₂
What type of table is pictured?
Jackson table
Name each of the following frame systems
What level of intentional/deliberate hypotension is acceptable for spine surgery?
- deliberate hypotension is not recommended in spine surgery
- risk of end-organ ischemia
With volatile agent use in neurophysiologic monitoring, what MAC should be avoided to prevent interference with monitoring?
Maintain 0.5 MAC or less to prevent interference
