Spinal Anesthesia Flashcards
What is spinal anesthesia?
Reversible chemical blockade of neuronal transmission produced by the injection of a local anesthetic drug into the CSF contained within the subarachnoid space
What nerve fibers transmission are temporarily inhibited with spinal anesthesia?
Sensory
Autonomic
Motor
How might a spinal anesthetic speed the patients recovery?
Surgical stress is reduced by the afferent block
How might spinal anesthesia decrease the occurrence of venous thrombosis and blood loss?
Reduction of arterial and venous pressure
What postoperative complications can the incidence be lowered with spinal anesthesia?
Nausea/Vomiting
Sedation
Cognitive impairment
Wound pain
Why is it important to cycle the blood pressure cuff immediately after administering spinal anesthesia?
Sympathetic blockade accompanies spinal anesthesia virtually 100% of the time
What are some complications often associated with spinal anesthesia?
Urinary retention
Post-dural puncture headache
Intense motor blockade
Why do many patients fear having a SAB?
Fear of being awake, educate the patient that sedation will be provided
Why might a SAB be a safer option in a patient with a full stomach?
Vomiting and pulmonary aspiration is less likely (unless over sedated)Patients with difficult airways may be easier to manage
Why might a SAB be useful in patients undergoing a TURP procedure?
The conscious patient is able to tell if bladder perforation has occurred, CHF can be monitored and electrolyte disturbances could be assessed
What are the benefits of a laboring mother receiving SAB?
Somatic motor function loss can be minimized when the level is kept lowMother remains awake and can see the child
Why is a SAB beneficial for metabolic diseases?
It has minimal effect on metabolism, beneficial for
- Liver disease
- Kidney disease
- Diabetes
What are some absolute contraindications to a SAB?
Patient refusal Infection at the injection site Coagulopathy or other bleeding diathesis Severe hypovolemia Severe aortic or mitral valve stenosis Increased ICP
Why is a SAB contraindicated if a patient has an infection at the injection site?
Risk of skin core introducing infection into the CSF
What is a SAB contraindicated in aortic or mitral valve stenosis?
It causes a decrease in after load which causes a decrease in CO which can’t keep up with the vasodilation a SAB causes
What can occur if a SAB is performed on a patient with an increased ICP?
It can cause the patient to herniate
Why might it not be a good idea to give a patient with a demyelinating disease spinal anesthesia?
It could potentially cause an exacerbation of the disease if it was in remission
Why wouldn’t a provider choose to give a patient a SAB if they had a history of metastatic CA of the lumbar vertebrae?
There is a potential for neurologic deficit in these patients
How can HIV effect a providers choice in giving a patient spinal anesthesia?
There is a potential for neurologic disorder and there is a thought that you could potentially be introducing the virus to the CSF
What local anesthetic would patients have an allergy to and why?
Esters, preservative PABA
What might the provider expect if they gave spinal anesthesia to a patient with uncontrolled HTN?
Massive HoTN due to a low tank and a sympthomectomy
What is the thought behind administering 1000-1500mL of a balanced crystalloid solution prior to spinal anesthesia?
It is supposed to help prevent against HoTN however, likely not effective
What must the provider have available and functioning prior to spinal anesthesia and why?
A patent IV, anticipate giving vasoactive agents to treat the sympathomectomy
How many total vertebrae are present in the spinal column?
33 vertebrae
How many cervical vertebrae are present in the spinal column?
C1-C7 = 7
How many thoracic vertebrae are present in the spinal column?
T1-T12 = 12
How many lumbar vertebrae are present in the spinal column?
L1-L5 = 5
How many sacral vertebrae are present in the spinal column?
5 Fused
How many vertebrae are present in the coccyx of the spinal column?
4 Fused
What two spinal regions have a lordosis curvature?
CervicalLumbar
What two spinal regions have a kyphosis curvature?
ThoracicSacral
What is the laymen’s term for the coccyx?
Tailbone
What is the typical shape of a lumbar vertebrae?
Kidney shaped
What are the structures called where vertebrae come into contact with each other?
Superior articular processInferior articular process
What is the typical shape of the body of a thoracic vertebrae?
Heart shaped
What is the order from skin to the subarachnoid space does a need pass to get spinal anesthesia?
Skin Subcutaneous tissue and fat Supraspinous ligament Interspinous ligament Ligamentum flavum Epidural space Dura Subarachnoid space
What is the tip of the spinal cord called and what is its function?
Conus Medullaris, it stabilizes the spinal cord
What is the name of the structure that extends beyond the conus medullaris as multiple nerves?
Cauda equina
What sensation can occur is the cauda equina is struck by a needle when attempting spinal anesthesia?
Paresthesis, however should resolve because they are floating structures
What is the outermost layer of the menenges that is tough, fibrous and runs longitudinally?
Dura mater
Where does the dura mater extend?
From the foramen magnum to S2-3
What is the name of the middle layer of the menenges that is delicate and nonvascular?
Arachnoid mater
When does the arachnoid mater end?
S2
What is the name of the innermost layer of the menenges that is delicate, highly vascular and covers the spinal cord?
Pia mater
Where is the subarachnoid space located?
Between the pia and arachnoid mater which is where CSF resides
What is the function of the CSF?
Mechanical buffer to protect the brain and spinal cord
What is the specific gravity of CSF and how does that relate to water?
1.003-1.009 slightly greater than that of water (1)
What is the total amount of CSF in an adult and how much of that is in the subarachnoid space?
150mL in an adult, 20-35mL is present in the subarachnoid space
How much CSF is produced in a day?
21mL/hr which is equivalent to about 500mL/day
What dermatome is represented at the little finger?
C8
What dermatome is represented at the nipple line at the 4-5th intercostal space?
T4
What dermatome is represented at the level of the xyphoid process?
T6
What dermatome is represented at the level of the umbilicus?
T10