week 3 Flashcards
in adults where does the spinal cord end
L1-L2
in pediatrics where does the spinal cord end
L3
In adults where does the dura sac end
S2
in pediatrics where does the dura sac end
S4
Name the largest interspace
L5-S1
name L Site placement for following surgeries
Hip surgery
lower extremity surgery
obstetric analgesia
lumbar l2-L5
draw imaginary line between the iliac crests
Nipple:
Xiphoid:
Umbilicus:
Cardioacceleators
T4
T6
T10
T 4 - 5
Characteristics of patient affecting level of spinal anesthesia
height position gender
other factors affecting level of spinal anesthesia
Type of needle, site of injection, and the direction of the needle
Dosage amount (most influential factor)
Characteristics of the local anesthetic (baricity):
hypobaric, isobaric, hyperbaric
Volume of CSF in the spinal canal
position for broken hip
TURN THEM OVER ON THE SIDE THAT THEIR HIP IS BROKEN.
Advantages of Spinal Over General Anesthesia
Reduced stress response to surgery
Less blood loss (hip surgery)
Less incidence of DVT
Pulmonary complications appear to be less
Possible less cardiac complications
Better in obstetrics (less medications are administered to mother and fetus)
level of insertion for colectomy, anterior resection, upper abdominal surgery
lower thoracic t6-t8
thoracic surgery level of insertion
t2-t6
What is the purpose of doing neuraxial regional anesthesia
A neuraxial regional anesthetic (spinal, epidural, caudal) is selected when maintenance of consciousness during surgery is desirable
spinal anesthesia advantages.
Takes less time to perform
Produces a more rapid onset of better-quality sensory and motor anesthesia
Is associated with less pain during surgery.
Unlike epidural anesthesia, a continuous spinal technique is rarely used because of post spinal headache and concern about the proper maintenance of the catheter in the subarachnoid space.
Epidural anesthesia
A lower risk for post–dural puncture headache
Less chance of systemic hypotension if epinephrine is added to the local anesthetic solution,
The ability to prolong or extend the anesthesia through an indwelling epidural catheter
The option of using the epidural catheter to provide postoperative analgesia.
Skeletal muscle relaxation and contraction of the gastrointestinal tract are also produced by a regional anesthetic.
Modified Bromage Scale
0 no motor block
1 can’t lift legs but can move knees and feet
2 can’t life legs can’t move knees but can move feet
3 complete block of motor limb
factors the can increase the incidence of headache after spinal pincture
age: younger more frequent sex females >males needle size: larger > smaller needle bevel: less when needle bevel is place in the long axis of the neuraxis pregnancy- more when pregnant dural punctures: multiple punctures
factors that do not increase the incidence of headache after spinal puncture
continuous spinal infusion
timing of ambulation
absolute contraindication to spinal/epidural anesthesia
The only absolute contraindication to spinal or epidural anesthesia is when a patient wishes another form of anesthesia.
(per class- obviously we would not stick patients through an abscess)
condition that may increase the risk associated with spinal/epidural anesthesia
hypovolemia increased intracranial pressure coagulopathy sepsis infection at the cutaneous puncture site preexisting neurological disease (MS)
regional anesthetic technique is best for procedures lasting how long?
A regional anesthetic technique is most often selected for surgery that involves the lower part of the abdomen or the lower extremities in which the level of sensory anesthesia required is associated with minimal sympathetic nervous system blockade.
For procedures lasting between 20 and 90 minutes, IV regional anesthesia provides reliable anesthesia for both the upper and lower extremities
Bier block
carpal tunnel surgery- wrapping the arm and desanguanating the arm and using tourniquets give the lidocaine and give the versed
disadvantage of peripheral nerve blocks
A disadvantage of peripheral nerve block as an anesthetic technique is the unpredictable attainment of adequate sensory and motor anesthesia for performance of the surgery
advantages of peripheral nerve blocks
Advantages of peripheral nerve blocks include maintenance of consciousness and the continued presence of protective upper airway reflexes. (ex. insertion of a vascular shunt in the upper extremity for hemodialysis in a patient who may have associated pulmonary and cardiac -avoidance of the need for neuromuscular blocking drugs in this type of patient circumvents the possible prolonged effect produced by these drugs in the absence of renal function.
success of a peripheral nerve block…
Success depends on :
Provider skill (U/S etc.)
Cooperative patient
advantages of spinal over general anesthesia
Reduced stress response to surgery
Less blood loss (hip surgery)
Less incidence of DVT
Pulmonary complications appear to be less
Possible less cardiac complications
Better in obstetrics (less medications are administered to mother and fetus)
Bupivacaine dose
0.75 % : 90– 120 minutes. There is a little increase with addition of vasoconstrictor 100-150 minutes
The anesthetic agent is reabsorbed from the CSF into the circulation for metabolism and elimination
lidocaine dose
5% : short to intermediate 60 – 75 minutes, with added vasoconstrictor possibly 60-90 minutes (usually epinephrine)
The anesthetic agent is reabsorbed from the CSF into the circulation for metabolism and elimination
miscellaneous facts about ester
Ester action prolonged in patients with atypical pseudocholinesterase
Ester may cause hypersenitivity: The Para-aminobenzoic acid is metabolic end-product of ester metabolism is the culprit
Esters do not accumulate in the blood: They are metabolized by pseudocholinesterase also known as plasma cholinesterase.
what structures do I enter for spinal anesthesia
Skin Subcutaneous structures Supraspinous ligament Interspinous ligament Ligamentum flavum Dura Mater Arachnoid membrane
spinal fail
Failure may derive from technical considerations such as an inability to identify the subarachnoid space or failure to inject all or part of the local anesthetic solution into the subarachnoid space.
A second cause of failure is local anesthetic maldistribution. In support of this mechanism is the correlation of success rate with the vertebral interspace, the more caudad interspaces being more prone to failure.
If a spinal anesthetic is to be repeated, one should assume that the first injection was delivered in the subarachnoid space as intended, and the combination of the two doses should not exceed that considered reasonable as a single injection for spinal anesthesia.
PDPH
Due to CSF leakage causing traction on the meninges and cranial nerves. The headache starts 24 – 48 hours after the puncture. Localized at the occipital region and neck. It improves with the patient in the supine position. It may be accompanied by double vision, blurred vision, and tinnitus (per class photophobia)(per class bad for mom baby bonding)
PDPH-treatment
bed rest
intravenous fluids
analgesics
possibly caffeine (500 mg IV)
More definitively, a blood patch can be performed, in which 15 to 20 mL of the patient’s blood, aseptically obtained, is injected into the epidural space. The injection should be made near or preferably below the site of initial puncture because there is preferential cephalad spread
nausea after tap
Nausea occurring after the initiation of spinal anesthesia must alert to the possibility of systemic hypotension sufficient to produce cerebral ischemia.
Alternatively, nausea may occur because of a predominance of parasympathetic activity as a result of selective block of sympathetic nervous system innervation to the gastrointestinal tract.
urinary retention
Because spinal anesthesia interferes with innervation of the bladder, administration of large amounts of intravenous fluids can cause bladder distention, which may require catheter drainage. (limit fluid minor case)
However, adequate intravascular fluid replacement must be administered to maintain effective preload and reduce the degree of hypotension and possible progression to bradycardia and asystole.
Inclusion of epinephrine in the local anesthetic solution may be associated with a prolonged time to voiding.
Back Pain
Minor, short-lived back pain frequently follows spinal anesthesia and is more likely with multiple attempts at correct advancement of the spinal needle.
Backache may also be related to the position required for surgery. Ligament strain may occur when anesthetic-induced sensory block and skeletal muscle relaxation permit the patient to be placed in a position that would normally be uncomfortable or unobtainable.
Backache can be confused with transient neurologic symptoms.
total spin
Depression of the cervical spinal cord and brain stem function
S/S: dysphonia, dyspnea, upper extremity weakness, loss of consciousness, mydriasis, hypotension, bradycardia, and cardiac arrest
Epidural Anesthesia- structures encountered
Skin Subcutaneous fat Supraspinous ligament Interspinous ligament Ligamentum flavum Epidural space
differences between spinal and epidural
Spinal: small amount of local anesthetic is injected directly into the CSF. It produces an intense, rapid, and predictable neural blockade
Epidural: it requires a tenfold increase in dose to fill the epidural space and penetrate the nerve roots. It has a slower onset.
advantages of spinal over general
There is no airway manipulation (good for asthmatics) Less hypertension and tachycardia Less thrombogenesis Less postoperative nausea and vomiting Better pain control Less pulmonary dysfunction
complications of epidural
Hypotension (sympathetic blockade) Intravascular injection of local anesthetic (important to use a marker such as epinephrine, and to perform a test dose Subarachnoid injection (high spinal) Postdural puncture headache Epidural hematoma
epidural hematoma
Clinically rare, but emergent. They are usually associated with preexisting coagulopathy in the patient. S/S are back pain and leg weakness.
NEVER STICK A PATIENT WITH PLATELETS BELOW 100
Diagnosed by CT or MRI. It must be surgically decompressed in 6 – 8 hours, otherwise there is irreversible neurological damage
Combine Spinal/Epidural
Combined spinal-Epidural technique (CSE) is a technique in which a spinal anesthetic and an epidural catheter are placed simultaneously
Combines the rapid onset on intense sensory anesthesia and skeletal muscle relaxation provide by spinal anesthesia with the ability to supplement and extend the duration the block, including postop pain management by an epidural catheter.
Most commonly used for C/S and orthopedic cases (THA and TKA)
