What nerves do you block for analgesia for the forelimb, distal to the elbow?
radial, ulnar, median and musculocutaneous nerves
Blocking the radial, ulnar, median, and musculocutaneous nerves blocks both _____ and _____ innervation.
T/F: A nerve block to the radial, ulnar, median, and musculocutaneous nerves can be the sole form of analgesia for a procedure to be performed distal to the elbow.
False- not completely reliable for analgesia
Which of these is not true about IV regional anesthesia in bovines?
A. needs to be a relatively short procedure
B. can be performed anywhere that bloodflow can be blocked to the area
C. start at the proximal end and apply pressure to exsanguinate the limb
D. less pain associated with tourniquet if it is placed lower on the limb
C (need to start distally and work your way up to exsanguinate the limb)
Where does the medicine get injected when performing an epidural?
A. between the arachnoid and dura mater
B. in the subarachnoid space
C. In the spinal cord
D. in the space outside the meninges of the spinal cord
Which of these have not been used as epidural analgesics?
B. Local Anesthetics
D. alpha 2 agonists
E. All of the above
E (also, steroids and cholinergic antagonists)
Which opioid has the longest duration when given epidurally?
T/F: Preservative-free morphine is used for epidural administration because some preservatives may be neurotoxic.
T/F: Morphine epidural is the same as a block.
False- morphine works at the dorsal horn to influence modulation of pain
What is the onset of analgesia in dogs? in horses? About how long does it last?
-dogs: 30-60 mins
-horses: up to 6 hrs
- lasts about 18 hours
Which of these are side effects associated with epidural morphine?
A. Pruritus and urinary retention
B. nausea and vomiting
C. A & B
D. none of the above
How can you treat for the pruritus associated with morphine epidural?
small dose of butorphanol or naloxone (antihistamine will not treat this!)
Which of these is not an advantage of epidural local anesthetic?
A. increased need for inhalational anesthetic
B. Good muscle relaxation
C. prevents nociceptive input at the dorsal horn
D. Frequently combined with epidural opioids
A (substantial decreased need for inhalational anesthetic)
With an epidural local anesthetic, what is the extent of anesthesia dependent on?
volume and concentration of drug injected
What spinal segment do you need to block to for abdominal sx? For hindlimb sx?
What nerves need to be blocked for cruciate sx?
femoral and sciatic nerves
What are some side effects associated with epidural local anesthetic?
-motor blockade and temporary paralysis
-inability to actively void urine
-hypotension secondary to blockade of sympathetic nerves
In what species do you perform the epidural in the lumbosacral space? Sacral coccygeal?
-dogs, cats, pigs
-horses, cattle, camelids
What is the difference between a hypodermic needle and a spinal needle?
the hypodermic needle is very sharp which makes it more difficult to determine when you have entered the epidural space
How to determine if the needle is on the floor of the vertebral canal or outside the vertebral canal?
there is a marked loss of resistance when the needle is advanced through the ligament between vertebral bodies
When the needle is appropriately placed, there should be (minimal/increased) resistance to flow through the needle.
Is it indicated to give a combo opioid and local anesthetic epidural for an animal in shock?
No- do not give local anesthetic because potential for increased hypotension secondary to sympathetic block
What is the type of epidural needle that has a curve at the end to facilitate the catheter entering the epidural space?
Once you start progessing the catheter, if you realize you are not in the epidural space, can you back out the needle?
Administration of drug into the subarachnoid space is known as what?
intrathecal or spinal administration
How much should you lower the dose if you enter the subarachnoid space when trying to place an epidural catheter?
1/2 to 1/3 the dose
What is the difference between hyperbaric, hypobaric, and isobaric?
-hyperbaric- drug has a greater weight than CSF
-hypobaric- drug has less weight than CSF
-isobaric- drug has the same weight as CSF
(may affect where the drug concentrates in the epidural space)