Caudal Block Flashcards
What is a caudal epidural?
A caudal epidural is an epidural anesthetic administered via the
sacral hiatus that acts on the sacral dermatomes.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1097.
For what procedures is a caudal anesthetic
indicated?
Caudal anesthesia is used most commonly as an adjunct to
general anesthesia in pediatric surgery. It can also be used for
perirectal surgery, urologic surgery, lower extremity orthopedic
surgery, labor and delivery, and chronic pain. Clubfoot repair,
inguinal herniorrhaphy, and circumcision are also surgeries that
would benefit from the pain relief provided by a caudal block.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1097.
What is the traditional technique for performing a
caudal anesthetic?
The patient is positioned prone or lateral. The sacral hiatus is
identified by palpation and a 22- to 25-gauge needle is inserted
in the midline between the two sacral cornua. Some clinicians
advocate using a 20-gauge IV catheter in place of a standard
needle. A popping sensation can be felt as the needle passes
through the sacrococygeal ligament. The angle of the needle is
lowered parallel to the sacrum and the needle is advanced 1-3
cm into the epidural space. Gentle aspiration is performed to
detect inadvertant entry in the subarachnoid space or a blood
vessel. The local anesthetic is injected incrementally while the
opposite hand palpates the skin over the sacrum for bulging
indicative of subcutaneous injection.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1098.
What are the anatomic landmarks that can be used
to identify the correct placement of the needle for a
caudal block?
The two sacral cornua, the coccyx, and the posterior superior
iliac spines.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 1197.
In what position is the patient typically placed for a
caudal anesthetic?
The patient can be placed in either the prone or lateral position.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1098.
How is the volume of local anesthetic estimated for
an adult undergoing caudal anesthesia?
A 3 mL test dose is administered first. For sacral procedures,
12-15 mL is sufficient. 20-30 mL is usually required for
anesthesia up to a T10 dermatome.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1098.
How is the appropriate volume of local anesthetic
calculated for a caudal anesthetic for a pediatric
patient?
0.5 to 1 mL of solution per kg of bodyweight should be injected
to achieve an umbilical level of anesthesia.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1098.
What is the ‘whoosh’ test used during caudal
anesthesia?
The ‘whoosh’ test is performed to determine correct placement
of the epidural needle. A stethoscope is placed over the lumbar
spine and 2-3 mLs of air is injected through the epidural
needle. If the needle is correctly placed, a ‘whoosh’ sound
should be heard.
Wong, CA. Spinal and Epidural Anesthesia. New York:
McGraw-Hill; 2007: 61.
If a catheter is to be inserted for a continuous caudal
epidural anesthetic, what needle is usually used and
why?
A Crawford needle is used because it has a bevel that faces
forward which more closely aligns with the direction the catheter
needs to travel in the caudal epidural space. The Tuohy needle
typically used in lumbar epidural anesthesia faces upward
toward the wall of the caudal epidural canal.
Wong, CA. Spinal and Epidural Anesthesia. New York:
McGraw-Hill; 2007: 60.
What ligament overlies the sacral hiatus?
The sacrococcygeal ligament
Wong, CA. Spinal and Epidural Anesthesia. New York:
McGraw-Hill; 2007: 61.
You are performing a caudal anesthetic on an awake
patient. As you begin to inject the local anesthetic,
the patient complains of paresthesia and a feeling of
‘fullness’ in the sacral area. What should you do
next?
These are typical sensations when performing a caudal epidural
correctly. You should reassure the patient that this is normal
and continue incremental injection.
Wong, CA. Spinal and Epidural Anesthesia. New York:
McGraw-Hill; 2007: 61.
What is the dose of clonidine that should be added
to the local anesthetic to augment a caudal
anesthetic?
1 mcg/kg of bodyweight
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1098.
What are the advantages of using clonidine rather
than opioids to augment a caudal anesthetic?
Clonidine is comparable to opioids in its ability to augment a
caudal epidural block without the accompanying respiratory
depression, nausea, and delayed recovery.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1098.
Why is caudal anesthesia used predominantly in
pediatric patients?
After the age of 12, the sacral bone structure begins to change.
The sacral hiatus is more difficult to locate and the spread of
local anesthetic in the caudal epidural space is less reliable.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1097-1098.
When during the perioperative period is a caudal
anesthetic usually performed in a pediatric patient?
It is usually performed after induction of general anesthesia.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 1098.
