Page 144 Guide to Pain Management in Low-Resource Settings

132 Katarina Jankovic

positioning and the size of pregnancy can infl uence the involved early on, if surgery seems likely. Th e epidural
spread and extent of the block. Reducing the dose of must be topped up as soon as possible, unless a very
local anesthetic to less than 10 mg hyperbaric or plain recent top-up has been given during labor, and then
0.5% bupivacaine without any opioid added can give an 20 mL of plain 0.5% bupivacaine seems to be the best
inadequate block. Fentanyl can be added at a dose range choice. Once the top-up has been given, the anesthe-
of 12.5–15 μg. Increasing the dose beyond this recom- siologist must stay with the patient all the time, check
mended dose does not seem to provide better analgesia her blood pressure, and have diluted ephedrine at
intra- or postoperatively. Patient positioning does not hand. Th e safest position for the mother during trans-
seem to infl uence the fi nal level or height of the block, port to the operating room is the full lateral position.
but it interferes with the rate of onset and spread of the If there is any inequality in the spread of the block on
local anesthetic. Th e sitting position is commonly used initial assessment, put the mother in the full lateral po-
by many anesthesiologists, but a lateral position can be sition on the side of the poor block and give the top-
used too. up. Th e average time for this block to take eff ect is
Th e block extended to T5 to light touch is an about 15 minutes.
eff ective level for this type of surgery, using either the
epidural or spinal technique. Th e only diff erence may be Pearls of wisdom
that a more profound block is achieved more easily with
the intrathecal block. Th ere are a variety of pharmacological options for
managing the pain of parturition. Opioids adminis-
tered systemically act primarily by inducing somno-
How to test the block
lence, rather than by producing analgesia. Moreover,
It has been found that absence of sensation to cold is placental transfer of opioids to the fetus may produce
two dermatomes higher than sensation of pinprick, neonatal respiratory depression. Th e advantage of sys-
which in turn is two dermatomes higher than sensation temic analgesia is its simplicity. Fancy techniques such
to light touch. Th at means that light touch is the best as intravenous patient-controlled analgesia (PCA) are
method to test the level of the block. If sensation to light nice but not necessary to achieve good analgesia. An
touch is lost at the level of S1 to T8–6 (the level of the adequately trained midwife or obstetrician is able to
nipples is around T5), there is adequate anesthesia for provide excellent nurse- or physician-controlled an-
the surgery. Th e extent of the motor block mirrors the algesia in locations where an anesthesiologist is not
block of light touch (with the corner of a tissue or a ny- available or if regional analgesia (epidural and/or spinal)
lon fi lament) and is mostly adequate with complete ab- is contraindicated.
sence of hip fl exion and ankle dorsifl exion. Th e anesthe- Regional analgesic techniques are the most reli-
tist should always use the same technique to assess the able means of relieving the pain of labor and delivery.
block, and it is important to do so bilaterally. Measuring Furthermore, by blocking the maternal stress response,
the thoracic dermatomes must be done about 5 cm lat- epidural and spinal analgesia may reverse the untow-
eral to the midline. ard physiological consequences of labor pain. Another
advantage of the epidural technique is that an in situ
epidural catheter may be used to administer anesthet-
If an epidural is already in use ics to provide pain relief for instrumental or cesarean
for a vaginal delivery, but cesarean delivery, if required. If no epidural catheter is in place
section is necessary, how should already, spinal anesthesia—a safe and easy technique—
one proceed? may be a good and perhaps even preferable alternative
for general anesthesia.
Th e volume of epidural top-up to convert epidural an- For cesarean delivery under neuraxial anesthe-
algesia for labor into epidural anesthesia for cesarian sia, the primary drug used is a local anesthetic. If an
section is variable. If surgery is urgent, a large initial epidural approach is used, 2% lidocaine with epineph-
bolus of local anesthetic is required for fast and reli- rine, 5 μg/mL, is a reasonable choice, because systemic
able onset of anesthesia. Initially, the existing block cardiotoxic eff ects are relatively unlikely to occur. Al-
must be assessed, and the anesthesiologist must be ternatively, 0.5% bupivacaine or ropivacaine may also