Understanding Anesthesiology - The Global Regional Anesthesia ...

SECTION 2
Post-operative Pain Management
In This Section
1. Intravenous Analgesia
2. Central Neuraxial Analgesia
3. Peripheral Nerve Blocks
Appropriate pain control not only contributes to
patient comfort, it decreases the incidence of
post-operative complications such as cardiac
ischemia, pulmonary atelectasis and delirium.
Many factors need to be considered when determining
the method of post-operative analgesia.
The most important factors are the patient’s medical
history and the nature of the surgical procedure.
Oral analgesics (acetaminophen, codeine
phosphate, non-steroidal anti-inflammatories) or
intramuscular opioids may be sufficient in many
cases. However, often, more sophisticated techniques
are required.
Patient-controlled analgesia
Patient-controlled analgesia (PCA) permits the
patient to administer the delivery of his own analgesic
by activating a button, which then triggers
the intravenous delivery of a predetermined
dose of an opioid such as morphine. Limits are
set on the number of doses per four-hour period
and on the minimum time that must elapse between
doses (lockout interval). The pharmacokinetic
advantage of PCA is that by selfadministering
frequent, small doses, the patient
is able to come closer to achieving a steady state
analgesic level in the blood, avoiding the high
peaks and low troughs that can be found with intermittent
(intramuscular) opioid administration.
Indeed, PCA has been shown to provide equivalent
analgesia with less total drug dose, less sedation,
fewer nocturnal disturbances and more
rapid return to physical activity. In addition, patient
acceptance is high since patients have a significant
level of control over their pain management.
PCA analgesia is not without side effects, the
most common of which is nausea and vomiting.
Excessive sedation and pruritis may also be seen.
Standardized orders provide “as needed” orders
for medications to counteract both nausea and
pruritis.
Although it does not obviate the need for close
monitoring, PCA frees nursing personnel from
administering analgesic medication. Since patients
titrate their own therapy with PCA, they
must be capable of understanding the principle,
willing to participate and physically able to activate
the trigger. Consequently, use is prohibited
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