doc
Spring 2016 • Kentucky
Post Operative Analgesia
Following Abdominal and Urologic
Endoscopic Surgery
By Thomas K.
Slabaugh, Jr., MD
Postoperative analgesia
can be a challenge to both
patients and surgeons. For
patients, postoperative
abdominal pain can limit mobility, inspiration effort and appetite potentially leading
to DVT, deconditioning, atelectasis, pneumonia and dehydration. It is clear that pain
can cause significant morbidity, and it is
paramount that the surgeon has knowledge
of multiple treatment modalities that can be
used together to avoid comorbidity while
optimizing patient comfort.
Classically, opioid analgesia is a mainstay
following abdominal surgery. Oral opiates
are often used and can be supplemented
with parenteral agents as needed if an
inpatient setting is appropriate. Patient controlled analgesia, PCA, is utilized frequently
as a way to avoid over use of parenteral
opioid analgesia. With this approach the
patient is able to control the dosing with
computer driven limits to avoid over sedation and respiratory depression. In extreme
cases, a basal rate of opiates can be administered with PCA in addition to the patient
controlled bolus. This should only be used
in cases where analgesia is difficult and
the practitioner is familiar with basal rate
administration.
Unfortunately, opioid analgesia has its
drawbacks, especially in abdominal surgery. First, respiratory depression must be
guarded against. Reversal agents should
be available especially in the case of PCA
use. Respiratory depression can also lead
to problems like atelectasis and pneumonia; thus, respiratory hygiene is imperative
while patients are using parenteral opiates.
Postoperative ileus is a second problem
that can be linked directly to opiate use.
Abdominal surgery, open or laparoscopic,
can certainly cause ileus, but this ileus can
be exacerbated by opiate use. Increased
inhibitory neural input, heightened inflammatory responses, decreased propulsive
movements and increased fluid absorption
in the gastrointestinal tract hallmark opioidinduced bowel dysfunction. Treatment
of this problem is typically supportive,
limiting opiate use as tolerated. There are
reversal agents, however, it is difficult to
induce reversal of the opioid-induced bowel
dysfunction without reversal of the pain
relief. Methyl naltrexone and alvimopan
are recently developed opioid antagonists
that are peripherally acting and have some
success at reversal of opioid-induced bowel
dysfunction.
With avoidance of opioid induced comorbidity in mind, there are several approaches
which have been successful in limiting
amount of narcotic needed in the post operative setting. Examples include: use of antiinflammatory supplemental agents, use of
continuous infusion analgesic pumps, use of
epidural analgesia, and use of nerve blocks.
Supplemental anti-inflammatory medication can significantly limit opiate analgesic
requirement for the postoperative patient.
Intravenous acetaminophen and ketorolac
are both anti-inflammatory agents that are
routinely used in treatment of postoperative pain associated with abdominal surgery.
Both agents significantly limit the need for
opiates thus preventing the potential opiate
induced- comorbidities. Intravenous acetaminophen and ketorolac both need to be
monitored for their toxicities, liver and renal
failure respectively. Ketorolac is especially
useful in the treatment of ureteral colic both
in the postoperative setting and the setting
of acute ureteral obstruction. In the case of
ureteral obstruction, it not only serves as an
anti-inflammatory but also limits ureteral
peristalsis and spa