Intravenous morphine after gynecological surgery : pain relief, endocrine and immune respone
- Publisher: Karolinska Institutet, false
MEDICAL AND HEALTH SCIENCES | MEDICIN OCH HÄLSOVETENSKAP | Anaesthesia: general, epidural. Postoperative pain: PCA, morphine, bupivacaine. Hormones: adrenocortical steroids, estrogens. Immune response: Interleukin-6.
Background: We need more efficient methods to alleviate postoperative
pain and reduce endocrine / immune stress response.
Subjects and methods: Patient controlled analgesia (PCA) with iv morphine
was evaluated with respect to pain relief and endocrine / immune response
to surgical trauma in 130 patients undergoing gynecological surgery.
Anesthetic regimens included general anesthesia, epidural anesthesia,
epidural morphine and combinations of these methods.
Results: Large individual differences in iv morphine consumption were
found. In the early hours after abdominal gynecological surgery in
general anesthesia high doses of iv morphine increased side effects
without improving pain relief. Infiltration of bupivacaine or morphine in
the wound did not improve pain relief although bupivacaine reduced
morphine consumption. Epidural anesthesia with addition of epidural
morphine provided superior pain relief and reduced the need for iv
morphine. The risk of side effects demands prolonged postoperative
supervision. We found no correlation between pain scores and morphine
concentrations or morphine consumption. The explanation may be inadequate
effects of iv opioids on the visceral component in pain after
A concomitant increase in adrenal C21 (cortisol,
17a-hydroxy-progesterone) and Cl9 steroids (dehydroepiandrosterone,
4-androstene-3, 17-dione) was observed during surgery and in the early
postoperative hours, reflecting increased ACTH stimulation. During the
later postoperative phase C21 steroid levels remained elevated while Clg
steroid levels decreased, indicating a redistribution of intraadrenal
steroid flux from androgens towards glucocorticoids, probably in order to
maintain an adequate prolonged cortisol secretion.
The endocrine response was alleviated by epidural morphine and to a
lesser extent by large doses of iv morphine. Infiltration of bupivacaine
or morphine into the edge of the wound did not improve pain relief or
modify the surgical trauma response. The immune response measured as
plasma IL-6 was influenced by the magnitude of the trauma and reduced by
epidural anesthesia and by large doses of iv morphine.
Conclusions: The method of anesthesia is important to postoperative pain
and stress. In the early hours after gynecological surgery iv morphine
provides inadequate pain relief. Epidural anesthesia together with
epidural morphine is superior with respect to pain relief and alleviation
of endocrine / immune response. The adrenocortical trauma response
follows a biphasic pattern. Postoperative use of PCA with iv morphine can
not compensate for the differences in peroperative anesthetic technique
with respect to postoperative pain and trauma response.
Key words: Anaesthesia: general, epidural. Postoperative pain: PCA,
morphine, bupivacaine. Hormones: adrenocortical steroids, estrogens.
Immune response: Interleukin-6.