Te. Salomaki et al., EPIDURAL VERSUS INTRAVENOUS FENTANYL FOR REDUCING HORMONAL, METABOLIC, AND PHYSIOLOGICAL-RESPONSES AFTER THORACOTOMY, Anesthesiology, 79(4), 1993, pp. 672-679
Background: Previous attempts to prevent all the unwanted postoperativ
e responses to major surgery with an epidural hydrophilic opioid, morp
hine, have not succeeded. The authors' hypothesis was that the lipophi
lic opioid fentanyl, infused epidurally close to the spinal-cord opioi
d receptors corresponding to the dermatome of the surgical incision, g
ives equal pain relief but attenuates postoperative hormonal and metab
olic responses more effectively than does systemic fentanyl. Methods:
Forty patients were randomly assigned to receive either fentanyl epidu
rally and saline intravenously, or fentanyl intravenously and saline e
pidurally, in a double-blind fashion for the first 20 h after thoracot
omy. For each patient, the fentanyl infusion was titrated to the rate
required for pain relief (pain score < 3, maximum 10). Postoperative c
hanges in blood pressure, heart rate, rectal temperature, and blood co
ncentrations of adrenocorticotrophic hormone, beta-endorphin immunorea
ctivity, cortisol, growth hormone, prolactin, glucose, and leukocytes
were assessed. Results: Patients reported similar median pain scores,
but the epidural group required about 40% less fentanyl than the intra
venous group. Four hours postoperatively, the beta-endorphin immunorea
ctivity concentrations were less in the epidural than in the intraveno
us group. Plasma cortisol increased in a similar manner in both groups
within 4 h of surgery, but the increase persisted to the next morning
only in patients receiving intravenous fentanyl. Adrenocorticotropin,
growth hormone, and prolactin responses were similar in both groups.
The postoperative hyperglycemic response, leukocytosis, and blood pres
sure were greater, and mean rectal temperature was lower, in the intra
venous than in the epidural fentanyl group. Conclusions: The authors'
results indicate that some aspects of the hormonal response to surgery
are blocked more completely with epidural than with intravenous fenta
nyl. Adequate pain relief with epidural fentanyl, with a smaller mean
dose, ted to a smaller increase of some hormonal, metabolic, and physi
ologic responses after thoracotomy than in association with the adequa
te pain relief provided by intravenous fentanyl.