Effects of protracted administration of FNT on immune function of surgical cancer patients

The opioid agonist fentanyl is widespread used for acute pain management and sedation in the ICU. The aim of this study was to investigate the effects of fentanyl on both innative and adapted immune function in surgical cancer patients recovered in the ICU.

Materials and methods

This study was prospectively performed in 10 cancer patients (mean age 66 ± 5, APACHE II 9 ± 3) who underwent elective surgery and who recovered in the ICU for 2 days. Fentanyl was administered for analgesia during surgery and postoperatively as the only analgesic and sedative for a total of 12 hours. The dose of FNT was regulated according to the demands of the patients in order to obtain optimal analgesia and sedation. Respiratory burst activity and phagocytosis of both polymorphonuclear cells (PMNC) and monocytes (MNC), as well as NKc percentage and phenotypes of peripheral blood lymphocytes were determined from blood samples drawn before induction of anesthesia and at 24 and 48 hours after surgery. Sample testing was performed utilizing the flow cytometric technique.

Statistical analysis was computed with the paired t test. P < 0.05 was considered significant.

Results

The cumulative dose of fentanyl was 2.58 ± 1.03 mg. MNCs presented a statistically significant (P < 0.05) increase in their phagocytic function at 48 hours while their respiratory burst activity increased significantly at 24 hours and returned to baseline values at 48 hours. Phagocytic function of PMNCs was significantly (P < 0.05) depressed at 24 hours but recovered at 48 hours while their respiratory burst activity remained unchanged. The percentage of NK cells decreased significantly (P < 0.05) at 48 hours.

Overall, T lymphocytes as well as the subsets of T-helper and T-cytotoxic cells decreased significantly (P < 0.05) at 24 hours but returned to baseline values at 48 hours. There was no effect on B lymphocytes.

Conclusion

Protracted administration of recommended doses of fentanyl affects both innative and adapted immune function in surgical cancer patients. It exerts a suppressive effect on PMNCs, NKc and T lymphocytes while it is enhancing in MNCs. This effect is generally transient, reversing 36 hours after the interruption of the administration with the exception of NKc and the phagocytic function of MNCs, the changes of which are significantly persistent

The different response between MNCs and PMNCs might be attributed to different opioid receptors.