Acute high dose-fentanyl exposure produces hyperalgesia and tactile allodynia after coronary artery bypass surgery

V. Yildirim, S. Doganci, S. Cinar, M.B. Eskin, G. Ozkan, S. Eksert, M.E. Ince, A. Dogrul

Department of Anesthesiology and Intensive Care, Gulhane Military Academy of Medicine, Ankara, Turkey. [email protected]

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• Anesthesiology

OBJECTIVE: Opioid-induced hyperalgesia is well known complication of acute high dose and chronic opioid therapy. In this study, we evaluated development of opioid-induced hyperalgesia following intraoperative short-term use of µ-opioid agonist fentanyl after coronary artery bypass surgery.

PATIENTS AND METHODS: 100 patients undergoing elective coronary artery bypass graft surgery is divided into two groups. In group I (low dose), anesthesia was induced with propofol 1-2.5 mg/kg and fentanyl 2 mcg/kg, in group II (high dose) fentanyl 40-70 mcg/kg was used. In group I, propofol 5-10 mg/kg/h, fentanyl 1-3 mcg/kg/h, in group II fentanyl 5-10 mcg/kg/h was used for maintenance of anesthesia. The tactile and thermal thresholds were measured before surgery and in 1st, 3rd and 7th postoperative days by using Von Frey filaments and a thermal source, respectively.

RESULTS: Tactile thresholds were significantly decreased at the first (6,08 ± 0.21 and 3.76 ± 0.13 g; p < 0.001) and third (6.76 ± 0.24 and 4.96 ± 0.16 g; p < 0.001) postoperative days compared to baseline preoperative values (7.72 ± 0.26, and 7.60 ± 0.21 g; p = 816) in two groups. Postoperative 1st (13.45 ± 0.33 and 10.05 ± 0.24 sec; p < 0.001) and 3rd day (14.77 ± 0.28 and 13.17 ± 0.26 sec; p < 0.001) assessments showed a statistically significant thermal hyperalgesia compared to the preoperative baseline values (16.67 ± 0.51 and 16.45 ± 0.42 sec; p = 0.997) in two groups. This decrease in both tactile and thermal thresholds returned to baseline control values at the 7th day of measurement.

CONCLUSIONS: Our results showed that patients undergoing coronary artery bypass surgery receiving fentanyl anesthesia developed postoperative tactile allodynia and thermal hyperalgesia and this was more prominent in high dose group.

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