척추마취 하에 무릎 전치환술을 받는 노인환자에서 dexmedetomidine의 스트레스 반응 경감, 혈역학적 안정성 및 수술 후 진통 효과

Abstract

Background: The beneficial effects of dexmedetomidine (DEX) have not been extensively investigated in elderly patients receiving spinal anesthesia. This study evaluated the effects of intravenous DEX infusion on stress biomarkers, the hemodynamic response, and postoperative analgesia in elderly patients undergoing total knee replacement arthroplasty (TKRA). Methods: We randomly allocated 45 adult American Society of Anesthesiologists(ASA) classification I–II patients undergoing elective TKRA under spinal anesthesia into 3 patient groups (n = 15 each); group C patients underwent unilateral TKRA without DEX administration, group D1 patients underwent unilateral TKRA with DEX administration, and group D2 patients underwent bilateral TKRA with DEX administration. In groups D1 and D2, DEX was initially infused at a concentration of 0.4 μg·kg-1·h-1 prior to anesthesia. After that time, the dose was adjusted to maintain 3 points on the Ramsay sedation score. Hemodynamic parameters were recorded intraoperatively at 5-min intervals. Serum interleukin-6 (IL-6), cortisol, and glucose concentrations were measured preoperatively, and at 6 and 24 h postoperatively. Postoperative patient satisfaction, pain scores, and analgesic requirements were also assessed. Results: The preoperative serum IL-6 levels were 1.0 ± 1.0 pg/mL, 0.9 ± 1.2 pg/mL, and 0.5 ± 0.8 pg/mL in group C, group D1, and group D2, respectively. The serum IL-6 level was significantly lower in group D2 compared to in group C at 6 h (35.8 ± 22.7 pg/mL vs. 52.5 ± 23.5 pg/mL, respectively; p < 0.05) and 24 h (50.7 ± 25.3 pg/mL vs. 84.1 ± 32.2 pg/mL, respectively; p < 0.05). Bradycardia occurred more frequently in groups D1 and D2 compared to group C (33.3% and 53.3% vs. 6.7%, respectively; p < 0.05). The number of patients who required rescue analgesic drug was greater in group C than in groups D1 and D2 at 6 h postoperatively (26.7% vs. 0% and 6.7%, respectively; p < 0.05). The patient satisfaction score was higher in groups D1 and D2 than it was in group C (8.8 ± 0.9 and 8.7 ± 1.7 vs. 7.7 ± 1.6, respectively; p < 0.05). Conclusion: Perioperative intravenous DEX administration has a postoperative analgesic-sparing effect and increases patient satisfaction without serious complications in elderly patients undergoing TKRA under spinal anesthesia. In addition, long-term administration of perioperative DEX was associated with a decreased postoperative serum IL-6 level.