Abstract
Background Clinical studies on the impact of dexmedetomidine on tourniquet-induced systemic effects have been inconsistent. We investigated the impact of dexmedetomidine on tourniquet-induced systemic effects in total knee arthroplasty. Methods Eighty patients were randomly assigned to either control (CON) or dexmedetomidine (DEX) group. The DEX group received an intravenous loading dose of 0.5 μg/kg DEX over 10 minutes, followed by a continuous infusion of 0.5 μg/kg/h from 10 minutes before the start of surgery until completion. The CON group received the same calculated volume of normal saline. Pain outcomes and metabolic and coagulative changes after tourniquet application and after tourniquet release were investigated. Results The frequency of fentanyl administration postoperatively, patient-controlled analgesia (PCA) volume at 24 hours postoperatively, total PCA volume consumed in 48 hours postoperatively, and VAS score for pain at 24 and 48 hours postoperatively were significantly lower in the DEX group than in the CON group. Ten minutes after the tourniquet release, the DEX group showed significantly higher pH and lower lactate level than those in the CON group. Antithrombin III activity and body temperature 10 minutes after tourniquet release were significantly lower in the DEX group than in the CON group. Ca2+, K+, HCO3−, base excess, and PCO2 levels 10 minutes after tourniquet release were not significantly different between the two groups. Conclusion We showed that DEX attenuated pain and hemodynamic, metabolic, and coagulative effects induced by the tourniquet. However, these metabolic and coagulative changes were within normal limits. Therefore, DEX could be used as an analgesic adjuvant, but should not be considered for routine use to prevent the systemic effects induced by tourniquet use.
Highlights
Tourniquet, which is widely used in surgeries of the extremities to induce a bloodless surgical field, can cause hemodynamic reaction, ischemia, and reperfusion injury, secondary to its inflation and deflation [1, 2]
Tourniquet time, tourniquet pain, amount of intraoperative fentanyl administration, the time between tourniquet application and the onset of pain, the peak level of sensory block, sensory dermatome at tourniquet pain, intraoperative blood loss, intravenous fluid administered, hypotension, postoperative delirium, amount of postoperative ketorolac administration, and patient-controlled analgesia (PCA) volume consumed at 48 hours after surgery were not significantly different between the two groups
24 hours after surgery (P < 0:01), total PCA volume consumed in 48 hours after surgery (P < 0:01), and visual analog scale (VAS) score for pain at 24 hours (P < 0:01) and 48 hours after surgery (P < 0:01) were significantly lower in the DEX group than the CON group (Table 2)
Summary
Tourniquet, which is widely used in surgeries of the extremities to induce a bloodless surgical field, can cause hemodynamic reaction, ischemia, and reperfusion injury, secondary to its inflation and deflation [1, 2]. It has been shown that alpha-2 receptor agonists, including DEX, have a preventive effect in various ischemia-reperfusion injury models; these agonists are effective in preventing hemodynamic reactions induced by tourniquet application during surgeries of the extremities by preventing the release of catecholamines [11,12,13]. Few studies have reported the effects of DEX on pain outcomes and metabolic, coagulative, and temperature changes by tourniquet-induced ischemia-reperfusion injury. Clinical studies on the impact of dexmedetomidine on tourniquet-induced systemic effects have been inconsistent. We showed that DEX attenuated pain and hemodynamic, metabolic, and coagulative effects induced by the tourniquet. These metabolic and coagulative changes were within normal limits. DEX could be used as an analgesic adjuvant, but should not be considered for routine use to prevent the systemic effects induced by tourniquet use
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