Preventive Effect Of Dexmedetomidine Research Articles

The role of perioperative sedative anesthetics in preventing postoperative delirium: a systematic review and network-meta analysis including 6679 patients

ObjectivePostoperative delirium is a common and debilitating complication that significantly affects patients and their families. The purpose of this study is to investigate whether there is an effective sedative that can prevent postoperative delirium while also examining the safety of using sedatives during the perioperative period.MethodsThe net-meta analysis was used to compare the incidence of postoperative delirium among four sedatives: sevoflurane, propofol, dexmedetomidine, and midazolam. Interventions were ranked according to their surface under the cumulative ranking curve (SUCRA).ResultsA total of 41 RCT studies involving 6679 patients were analyzed. Dexmedetomidine can effectively reduce the incidence of postoperative delirium than propofol (OR 0.47 95% CI 0.25–0.90), midazolam (OR 0.42 95% CI 0.17-1.00), normal saline (OR 0.42 95% CI 0.33–0.54) and sevoflurane (OR 0.39 95% CI 0.18–0.82). The saline group showed a significantly lower incidence of bradycardia compared to the group receiving dexmedetomidine (OR 0.55 95% CI 0.37–0.80). In cardiac surgery, midazolam (OR 3.34 95%CI 2.04–5.48) and normal saline (OR 2.27 95%CI 1.17–4.39) had a higher rate of postoperative delirium than dexmedetomidine, while in non-cardiac surgery, normal saline (OR 1.98 95%CI 1.44–2.71) was more susceptible to postoperative delirium than dexmedetomidine.ConclusionOur analysis suggests that dexmedetomidine is an effective sedative in preventing postoperative delirium whether in cardiac surgery or non-cardiac surgery. The preventive effect of dexmedetomidine on postoperative delirium becomes more apparent with longer surgical and extubation times. However, it should be administered with caution as it was found to be associated with bradycardia.

The preventive effect of dexmedetomidine on anesthesia complications in strabismus surgery: a systematic review and meta-analysis

ObjectiveDexmedetomidine is a medication that has analgesic, sedative, and anti-anxiety properties. In the clinical, it is often used to prevent common complications associated with strabismus surgery, including postoperative delirium, postoperative nausea and vomiting, postoperative pain, and oculocardiac reflex. However, its effectiveness and side effects of the present studies are different. The sample sizes of the present studies on the prevention of complications of dexmedetomidine are small. Therefore, this study evaluates the efficacy of dexmedetomidine in preventing anesthesia-related complications in strabismus surgery through a systematic review and meta-analysis.MethodsLiterature was retrieved from 10 commonly used databases and randomized controlled trials published up to May 2022 were sought. The included studies compared the intervention effects of dexmedetomidine versus placebo on anesthesia-related complications in surgery. The occurrence rates of postoperative delirium, postoperative nausea and vomiting, postoperative pain, and oculocardiac reflex in patients undergoing strabismus surgery were evaluated. Statistical analyses and forest plots were generated using Review Manager and STATA software. Binary outcomes were measured using relative risk (RR) with a 95% confidence interval for each outcome. The Cochrane risk of bias tool was used to assess the bias and risk in the studies that met the inclusion criteria.ResultsA total of 13 articles were ultimately included in the analysis, comprising 1,018 patients who underwent strabismus surgery. The dexmedetomidine group, compared to the placebo group, demonstrated significant reductions in the incidence of postoperative delirium (RR = 0.73, P = 0.001), severe postoperative delirium (RR = 0.45, P = 0.005), postoperative nausea and vomiting (RR = 0.48, P < 0.0001), and the need for supplemental analgesia postoperatively (RR = 0.60, P = 0.004). Additionally, subgroup analysis revealed that intravenous administration of dexmedetomidine significantly reduced the incidence of oculocardiac reflex (RR = 0.50, P = 0.001). In contrast, intranasal administration of dexmedetomidine did not have a significant effect on the incidence of oculocardiac reflex (RR = 1.22, P = 0.15). There was a significant difference between the subgroups (P = 0.0005, I2 = 91.7%).ConclusionAmong patients undergoing strabismus surgery, the use of dexmedetomidine can alleviate postoperative delirium and reduce the incidence of postoperative nausea and vomiting, as well as postoperative pain. Moreover, intravenous administration of dexmedetomidine can lower the occurrence rate of the oculocardiac reflex.

The Preventive Effect of Dexmedetomidine Against Delirium in Patients with Aortic Dissection: A Retrospective Cohort Study

Background: Dexmedetomidine (DEX) is often used to reduce the incidence of delirium in intensive care unit (ICU) patients. However, it was found in our clinical practice that the incidence of delirium in some patients with aortic dissection (AD) remained high even after using DEX. The aim of the present study was to clarify whether the protective effects of DEX against delirium were different between Stanford type A and B AD patients during ICU stay. Methods: Data of patients with Stanford type A or B AD who were treated in the ICU of our hospital between 2015 and 2018 retrospectively were reviewed. They were divided into four groups: A1 group (Stanford type A AD patients using DEX), A2 group (Stanford type A AD patients without using DEX), B1 group (Stanford type B AD patients using DEX), and B2 group (Stanford type B AD patients without using DEX). Patients in A1 and B1 groups received intravenous administration of DEX within 1 h admission to the ICU and after surgery or stent implantation at a loading dose of 1 µg/kg, followed by continuous infusion of 0.2–0.7 µg/(kg·h) for &gt;24 h. The mortality rate, delirium incidence, length of ICU stay, and drug administration were compared between the four groups. Results: After intravenous administration of DEX, the delirium incidence in B1 group was reduced significantly compared with that in B2 group (2.8% vs. 17.8%, P = 0.04), while there was no significant difference between A1 and A2 group (20.8% vs. 24.3%, P = 0.7). However, DEX administration significantly reduced the use of anti-hypertensive drugs (P = 0.04) and morphine (P = 0.02) in Stanford type A AD patients. Conclusion: The use of DEX reduced the incidence of delirium in Stanford type B AD patients during ICU stay, therefore reducing the risk of medical accidents and risk of rupture of the aortic dissecting aneurysm. The preventive effect of DEX against delirium in Stanford type A AD patients was not obvious, and whether increasing the dosage of DEX could enhance the therapeutic efficacy in this group of patients needs to be further observed in future studies.

The preventive effect of dexmedetomidine combined with nalbuphine on fentany-linduced hyperalgesia after nanocarbon laparoscopic hysterectomy

This study aimed to explore the preventive effect of dexmedetomidine combined with nalbuphine on fentany-linduced hyperalgesia after nanocarbon laparoscopic hysterectomy. A total of 172 patients diagnosed with cervical cancer and undergoing nanocarbon laparoscopic hysterectomy at Second Hospital of Lanzhou University from February 2017 to October 2019 were selected and divided into a control group (Group C), patients treated with dexmedetomidine (DEX) combined with nalbuphine as the combined group (Group M), the dexmedetomidine group (Group D), and the nalbuphine group (Group N). The imaging and detection rate of sentinel lymph nodes traced by carbon nanoparticles (CNP) was observed and counted, the sedation score and visual analog score (VAS), mechanical pain threshold 24 h before and after the operation, mean arterial pressure (MBP) at each time, heart rate (HR), and adverse reactions were all recorded. The results showed that the total detection rate, sensitivity, and accuracy of CNP tracer sentinel lymph nodes were 97.67%, 90.47%, 95.34%, and 97.67%, respectively. The sentinel and black-stained lymph nodes removed after surgery did not fade. The time of recovery, the HR after intubation, pneumoperitoneum, and extubation in group D were significantly different from the other three groups (P &lt; 0.05). The pain threshold, MBP P &lt; after intubation, and VAS scores at T0–T3 were significantly different from those in other groups (P &lt; 0.05); the Ramsay sedation score was higher in group D than T0–T2 (P &lt; 0.05); the time of first analgesia, the amount of sufentanil, and the number of analgesic pump compressions in group C were significantly different from those in other groups (P &lt; 0.05). The incidence rate of bradycardia in group D was 48.83%, and that of postoperative chills in group C was 30.23%, which was significantly different from other groups (P &lt; 0.05). Therefore, DEX combined with nalbuphine based on nano-carbon laparoscopic hysterectomy could reduce remifentanil-induced hyperalgesia and postoperative side effects, which provided a reference for the prevention of hyperalgesia.

Bispectral-Based Ultrasound Image Restoration Algorithm for Neurological Disorders Analysis in Patients Anesthetized with Sevoflurane

The aim of this work was to investigate preventive effect of dexmedetomidine combined with sevoflurane on neurological disorders in liver cancer patients during postoperative recovery under the ultrasound image restoration (UIR) algorithm. A blind deconvolution medical UIR algorithm was established in this study. The patients anesthetized with sevoflurane for liver cancer surgery were rolled into an experimental group (group A) (dexmedetomidine treatment before surgery) and a control group (group B) (normal saline treatment before surgery). They were monitored routinely before, during, and after surgery, and immune and liver functions of patients were observed before and after surgery. Besides, their cognitive function and adverse reactions were assessed after surgery. Results showed that patients from group A had smaller fluctuation in average arterial blood pressure and heart rate, but their bispectral index (BIS) increased obviously after surgery in contrast to those of group B ( P &lt; 0.05 ). Moreover, changes of immune and liver functions in patients from group A decreased sharply compared with group B ( P &lt; 0.05 ). The postoperative minimental state examination (MoCA) score of patients from group A was 27.51 ± 2.02, while the score of group B was 25.79 ± 2.35. The postoperative (MoCA) score of group A was markedly higher than the score of group B, and the difference was statistically obvious ( P &lt; 0.05 ). Besides, the incidence of postoperative cognitive dysfunction (POCD) in patients from group A and B was 12.91% and 32.26% in turn. The incidence of POCD in patients from group A was sharply lower than the incidence of group B ( P &lt; 0.05 ). In addition, the total incidence of adverse reactions in patients from group A was 6.45%, which was significantly lower than the 22.58% of group B, and the difference was statistically substantial ( P &lt; 0.05 ). In summary, dexmedetomidine combined with sevoflurane could effectively reduce POCD and promote systemic circulation recovery, which had clinical application value.

Preventive effect of dexmedetomidine on postictal delirium after electroconvulsive therapy: A randomised controlled study.

Postictal delirium (PID) is a relatively common complication following electroconvulsive therapy (ECT). We investigated whether prophylactic dexmedetomidine administration would safely decrease the incidence of PID in psychiatric patients after ECT. A randomised, double-blind, placebo-controlled trial. A total of 223 patients undergoing ECT were randomly allocated to two groups. Patients received 0.5 μg kg dexmedetomidine (Dex group, n=111) or 0.9% sodium chloride (Con group, n=112) before ECT. Propofol was used for anaesthesia and succinylcholine for muscle relaxation. The incidence of PID was measured using the Confusion Assessment Method for the Intensive Care Unit. The percentage of patients who were diagnosed with PID at any ECT session during the whole treatment. PID occurred in 76 (67.9%) of 112 patients given saline (0.9% sodium chloride), and in 49 (44.1%) of 111 patients given dexmedetomidine during the whole treatment. There was a significant difference in the incidence of PID between two groups (P < 0.001). Post hoc analyses showed that the incidence of PID was significantly lower in the Dex group than in the Con group from the first to the seventh ECT session (P < 0.005). There were no significant differences in seizure duration or recovery time between the two groups. Heart rate and mean arterial pressure in the Dex group were significantly lower than in the Con group at 0, 5 and 15 min after electrical stimulation. No patients developed bradycardia, hypotension or respiratory depression during recovery. Pretreatment with dexmedetomidine leads to a significant reduction in the incidence of PID with no respiratory depressant effect. Dexmedetomidine might be considered an effective method for the prevention of PID post-ECT. Chinese Clinical Trial Registry ChiCTR-IOR-17012306.

Preventive Effects of Dexmedetomidine on Renal Dysfunction and Hemodynamic Stability in Malignant Obstructive Jaundice Patients During Peri-Operative Period.

BackgroundThis study aimed to investigate effects of intra-operative administration with dexmedetomidine (Dex) on hemodynamics and renal function in patients with malignant obstructive jaundice.Material/MethodsOur randomized, double-blinded, placebo-controlled study was conducted among 40 patients with malignant obstructive jaundice between August 2009 and March 2011 in The Affiliated Hospital of Inner Mongolia Medical University. The 40 patients were randomly divided into 2 groups: the Dex group (receiving Dex 0.5 μg/kg 10-minutes before induction and then a 0.5 μg/kg/hour maintenance infusion until end of operation 30 minutes) and the Control group (receiving normal saline of same amount and at same rate). The adverse events, including incidence of cardiovascular complications and nausea and vomiting, and length of hospital stay were determined. The level of cystatin C (CysC), retinol-binding protein (RBP), creatinine (Scr), and blood urea nitrogen (BUN) were also evaluated.ResultsDexmedetomidine administration significantly decreased heart rate (HR) and stroke volume variation (SVV) and significantly increased capital venous pressure (CVP) and mean arterial pressure (MAP) values compared to that in the Control group (P<0.05). Dexmedetomidine administration significantly upregulated urine volume and significantly downregulated atropine levels compared to the Control group (P<0.05). Dexmedetomidine administration significantly improved renal functions, by modulating CysC, RBP, Scr and BUN levels compared to the Control group (P<0.05). Dexmedetomidine administration demonstrated no additional side-effects. Dexmedetomidine administration significantly shortened length of hospitalization in the Dex group compared to the Control group (P<0.05).ConclusionsDexmedetomidine plays preventive effects on renal dysfunction and hemodynamic stability in malignant obstructive jaundice patients during peri-operative period.

The preventive effects of dexmedetomidine on endotoxin-induced exacerbated post-incisional pain in rats.

Low-grade endotoxin (lipopolysaccharide; LPS) exposure may contribute to the development of exaggerated acute postoperative pain. In the present study, we investigated the possible impact of intraoperative administration of dexmedetomidine (DEX) on LPS-induced postoperative hyperalgesia in a rat incisional pain model. The surgical and sham-surgical animals were randomly divided into saline-treated control, 5.0mg/kg LPS-treated, 10µg/kg DEX-treated, and 5.0mg/kg LPS+10µg/kg DEX-treated groups. In the surgical animals, a 1-cm-long plantar incision was made through the skin and fascia under isoflurane anesthesia. The sham-surgical rats were only anesthetized. All treatments were administered by a single intraperitoneal (i.p.) injection 60min before surgery. Acute postoperative pain was assessed using the Rat Grimace Scale (RGS) one day before surgery (baseline) and at 2h post incision. In another experiment, the involvement of the α2-adrenergic receptor was tested using atipamezole, an α2-adrenergic receptor antagonist. In the sham-surgical animals, the RGS did not increase at 2h after sham surgery compared with the corresponding baseline values in all groups. In the surgical rats, however, the postoperative RGS value of the LPS group was significantly higher than the control group, indicating LPS-induced postoperative hyperalgesia. Administration of intraoperative DEX could prevent the development of such LPS-induced exacerbated post-incisional pain. In addition, the preventive effects of intraoperative DEX were inhibited by pretreatment with atipamezole. Our findings indicate that intraoperative DEX treatment can prevent LPS-induced exacerbated post-incisional pain via the α2-adrenergic receptor signaling pathway.

The preventive effect of dexmedetomidine on paroxysmal sympathetic hyperactivity in severe traumatic brain injury patients who have undergone surgery: a retrospective study.

BackgroundParoxysmal sympathetic hyperactivity (PSH) results and aggravates in secondary brain injury, which seriously affects the prognosis of severe traumatic brain injury patients. Although several studies have focused on the treatment of PSH, few have concentrated on its prevention.MethodsNinety post-operation (post-op) severe traumatic brain injury (sTBI) patients admitted from October 2014 to April 2016 were chosen to participate in this study. Fifty of the post-op sTBI patients were sedated with dexmedetomidine and were referred as the “dexmedetomidine group” (admitted from May 2015 to April 2016). The other 40 patients (admitted from October 2014 to May 2015) received other sedations and were referred as the “control group.” The two groups were then compared based on their PSH scores and the scores and ratios of those patients who met the criteria of “probable,” “possible” and “unlikely” using the PSH assessment measure (PSH-AM) designed by Baguley et al. (2014). The durations of the neurosurgery intensive care unit (NICU) and hospital stays and the Glasgow outcome scale (GOS) values for the two groups were also compared to evaluate the therapeutic effects and the patients’ prognosis.ResultsThe overall PSH score for the dexmedetomidine group was 5.26 ± 4.66, compared with 8.58 ± 8.09 for the control group. The difference between the two groups’ PSH scores was significant (P = 0.017). The score of the patients who met the criterion of “probable” was 18.33 ± 1.53 in the dexmedetomidine group and 22.63 ± 2.97 in the control group, and the difference was statistically significant (P = 0.045). The ratio of patients who were classified as “unlikely” between the two groups was statistically significant (P = 0.028); that is, 42 (84%) in the dexmedetomidine group and 25 (62.5%) in the control group. The differences in NICU, hospital stays and GOS values between the two groups were not significant.ConclusionDexmedetomidine has a preventive effect on PSH in sTBI patients who have undergone surgery.

Preventive effects of dexmedetomidine on the development of cognitive dysfunction following systemic inflammation in aged rats.

In the present study, we examined whether and by what mechanisms dexmedetomidine (DMED) prevents the development of systemic inflammation (SI)-induced cognitive dysfunction in aged rats. Animals received a single intraperitoneal (i.p.) injection of either 5.0mg/kg lipopolysaccharide (LPS) or vehicle. LPS-treated rats were further divided into three groups: early DMED, late DMED, or midazolam (MDZ) treatment (n=12 each). Seven days after LPS injection, cognitive function was evaluated using a novel object recognition task, followed by measurement of hippocampal levels of proinflammatory cytokines and Toll-like receptor 4 (TLR-4) expression. For ex vivo experiments, microglia were isolated from the hippocampus for assessment of cytokine response to LPS. LPS-treated rats showed memory deficits, hippocampal neuroinflammation, and TLR-4 upregulation as compared to saline-treated animals. However, early DMED treatment was able to attenuate these SI-induced neurocognitive changes, whereas no benefits were observed in the MDZ and late DMED treatment groups. In ex vivo experiments, early DMED treatment prevented the development of SI-induced excessive microglial hyperactivation, which was blocked by the nonspecific α2-adrenergic receptor (AR) antagonist atipamezole or the specific α2A-AR antagonist BRL-44408, but not by the specific α2B/C-AR antagonist ARC-239. On the other hand, neither DMED nor MDZ had a direct effect on LPS-induced release of pro-inflammatory cytokines from hippocampal microglia at clinically relevant concentrations. Our findings highlight that treatment with DMED during, but not after, peripheral SI can prevent subsequent hippocampal neuroinflammation, overexpression of TLR-4 in microglia, and cognitive dysfunction, as mediated by the α2A-AR signaling pathway.

The preventive effects of dexmedetomidine against intestinal ischemia-reperfusion injury in Wistar rats.

Intestinal ischemia-reperfusion is a major problem, which may lead to multiorgan failure and death. The aim of this study was to evaluate the protective effects of dexmedetomidine on cell proliferation, antioxidant system, cell death, and structural integrity in intestinal injury induced by ischemia-reperfusion in rats. Animals were randomized into three groups: group A, sham-operated or control; group B, intestinal ischemia/reperfusion (IR); and group C, intestinal IR pretreated with 50 μg of dexmedetomidine. Intestine tissue was collected from all rats 30 min after desufflation, and fresh frozen for histological and biochemical evaluation. The intestinal tissue of group B rats showed a significant decrease in the antioxidant enzyme activities. However, these enzyme activities were improved by the administration of dexmedetomidine. Inhibiting the protein expression of MCP7, PAR2, P-JAK, P-STAT1, and P-STAT3 proved the protective effect of dexmedetomidine. The immunohistochemical staining revealed its protective effect by maintaining the normal structural integrity, less caspase-3 immuno reactivity, and increased cell proliferation count in the intestinal tissues. Intraperitoneal injection of dexmedetomidine significantly protected intestine IR injury in rats by inhibiting the inflammatory response, intestinal epithelial apoptosis, and maintaining structural integrity of intestinal cells.

The Preventive Effect of Dexmedetomidine Against Postoperative Intra-abdominal Adhesions in Rats.

This study aimed to determine the possible preventive effects of dexmedetomidine on postoperative intra-abdominal adhesions. Dexmedetomidine is a highly selective and potent α2 adrenergic agonist with sedative, analgesic, anxiolytic, sympatholytic, hemodynamic, and diuretic properties. In recent years, investigations have shown that dexmedetomidine possesses secondary antioxidant and also anti-inflammatory effects. Thirty Wistar albino male rats were randomized and divided into 3 groups of 10 animals each: group 1, sham-operated; group 2, cecal abrasion + peritoneal dissection; group 3, cecal abrasion + peritoneal dissection followed by daily intravenous injection of 10 μg/kg dexmedetomidine for 10 days. The animals were killed on postoperative day 21. Blood and cecal samples were taken for biochemical and histopathologic evaluation. In this study, biochemical and pathologic parameters were significantly better in the cecal abrasion + peritoneal dissection + dexmedetomidine group when compared with the cecal abrasion + peritoneal dissection group. Tissue malondialdehyde, myeloperoxidase, total sulfhydryl, and catalase were found to be significantly different between the cecal abrasion/peritoneal dissection + dexmedetomidine and the cecal abrasion/peritoneal dissection groups. Plasma malondialdehyde and total sulfhydryl values were also statistically different between these groups (P < 0.05). Statistical analyses of mean pathologic scores showed that the histopathologic damage in the cecal abrasion/peritoneal dissection + dexmedetomidine group was significantly less than the damage in the control group (P < 0.05 for all pathologic parameters). The results of this study show that dexmedetomidine had a significant preventive effect on postoperative intra-abdominal adhesions. We concluded that these effects might be due to antioxidant and anti-inflammatory activities.

Effect of dexmeditomidine on postoperative junctional ectopic tachycardia after complete surgical repair of tetralogy of Fallot: A prospective randomized controlled study

Introduction:Incidence of junctional ectopic tachycardia (JET) after repair of tetralogy of Fallot (TOF) is 5.6–14%. Dexmeditomidine is a α-2 adrenoceptor agonist modulates the release of catecholamine, resulting in bradycardia and hypotension. These effects are being explored as a therapeutic option for the prevention of perioperative tachyarrhythmia. We undertook this study to examine possible preventive effects of dexmedetomidine on postoperative JET and its impact on the duration of ventilation time and length of Intensive Care Unit stay.Methods:After obtaining approval from the hospitals ethics committee and written informed consent from parents, this quasi-randomized trial was initiated. Of 94 patients, 47 patients received dexmedetomidine (dexmedetomidine group) and 47 patients did not receive the drug (control group).Results:Dexmedetomidine group had more number of complex variants like TOF with an absent pulmonary valve or pulmonary atresia (P = 0.041). Hematocrit on cardiopulmonary bypass (CPB), heart rate while coming off from CPB and inotrope score was significantly low in the dexmedetomidine group compared to control group. The incidence of JET was significantly low in dexmedetomidine group (P = 0.040) compared to control group.Conclusions:Dexmedetomidine may have a potential benefit of preventing perioperative JET.

Preventive effects of dexmedetomidine on the liver in a rat model of acid-induced acute lung injury.

The aim of this study was to examine whether dexmedetomidine improves acute liver injury in a rat model. Twenty-eight male Wistar albino rats weighing 300–350 g were allocated randomly to four groups. In group 1, normal saline (NS) was injected into the lungs and rats were allowed to breathe spontaneously. In group 2, rats received standard ventilation (SV) in addition to NS. In group 3, hydrochloric acid was injected into the lungs and rats received SV. In group 4, rats received SV and 100 µg/kg intraperitoneal dexmedetomidine before intratracheal HCl instillation. Blood samples and liver tissue specimens were examined by biochemical, histopathological, and immunohistochemical methods. Acute lung injury (ALI) was found to be associated with increased malondialdehyde (MDA), total oxidant activity (TOA), oxidative stress index (OSI), and decreased total antioxidant capacity (TAC). Significantly decreased MDA, TOA, and OSI levels and significantly increased TAC levels were found with dexmedetomidine injection in group 4 (P < 0.05). The highest histologic injury scores were detected in group 3. Enhanced hepatic vascular endothelial growth factor (VEGF) expression and reduced CD68 expression were found in dexmedetomidine group compared with the group 3. In conclusion, the presented data provide the first evidence that dexmedetomidine has a protective effect on experimental liver injury induced by ALI.

Preventive Effect of Dexmedetomidine in Ischemia-Reperfusion Injury

The aim of this study was to evaluate the effects of dexmedetomidine on ischemia-reperfusion injury of epigastric island flaps of rats. Eighty Wistar rats were divided into 4 groups. After the flap elevation, in group 1, the flaps were sutured back without ischemic insult. Groups 2, 3, and 4 were exposed to ischemia for 12 hours. In groups 1 and 2, saline, in group 3, 10 μg/kg dexmedetomidine, and in group 4, 30 μg/kg dexmedetomidine were administered i.p. 45 minutes before I/R periods. Each group was subdivided further into 2 equal groups (a and b). Tissue samples of groups 1a, 2a, 3a, and 4a were obtained 12 hours after the reperfusion, and those of groups 1b, 2b, 3b, and 4b were obtained after 7 days. The necrotic areas were also calculated. Nitric oxide, malondialdehyde (MDA), and myeloperoxidase (MPO) activity were assessed in the tissue samples. Nitric oxide, MDA, and MPO activity levels in group 2a were significantly higher those in group 1a (P < 0.05). The levels in groups 3a and 4a were lower than those in group 2a (P < 0.05). Nitric oxide, MDA, and MPO activity levels were significantly higher in group 2b compared with group 1b (P < 0.05). The levels were lower in Groups 3b and 4b compared with group 2b (P < 0.05). Flap necrosis area was significantly lower in groups 3b and 4b than that in group 2b (P < 0.05). We conclude that administering dexmedetomidine before I/R periods can reduce ischemia-reperfusion injury of flaps, and it has a beneficial effect on flap survival.