Ketamine Sedation During Spinal Anesthesia for Arthroscopic Knee Surgery Reduced the Ischemia-Reperfusion Injury Markers

Association between Preoperative Long-Chain Polyunsaturated Fatty Acids and Oxidative Stress Immediately after Total Knee Arthroplasty: A Pilot Study

Quadriceps muscle atrophy following total knee arthroplasty (TKA) can be caused by tourniquet-induced ischemia–reperfusion (IR) injury, which is often accompanied by oxidative stress and inflammatory responses. n-3 long-chain polyunsaturated fatty acids (LCPUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), exert antioxidant and anti-inflammatory effects against IR injury, whereas n-6 LCPUFAs, particularly arachidonic acid (AA), exhibit pro-inflammatory effects and promote IR injury. This study aimed to examine whether preoperative serum EPA + DHA levels and the (EPA + DHA)/AA ratio are associated with oxidative stress immediately after TKA. Fourteen eligible patients with knee osteoarthritis scheduled for unilateral TKA participated in this study. The levels of serum EPA, DHA, and AA were measured immediately before surgery. Derivatives of reactive oxygen metabolites (d-ROMs) were used as biomarkers for oxidative stress. The preoperative serum EPA + DHA levels and the (EPA + DHA)/AA ratio were found to be significantly negatively correlated with the serum d-ROM levels at 96 h after surgery, and the rate of increase in serum d-ROM levels between baseline and 96 h postoperatively. This study suggested the preoperative serum EPA + DHA levels and the (EPA + DHA)/AA ratio can be negatively associated with oxidative stress immediately after TKA.

The effect of pregabalin on tourniquet-induced ischemia-reperfusion injury: a prospective randomized study

Background/aim

The aim of this study was to investigate the efficacy of pregabalin on ischemia-reperfusion injuries.

Materials and methods

Fifty-four patients were randomly assigned into 2 groups. A 150-mg tablet of pregabalin was given the night before and then 1 h before the operation for patients in Group P (pregabalin group, n = 27). A placebo was given to patients in Group C (control group, n = 27) at the same times. After combined spinal-epidural anesthesia was performed, venous blood samples were taken before tourniquet inflation (t₁), just before tourniquet deflation (t₂), and 20 min after tourniquet deflation (t₃) for the analysis of total antioxidant status (TAS), total oxidant status (TOS), catalase (CAT), and ischemia-modified albumin (IMA).

Results

There was no significant difference in TAS levels between the groups for the t₃ period. However, the TAS in Group P was significantly higher in the t₃ period than the t₂ period (mean ± SD, 0.46 ± 0.1 vs. 0.38 ± 0.2 mmol of Trolox equivalent/L, respectively; P < 0.05). The CAT level in the t₃ period was significantly higher in Group P than Group C (mean ± SD, 53.04 ± 32.1 vs. 35.46 ± 17.2 µmol/formaldehyde, respectively; P < 0.05). In the t₃ period, the TOS was significantly lower in Group P than Group C (mean ± SD, 11.97 ± 5 vs. 18.29 ± 9.9 pg/mL, respectively; P < 0.05). The TOS in Group P was significantly lower in the t₃ period than the t₂ period (mean ± SD, 11.97 ± 5 vs. 18.98 ± 10.7 pg/mL, respectively; P < 0.0001).

Conclusion

Pregabalin has no marked antioxidant activity, but it contributes to the antioxidant defense system of an organism.

The efficacy of ketamine supplementation on pain management for knee arthroscopy: A meta-analysis of randomized controlled trials

INTRODUCTION

The efficacy of ketamine supplementation on pain management for knee arthroscopy remains controversial. We conduct a systematic review and meta-analysis to explore the influence of ketamine supplementation for knee arthroscopy.

METHODS

We search PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through October 2018 for randomized controlled trials (RCTs) assessing the effect of ketamine supplementation on pain control for knee arthroscopy. This meta-analysis is performed using the random-effect model.

RESULTS

Seven RCTs involving 300 patients are included in the meta-analysis. Overall, compared with control group for knee arthroscopy, ketamine supplementation reveals favorable impact on pain scores (mean difference [MD] = -2.95; 95% confidence interval [CI] = -3.36 to -2.54; P < .00001), analgesic consumption (standard mean difference [Std. MD] = -1.03; 95% CI = -1.70 to -0.36; P = .002), time to first analgesic requirement (Std. MD = 1.21; 95% CI = 0.45-1.96; P = .002) and malondialdehyde (Std. MD = -0.63; 95% CI = -1.05 to 3.10; P = -.20), and shows no increase in nausea and vomiting (RR = 1.87; 95% CI = 0.65-3.10; P = .003).

CONCLUSIONS

Ketamine supplementation benefits to pain management and may reduce ischemia reperfusion injury in patients with knee arthroscopy.

Electroporation-enhanced transdermal diclofenac sodium delivery into the knee joint in a rat model of acute arthritis

Purpose

Since electroporation (EP) can increase the permeability of biological membranes, we hypothesized that it offers an opportunity to enhance the transdermal delivery of drugs for intra-articular indications. Our aim was to compare the anti-inflammatory and analgesic efficacy of EP-combined topical administration of diclofenac sodium hydrogel (50 mg mL^-1 in 230 µL volume) with that of an equivalent dose of oral (75 mg kg^-1) and simple topical administration.

Methods

Arthritis was induced with the injection of 2% λ-carrageenan and 4% kaolin into the right knee joints of male Sprague Dawley rats. EP was applied for 8 min with 900 V high-voltage pulses for 5 ms followed by a 20 ms break. Drug penetration into the synovial fluid and plasma was detected by high-performance liquid chromatography. Leukocyte-endothelial interactions were visualized by intravital videomicroscopy on the internal surface of the synovium. Inflammation-induced thermal and mechanical hyperalgesia reactions, knee joint edema, and inflammatory enzyme activities were assessed at 24 and 48 h after arthritis induction.

Results

EP significantly increased the plasma level of diclofenac as compared with the topical controls 10 min after the 2% λ-carrageenan and 4% kaolin injection. Increased leukocyte-endothelial interactions were accompanied by joint inflammation, which was significantly reduced by oral and EP diclofenac (by 45% and by 30%, respectively) and only slightly ameliorated by simple topical diclofenac treatment (by 18%). The arthritis-related secondary hyperalgesic reactions were significantly ameliorated by oral and EP-enhanced topical diclofenac treatments. The knee cross-section area (which increased by 35%) was also reduced with both approaches. However, simple topical application did not influence the development of joint edema and secondary hyperalgesia.

Conclusion

The study provides evidence for the first time of the potent anti-inflammatory and analgesic effects of EP-enhanced topical diclofenac during arthritis. The therapeutic benefit provided by EP is comparable with that of oral diclofenac; EP is a useful alternative to conventional routes of administration.

[Tourniquet-induced ischaemia-reperfusion injury: the comparison of antioxidative effects of small-dose propofol and ketamine]

OBJECTIVES

The aim of the present study was to investigate the preventive effects of propofol and ketamine as small dose sedation during spinal anesthesia on tourniquet-induced ischemia-reperfusion injury.

METHODS

30 patients were randomly assigned into two groups of 15 patients. In the propofol group, sedation was performed with propofol 0.2mg.kg^-1 followed by infusion at a rate of 2mg.kg^-1.h^-1. In the ketamine group, a continuous infusion of ketamine 0.5mg.kg^-1.h^-1 was used until the end of surgery. Intravenous administration of midazolam was not used in any patients. Ramsay sedation scale was used for assessing the sedation level. Venous blood samples were obtained before propofol and ketamine infusion (T1), at 30minutes (min) of tourniquet ischemia (T2), and 5min after tourniquet deflation (T3) for malondialdehyde (MDA) measurements.

RESULTS

No differences were noted between the groups in hemodynamic (p>0.05) and demographic data (p>0.05). There was no statistically significant difference between the two groups in terms of T1, T2 and T3 periods (p>0.05). There was a statistically increase observed in MDA values respectively both in Group P and Group K between the reperfusion period (1.95±0.59, 2.31±0.48) and pre-ischemia (1.41±0.38, 1.54±0.45), and ischemia (1.76±0.70, 1.71±0.38) (μmoL^-1) periods (p<0.05).

CONCLUSIONS

Small-dose propofol and ketamine has similar potential to reduce the oxidative stress caused by tourniquet-induced ischemia-reperfusion injury in patients undergoing arthroscopic knee surgery under spinal anesthesia.

Ketamine: Current applications in anesthesia, pain, and critical care

Ketamine was introduced commercially in 1970 with the manufacturer's description as a "rapidly acting, nonbarbiturate general anesthetic" and a suggestion that it would be useful for short procedures. With the help of its old unique pharmacological properties and newly found beneficial clinical properties, ketamine has survived the strong winds of time, and it currently has a wide variety of clinical applications. It's newly found neuroprotective, antiinflammatory and antitumor effects, and the finding of the usefulness of low dose ketamine regimens have helped to widen the clinical application profile of ketamine. The present article attempts to review the current useful applications of ketamine in anesthesia, pain and critical care. It is based on scientific evidence gathered from textbooks, journals, and electronic databases.

The effects of dexmedetomidine on ischemia reperfusion injury in patients undergoing arthroscopy under spinal anesthesia

OBJECTIVE

Ischemia and reperfusion injury due to tourniquet application during arthroscopy is a well known problem. This study aimed to compare the effects of dexmedetomidine and ketamine on hemodynamic and respiratory variables and on total anti-oxidant status (TAS), total oxidant status (TOS) and malondialdehyde (MDA) as markers of ischemia-reperfusion injury.

MATERIALS AND METHODS

This study was approved by a local ethics committee. The study was performed on patients undergoing arthroscopic operation under spinal anesthesia. Thirty patients were randomized into two groups: Group D (dexmedetomidine; n=15) and Group K (Ketamine; n=15). Spinal anesthesia at the L2-4 level was achieved using a 25G spinal needle with hyperbaric bupivacaine at a dose of 12-15 mg in all patients. In Group D, patients were sedated with dexmedetomidine at a dose of 0.3-0.5 μg/kg/h, while Group K received ketamine at a dose of 1-1.5 mg/kg/h. Hemodynamic parameters, oxygen saturation, Ramsey sedation scale (RSS), and TAS, TOS, and MDA levels were recorded.

RESULTS

Demographic parameters, TAS, TOS and MDA levels were similar between groups. In Group K, the TOS levels after tourniquet removal were significantly lower than at baseline and during the use of the tourniquet. Preoperative hemodynamic and respiratory variables were similar in both groups. Blood pressure values were decreased compared to baseline but these decreases were not statistically significant.

CONCLUSION

In patients undergoing arthroscopy under spinal anesthesia, dexmedetomidine had effects similar to ketamine, led to insignificant alterations in hemodynamic and respiratory variables during surgery and had comparable effects on ischemia-reperfusion injury. Thus, we think that dexmedetomidine can be a safe alternative to ketamine as an intraoperative sedative.

[Effects of various anesthesia maintenance on serum levels of selenium, copper, zinc, iron and antioxidant capacity]

BACKGROUND AND OBJECTIVES

In this study, we aimed to investigate the effects of sevoflurane, desflurane and propofol maintenances on serum levels of selenium, copper, zinc, iron, malondialdehyde, and glutathion peroxidase measurements, and antioxidant capacity.

METHODS

60 patients scheduled for unilateral lower extremity surgery which would be performed with tourniquet under general anesthesia were divided into three groups. Blood samples were collected to determine the baseline serum levels of selenium, copper, zinc, iron, malondialdehyde and glutathion peroxidase. Anesthesia was induced using 2-2.5mgkg(-1) propofol, 1mgkg(-1) lidocaine and 0.6mgkg(-1) rocuronium. In the maintenance of anesthesia, under carrier gas of 50:50% O2:N2O 4Lmin(-1), 1 MAC sevoflorane was administered to Group S and 1 MAC desflurane to Group D; and under carrier gas of 50:50% O2:air 4Lmin(-1) 6mgkgh(-1) propofol and 1μgkgh(-1) fentanyl infusion were administered to Group P. At postoperative blood specimens were collected again.

RESULTS

It was observed that only in Group S and P, levels of MDA decreased at postoperative 48th hour; levels of glutathion peroxidase increased in comparison to the baseline values. Selenium levels decreased in Group S and Group P, zinc levels decreased in Group P, and iron levels decreased in all three groups, and copper levels did not change in any groups in the postoperative period.

CONCLUSION

According to the markers of malondialdehyde and glutathion peroxidase, it was concluded that maintenance of general anesthesia using propofol and sevoflurane activated the antioxidant system against oxidative stress and using desflurane had no effects on oxidative stress and antioxidant system.

Ultrasound-guided femoral and sciatic nerve blocks combined with sedoanalgesia versus spinal anesthesia in total knee arthroplasty

Background

Although regional anesthesia is the first choice for patients undergoing total knee arthroplasty (TKA), it may not be effective and the risk of complications is greater in patients who are obese or who have spinal deformities. We compared the success of ultrasound-guided femoral and sciatic nerve blocks with sedoanalgesia versus spinal anesthesia in unilateral TKA patients in whom spinal anesthesia was difficult.

Methods

We enrolled 30 patients; 15 for whom spinal anesthesia was expected to be difficult were classified as the block group, and 15 received spinal anesthesia. Regional anesthesia was achieved with bupivacaine 62.5 mg and prilocaine 250 mg to the sciatic nerve, and bupivacaine 37.5 mg and prilocaine 150 mg to the femoral nerve. Bupivacaine 20 mg was administered to induce spinal anesthesia. Hemodynamic parameters, pain and sedation scores, and surgical and patient satisfaction were compared.

Results

A sufficient block could not be obtained in three patients in the block group. The arterial pressure was significantly lower in the spinal group (P < 0.001), and the incidence of nausea was higher (P = 0.017) in this group. Saturation and patient satisfaction were lower in the block group (P < 0.028), while the numerical pain score (P < 0.046) and the Ramsay sedation score were higher (P = 0.007).

Conclusions

Ultrasound-guided sciatic and femoral nerve blocks combined with sedoanalgesia were an alternative anesthesia method in selected TKA patients.

Lower limb ischaemia and reperfusion injury in healthy volunteers measured by oxidative and inflammatory biomarkers

Objective:

Ischaemia-reperfusion (IR) injury is partly caused by the release of reactive oxygen species and cytokines and may result in remote organ injury. Surgical patients are exposed to surgical stress and anaesthesia, both of which can influence the IR response. An IR model without these interfering factors of surgery is, therefore, useful to test the potential of antioxidant and cytokine-modulatory treatments. The aim of this study was to characterize a human ischaemia-reperfusion model with respect to oxidative and inflammatory biomarkers.

Materials and methods:

Ten male volunteers were exposed to 20 minutes of lower limb ischaemia. Muscle biopsies and blood samples were taken at baseline and 5, 15, 30, 60 and 90 minutes after tourniquet release and analysed for malondialdehyde (MDA), ascorbic acid, dehydroascorbic acid, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-1 receptor antagonist (IL-1Ra), IL-6, IL-10, TNF-receptor (TNF-R)I, TNF-RII and YKL-40.

Results:

We found no significant increase in MDA in the muscle biopsies after reperfusion. Plasma levels of oxidative and pro- and anti-inflammatory parameters showed no significant differences between baseline and after reperfusion at any sampling time.

Conclusion:

Twenty minutes of lower limb ischaemia does not result in an ischaemia-reperfusion injury in healthy volunteers, measurable by oxidative and pro- and anti-inflammatory biomarkers in muscle biopsies and in the systemic circulation.

The effects of a small-dose ketamine-propofol combination on tourniquet-induced ischemia-reperfusion injury during arthroscopic knee surgery

STUDY OBJECTIVE

To determine the effects of a small-dose ketamine-propofol combination used for sedation during spinal anesthesia on tourniquet-induced ischemia-reperfusion injury.

STUDY DESIGN

Prospective randomized study.

SETTING

Training and research hospital.

PATIENTS

60 adult, ASA physical status 1 and 2 patients, ages 20-60 years, scheduled for elective arthroscopic knee surgery for meniscal and chondral lesions.

INTERVENTIONS

The initial hemodynamic parameters were recorded and blood samples were collected at baseline (T1); then spinal anesthesia was performed. In Group I (n=30), a combination of 0.5 mg/kg/hr of ketamine and 2 mg/kg/hr of propofol was administered; Group II (n=30) received an equivalent volume of saline as an infusion. A pneumatic tourniquet was applied.

MEASUREMENTS

Malondialdehyde (MDA), superoxide dismutase (SOD), and catalase levels were measured one minute before tournique deflation in the ischemic period (T2), then 5 (T3) and 30 (T4) minutes following tourniquet deflation in the reperfusion period.

MAIN RESULTS

No differences were noted between groups in hemodynamic data (P > 0.05) or SOD levels (P > 0.05). In Group I, MDA levels at T2 were lower than in Group II (P < 0.05). In Group I, catalase levels were lower at T2 and T4 than they were in Group II (P < 0.05).

CONCLUSION

Small-dose ketamine-propofol combination may be useful in reducing tourniquet-induced ischemia-reperfusion injury in arthroscopic knee surgery.

Does the method of expression of venous blood affect ischaemia/reperfusion damage in tourniquet use? An experimental study on rabbits

The aim of this study was to compare the ischaemia and reperfusion phases of two tourniquet application models (Group 1: expressing the blood by a sterile rubber bandage and Group 2: elevation of the limb for several minutes) using an analysis of ischaemia/reperfusion parameters and blood pH. Sixteen New Zealand rabbits were used. Muscle samples were extracted from the triceps surae; at phase A (baseline: just before tourniquet application), phase B (ischaemia: 3h after tourniquet inflation) and phase C (2h after tourniquet deflation). Nitrite, nitrate, reduced glutathione, myeloperoxidase, malondyaldehyde were measured in the samples. Blood pH was also measured at each phase. Group 2 had significantly decreased nitrite (p=0.007) and nitrate (p=0.01) levels compared to Group 1 while passing from phase A to phase B. The pH decrease through the phases was significant within Group 1 (p=0.006) and was not significant within Group 2 (p=0.052). Lower levels of NO metabolites nitrate and nitrite, result from tourniquet use with incomplete venous blood expression by elevation. Also, with this technique severe acidosis is less likely to occur than when a tourniquet is used with expression of the venous blood by rubber bandage. These findings may help in the decision of which tourniquet technique is to be used for potentially long operations which may exceed 2h.

Tourniquet-induced ischemia-reperfusion injuries during extremity surgery at children's age: impact of anesthetic chemical structure

OBJECTIVES

The aim of this study was to determine the relationship between the antioxidant profile of anesthetics and its relation to total antioxidant capacity (TAC) of plasma in children who underwent tourniquet-induced ischemia-reperfusion (IR) injury during extremity operations.

METHODS

Children were randomized into three groups: general inhalational anesthesia with sevoflurane (group S), total intravenous anesthesia (TIVA) with propofol (group T), and regional anesthesia (group R). Venous blood samples were obtained before peripheral nerve block and induction of general anesthesia (baseline), 1 minute before tourniquet release (BTR), and 5 and 20 minutes after tourniquet release (ATR). Plasma TAC as well as antioxidant potential of propofol, thiopental, and bupivacaine were measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay.

RESULTS

Plasma TAC in group T was increased significantly at 20 minutes ATR in comparison with basal and BTR values, and also was significantly higher in comparison with plasma TAC in groups S and R measured at the same time point. The radical scavenging activity of anesthetics in vitro indicated that only propofol possessed a significant antioxidative activity in the reaction with DPPH radical in comparison with thiopental and bupivacaine.

DISCUSSION

These data confirm that TIVA with propofol attenuates oxidative stress related to tourniquet-induced ischaemia-reperfusion injury in children.

Ketamine: use in anesthesia

The role of ketamine anesthesia in the prehospital, emergency department and operating theater settings is not well defined. A nonsystematic review of ketamine was performed by authors from Australia, Europe, and North America. Results were discussed among authors and the final manuscript accepted. Ketamine is a useful agent for induction of anesthesia, procedural sedation, and analgesia. Its properties are appealing in many awkward clinical scenarios. Practitioners need to be cognizant of its side effects and limitations.

Dexmedetomidine did not reduce the effects of tourniquet-induced ischemia-reperfusion injury during general anesthesia

Ischemia reperfusion injury causes the release of free oxygen radicals. Free oxygen radicals initiate the production of toxic metabolites, such as malondialdehyde (MDA), through the lipid peroxidation of cellular membranes. Following lipid peroxidation, the antioxidant enzyme system is activated against reactive oxygen species (ROS) and attempts to protect cells from oxidative damage. There is a balance between the scavenging capacity of antioxidant enzymes and ROS. Because of this balance, the total antioxidant capacity (TAC) measurement is a sensitive indicator of the overall protective effects of the antioxidants. Alpha(2) receptor agonists are effective in preventing hemodynamic reactions during extremity surgeries by preventing the release of catecholamines secondary to tourniquet application. They have also been shown to possess preventive effects in various ischemia-reperfusion injury models. In our study, we examined the effects of dexmedetomidine on tourniquet-induced ischemia-reperfusion injury in lower extremity surgeries performed under general anesthesia. The effects of dexmedetomidine were measured with serum MDA and TAC levels. We studied 60 adult American Society of Anesthesiologists (ASA) physical status I or II patients undergoing one-sided lower extremity surgery with tourniquet. The patients were randomly divided into two groups. Group D was administered a dexmedetomidine infusion at a rate of 0.1μg/kg/minute(-1) for 10 minutes prior to induction and then at 0.7μg/kg/hour(-1) until 10 minutes before the end of the operation. The control group (Group C) received a saline infusion of the same amount and for the same period of time. General anesthesia was induced with thiopental, fentanyl, and rocuronium and maintained with nitrous oxide and sevoflurane in both groups. Venous blood samples were obtained before the administration of the study drugs (basal) at 1 minute before tourniquet release and at 5 and 20 minutes after tourniquet release (ATR). In both groups, MDA levels decreased at 5 and 20 minutes ATR when compared with the basal values (p<0.05). TAC levels decreased at 1 and 5 minutes ATR and then returned to basal values at 20 minutes ATR (p<0.05). In reference to the prevention of lipid peroxidation in tourniquet-induced ischemia-reperfusion injury, the results from the two groups in our study showed that dexmedetomidine did not have an additional protective role during routine general anesthesia.

Biomarkers of Oxidative Stress and Endothelial Dysfunction After Tourniquet Release in Children

Pneumatic tourniquets are widely used in pediatric extremity surgery to provide a bloodless field and facilitate dissection. This prospective study was carried out to examine possible effect of different anesthesia techniques on oxidative stress and endothelial dysfunction connected with ischemia-reperfusion injury during extremity operations at children's age. Patients were randomized into three groups of 15 patients each: general inhalational anesthesia with sevoflurane (group S), total intravenous anesthesia with propofol (group T) and regional anesthesia (group R). Venous blood samples for determination of the malondialdehyde in plasma and erythrocytes, protein carbonyl groups concentration as well as plasma nitrites and nitrates level and xanthine oxidase activity were obtained at four time points: before peripheral nerve block and induction of general anesthesia (baseline), 1 min before tourniquet release, 5 and 20 min after tourniquet release. This study demonstrates that total intravenous anesthesia with propofol and regional anesthesia techniques provide better antioxidant defense and reduce endothelial dysfunction than general inhalational anesthesia with sevoflurane during tourniquet application in pediatric extremity surgery.

Effect of chronic administration of ketamine on the mitochondrial respiratory chain activity caused by chronic mild stress

Rezin GT, Gonçalves CL, Daufenbach JF, Carvalho-Silva M, Borges LS, Vieira JS, Hermani FV, Comim CM, Quevedo J, Streck EL. Effect of chronic administration of ketamine on the mitochondrial respiratory chain activity caused by chronic mild stress.

OBJECTIVE

Recently, we reported that mitochondrial respiratory chain complexes I, III and IV were inhibited in the cerebral cortex and cerebellum of rats submitted to chronic mild stress (CMS) and that acute ketamine administration reversed this effect. Therefore, we investigated whether the inhibition of these enzymes may be reversed by chronic administration of ketamine.

METHODS

Adult male Wistar rats were submitted to CMS and chronically treated with ketamine. After 40 days of CMS, consumption of sweet food, adrenal gland weight, body weight and enzymatic activity of the complexes were measured.

RESULTS

We verified that CMS decreased the intake of sweet food, increased the adrenal gland weight and the control group gained weight after 40 days but the stressed group did not; ketamine administration reversed these effects. We also verified that chronic administration of ketamine reversed the inhibition of complexes I, III and IV in cerebral cortex. However, in cerebellum, only complex IV inhibition was reversed. The chronic ketamine administration partially reverses the inhibition caused by CMS.

CONCLUSION

We hypothesise that CMS inhibits complexes I, III and IV activities and that chronic administration of ketamine administration partially reverses such an effect. Therefore, it seems reasonable to propose that ketamine administration might be a useful therapy for patients affected by major depression.

The effects of different anesthesia techniques on free radical production after tourniquet-induced ischemia-reperfusion injury at children's age

Background/Aim. Reperfusion of previously ischemic tissue leads to injuries mediated by reactive oxygen species. The aim of the study was to investigate the effects of different anesthesia techniques on oxidative stress caused by tourniquetinduced ischemia-reperfusion (IR) injury during extremity operations at children's age. Methods. The study included 45 patients American Society of Anesthesiologists (ASA) classification I or II, 8 to 17 years of age, undergoing orthopedic procedures that required bloodless limb surgery. The children were randomized into three groups of 15 patients each: general inhalational anesthesia with sevoflurane (group S), total intravenous anesthesia with propofol (group T) and regional anesthesia (group R). Venous blood samples were obtained at four time points: before peripheral nerve block and induction of general anesthesia (baseline), 1 min before tourniquet release (BTR), 5 and 20 min after tourniquet release (ATR). Postischemic reperfusion injury was estimated by measurement of concentration of malondialdehyde (MDA) in plasma and erythrocytes as well as catalase (CAT) activity. Results. Plasma MDA concentration in the group S was significantly higher at 20 min ATR in comparison with the groups T and R (6.78 ? 0.33 ?molL-1-1 vs 4.07 ? 1.53 and 3.22 ? 0.9. ?molL-1-1, respectively). There was a significant difference in MDA concentration in erytrocythes between the groups S and T after 5 min of reperfusion (5.88 ? 0.88 vs 4.27 ? 1.04 nmol/mlEr, p < 0.05). Although not statistically significant, CAT activity was slightly increased as compared to baseline in both groups S and R. In the group T, CAT activity decreased at all time points when compared with baseline, but the observed decrease was only statistically significant at BTR (34.70 ? 9.27 vs 39.69 ? 12.91 UL-1, p < 0.05). Conclusion. Continuous propofol infusion and regional anesthesia techniques attenuate lipid peroxidation and IR injury connected with tourniquet application in pediatric extremity surgery.

Dexmedetomidine reduces the ischemia-reperfusion injury markers during upper extremity surgery with tourniquet

PURPOSE

We examined the effect of dexmedetomidine on ischemia-reperfusion injury due to tourniquet application during upper-extremity surgery by determining blood malondialdehyde and hypoxanthine levels. Alterations in aspartate aminotransferase, alanine aminotransferase, creatine phosphokinase, lactate dehydrogenase, uric acid, and creatinine levels were also assessed.

METHODS

Forty patients of American Society of Anesthesiologists physical status I to II having hand and forearm surgery with tourniquet were randomly allocated into 2 groups. Brachial plexus anesthesia via axillary approach was performed for upper-limb block in all patients. In the dexmedetomidine group, a continuous infusion of dexmedetomidine (1 microg/kg for 10 minutes, followed by 0.5 microg kg(-1) h(-1)) was used until the end of surgery, whereas the control group received an equivalent volume of saline. Venous blood samples were obtained before brachial plexus anesthesia, at 1 minute before tourniquet release, and 15 minutes after tourniquet release for biochemical analysis.

RESULTS

Dexmedetomidine significantly attenuated plasma hypoxanthine production in the ischemia and plasma malondialdehyde production in the reperfusion periods. Blood creatine phosphokinase and uric acid levels were significantly lower in the dexmedetomidine group compared with those in the control group after reperfusion.

CONCLUSIONS

Our results suggest that dexmedetomidine may offer advantages by inhibiting lipid peroxidation in the case of anticipated ischemia-reperfusion injury, such as would occur in upper-extremity surgery requiring tourniquet application.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.