Tourniquet Release Research Articles

Use of Ketorolac As An Adjuvant in Bier’s Block

Background: Bier’s block has been most commonly used for hand and wrist surgery of short duration. Though it reduces the potential complication of general anaesthesia, significant post-operative pain is very common just after tourniquet release. Many adjuvants eg. fentanyl, pethidine, morphine, sodi-bicarb, pancuronium, ketorolac etc. have been used so far with local anaesthetic to produce a dense block and to provide adequate post-operative analgesia. Of them Ketorolac was used very successfully as it has got less potential side-effects. This study was done to see the effect of ketorolac in Bier’s block whether and how much it provides post-operative analgesia after tourniquet release. Method: The effectiveness of combination of Lignocaine and Ketorolac as an anaesthetic solution in Bier’s block was assessed in terms of reduction of tourniquet pain, quality of anaesthesia, the time of first analgesic demanmd and the amount of total analgesic needed in post-operative 24-hours period. A total of sixty patients of ASA grade-1 and ASA grade-2 undergoing hand and wrist surgery of less than 40 minute duration were enrolled for the study. Patients in control group (Gr-L) were received forty ml of 0.5%Lignocaine and patients in trial group (Gr-LK) were received 39-ml of 0.5% Lignocaine with 1 ml (30 mg) of Ketorolac as an anaesthetic solution. Patient was observed postoperatively for 24 hours. Result: Pain was assessed in terms of VAS , and by measuring Heart rate and Blood pressure to assess sympathetic stimulation due to pain. Tourniquet pain was significantly less in Gr- LK (p<0.000). Postoperative analgesia was also significantly prolonged in Gr- LK (76.40 ± 11.78 min) than in Gr- L (27.30 ± 8.18 min). The number of total analgesic demand in postoperative 24 hours period was also significantly reduced in Gr-LK (p<0.000) Conclusion: The Lignocaine and Ketorolac mixture in Bier’s block produces significant anaesthesia and also provides adequate postoperative analgesia and causes less analgesic demand in postoperative period. These advantages ensure cost-effectiveness, shorter hospital stay and ultimately satisfactory patient outcome. JBSA 2016; 29(2): 54-61

Topical vs. intravenous administration of tranexamic acid in knee arthroplasty and prevalence of deep venous thrombosis: a randomized clinical trial.

BackgroundTranexamic acid (TXA) is widely used in orthopedic surgery to reduce perioperative bleeding. Since TXA inhibits fibrinolysis, there is concern that it may increase the risk of thromboembolic events.ObjectivesTo verify the prevalence of deep venous thrombosis (DVT) in patients receiving TXA during total knee arthroplasty and to compare topical with intravenous administration of the drug.MethodsAll patients admitted for total knee arthroplasty due to primary arthrosis between June and November of 2014 were recruited consecutively. Thirty patients were randomized to a “topical group” (1.5 g TXA diluted in 50ml saline sprayed over the area operated, before tourniquet release), 30 to an “intravenous group” (20mg/kg TXA in 100 ml of saline, given at the same time as anesthesia), and 30 to a control group (100 ml of saline, given at the same time as anesthesia). All patients had duplex ultrasound scans of the legs on the 15th postoperative day.ResultsDeep venous thrombosis events occurred in five of the 90 patients operated (one out of 30 in the topical group [3.3%], four out of 30 in the control group [13.3%], and zero in the intravenous group). All were confirmed by duplex ultrasound scans and all were asymptomatic. Prevalence rates of DVT were similar between groups (p = 0.112 for control vs. intravenous; p = 0.353 for control vs. topical; and p =1.000 for intravenous vs. topical, according to two-sided exact tests).ConclusionsBoth topical and intravenous administration of TXA are safe with regard to occurrence of DVT, since the number of DVT cases in patients given TXA was not different to the number in those given placebo.

The Impact of Tourniquet Release Time on Wound Healing in Patients Undergoing Tibia Fracture Plating Surgery

Background: The use of tourniquet is very common in orthopedic surgeries. By obstructing blood flow in the limb, tourniquet may result in muscle ischemia and skin flap hypoxia. This study aimed at determining and comparing the effects of tourniquet release time on wound healing in patients undergoing tibia fracture plating surgery. Methods: This study was a randomized clinical trial, wherein 40 patients with acute extra-articular tibia fractures were randomly assigned to 2 groups of A (releasing the tourniquet after fracture fixation and before wound closure) and B (releasing the tourniquet after wound closure and application of compression dressing). Duration of surgery in each group was recorded and independent t test was utilized to compare the 2 groups. The wound healing rate was investigated in the patients 24 hours and 14 days after surgery using the Redness, Oedema, Ecchymosis, Discharge, Approximation (REEDA) scale. In this tool, 0 represents “lack of the variable” and 3 indicates “maximum variable score”. The scores in this scale range from 0 to 15. The Mann-Whitney test was used in order to compare the wound healing rates between the 2 groups. Results: There was no significant difference between the 2 groups concerning the average duration of surgery. Wound redness, edema, ecchymosis, discharge, approximation, and the general condition of wound healing showed no significant difference in the 2 groups 24 hours after surgery, while there was a significant difference 14 days after surgery with the aforementioned parameters being greater in group B than group A. Conclusions: The results showed that releasing the tourniquet before wound closure in group A led to improved wound healing. Wounds need oxygen for restoration and prevention from infections. As the use of tourniquet occludes blood flow to the limb for a while, it can result in increased wound hypoxia after surgery and delayed healing process; hence, less tourniquet time is more desirable for oxygenation of tissues and wound dryness.

Postischemic conditioning does not reduce muscle injury after tourniquet-induced ischemia-reperfusion injury in rats

BackgroundThe widespread application of tourniquets has reduced battlefield mortality related to extremity exsanguinations. Tourniquet-induced ischemia-reperfusion injury (I/R) can contribute to muscle loss. Postischemic conditioning (PostC) confers protection against I/R in cardiac muscle and skeletal muscle flaps. The objective of this study was to determine the effect of PostC on extremity muscle viability in an established rat hindlimb tourniquet model. MethodsRats were randomly assigned to PostC-1, PostC-2, or no conditioning ischemic groups (n = 10 per group). Postischemic conditioning, performed immediately after tourniquet release, consisted of four 15-second cycles (PostC-1) or eight 15-second cycles (PostC-2) of alternating occlusion and perfusion of hindlimbs. Twenty-four hours later, muscles were excised. The primary end points were muscle edema and viability; secondary end points were histologic and markers of oxidative stress. ResultsIschemia-reperfusion injury decreased viability in all tourniquet limbs, but viability was not improved in either PostC group. Likewise, I/R resulted in substantial muscle edema that was not reduced by PostC. The predominant histologic feature was necrosis, but no significant differences were found among groups. Markers of oxidative stress were increased similarly among groups after I/R, although myeloperoxidase activity was significantly increased only in the no conditioning ischemic group. A protective effect from PostC was not observed in our model suggesting that PostC was not effective in reducing I/R skeletal muscle injury or any benefits of PostC were not sustained for 24 hours when tissues were assessed. ConclusionThese negative findings are pertinent as the military investigates different strategies to extend the safe time for tourniquet application.

Evaluation of 10-minute versus 30-minute tourniquet time for intravenous regional limb perfusion with amikacin sulfate in standing sedated horses

The objective of the article is to determine the synovial fluid concentrations of amikacin sulfate (AS) after performing an intravenous regional limb perfusion (IVRLP) with the tourniquet in place for...

Effect of dexmedetomidine on acute lung injury in experimental ischemia–reperfusion model

PurposeIschemia–reperfusion injury is one of the consequences of tourniquet application for extremity surgery. The aim of the study was to establish the effect of dexmedetomidine on the acute lung injury following lower extremity experimental ischemia–reperfusion model in rats. MethodsTwenty-eight Wistar-Albino breed Rats were recruited after Ethics Committee approval and allocated into 4 groups, each with 7 subjects. Group 1 (SHAM) received only anesthesia. Group 2 (IR) had experienced 3h of ischemia and 3h of reperfusion using left lower extremity tourniquet after anesthesia application. Groups 3 (D-50) and 4 (D-100) had undergone the same procedures as in the Group 2, except for receiving 50 and 100mg·kg−1, respectively, dexmedetomidine intraperitoneally 1h before the tourniquet release. Blood samples were obtained for the analysis of tumor necrosing factor-α and interleukin-6. Pulmonary tissue samples were obtained for histological analysis. ResultsNo significant difference regarding blood tumor necrosing factor-α and interleukin-6 values was found among the groups, whereas pulmonary tissue injury scores revealed significant difference. Histological scores obtained from the Group 2 were significantly higher from those in the Groups 1, 3 and 4 with p-values 0.001 for each comparison. Moreover, Group 1 scores were found to be significantly lower than those in the Groups 3 and 4 with p-values 0.001 and 0.011, respectively. No significant difference was observed between the Groups 3 and 4. ConclusionDexmedetomidine is effective in reduction of the experimental ischemia–reperfusion induced pulmonary tissue injury in rats, formed by extremity tourniquet application.

Abstracts and Highlight Papers of the 35th Annual European Society of Regional Anaesthesia & Pain Therapy (ESRA) Congress 2016.

Background and Aims: Although considered safe, no pharmacokinetic data of high dose, high volume local infiltration analgesia (LIA) with ropivacaine without the use of a surgical drain or intra-articular catheter have been described. The purpose of this study is to describe the maximum total and unbound ropivacaine concentrations (Cmax) and corresponding times to maximum concentration (Tmax) of a single shot ropivacaine (200ml 0.2%) and 0.75 mg epinephrine (1000μg mL-1) when used for LIA. Methods: In this prospective cohort study twenty patients were treated with LIA of the knee for primary total knee arthroplasty. Plasma samples were taken at 20, 40, 60, 90, 120, 240, 360 minutes and at 24 hours after tourniquet release, in which total and unbound ropivacaine concentrations were determined. Results: Results are given as mean (SD); median (range). Maximum total ropivacaine concentration was 1.06 (0.36); 1.00 (0.61 - 2.26) μg mL-1, corresponding Tmax was 311 (227); 240 (40-1440) minutes after tourniquet release (Figure 1). The highest measured unbound ropivacaine concentration was 0.13 μg mL-1. Conclusions: Maximumtotal and unbound serum concentrations of ropivacaine remained well below the assumed toxic thresholds of 4.3 and 0.56 μg mL-1, respectively, for systemic toxicity. (Figure Presented).

Nalbuphine versus Dexmedetomidine as an Analgesic Additive to Lidocaine in Intravenous Regional Anesthesia IVRA

Intravenous Regional Anesthesia (IVRA) is easy to administer and reliable. But delayed onset and lack of postoperative analgesia are the major limitations. Accordingly, many additives have been tried. Dexmedetomidine is a highly selective α-2 adrenoceptor agonist. Addition of dexmedetomidine to lignocaine is effective in decreasing the anesthetic requirements and prolonging the analgesic duration. On the other hand, many theories explain that opioids may exert their peripheral action through peripheral opioid receptors. The aim of the study was to compare the analgesic efficacy of nalbuphine and dexmedetomidine when used separately as adjuvants to lidocaine during IVRA with the effect of lidocaine alone. Sixty adult patients, who were scheduled for surgery of the hand or the forearm under intravenous regional anesthesia, were included in this study. The patients were randomly allocated into three equal groups. The syringes in all groups contained 3 mg/kg of lidocaine 0.5% diluted in 40 ml isotonic saline. Group C: Control group. Group D: Dexmedetomidine group, 1 mic/kg dexmedetomidine diluted was added. Group N: Nalbuphine group, 20 mg nalbuphine was added. Sensory onset time (min) as well as motor block onset time (min) were significantly shorter in Groups N (2.0 ± 1.7) (3.8 ± 2.1) respectively, and D (2.2 ± 1.8) (4.6 ± 2.2) respectively compared to Group C (3.6 ± 1.6) (7.1 ± 1.4) (P < 0.05), with no significant differences between nalbuphine and dexmedetomidine groups. Sensory and motor block recovery times (min) were significantly longer in Groups N (9.6 ± 0.7) (10.3 ± 1.2) and D (8.1 ± 1.1) (9.1 ± 2.1) when compared to Group C (3.4 ± 2.1) (3.7 ± 3.1) (P < 0.05), without significant differences between nalbuphine and dexmedetomidine. Ramsay sedation score was significantly higher (RSS = 2) in 14 patients (70%) in Group D compared to Groups C and N during the first 30 min after the release of tourniquet.

Intracompartmental pressure changes after anterolateral bridge plating of tibial fractures.

Compartment syndrome is one of the most devastating complications in orthopedics both for the patient and the treating physician. Among the many causes, trauma and its treatment are the most common reasons for compartment syndrome, which most frequently occurs in the lower leg following tibial fractures. Since bridge plating of difficult metadiaphyseal tibial fractures is becoming increasingly popular, serious concerns have been raised about the increased intracompartmental pressures and possible compartment syndrome. This study investigated the intracompartmental pressure changes in anterolateral compartment of the leg during and immediately after anterolateral bridge plating of tibial fractures. Intracompartmental pressures were measured before and during plate application, just after the completion of fixation, and immediately and 4-5 min after the tourniquet release in 22 isolated closed comminuted tibial fractures. Baseline anterolateral compartment pressures were higher than those on the uninjured side (9.3 vs 27.8 mmHg). Pressures were 69.5, 57.4, 65.8, and 56.8 mmHg, respectively, for the other measurements times. None of the patients received prophylactic fasciotomy, and none developed clinical compartment syndrome. We found that anterolateral compartmental pressures were higher than pressures on the uninjured side in all patients. Although there is a considerable increase in intracompartmental pressures during and immediately after anterolateral percutaneous bridge plating of comminuted tibial fractures, intraoperative prophylactic fasciotomy is not routinely needed. One should monitor the patients on the first postoperative day for signs of compartment syndrome. Fasciotomy decisions should be based on both clinical symptoms and serial intracompartmental pressure measurements rather than a single measurement.

Influence of Thigh Tourniquet Release on Cardiovascular Parameters While Operated Limb in Elevated Position

Background: Release of pneumatic tourniquet causes hypotension, tachycardia and compensatory increase in cardiac index. Objectives: This study was conducted to assess the effect of tourniquet release on cardiovascular parameters while operated leg in 20 degrees up position. Design: Prospective randomized comparative study. Setting: University hospital. Methods: This study included 60 patients, ASA I scheduled for meniscal surgery through knee arthroscopy under general anesthesia. Patients were divided into two groups: group C (n=30) in which tourniquet was deflated with leg in neutral position while group S (n=30) tourniquet was released with leg in 20 degrees up position. Cardiovascular parameters displayed by ccNexfin monitor eg cardiac output (COP), cardiac index (CI), stroke volume (SV), mean arterial pressure (MAP), systemic vascular resistance (SVR), heart rate (HR), as well as arterial blood gas measurements. End tidal carbon dioxide, respiratory rate, end tidal sevoflurane and bispectral index values were also recorded before and after tourniquet deflation. Results: There was significant decrease in MAP and SVR at all intervals post deflation in group C compared to group S whereas COP, CI, SV and HR were significantly increased in group C post deflation compared to group S. But there were no significant differences between groups regarding metabolic and respiratory parameters. Conclusion: Tourniquet deflation while leg in elevated position caused attenuation in both the decrease in MAP, SVR and the compensatory increase in CI, COP and SV. Limitations: This study is limited by its small sample size.

Comparing the Analgesic Effects of Lidocaine and Lidocaine with Ketamine in Intravenous Regional Anesthesia on Postoperative Pain

Background and purpose: The main and the most known complication of intravenous regional anesthesia (IVRA) is systemic toxicity due to local anesthetics that occurs following the accidental tourniquet release immediately after injection. This study aims to evaluate the effect of adding ketamine to lower dose of lidocaine on reducing the dose and side effects of lidocaine. Materials and Methods: In this randomized clinical trial, 60 patients undergoing the surgery of upper limb below the elbow under IVRA were randomly divided into two groups. In group 1 (control group), 40 ml lidocaine 0.5% (200 mg) and in group 2 (intervention group), 40 ml lidocaine 0.25% (100 mg) plus 40 mg of ketamine 0.1% injected intravenously. Outcomes included postoperative pain at 15, 30 and 60 minutes after surgery. The pain of the patients was assessed by using the Visual Analogue Scale (VAS Score). Results: Both groups were comparable in demographic and surgical parameters. The average pain based on the VAS score at 15, 30 and 60 minutes after surgery was similar in both groups and there was no significant difference between the two groups (p> 0.05). Moreover, postoperative complications including unconsciousness, restlessness, dizziness, nausea, vomiting, tinnitus, seizure, delirium and hallucination had no significant differences (p> 0.05). Conclusion: Results of this study showed that the addition of ketamine to lower dose of lidocaine in patients receiving IVRA significantly reduced postoperative pain, and reduces the likelihood of systemic toxicity with lidocaine without causing significant adverse effects.

Comparative evaluation between ascorbic acid and N-acetyl cysteine for preventing tourniquet induced ischaemic reperfusion injury during lower limb surgery, a randomized controlled trial

BackgroundDuring tourniquet induced ischemic reperfusion, reactive oxygen species and cytokines appear and cause cellular damage and remote tissue injury.AimTo compare the effects of preoperative intravenous infusion of N-acetyl cysteine or ascorbic acid on the production of malonyldialdehyde as a marker of oxidative stress and IL-6 and IL-8 as markers of systemic inflammation after ischemic reperfusion as primary outcomes. Also both agents were compared regarding post-deflation hemodynamic effects and post-deflation changes in arterial pH and lactic acid as secondary outcomes.Patient and methods60 patients, scheduled for unilateral lower extremity surgery with a pneumatic tourniquet, were included. The study was designed as a randomized controlled parallel arms superiority trial. Baseline collection of blood samples was done and then patients were randomly classified into three groups: Group A; received 1 g Ascorbic acid, group N; received 10 mg/kg NAC and group C (control group): received 100 ml saline infusion. Epidural anesthesia was administrated. Two blood samples were drawn at each assessment time. One sample for arterial blood pH and lactic acid measurement and the other blood sample was centrifuged and stored at −20 °C for subsequent analysis of MDA, IL-6 and IL-8.ResultsLevels of MDA, IL-6, and IL-8 were significantly increased in group C after tourniquet release compared with the baseline. In groups A and N, MDA did not increase over baseline values, but IL-6 and IL-8 levels were increased and their levels were significantly less than in the control group. Changes in hemodynamics, pH and serum lactate were more evident in group C than groups A and N.ConclusionBoth N-acetyl cysteine and ascorbic acid reduce post-deflation increase in blood levels of markers of oxidative stress and markers of systemic inflammation and thus both are beneficial in preventing post-tourniquet deflation ischemic reperfusion injury in lower limb surgery.

Widespread of total knee arthroplasty perioperative blood management techniques based on tranexamic acid: barriers and opportunities.

Current interest of orthopaedic surgeons in tranexamic acid (TXA) is rapidly increasing in the literature, and controversial issues, appropriately highlighted by intelligent and deep comments (1-3), deserve some reflections. Perioperative total knee replacement (TKR) clinical management has significantly improved in the last 10 years due to the widespread, highly effective and safe blood loss control with different protocols that incorporate the use of TXA. It is amazing how the rediscovery by the Orthopaedic community of an old medication (TXA has been in use during more than 50 years by different manufacturers under different commercial names such as Transamin, Cyclokapron, Amcha or Amchafibrin, for various indications related to non-orthopaedic bleeding) has transformed the perioperative management of orthopaedic elective procedures that involved significant postoperative bleeding such as total knee arthroplasty after tourniquet release. But besides the arthroplasty field, major benefits in the use of this medication have also been elicited in other areas of orthopaedics and traumatology that reinforce the interest in the drug and provide valuable experience. It is worth mentioning, among other fields of interest, the survivorship increase of severely traumatized patients with early TXA administration, a key aspect that became recognized by most prestigious opinion leaders and publications, not without controversy (4,5).

After early release of tourniquet in total knee arthroplasty, should it be reinflated or kept deflated? A randomized trial.

This study was undertaken to determine the efficacy of reinflation of the tourniquet after its early release in TKA compared to early release alone, in terms of surgical field visualization and operative time. We also questioned whether tourniquet reinflation after its early release is safe, with respect to post-operative blood loss, post-operative pain and other tourniquet-related complications. Two hundred and six patients undergoing TKA were randomly allocated to either the early release (deflation) group (n=105) or reinflation after early release (reinflation) group (n=101). Efficacy was measured in terms of surgical field visualization, specifically the number of wound clearances, and operative time. Safety outcomes were drained volume, decline in haemoglobin on post-operative days 2 and 5, the frequency of transfusion, knee and thigh pain visual analog scale, local wound complications, tourniquet site complications and other complications, including infection, deep vein thrombosis and pulmonary embolism. Surgical field visualization was better in the reinflation group; however, the operative time did not differ between the two groups. There were no differences between the two groups in post-operative blood loss, decline in haemoglobin on days 2 and 5, transfusion rate, pain level, local complications and other complications. Reinflation of tourniquet is a safe alternative to its early release after deflation in that it improves surgical field visualization during TKA. Therapeutic study, Level I.

Timing of Tourniquet Release in Total Knee Arthroplasty.

EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Describe the available tourniquet application strategies for patients treated with total knee arthroplasty (TKA). 2. Differentiate the potential strengths and limitations of tourniquet release before and after wound closure in TKA. 3. Cite the available evidence regarding tourniquet release before and after wound closure in TKA. 4. Recognize the optimal tourniquet application strategy in TKA based on the available evidence. The authors conducted a meta-analysis to determine the optimal tourniquet application strategy in total knee arthroplasty (TKA). Fourteen high-quality randomized, controlled trials were retrieved. The results showed tourniquet release before wound closure for hemostasis could significantly increase not only the total measured blood loss but also the calculated blood loss in patients treated with TKA, regardless of fixation type. With proper control of the amount of pressure (less than 293 mm Hg) and the duration of application (less than 150 minutes), tourniquet release after wound closure can reduce blood loss in patients treated with primary TKA without increasing the risk of complications. [Orthopedics. 2015; 38(7):445-451.].

Can Cytoprotective Cobalt Protoporphyrin Protect Skeletal Muscle and Muscle-derived Stem Cells From Ischemic Injury?

Extremity trauma is the most common injury seen in combat hospitals as well as in civilian trauma centers. Major skeletal muscle injuries that are complicated by ischemia often result in substantial muscle loss, residual disability, or even amputation, yet few treatment options are available. A therapy that would increase skeletal muscle tolerance to hypoxic damage could reduce acute myocyte loss and enhance preservation of muscle mass in these situations. In these experiments, we investigated (1) whether cobalt protoporphyrin (CoPP), a pharmacologic inducer of cytoprotective heme oxygenase-1 (HO-1), would upregulate HO-1 expression and activity in skeletal muscle, tested in muscle-derived stem cells (MDSCs); and (2) whether CoPP exposure would protect MDSCs from cell death during in vitro hypoxia/reoxygenation. Then, using an in vivo mouse model of hindlimb ischemia/reperfusion injury, we examined (3) whether CoPP pharmacotherapy would reduce skeletal muscle damage when delivered after injury; and (4) whether it would alter the host inflammatory response to injury. MDSCs were exposed in vitro to a single dose of 25 μΜ CoPP and harvested over 24 to 96 hours, assessing HO-1 protein expression by Western blot densitometry and HO-1 enzyme activity by cGMP levels. To generate hypoxia/reoxygenation stress, MDSCs were treated in vitro with phosphate-buffered saline (vehicle), CoPP, or CoPP plus an HO-1 inhibitor, tin protoporphyrin (SnPP), and then subjected to 5 hours of hypoxia (< 0.5% O2) followed by 24 hours of reoxygenation and evaluated for apoptosis. In vivo, hindlimb ischemia/reperfusion injury was produced in mice by unilateral 2-hour tourniquet application followed by 24 hours of reperfusion. In three postinjury treatment groups (n = 7 mice/group), CoPP was administered intraperitoneally during ischemia, at the onset of reperfusion, or 1 hour later. Two control groups of mice with the same injury received phosphate-buffered saline (vehicle) or the HO-1 inhibitor, SnPP. Myocyte damage in the gastrocnemius and tibialis anterior muscles was determined by uptake of intraperitoneally delivered Evans blue dye (EBD), quantified by image analysis. On serial sections, inflammation was gauged by the mean myeloperoxidase staining intensity per unit area over the entirety of each muscle. In MDSCs, a single exposure to CoPP increased HO-1 protein expression and enzyme activity, both of which were sustained for 96 hours. CoPP treatment of MDSCs reduced apoptotic cell populations by 55% after in vitro hypoxia/reoxygenation injury (from a mean of 57.3% apoptotic cells in vehicle-treated controls to 25.7% in CoPP-treated cells, mean difference 31.6%; confidence interval [CI], 28.1-35.0; p < 0.001). In the hindlimb ischemia/reperfusion model, CoPP delivered during ischemia produced a 38% reduction in myocyte damage in the gastrocnemius muscle (from 86.4% ± 7% EBD(+) myofibers in vehicle-treated, injured controls to 53.2% EBD(+) in CoPP-treated muscle, mean difference 33.2%; 95% CI, 18.3, 48.4; p < 0.001). A 30% reduction in injury to the gastrocnemius was seen with drug delivery at the onset of reperfusion (to 60.6% ± 13% EBD(+) with CoPP treatment, mean difference 25.8%; CI, 12.2-39.4; p < 0.001). In the tibialis anterior, however, myocyte damage was decreased only when CoPP was given at the onset of reperfusion, resulting in a 27% reduction in injury (from 78.8% ± 8% EBD(+) myofibers in injured controls to 58.3% ± 14% with CoPP treatment, mean difference 20.5%; CI, 6.1-35.0; p = 0.004). Delaying CoPP delivery until 1 hour after tourniquet release obviated the protective effect in both muscles. Mean MPO staining intensity per unit area, indicating the host inflammatory response, decreased by 27-34% across both the gastrocnemius and tibialis anterior muscles when CoPP was given either during ischemia or at the time of reperfusion. Delaying drug delivery until 1 hour after the start of reperfusion abrogated this antiinflammatory effect. CoPP can decrease skeletal muscle damage when given early in the course of ischemia/reperfusion injury and also provide protection for regenerative stem cell populations. Pharmacotherapy with HO-1 inducers, delivered in the field, on hospital arrival, or during trauma surgery, may improve preservation of muscle mass and muscle-inherent stem cells after severe ischemic limb injury.

Intra-articular versus intravenous tranexamic acid in primary total knee replacement.

We commend Gomez-Barrena E et al. on their recent study entitled “Topical intra-articular compared with intravenous tranexamic acid to reduce blood loss in primary total knee replacement: a double-blind, randomized, controlled, noninferiority clinical trial”. The study was well-designed and appropriate statistical analysis was performed. They compared 39 patients who received 3 grams of intraarticular tranexamic acid (TXA) with another 39 patients who had two doses of 15 milligrams/kilogram of intravenous TXA (one dose before tourniquet release and another three hours after surgery). There was zero incidence of blood transfusion. The visible blood loss as measured in the drain output at 24 hours postoperatively and the invisible blood loss estimated using the Nadler formula at 48 hours postoperatively were comparable in both groups of patients. They conclude that intra-articular TXA according to their described protocol demonstrated noninferiority when compared with intravenous TXA (1).

Tourniquet Release Prior to Dressing Application Reduces Blistering Following Total Knee Arthroplasty

Skin blisters occur in up to 20% of patients after total knee arthroplasty (TKA). Tourniquet release results in a limb volume increase of 10%. We hypothesized that releasing tourniquet before application of circumferential dressing will decrease blister formation. A prospective study was conducted on 135 consecutive primary TKAs. The tourniquet was released immediately after wound closure to allow for re-perfusion and then a dressing was applied. These patients were compared to a historical cohort of 200 primary TKAs, where the tourniquet was released after application of dressing. There was a significant difference in the incidence of blisters between the two groups [Late 7.5% (15/200) vs early release 2.2% (3/135) P=0.028]. Releasing the tourniquet prior to dressing application has reduced the incidence of blistering following TKA.

Ropivacaine plasma levels following high-dose local infiltration analgesia for total knee arthroplasty.

We measured total and free plasma concentrations of ropivacaine following high-volume, high-dose local infiltration analgesia in 28 patients aged 65 years or over undergoing unilateral total knee arthroplasty. Patients received infiltration of ropivacaine 400 mg followed by infusion at 20 mg.h(-1) through an intra-articular catheter. Total and free plasma levels of ropivacaine were measured at specified time intervals during a 24-h period after tourniquet release. Patients were monitored for symptoms and signs of local anaesthetic toxicity. Total levels of plasma ropivacaine varied from 0.147 to 3.093 μg.ml(-1) (mean (SD) 1.105 (0.518) μg.ml(-1) ). Free levels of plasma ropivaca-ine varied from 0.001 to 0.104 μg.ml(-1) (mean (SD) 0.037 (0.020) μg.ml(-1) ). Six samples had total plasma ropivacaine levels greater the toxic threshold of 2.2 μg.ml(-1) . No samples reached the toxic threshold for free venous ropivacaine concentration. We conclude that the use of high-dose ropivacaine infiltration and catheter infusion for total knee arthroplasty in an elderly population does not result in free plasma ropivacaine levels previously associated with toxicity but that raised total plasma levels may be observed.

Gelatin matrix use reduces postoperative bleeding after total knee arthroplasty.

Bleeding after total knee arthroplasty can result in significant morbidity and increases the need for blood transfusion. The proper use of intraoperative adjunctive topical hemostatic agents can enhance hemostasis perioperatively, potentially reducing blood transfusions. In this prospective study, 157 consecutive patients undergoing primary total knee arthroplasty received FLOSEAL (FLOSEAL Hemostatic Matrix; Baxter Healthcare Corporation, Hayward, California), a gelatin thrombin hemostatic matrix, 5 mL (74 patients) or 10 mL (83 patients). All patients received warfarin as thromboprophylaxis starting the day after surgery. Data were extracted via hospital chart review from 100 consecutive patients who underwent total knee arthroplasty and immediately preceded the FLOSEAL groups and did not receive FLOSEAL (control group). Postoperative drainage was significantly lower in the FLOSEAL 5 mL (236.9 mL) and 10 mL (120.5 mL) groups compared with the control group (430.8 mL; P<.0001 for both). The FLOSEAL 10 mL group had significantly less drainage than the FLOSEAL 5 mL group (P<.0001). The predicted probability of transfusion in the FLOSEAL 5 mL group was not significantly different compared with the control group (6.0% vs 7.6%, P=.650). The predicted probability of transfusion was lower in the FLOSEAL 10 mL group compared with the control group (0.5% vs 5.5%; P=.004). Within the FLOSEAL 10 mL group, application of FLOSEAL either before or after tourniquet release had a similarly significant effect on drainage volume and predicted probability of blood transfusion. No differences in outcomes were observed by type of anesthesia used. No adverse events occurred related to FLOSEAL use.