Sufentanil Improves the Analgesia Effect of Continuous Femoral Nerve Block After Total Knee Arthroplasty.

Purpose: We examined whether the addition of sufentanil to local anesthetics improves the quality of continuous femoral nerve block in patients undergoing total knee arthroplasty (TKA). Patients and Methods: With institutional ethical approval and having obtained written informed consent from each, 35 patients scheduled for elective bilateral TKA with ASA I or II physical status were studied. Bilateral femoral perineural catheters were preoperatively inserted. Both-sided catheters were randomly assigned to receive perineural ropivacaine of 0.2% plus 0.5µg/mL sufentanil deemed as RS group or 0.2% ropivacaine alone deemed as R group at the end of surgery. Visual analogue pain scores (VAS) during activity and at rest of each lower limb were recorded at 6,12,18,24,30,36,42 and 48h after surgery. During the first 48 postoperative hours, the number and reason of patients sleep interruption at night, the number of painful compressions, patient satisfaction and morphine requirements were recorded for each lower limb of patients. Results: Pain scores of RS group on movement were significantly lower than R group, but no difference was noted at rest. When compared to R group, RS group had a lower incidence of sleep interruption at night, fewer painful compressions, higher satisfaction scores and less morphine requirement. Conclusion: The addition of sufentanil to ropivacaine improved analgesia quality of continuous femoral nerve block after arthroplasty.

KGF-2 Protects against Lung Ischemia-Reperfusion Injury by Inhibiting Inflammation-Induced Damage to Endothelial Barrier Function.

Lung ischemia-reperfusion injury (LIRI), which has a mortality rate of approximately 50%, is a popular topic in critical care research. Keratinocyte growth factor-2 (KGF-2) is secreted by mesenchymal cells, and it is effective in promoting the proliferation, migration, and differentiation of various epithelial cells. To date, however, only a few reports on KGF-2-related regulators in LIRI have been published. In the current study, an LIRI rat model is constructed, and the upregulation of the fibroblast growth factor receptor 2 (FGFR2) is observed in the LIRI rat model. In addition, LIRI induces NLRP1 inflammasome activation in vivo and in vitro, and KGF-2 inhibits LIRI-induced damage to pulmonary microvascular endothelial cells. Mechanistically, KGF-2 inhibits NLRP1 inflammasome and NF-κB activity. KGF-2 inhibition attenuates LIRI injury-induced damage to endothelial integrity. In conclusion, KGF-2 protects against LIRI by inhibiting inflammation-induced endothelial barrier damage.

Apelin-13 Reverses Bupivacaine-Induced Cardiotoxicity via the Adenosine Monophosphate-Activated Protein Kinase Pathway.

BACKGROUND: Cardiotoxicity can be induced by the commonly used amide local anesthetic, bupivacaine. Bupivacaine can inhibit protein kinase B (AKT) phosphorylation and activated adenosine monophosphate-activated protein kinase alpha (AMPKα). It can decouple mitochondrial oxidative phosphorylation and enhance reactive oxygen species (ROS) production. Apelin enhances the phosphatidylinositol 3-kinase (PI3K)/AKT and AMPK/acetyl-CoA carboxylase (ACC) pathways, promotes the complete fatty acid oxidation in the heart, and reduces the release of ROS. In this study, we examined whether exogenous (Pyr1) apelin-13 could reverse bupivacaine-induced cardiotoxicity. METHODS: We used the bupivacaine-induced inhibition model in adult male Sprague Dawley (SD) rats (n = 48) and H9c2 cardiomyocyte cell cultures to explore the role of apelin-13 in the reversal of bupivacaine cardiotoxicity, and its possible mechanism of action. AMPKα, ACC, carnitine palmitoyl transferase (CPT), PI3K, AKT, superoxide dismutase 1 (SOD1), and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (p47-phox) were quantified. Changes in mitochondrial ultrastructure were examined, and mitochondrial DNA, cell viability, ROS release, oxygen consumption rate (OCR) were determined. RESULTS: Apelin-13 reduced bupivacaine-induced mitochondrial DNA lesions in SD rats (P < .001), while increasing the expression of AMPKα (P = .007) and PI3K (P = .002). Furthermore, apelin-13 blocked bupivacaine-induced depolarization of the mitochondrial membrane potential (P = .019) and the bupivacaine-induced increases in ROS (P = .001). Also, the AMPK pathway was activated by bupivacaine as well as apelin-13 (P = .002) in H9c2 cardiomyocytes. Additionally, the reduction in the PI3K expression by bupivacaine was mitigated by apelin-13 in H9c2 cardiomyocytes (P = .001). While the aforementioned changes induced by bupivacaine were not abated by apelin-13 after pretreatment with AMPK inhibitor compound C; the bupivacaine-induced changes were still mitigated by apelin-13, even when pretreated with PI3K inhibitor-LY294002. CONCLUSIONS: Apelin-13 treatment reduced bupivacaine-induced oxidative stress, attenuated mitochondrial morphological changes and mitochondrial DNA damage, enhanced mitochondrial energy metabolism, and ultimately reversed bupivacaine-induced cardiotoxicity. Our results suggest a role for the AMPK in apelin-13 reversal of bupivacaine-induced cardiotoxicity.

Dexmedetomidine preconditioning ameliorates lung injury induced by pulmonary ischemia/reperfusion by upregulating promoter histone H3K4me3 modification of KGF-2.

Keratinocyte growth factor (KGF)-2 has been highlighted to play a significant role in maintaining the endothelial barrier integrity in lung injury induced by ischemia-reperfusion (I/R). However, the underlying mechanism remains largely unknown. The aims of this study were to determine whether dexmedetomidine preconditioning (DexP) modulates pulmonary I/R-induced lung injury through the alteration in KGF-2 expression. In our I/R-modeled mice, DexP significantly inhibited pathological injury, inflammatory response, and inflammatory cell infiltration, while promoted endothelial barrier integrity and KGF-2 promoter activity in lung tissues. Bioinformatics prediction and ChIP-seq revealed that I/R significantly diminished the level of H3K4me3 modification in the KGF-2 promoter, which was significantly reversed by DexP. Moreover, DexP inhibited the expression of histone demethylase JMJD3, which in turn promoted the expression of KGF-2. In addition, overexpression of JMJD3 weakened the protective effect of DexP on lung injury in mice with I/R. Collectively, the present results demonstrated that DexP ameliorates endothelial barrier dysfunction via the JMJD3/KGF-2 axis.

Dexmedetomidine may decrease the bupivacaine toxicity to heart.

OBJECTIVE: The purpose of our study was to explore the effect of dexmedetomidine on cardiac tolerance to bupivacaine. METHOD: Human coronary endothelial cells were used to establish in vitro model. They were randomly divided into control (Con) group, dexmedetomidine (Dex) group, bupivacaine (Bupi) group, dexmedetomidine + bupivacaine group (DB group), and dexmedetomidine + bupivacaine + PI3K inhibitor (DB-inhibitor) group. Cell activity was measured by Cell counting kit-8 (CCK-8). Transwell was used to detect cell permeability. Western blotting was used to detect the protein expression of related factors. RESULTS: There were no notable differences in cell activity among the five groups (P > 0.05). Dexmedetomidine significantly reduced the permeability of endothelial cells to bupivacaine and increased the protein expression of Zonulaoeeludens-1 (ZO-1) (P < 0.01). However, the aforementioned effects of dexmedetomidine were disappeared after the addition of PI3K inhibitors. Furthermore, Dex and DB markedly increased the protein expression of PI3K, p-Akt, and p-PTEN in comparison with Con group (P < 0.001), but there was no significant difference in p-PTEN among DB-inhibitor, Con, and Bupi groups (P > 0.05). CONCLUSION: Dex reduced Bupi-induced vasopermeability through protein expression of ZO-1 and PI3K/Akt pathway, which may lead to the decrease of Bupi-induced cardiotoxicity.

Self-produced audio-visual animation introduction alleviates preoperative anxiety in pediatric strabismus surgery: a randomized controlled study.

BACKGROUND: Hospital anxiety caused by strabismus surgery has an unpleasant and disturbing feeling for both children and their parents. This study aimed to determine the effect of viewing a self-produced audio-visual animation introduction on preoperative anxiety and emergence agitation of pediatric patients undergoing strabismus surgery. METHODS: In this prospective randomized study, 1 hundred children scheduled for strabismus surgery with aged 3 ~ 6 years. The children were randomly divided into 2 groups (n = 50 for each), Group A: using a self-produced audio-visual animation introduction; Group C: controlled group without audio-visual animation introduction. Children's preoperative anxiety was determined by the modified Yale Preoperative Anxiety Scale (mYPAS) at different time points: the night before surgery(T1), at pre-anesthetic holding room(T2), and just before anesthesia induction(T3). The Spielberger State-Trait Anxiety Inventory (STAI) was used to record the anxiety of parents at T1,T2 and T3. The incidence and the degree of emergence agitation were recorded. RESULTS: The mYPAS scores at T2 and T3 were higher than T1(p < 0.05) in both groups. The average score of mYPAS in Group A was significantly lower than in Group C at T2 and T3(p < 0.05). The STAI scores in Group A at T2 and T3 were significantly lower than in Group C(p < 0.05). The incidence of agitation in Group A was lower than that in Group C(p < 0.05). CONCLUSIONS: Based on the findings, viewing a self-produced audio-visual animation can effectively alleviate the preoperative anxiety for both children and their parents in pediatric strabismus surgery, and it was effective for reducing emergence agitation as well. TRIAL REGISTRATION: The trial was prospectively registered before patient enrollment at Chinese Clinical Trial Registry (Clinical Trial Number: ChiCTR1900025116 , Date: 08/12/2019).

Bupivacaine inhibits a small conductance calcium-activated potassium type 2 channel in human embryonic kidney 293 cells.

BACKGROUND: Bupivacaine blocks many ion channels in the heart muscle, causing severe cardiotoxicity. Small-conductance calcium-activated potassium type 2 channels (SK2 channels) are widely distributed in the heart cells and are involved in relevant physiological functions. However, whether bupivacaine can inhibit SK2 channels is still unclear. This study investigated the effect of bupivacaine on SK2 channels. METHODS: The SK2 channel gene was transfected into human embryonic kidney 293 cells (HEK-293 cells) with Lipofectamine 2000. The whole-cell patch-clamp technique was used to examine the effect of bupivacaine on SK2 channels. The concentration-response relationship of bupivacaine for inhibiting SK2 currents (0 mV) was fitted to a Hill equation, and the half-maximal inhibitory concentration (IC50) value was determined. RESULTS: Bupivacaine inhibited the SK2 channels reversibly in a dose-dependent manner. The IC50 value of bupivacaine, ropivacaine, and lidocaine on SK2 currents was 16.5, 46.5, and 77.8µM, respectively. The degree of SK2 current inhibition by bupivacaine depended on the intracellular concentration of free calcium. CONCLUSIONS: The results of this study suggested the inhibitory effect of bupivacaine on SK2 channels. Future studies should explore the effects of SK2 on bupivacaine cardiotoxicity.

Omentin-1 attenuates glucocorticoid-induced cardiac injury by phosphorylating GSK3ß.

Glucocorticoid excess often causes a variety of cardiovascular complications, including hypertension, atherosclerosis, and cardiac hypertrophy. To abrogate its cardiac side effects, it is necessary to fully disclose the pathophysiological role of glucocorticoid in cardiac remodelling. Previous clinical and experimental studies have found that omentin-1, one of the adipokines, has beneficial effects in cardiovascular diseases, and is closely associated with metabolic disorders. However, there is no evidence to address the potential role of omentin-1 in glucocorticoid excess-induced cardiac injuries. To uncover the links, the present study utilized rat model with glucocorticoid-induced cardiac injuries and clinical patients with abnormal cardiac function. Chronic administration of glucocorticoid excess reduced rat serum omentin-1 concentration, which closely correlated with cardiac functional parameters. Intravenous administration of adeno-associated virus encoding omentin-1 upregulated the circulating omentin-1 level and attenuated glucocorticoid excess-induced cardiac hypertrophy and functional disorders. Overexpression of omentin-1 also improved cardiac mitochondrial function, including the reduction of lipid deposits, induction of mitochondrial biogenesis, and enhanced mitochondrial activities. Mechanistically, omentin-1 phosphorylated and activated the GSK3ß pathway in the heart. From a study of 28 patients with Cushing's syndrome and 23 healthy subjects, the plasma level of glucocorticoid was negatively correlated with omentin-1, and was positively associated with cardiac ejection fraction and fractional shortening. Collectively, the present study provided a novel role of omentin-1 in glucocorticoid excess-induced cardiac injuries and found that the omentin-1/GSK3ß pathway was a potential therapeutic target in combating the side effects of glucocorticoid.

Evaluation of Recombinant CYP3A4 Variants on the Metabolism of Oxycodone In Vitro.

Cytochrome P450 3A4 is a highly polymorphic enzyme and metabolizes approximately 40%-60% of therapeutic drugs. Its genetic polymorphism may significantly affect the expression and function of CYP3A4 resulting in alterations of the pharmacokinetics and pharmacodynamics of the CYP3A4-mediated drugs. The purpose of this study was to evaluate the catalytic activities of 30 CYP3A4 nonsynonymous variants and wild type toward oxycodone in vitro. CYP3A4 proteins were incubated with oxycodone for 30 min at 37 °C and the reaction was terminated by cooling to -80 °C immediately. Ultraperformance liquid chromatography tandem mass-spectrometry was used to analyze noroxycodone, and kinetic parameters Km, Vmax, and intrinsic clearance (Vmax/Km) of noroxycodone were also determined. Compared with CYP3A4.1, 24 CYP3A4 variants (CYP3A4.2-.5, -.7-.16, -.18 and -.19, -.23 and -.24, -.28 and -.29, and -.31-.34) exhibited significantly decreased relative clearance values (from 4.82% ± 0.31% to 80.98% ± 5.08%), whereas CYP3A4.6, -.17, -.20, -.21, -.26, and -.30 displayed no detectable enzyme activity. As the first study of these alleles for oxycodone metabolism in vitro, results of this study may provide insight into establishing the genotype-phenotype relationship for oxycodone and serve as a reference for clinical administrators and advance the provision of personalized precision medicine.

Ganoderic acid A attenuates high-fat-diet-induced liver injury in rats by regulating the lipid oxidation and liver inflammation.

Ganoderic Acid A (GA) has many pharmacological effects such as anti-tumor, antibacterial, anti-inflammatory, and immunosuppressive effects. However, the protective effect of GA on liver injury has not been reported. This study aimed to investigate the action of GA on insufficient methionine and choline combined with high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) in rats. NAFLD model was established by insufficient methionine and choline combined with high fat feeding to rats. The levels of Acetyl-CoA carboxylase, fatty acid synthase, sterol regulatory element binding protein, liver X receptors, AMP-activated protein kinase, peroxisome proliferator-activated receptor α, PPARg coactivator 1α and NF-κB pathway in the liver were detected by western blot. The results of this study demonstrated that the expression of GA can not only significantly decrease the live weight and liver weight per body weight of HFD mice, but also restore the alanine aminotransferase, aspartate aminotransferase, total bilirubin levels, triglyceride and cholesterol in serum. In addition, the expression of GA increased the levels of high-density lipoprotein cholesterol in serum, ameliorated pathological changes and decreased NAS score of mice's liver. In conclusion, the treatment with GA could improve NAFLD in rats by regulating the levels of signaling events involved in free fatty acid production, lipid oxidation and liver inflammation.

Dexmedetomidine enhances tolerance to bupivacaine cardiotoxicity in the isolated rat hearts: alpha 2 adrenoceptors were not involved.

BACKGROUND: Dexmedetomidine was proved to mitigate bupivacaine-induced cardiotoxicity but mechanism of this ability is still unclear. This study was designed to investigate the direct effects of dexmedetomidine on cardiotoxicity induced by bupivacaine on Langendorff rat heart preparation and the role of alpha 2 adrenoceptors in this process was explored. METHODS: Hearts of rat were isolated, mounted on a Langendorff system. Five experimental groups were assessed after 10 min Krebs-Henseleit buffer (KHB) infusions as follow: (1) Group Con, only KHB was perfused; (2) Group Dex, KHB was perfused for 5 min, then dexmedetomidine (10 nmol/L) was added; (3) Group Bupi, KHB was perfused for 25 min, then bupivacaine (50 µmol/L) was added; (4) Group Bupi + Dex, KHB was perfused for 5 min, then the dexmedetomidine (10 nmol/L) was added for 20 min, at last a mixture of KHB + dexmedetomidine + bupivacaine were perfused; (5) Group Bupi + Dex + Yoh, a combination of KHB + yohimbine (alpha 2 adrenoceptor antagonists, 1 µmol/L) was perfusion for 5 min, then dexmedetomidine (10 nmol/L) was added for 20 min, at last a mixture of KHB + yohimbine + dexmedetomidine + bupivacaine was perfused. The experimental perfusion was maintained for 35 min in group Con and group Dex, and the experimental perfusion was sustained until asystole in the other three groups. RESULTS: Compared with group Bupi, dexmedetomidine significantly increased the time to first arrhythmia (P <  0.001) and time to asystole (P <  0.001) in group Bupi + Dex. In addition, dexmedetomidine also significantly increased the time to 25, 50 and 75% reductions in heart rate (P <  0.001) and the time to 25, 50 and 75% reductions in rate-pressure product (P <  0.001) in group Bupi + Dex. Dexmedetomidine increased the cardiac tissue bupivacaine content when asystole (Bupi + Dex vs. Bupi, 58.5 ± 6.3 vs. 46.8 ± 5.6 nmol/g, P = 0.003). The benefit of dexmedetomidine on bupivacaine-induced cardiotoxicity were not eliminated by yohimbine. CONCLUSIONS: Dexmedetomidine could delay the occurrence of bupivacaine-induced arrhythmia and asystole in the isolated rat hearts, but the alpha 2 adrenoceptors were not involved in this process.

ω-3 fish oil fat emulsion preconditioning mitigates myocardial oxidative damage in rats through aldehydes stress.

ω-3 fish oil fat emulsions contain a considerable quantity of unsaturated carbon-carbon double bonds, which undergo lipid peroxidation to yield low-dose aldehydes. These aldehydes may stimulate the production of antioxidant enzymes, thereby mitigating myocardial oxidative damage. This study aims to (1) verify the cardioprotective effect of ω-3 fish oil fat emulsion in vivo and in vitro, and (2) determine whether aldehyde stress is a protective mechanism. For modeling purposes, we pretreated rats with 2 ml/kg of a 10% ω-3 fish oil fat emulsion for 5 days in order to generate a sufficient aldehyde stress response to trigger the production of antioxidant enzymes, and we obtained similar response with H9C2 cells that were pretreated with a 0.5% ω-3 fish oil fat emulsion for 24 h. ω-3 fish oil fat emulsion pretreatment in vivo reduced the myocardial infarct size, decreased the incidence of arrhythmias, and promoted the recovery of cardiac function after myocardial ischemia/reperfusion injury. Once the expression of nuclear factor E2-related factor 2 (Nrf2) was silenced in H9C2 cells, aldehydes no longer produced enough antioxidant enzymes to reverse the oxidative damage caused by tert-butyl hydroperoxide (TBHP). Our results demonstrated that ω-3 fish oil fat emulsion enhanced the inhibition of oxidation and production of free radicals, and alleviated myocardial oxidative injury via activation of the Nrf2 signaling pathway.

Comparative Regimens of Lipid Rescue From Bupivacaine-Induced Asystole in a Rat Model.

BACKGROUND: It is currently unknown whether bupivacaine-induced asystole is better resuscitated with lipid emulsion (LE) administered peripherally or centrally, and whether different LE regimens administered peripherally demonstrated similar effects. In this study, we compared the effects of various regimens of lipid administration in a rat model of bupivacaine-induced asystole. METHODS: Forty-five adult male Sprague-Dawley rats were subjected to bupivacaine-induced asystole and randomly divided into 3 lipid regimens groups: (1) 20% LE was administered continuously via the internal jugular vein (CV-infusion group); (2) 20% LE was administered continuously via the tail vein (PV-infusion group); and (3) 20% LE was administered as divided boluses via the tail vein (PV-bolus group). The maximum dose of LE did not exceed 10 mL·kg(-1). External chest compressions were administered until the return of spontaneous circulation (ROSC) or the end of a 40-minute resuscitation period. RESULTS: The survival rate, rate of ROSC, systolic blood pressure, heart rate, heart rate-blood pressure product, and coronary perfusion pressure during 2-40 minutes in the CV-infusion and PV-bolus groups were significantly higher than those in the PV-infusion group (P < .01), and the plasma total bupivacaine concentration and myocardial bupivacaine content were significantly lower (P < .05). Time to heartbeat return and time to ROSC in the CV-infusion and PV-bolus groups were significantly shorter than those in the PV-infusion group (P < .05). CONCLUSIONS: In the rat model of bupivacaine-induced asystole, a divided LE bolus regimen administered peripherally provided a better resuscitation outcome than that of a continuous LE infusion regimen peripherally, and performed in a similar fashion as the continuous LE infusion regimen administered centrally.

Levosimendan is superior to epinephrine on coronary flow for lipid-base resuscitation of bupivacaine-induced asystole in the isolated rat heart.

BACKGROUND: Successful resuscitation from asystole induced by bupivacaine requires the reestablishment of a sufficient coronary flow (CF) quickly. This study was designed to test whether levosimendan was superior to epinephrine in the reestablishment of crucial coronary flows after bupivacaine-induced asystole. METHODS: The isolated, perfused, nonrecirculating, Langendorff rat heart preparation was used. Bupivacaine 100 µmol/L was perfused into rat hearts to induce asystole, and then for 3 min thereafter. Three experimental groups were assessed after asystole with infusions as follow: (1) a mixture of 2% lipid emulsion and 40 µmol/L bupivacaine (control group), (2) a mixture of 0.15 µg/mL epinephrine combined with 2% lipid emulsion and 40 µmol/L bupivacaine (epinephrine group), and (3) a mixture of 5 µmol/L levosimendan combined with a 2% lipid emulsion and 40 µmol/L bupivacaine mixture (levosimendan group). Coronary flow (CF), the time to recovery (Trecovery), the number of ventricular arrhythmias, and cardiac function parameters were recorded for 40 min after heartbeat recovery. RESULTS: All hearts in the control, epinephrine and levosimendan groups had heartbeat recovery. The rank order of the mean CF from highest to lowest was the levosimendan group > the epinepgrine group > the control group (P < 0.05). The rank order of Trecovery from shortest to longest was the levosimendan group < the epinephrine group < the control group (P < 0.01). During the recovery phase, isolated rat hearts developed more ventricular arrhythmias in the epinephrine group than in the levosimendan group (P = 0.01). CONCLUSION: Levosimendan is superior to epinephrine in producing higher CFs and faster recovery when reversing bupivacaine-induced asystole in the isolated rat hearts.

The protective effect of lipid emulsion in preventing bupivacaine-induced mitochondrial injury and apoptosis of H9C2 cardiomyocytes.

Lipid emulsion (LE) has been shown to be effective in the resuscitation of bupivacaine-induced cardiac arrest, but the precise mechanism of this action has not been fully elucidated. Pursuant to this lack of information on the mechanism in which LE protects the myocardium during bupivacaine-induced toxicity, we explored mitochondrial function and cell apoptosis. H9C2 cardiomyocytes were used in study. Cells were randomly divided in different groups and were cultivated 6 h, 12 h, and 24 h. The mitochondria were extracted and mitochondrial ATP content was measured, as was mitochondrial membrane potential, the concentration of calcium ion (Ca2+), and the activity of Ca2+-ATP enzyme (Ca2+-ATPase). Cells from groups Bup1000, LE group, and Bup1000LE were collected to determine cell viability, cell apoptosis, and electron microscopy scanning of mitochondrial ultrastructure (after 24 h). We found that LE can reverse the inhibition of the mitochondrial function induced by bupivacaine, regulate the concentration of calcium ion in mitochondria, resulting in the protection of myocardial cells from toxicity induced by bupivacaine.

Giving Priority to Lipid Administration Can Reduce Lung Injury Caused by Epinephrine in Bupivacaine-Induced Cardiac Depression.

BACKGROUND AND OBJECTIVES: Epinephrine is usually administered in concert with a lipid emulsion during local anesthetic toxicity. However, the timing and role of epinephrine administration in combination with a lipid emulsion remain unclear. Specifically, the temporal association of epinephrine and lipid emulsion administration with related changes in pulmonary vascular pressures that may lead to pulmonary edema and hemorrhage needs to be determined. METHODS: This study consisted of 2 parts, experiments A and B. In experiment A, 24 adult male Sprague-Dawley rats were randomly divided into 3 groups (n = 8) to receive 1 of 3 treatments. All rats were anesthetized with an intraperitoneal injection of chloral hydrate, and anesthesia was maintained by sevoflurane. Each treatment group was initially given an infusion of bupivacaine (15 mg/kg) in order to produce cardiac depression. Group 1 (A-LEN) received a 30% lipid infusion (3 mL/kg) followed by a rapid epinephrine bolus (10 µg/kg), which was then followed by a normal saline infusion (3 mL/kg). Group 2 (A-NEL) first received a normal saline infusion (3 mL/kg) followed by a rapid epinephrine bolus, which was then followed by a 30% lipid emulsion. Group 3 (A-NEN, considered a control group) first received a normal saline infusion (3 mL/kg) followed by a rapid epinephrine bolus (10 µg/kg), which was then followed by another normal saline infusion (3 mL/kg). Lipid and normal saline infusions were administered over 1 minute, whereas epinephrine was injected rapidly. The continuous monitoring of blood pressure, heart rate, pulmonary arterial pressure, and pulmonary venous pressure occurred for 30 minutes. After the 30-minute monitoring period, lung tissue was sampled, and bronchoalveolar lavage fluid was collected. In experiment B, the experimental model and resuscitation protocol were similar to experiment A (B-LEN and B-NEL groups). In this arm of the experiment, bupivacaine concentrations of cardiac tissue were determined after the second minute of normal saline infusion. RESULTS: The A-LEN group produced the best rate pressure product when compared with the A-NEL or A-NEN group (P = 0.045, P = 0.011, respectively). In regard to pulmonary venous pressure, the A-LEN group was lower than the A-NEL or A-NEN group (P = 0.031, P = 0.006, respectively). Animals in the A-NEL and A-NEN groups rapidly developed pulmonary edema after infusion of epinephrine. The wet-to-dry ratio of the lungs in the A-LEN group was lower than that of the lungs in the A-NEL group (P = 0.024).The lung permeability index of the A-LEN group was lower than that of the A-NEL group (P = 0.011). In experiment B, concentrations of bupivacaine in cardiac tissue and plasma of the B-LEN group were lower than those of the B-NEL group (P = 0.001, P = 0.03, respectively). CONCLUSIONS: Giving priority to the administration of a lipid emulsion before the administration of epinephrine can reduce lung injury in bupivacaine-induced cardiac depression in rats.

Epinephrine reversed high-concentration bupivacaine-induced inhibition of calcium channels and transient outward potassium current channels, but not on sodium channel in ventricular myocytes of rats.

BACKGROUND: Epinephrine is a first-line drug for cardiopulmonary resuscitation, but its efficacy in the treatment of bupivacaine-induced cardiac toxicity is still in question. We hypothesized that epinephrine can reverse cardiac inhibition of bupivacaine by modulating ion flows through the ventricular myocyte membrane channels of rats. The aim of this study was to observe and report the effects of epinephrine on high-concentration bupivacaine-induced inhibition of sodium (INa), L-type calcium (ICa-L), and transient outward potassium (Ito) currents in the ventricular myocytes of rats. METHODS: The ventricular myocytes were isolated from Sprague-Dawley rats (250-300 g) by acute enzymatic dissociation. The whole-cell patch clamp technique was used to record the ion channel currents in single ventricular myocytes both before and after administration of medications. RESULT: Administration of bupivacaine 100 µmol/L significantly reduced INa, (P < 0.05). However, administration of bupivacaine 100 µmol/L in conjunction with epinephrine 0.15 µg/ml had no effect in restoring INa to its previous state. Similarly, a sharp decline of ICa-L and Ito was observed after administration of bupivacaine 100 µmol/L (P < 0.05). In contrast to INa, ICa-L and Ito were significantly improved after the administration of the aforementioned combination of bupivacaine and epinephrine (P < 0.05). CONCLUSION: Epinephrine can reverse high-concentration bupivacaine induced inhibition of ICa-L and Ito, but not INa. Thus, epinephrine's effectiveness in reversal of bupivacaine-induced cardiac toxicity secondary to sodium channel inhibition may be limited.

Epinephrine administration in lipid-based resuscitation in a rat model of bupivacaine-induced cardiac arrest: optimal timing.

BACKGROUND AND OBJECTIVES: The medical community commonly uses lipid emulsion combined with epinephrine in local anesthetic-induced cardiac arrest, but the optimal timing of epinephrine administration relative to lipid emulsion is currently unknown and needs to be determined. METHODS: Thirty adult male Sprague-Dawley rats were subjected to bupivacaine-induced asystole and were then randomly divided into 3 groups. The temporal administration of epinephrine varied in each group: (1) immediately after the completion of the initial bolus of lipid emulsion therapy (postILE0); (2) immediately after cardiac arrest before the initial bolus of lipid emulsion (preILE); or (3) 1 minute after the completion of the initial bolus of lipid emulsion (postILE1). External chest compression was administered until the return of spontaneous circulation or the end of a 20-minute resuscitation period. RESULTS: The postILE0, preILE, and postILE1 groups displayed different survival rates (100%, 30%, and 40%; P = 0.003). After return of spontaneous circulation, the rate-pressure product of the postILE0 group was higher than that of the postILE1 group (P < 0.001). Wet-to-dry lung weight ratio of preILE and postILE1 groups was higher than that of the postILE0 group (P < 0.05). The rate of damaged alveoli of the postILE0 group was lower than those of the preILE (P = 0.001) and postILE1 (P < 0.001) groups. Concentrations of bupivacaine in the cardiac tissues of the postILE0 group were lower than that of the postILE1 group (P = 0.01). CONCLUSIONS: In the rat model of bupivacaine-induced cardiac arrest, the optimal timing for the administration of epinephrine to produce best outcomes of successful cardiopulmonary resuscitation is immediately after the completion of the lipid emulsion bolus. This optimal timing/therapeutic window is of paramount importance.

Lipid resuscitation of bupivacaine toxicity: long-chain triglyceride emulsion provides benefits over long- and medium-chain triglyceride emulsion.

BACKGROUND: The superiority of Intralipid, a long-chain triglyceride (LCT) emulsion versus Lipovenoes, a long- and medium-chain triglyceride (LCT/MCT) emulsion, in reversing local anesthetic-induced cardiac arrest is poorly defined and needs to be determined. METHODS: The study included two parts: in experiment A, bupivacaine (20 mg/kg) was injected to produce asystole. Either Intralipid 20% (LCT group, n = 30) or Lipovenoes 20% (LCT/MCT group, n = 30) with epinephrine was infused immediately. Return of spontaneous circulation and recurrence of asystole after resuscitation were recorded. In experiment B, 80 rats using the same model and resuscitation protocol were divided into 10 groups: LCT0, LCT15, LCT30, LCT60, and LCT120 and LCT/MCT0, LCT/MCT15, LCT/MCT30, LCT/MCT60, and LCT/MCT120 (n = 8 each; the subscripts represent respective observation period). LCT15-LCT120 and LCT/MCT15-LCT/MCT120 groups received Intralipid 20% or Lipovenoes 20%, respectively. Plasma and myocardial bupivacaine and triglyceride concentrations, as well as myocardial bioenergetics, were determined. RESULTS: In experiment A, 24 rats in LCT group and 23 in LCT/MCT group achieved return of spontaneous circulation (P = 0.754); among them, 2 (8.3%) and 8 (34.8%) rats suffered a repeated asystole, respectively (P = 0.027). In experiment B, plasma and myocardial bupivacaine concentrations in LCT15 and LCT60 groups were lower than LCT/MCT15 and LCT/MCT60 groups, respectively. Furthermore, the plasma bupivacaine level in LCT/MCT60 group was higher than LCT/MCT30 group (P = 0.003). CONCLUSIONS: LCT emulsion may be superior to LCT/MCT emulsion in treating bupivacaine-related cardiotoxicity as it was associated with fewer recurrences of asystole after resuscitation and lower myocardial bupivacaine concentrations.