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.

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.

The ultrasound-guided selective nerve block in the upper arm: an approach of retaining the motor function in elbow.

BACKGROUND: Proximal brachial plexus blocks can lead to an extended period of motor paralysis and delay the return of motor function. This could influence patient satisfaction, and extend hospitalizations. The aim of the study is to compare a selective distal nerve block of the arm to a proximal axillary block, both ultrasound-guided, in terms of their motor block intensity of the elbow. Our hypothesis is that a selective nerve block of the arm would result in a different motor block of the elbow, compared to the axillary block. METHODS: A sample size of 24 patients who were undergoing elective surgery (ASA I-III) of the wrist, hand or forearm was randomly divided into two groups: Arm Group (n = 12) and Axillary Group (n = 12). The Arm Group received ultrasound-guided block of the median, ulnar, and medial antebrachial cutaneous nerves at the level of upper-median 1/3 of the arm, and a block of the radial and musculocutaneous nerves at the level of low-median 1/3 of the arm, while the Axillary Group received ultrasound-guided axillary brachial plexus blocks. Both blocks used in combination with general anesthesia. RESULTS: Our results demonstrated that the incidence of motor block at the elbow in the Arm Group was lower than in the Axillary Group. Compared with the Axillary Group, the duration of motor block at the elbow and the onset time of sensory block in the Arm Group were shortened. The patient satisfaction was increased in the Arm Group. There were no differences in the duration of the sensory block, the effect on postoperative analgesia, or in the duration of the motor block at the shoulder between both groups. CONCLUSION: Our study showed that ultrasound-guided selective nerve block in the upper arm allowed improved retention of motor function at the elbow compared to axillary block. Secondarily, the ultrasound-guided selective nerve block seemed to provide similar analgesia after surgery of the hand or forearm with an enhanced patient satisfaction. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR-IOR-16008769 . Registered 3 July 2016.

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.

Levosimendan combined with epinephrine improves rescue outcomes in a rat model of lipid-based resuscitation from bupivacaine-induced cardiac arrest.

BACKGROUND: The effectiveness of a combination of a lipid emulsion with epinephrine in reversing local anesthetic-induced cardiac arrest has been confirmed. The combination of a lipid emulsion with levosimendan, was shown to be superior to administration of a lipid emulsion alone with regard to successful resuscitation. In this study, we compared the reversal effects of levosimendan, epinephrine, and a combination of the two agents in lipid-based resuscitation in a rat model of bupivacaine-induced cardiac arrest. METHODS: Fifty-four adult male Sprague-Dawley rats were subjected to bupivacaine (15 mg·kg-1) -induced asystole and were then randomly divided into 3 groups. A lipid emulsion was used as the basic treatment, and administration of drug combinations varied in each group as follows: (1) levosimendan combined with epinephrine (LiEL); (2) epinephrine (LiE); and (3) levosimendan (LiL). The resuscitation outcomes were recorded and included the rate of return of spontaneous circulation (ROSC) and survival at 40 min, time to first heartbeat, time to ROSC, and cumulative dose of epinephrine. We calculated the wet-to-dry ratio of the lung, blood gas values at 40 min and bupivacaine concentration of cardiac tissue and plasma. RESULTS: The rates of ROSC in LiEL and LiE groups were higher than LiL group (P < 0.001; LiEL vs LiL, P = 0.001; LiE vs LiL, P = 0.007). The survival rate in LiEL group was higher than LiE group (P = 0.003; LiEL vs LiE, P = 0.008; LiEL vs LiL, P = 0.001). The time to first heart beat in LiEL group was shorter than LiE, LiL groups. (P < 0.001; LiE vs LiEL, P = 0.001; LiL vs LiEL, P < 0.001). The time to ROSC in LiEL group was shorter than LiE, LiL groups (P < 0.001; LiEL vs LiE, P < 0.001; LiEL vs LiL, P < 0.001). The result was similar for the bupivacaine concentration of cardiac tissue and plasma (cardiac tissue: P = 0.002; plasma: P = 0.011). Furthermore, there were significant differences in the blood-gas values at 40 min, wet-to-dry lung weight ratio, and ratio of damaged alveoli among groups. The LiEL group had the best result for all parameters (P < 0.01, P = 0.008, P < 0.001, respectively). Additionally, significantly less epinephrine was used in the LiEL group (P < 0.001). CONCLUSIONS: Levosimendan combined with epinephrine may be superior to either drug alone for lipid-based resuscitation in a rat model of bupivacaine-induced cardiac arrest. The drug combination was associated with a higher survival rate as well as decreased epinephrine consumption and lung damage.

Supplement of levosimendan to epinephrine improves initial resuscitation outcomes from asphyxial cardiac arrest.

BACKGROUND: Levosimendan exerted favorable effects on the initial outcome in the treatment of ventricular fibrillation cardiac arrest. This study investigated the efficacy of levosimendan in the treatment of asphyxia-induced cardiac arrest in rats. METHODS: Animals underwent asphyxial cardiac arrest/cardiopulmonary resuscitation, randomized to three treatment groups: epinephrine (10 µg/kg) supplemented with levosimendan (bolus 12 µg/kg and infusion for 1 h, EL group); epinephrine only (10 µg/kg, E group), or levosimendan only (bolus 12 µg/kg and infusion for 1 h, L group). The resuscitation success rate, wet-to-dry ratio of lung, and rate of alveolar and blood gas analysis were recorded. RESULTS: 10 rats in the EL group, 8 in the E group, and 2 in the L group showed an initial return of spontaneous circulation (P < 0.001); among them, 10, 4, and 2 rats survived at the end of a 60-min observation period from each group, respectively (P = 0.001). The coronary perfusion pressure in the EL group was higher than that of either the E or L group (P < 0.05). The lung wet-to-dry weight ratio and rate of damaged alveoli were lower in the EL group than the E group (P < 0.05). CONCLUSIONS: In the early stage of resuscitation for asphyxia-induced cardiac arrest in rats, levosimendan supplemented with epinephrine can significantly increase coronary perfusion pressure, reduce lung injury, and ultimately enhance the survival rate.

Lipid emulsion mitigates impaired pulmonary function induced by limb I/R in rats through attenuation of local cellular injury and the subsequent systemic inflammatory response/inflammation.

BACKGROUND: Limb ischemia/reperfusion causes inflammation and elicits oxidative stress that may lead to local tissue damage and remote organ such as lung injury. This study investigates pulmonary function after limb ischemia/reperfusion and the protective effect of a lipid emulsion (Intralipid). METHODS: Twenty-four rats were divided into three groups: sham operation group (group S), ischemia/reperfusion group (group IR), and lipid emulsion treatment group (group LE). limb ischemia/reperfusion was induced through occlusion of the infrarenal abdominal aorta for 3 h. The microvascular clamp was removed carefully and reperfusion was provided for 3 h. RESULTS: The mean arterial pressure in group LE was higher than group IR during the reperfusion period (P = 0.024). The heart rate of both group LE and IR are significantly higher than group S during the ischemia period(P < 0.001, P < 0.001, respectively). The arterial oxygen pressure of group LE was significantly higher than group IR (P = 0.003), the arterial carbon dioxide pressure of group LE were lower than that of group IR (P = 0.005). The concentration of plasma interleukin-6, tumor necrosis factor-α and malondialdehyde in group LE were significantly lower than group IR (P < 0.001, P = 0.009 and 0.029, respectively). The plasma superoxide dismutase activity in group LE was significantly higher than group IR (P = 0.029). The myeloperoxidase activity in lung tissues of group LE was significantly less than group IR (P = 0.046). Both muscle and lung in group IR were damaged seriously, whereas lipid emulsion (Intralipid) effectively reversed the damage. In summary, Intralipid administration resulted in several beneficial effects as compared to group IR, such as the pulmonary gas exchange and inflammatory. CONCLUSIONS: The ischemic/reperfusion injury of limb muscles with resultant inflammatory damage to lung tissue can be mitigated by administration of a lipid emulsion (Intralipid, 20%, 5 ml/kg). The mechanisms attenuating such a physiological may be attributed to reduction of the degree of limb injury through a decrease in the release of local inflammatory mediators, a reduction of lipid peroxidation, and a blunting of the subsequent remote inflammatory response.

The Effect of Lipid Emulsion on Pharmacokinetics of Bupivacaine in Rats: Long-Chain Triglyceride Versus Long- and Medium-Chain Triglyceride.

BACKGROUND: Lipid infusions have been proposed to treat local anesthetic-induced cardiac toxicity. This study compared the effects of long-chain triglyceride (LCT) emulsions with those of long- and medium-chain triglyceride (LCT/MCT) emulsions on the pharmacokinetics of bupivacaine in a rat model. METHODS: After administration of intravenous infusion of bupivacaine at 2 mg·kg·min for 5 minutes in Sprague-Dawley (SD) rats, either Intralipid 20%, an LCT emulsion (LCT group, n = 6), or Lipovenoes 20%, an LCT/MCT emulsion (LCT/MCT group, n = 6), was infused at 2mg·kg·min for 5 minutes. The concentrations of total plasma bupivacaine and bupivacaine that were not bound by lipid (lipid unbound) were measured by a liquid chromatography-tandem mass spectrometric method. A 2-compartmental analysis was performed to calculate the lipid-bound percentage of bupivacaine and its pharmacokinetics. RESULTS: In the LCT group, the clearance (15 ± 2 vs 10 ± 1 mL·min·kg, P = .003) was higher; the volume of distribution (0.57 ± 0.10 vs 0.36 ± 0.11 L·kg, P = .007) and K21 (0.0100 ± 0.0018 vs 0.0070 ± 0.0020 min, P = .021, P' = .032) were larger; and the area under the blood concentration-time curve 0 - t; (605 ± 82 vs 867 ± 110 mgL·min, P =.001) and the area under the blood concentration-time curve (0 - ∞) (697 ± 111 vs 991 ± 121 mgL·min, P =.001) were less, when compared with the LCT/MCT group. CONCLUSIONS: LCT emulsions are more effective than LCT/MCT emulsions in the metabolism of bupivacaine through demonstration of a superior pharmacokinetic profile.

A comparison of intrathecal magnesium and ketamine in attenuating remifentanil-induced hyperalgesia in rats.

BACKGROUND: Activation of NMDA receptors play an important role in the development of remifentanil-induced hyperalgesia. We hypothesized that in addition to ketamine, intrathecal MgSO4 could also relieve thermal and mechanical hyperalgesia in rats. METHODS: Initially, 24 Sprague-Dawley rats were divided into control group, remifentanil group, surgical incision group and remifentanil combined with surgical incision group to create an experimental model. Subsequently, 40 rats were divided into control group, model group, model group plus 100 µg MgSO4, 300 µg MgSO4 and 10 µg ketamine respectively. Paw withdrawal mechanical thresholds and paw withdrawal thermal latency tests were performed at -24 h, 2 h, 6 h, 24 h, 48 h, 72 h and 7 day after the surgical procedure. After behavior assessment on the 7th day, remifentanil was given again to ascertain whether or not NMDA antagonists could suppress the re-exposure of remifentanil-induced hyperalgesia. RESULTS: Remifentanil administration plus surgical incision induced significant postoperative hyperalgesia, as indicated by decreased paw withdrawal mechanical thresholds and paw withdrawal thermal latency to mechanical and thermal stimulation. In addition to ketamine, intrathecal MgSO4 (100, 300 µg) dose-dependently reduced remifentanil-induced mechanical and thermal hyperalgesia. Ketamine had less mechanical hyperalgesia in 6 h (p = 0.018), 24 h (p = 0.014) and 48 h (p = 0.011) than 300 µg MgSO4. There was no difference in inhibiting thermal hyperalgesia between the group ketamine and group MgSO4 (300 µg). The rats were given remifentanil again 7 days later after the first exposure of remifentanil. The hyperalgesic effect induced by re-exposure of remifentanil was not reversed in any groups of MgSO4 or ketamine. CONCLUSIONS: In addition to ketamine, intrathecal administration of MgSO4 dose-dependently reduced remifentanil-induced hyperalgesia in a surgical incision mode. Re-exposure to remifentanil 1 week later again produced hyperalgesia, and this was not altered by the prior intrathecal treatments in any 4 groups treated with MgSO4 or ketamine.

Regional anesthesia and lipid resuscitation for local anesthetic systemic toxicity in China: results of a survey by the orthopedic anesthesia group of the Chinese Society Of Anesthesiology.

BACKGROUND: Intravenous lipid emulsions have been introduced for the management of patients with Local Anesthetic Systemic Toxicity (LAST). These emulsions have been stated as a first-line treatment in the guidelines of several international anesthesia organizations. Nevertheless, the adoption of lipid rescue therapy by Chinese practitioners remains unknown. We, therefore, evaluated the current approaches to treat LAST and the use of lipid rescue therapy among anesthesiologists in China. METHODS: In September 2013, a 23-question survey on regional anesthesia practice and availability of lipid emulsions was sent by e-mail to directors or designated individuals at 41 academic anesthesiology departments listed by the orthopedic anesthesia group of the Chinese Society of Anesthesiology. RESULTS: Responses were received from 36 of the 41 (88 %) anesthesiology departments. To simplify the analysis, responses were divided into two groups according to the annual percentage of patients who received regional anesthesia (RA) for orthopedic anesthesia: 14 departments (39%) with high-utilization (≥ 50%) and 22 departments (61%) low-utilization (<50%) of RA. Ropivacaine and bupivacaine were the common drugs used for RA, which were independent of RA utilization. Interestingly, ultrasound-guided techniques were much more frequently used in low-utilization institutions than in high-utilization institutions (P = 0.025). Lipid emulsion was readily available in 8 of the 36 (22%) responding institutions, with 7 of the other 28 (25%) institutions planning to stock lipid emulsion. No differences in lipid availability and storage plans were observed between high- and low-utilization institutions. Lipid resuscitation was performed in five of the eight departments that had lipid emulsion. Eleven patients were successfully resuscitated and one was not. CONCLUSION: Lipid emulsion is not widely available in China to treat LAST resulted from RA for orthopedic patients. Efforts are required to promote lipid rescue therapy nationwide. TRIAL REGISTRATION: Chinese Clinical Trail Registry (Registration number # ChiCTR-EOR-15006960; Date of Retrospective Registration on August 23rd, 2015) http://www.chictr.org.cn/showproj.aspx?proj=11703 .

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.

Feasibility of ultrasound-guided capsule-sheath space block combined with anterior cervical cutaneous nerves block for thyroidectomy: an observational pilot study.

BACKGROUND: We evaluated the efficacy of a new anesthetic technique termed ultrasound-guided capsule-sheath space block (CSSB) combined with anterior cervical cutaneous nerve block (CCNB) for thyroidectomy. METHODS: The study included two parts: Part one was an imaging study to determine technique feasibility. The CSSB was performed on five healthy volunteers by introducing the needle 0.5 cm lateral to the probe under in-plane needle ultrasound guidance. After puncture of the false capsule and its subsequent contraction with the true capsule of thyroid, 10 mL of contrast medium was deposited slowly in the capsule-sheath space. The CCNB was performed bilaterally as follows: Under ultrasound guidance, a subcutaneous injection was made along the sternocleidomastoid using 10 mL of contrast medium which was followed by a girdle-shaped picchu raised from the cricoid cartilage to supraclavicular region. The spreading pattern of contrast medium was imaged using computed tomographic scanning. In part two (a clinical case series) the technique efficacy was evaluated. Seventy-eight patients undergoing thyroidectomy had ultrasound-guided CSSB and CCNB with local anesthetics. The sensory onset of CCNB, intraoperative hemodynamic parameters, and analgesic effect were assessed and complications were noted. RESULTS: The distribution of contrast medium was well defined. In part two the onset time of CCNB was 2.2 ± 0.7 min, and the hemodynamic parameters remained stable intraoperatively. The recall of visual analogue scale scores during surgery was 2 [1-4] for median (range). The patients' and surgeons' satisfaction scores were 2 [1-4] and 1 [1-3] for median (range). No serious complications occurred. CONCLUSIONS: Combining ultrasound-guided CSSB and CCNB is a feasible, effective and safe technique for thyroidectomy. TRIAL REGISTRATION: Current Controlled Trials ChiCTR-ONC-12002025. Registered 19 March 2012.

Comparison Between Intraoperative Two-Space Injection Thoracic Paravertebral Block and Wound Infiltration as a Component of Multimodal Analgesia for Postoperative Pain Management After Video-Assisted Thoracoscopic Lobectomy: A Randomized Controlled Trial.

OBJECTIVE: To compare paravertebral block under thoracoscopy with wound infiltration at an early stage after video-assisted thoracic lobectomy surgery. DESIGN: A prospective, randomized, triple-blinded, placebo-controlled trial. SETTING: A single-center university hospital. PARTICIPANTS: Patients scheduled for video-assisted thoracic lobectomy surgery between February 20, 2014 and June 1, 2014 randomly were allocated into paravertebral block (PVB) (n = 35) and infiltration (n = 35) groups. INTERVENTIONS: In the PVB group, 0.5% ropivacaine was injected into the paravertebral space by the surgeon under direct vision with placebo infiltration of saline in the wounds. In the infiltration group, the wounds were infiltrated with 0.5% ropivacaine by the surgeon with a placebo paravertebral block. Subsequently, patient-controlled intravenous morphine analgesia and paracoxib were administered. MEASUREMENTS AND MAIN RESULTS: The primary endpoints were visual analog scale (VAS) pain scores at rest and on cough 0, 2, 6, and 24 hours after surgery. The secondary endpoints were the total morphine during postoperative 0 hours to 24 hours, adverse events, and patient satisfaction with the analgesia. Sixty-one patients completed the study. VAS score on cough at each time point was significantly lower (p<0.05) and median (25th, 75th) morphine consumption was lower in the PVB group than in the infiltration group (26 [10, 35] mg and 42 [29, 58] mg, p<0.001, respectively). There was no difference in VAS score at rest. Patients in the PVB group had higher satisfaction with analgesia than in the infiltration group (p = 0.003). CONCLUSIONS: As part of the multimodal postoperative analgesia, intraoperative paravertebral block provided better dynamic pain relief and reduced morphine consumption compared with local wound infiltration.

Measurement of the efficacy of 2% lipid in reversing bupivacaine- induced asystole in isolated rat hearts.

BACKGROUND: The reversal efficacy of 2% lipid emulsion in cardiac asystole induced by different concentrations of bupivacaine is poorly defined and needs to be determined. METHODS: Forty-two male Sprague-Dawley rats were randomly divided into seven groups: B40, B60, B80, B100, B120, B140 and B160, n = 6. The Langendorff isolated heart perfusion model was used, which consisted of a balanced perfusion with Krebs-Henseleit solution for 25 minutes and a continuous infusion of 100 µmol/L bupivacaine until asystole had been induced for 3 minutes. The hearts in the seven groups were perfused with Krebs-Henseleit solution containing a 2% lipid emulsion, and 40, 60, 80, 100, 120, 140 or 160 µmol/L bupivacaine, respectively. Cardiac recovery was defined as a spontaneous and regular rhythm with a rate-pressure product > 10% of the baseline value for more than 1 minute. Our primary outcome was the rate-pressure product 25 minutes after cardiac recovery. Other cardiac function parameters were also recorded. RESULTS: All groups demonstrated cardiac recovery. During the recovery phase, heart rate, rate-pressure product, the maximum left ventricular pressure rise and decline in heart rate in the B120-B160 groups was significantly lower than those in the B40-B80 groups (P < 0.05). The concentration of bupivacaine and the reversal effects of a 2% lipid emulsion showed a typical transoid S-shaped curve, R(2) = 0.9983, IC50 value was 102.5 µmol/L (95% CI: 92.44 - 113.6). CONCLUSIONS: There is a concentration-response relationship between the concentrations of bupivacaine and the reversal effects of 2% lipid emulsion.

Veno-venous ECMO: a synopsis of nine key potential challenges, considerations, and controversies.

BACKGROUND: Following the 2009 H1N1 Influenza pandemic, extracorporeal membrane oxygenation (ECMO) emerged as a viable alternative in selected, severe cases of ARDS. Acute Respiratory Distress Syndrome (ARDS) is a major public health problem. Average medical costs for ARDS survivors on an annual basis are multiple times those dedicated to a healthy individual. Advances in medical and ventilatory management of severe lung injury and ARDS have improved outcomes in some patients, but these advances fail to consistently "rescue" a significant proportion of those affected. DISCUSSION: Here we present a synopsis of the challenges, considerations, and potential controversies regarding veno-venous ECMO that will be of benefit to anesthesiologists, surgeons, and intensivists, especially those newly confronted with care of the ECMO patient. We outline a number of points related to ECMO, particularly regarding cannulation, pump/oxygenator design, anticoagulation, and intravascular fluid management of patients. We then address these challenges/considerations/controversies in the context of their potential future implications on clinical approaches to ECMO patients, focusing on the development and advancement of standardized ECMO clinical practices. SUMMARY: Since the 2009 H1N1 pandemic ECMO has gained a wider acceptance. There are challenges that still must be overcome. Further investigations of the benefits and effects of ECMO need to be undertaken in order to facilitate the implementation of this technology on a larger scale.

The effect of lipid emulsion on pharmacokinetics and tissue distribution of bupivacaine in rats.

BACKGROUND: While lipid emulsion may reverse the systemic toxicity of bupivacaine, the pharmacokinetics and tissue distribution of bupivacaine after lipid emulsion infusion are not clear. In this study, we assessed the influence of lipid emulsion administration on the pharmacokinetics and tissue distribution of bupivacaine. METHODS: Rats in the lipid group were administered IV bupivacaine at the rate of 2 mg·kg(-1)·min(-1) for 4 minutes, and then were treated with an infusion of 30% lipid emulsion at the rate of 3 mL·kg(-1)·min(-1) for 5 minutes; saline was substituted in the control group (n = 6 for pharmacokinetics). We then randomly assigned 100 rats into the lipid group and control group (n = 50 for distribution). The toxicity model and treatment were the same as the pharmacokinetic portion. Plasma and tissues including brain, heart, liver, spleen, lung, kidney, omentum, and muscle were collected. The plasma concentration and tissue content of bupivacaine were measured by a liquid chromatography-tandem mass spectrometric method. A 2-compartmental analysis was performed to calculate the pharmacokinetics of bupivacaine. RESULTS: All data are shown as mean ± SD. After treatment with the lipid emulsion, t1/2ß of bupivacaine in the lipid group was significantly shorter (110 ± 25 minutes vs 199 ± 38 minutes, P = 0.001), the clearance was higher (14 ± 4 mL·mg(-1)·kg(-1) vs 9 ± 4 mL·mg(-1)·kg(-1), P = 0.038), and the t1/2α was longer than that of the control group (4 ± 1 minutes vs 2 ± 1 minutes, P = 0.014); the K12 in the lipid group was less than that of the control group (0.13 ± 0.04 vs 0.32 ± 0.13, P = 0.011). In the lipid group, the bupivacaine content in heart, brain, lung, kidney, and spleen was lower than that in the control group, but higher in the liver at 20, 30, and 45 minutes. CONCLUSION: The lipid sink phenomenon was observed in this study. The use of a lipid emulsion accelerated the elimination of bupivacaine.

The analgesic efficacy of subcostal transversus abdominis plane block compared with thoracic epidural analgesia and intravenous opioid analgesia after radical gastrectomy.

BACKGROUND: The transversus abdominis plane (TAP) block has been shown to provide effective postoperative analgesia in lower abdominal surgery. Subcostal TAP block has also been proposed as a new technique to provide analgesia for the supraumbilical abdomen. We compared the analgesic and opioid-sparing effects of a single-injection subcostal TAP block with continuous thoracic epidural analgesia and IV opioid analgesia. METHODS: Ninety patients undergoing elective radical gastrectomy were randomized to receive either combined general-subcostal TAP anesthesia (group TAP), combined general-epidural anesthesia (group EA), or general anesthesia (group GA), and were analyzed on an intention-to-treat basis. In group TAP, a bilateral subcostal TAP block was performed after induction of general anesthesia using 20 mL of 0.375% ropivacaine. In group EA, a thoracic epidural was placed between T8 and T9 and bolused with 8 mL of 0.25% ropivacaine before induction of general anesthesia. The epidural was maintained with 5 mL/h of 0.25% ropivacaine during the surgery. Group GA received standard general anesthesia. In the postanesthesia care unit (PACU), all groups received IV morphine titration for visual analog scale (VAS) pain scores >3. All patients were started on IV patient-controlled analgesia with morphine after morphine titration in the PACU, while group EA also had their epidural maintained with 5 mL/h of 0.125% bupivacaine with 8 µg/mL morphine. Patients were assessed in the PACU and at 1, 3, 6, 24, 48, and 72 hours postoperatively. Primary outcomes measured were morphine consumption at 24 hours and all VAS pain scores. RESULTS: Data from 82 of 90 (91.1%) patients were included in the study. Group TAP demonstrated decreased cumulative morphine consumption at 24 hours (98.75% confidence intervals, -29 to -9 mg) and noninferiority on VAS pain scores at all measurement times, as compared with group GA with standard opioid analgesia. However, group EA was superior to group TAP regarding cumulative morphine consumption at 24 hours (98.75% confidence intervals, -23 to -4 mg) and noninferior to group TAP on VAS pain scores at all comparison points. Group TAP had reduced morphine consumption from PACU admission to 6 hours as compared with group GA, but increased morphine consumption for 6 to 24 hours as compared with group EA. CONCLUSION: Single-injection subcostal TAP block was more effective than IV opioid analgesia, while continuous thoracic epidural analgesia was more effective than the single-injection subcostal TAP block.

The comparative effects of lipid, epinephrine, and their combination in the reversal of bupivacaine-induced asystole in the isolated rat heart.

BACKGROUND: It remains unclear whether lipid combined with epinephrine is superior or inferior to either drug alone in treating bupivacaine cardiotoxicity. We compared the effects of lipid, epinephrine, and the combination of the two in reversing bupivacaine-induced asystole in the isolated rat heart model. We also measured the effects of lipid, epinephrine, and the combination of the two on bupivacaine content in cardiac tissue. METHODS: Hearts from male Sprague-Dawley rats were excised and retrograde-perfused in a nonrecirculating Langendorff preparation. Bupivacaine 100 µmol/L was perfused until 3 minutes after asystole. Two percent lipid and 30 µmol/L bupivacaine mixture was then perfused in the lipid group; 0.15 µg/mL epinephrine and 30 µmol/L bupivacaine mixture in the epinephrine group; 2% lipid combined with 0.15 µg/mL epinephrine and 30 µmol/L bupivacaine in the combination group; and 30 µmol/L bupivacaine alone in the control group. Recovery of heartbeat was defined as unassisted regular rhythm with a rate-pressure product (RPP) >10% of baseline for >1 minute. We compared the time from the end of 100 µmol/L bupivacaine infusion to recovery of heartbeat (T(recovery)) for each group. The variables of cardiac function were recorded for 40 minutes after recovery of heartbeat. The cardiac apex of each heart was taken for measurement of the bupivacaine content by liquid chromatography-tandem mass spectrometry at the end of the experiment. RESULTS: Time to recovery (T(recovery)) in the lipid and combination groups was significantly shorter than that in the epinephrine and control groups (P < 0.001), and T(recovery) in the epinephrine group was shorter than that in the control group (P < 0.05). The rank order of the mean RPP during the 40 minutes after recovery of heartbeat from highest to lowest was the combination group > the lipid and epinephrine groups > the control group (P < 0.01). The rank order of the highest RPP value during recovery (RPP(maximum)) and the ratio of RPP(maximum) to baseline value (RPP(maximum)/RPP(baseline)) from highest to lowest was the combination group > the lipid and epinephrine groups > the control group (P < 0.01). There was no significant difference between the lipid and epinephrine groups for RPP, RPP(maximum), and RPP(maximum)/RPP(baseline). Cardiac tissue bupivacaine content in the epinephrine and control groups was higher than that in the lipid and combination groups (P < 0.001). CONCLUSIONS: Lipid combined with epinephrine resulted in better recovery of cardiac function than either drug alone in reversal of bupivacaine-induced asystole in the isolated rat heart model.

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.