Benefits of a multimodal analgesia compared to local anesthesia alone to alleviate pain following castration in sheep: a multiparametric approach.

Castration of male ruminants is a common livestock management practice, but induces pain. However, little is known about the effectiveness of multimodal analgesia compared to local anesthesia (LA) alone in reducing pain associated with burdizzo castration in sheep. This study aimed to monitor the pain response induced by castration in sheep and to assess the efficacy of analgesia strategies. Twenty-four 12-month-old male Texel sheep were burdizzo-castrated after administration of physiological serum (Burd), local anesthetic (Burd+LA) or LA plus non-steroidal anti-inflammatory drug (Burd+LA+NSAID). Sheep responses were monitored using behavioral and physiological indices of pain. Sampling occurred from 24 h pre-castration to 78 h post-castration, split into four periods based on the duration of analgesia: P0 (T-24 to T-1 h), P1 (T0 to T+2 h), P2 (T+3 to T+32 h) and P3 (T+36 to T+78 h). Behavioral indices were attention and head position, ear position, position of the eyelid, other facial expression, standing/lying postures, postures of the legs, clinical signs and abnormal activities. Physiological indices consisted in indicators of inflammation (haptoglobin, serum amyloid A (SAA), body temperature), hypothalamo-pituitary-adrenal axis (cortisol, non-esterified fatty acids, glucose), autonomous nervous system (heart rate variability (HRV)) and oxidative stress. The variables contributing most to discrimination of the period×treatment groups were analyzed by factorial discrimination analysis. Pre-castration (P0), there was no significant difference between treatments for all indicators (P > 0.05). Post-castration, eight indicators varied significantly according to period and treatment: cortisol, clinical signs, ratio of low frequency/high frequency (LF/HF) bands of the HRV, attention and head position, SAA, haptoglobin, body temperature and glucose. The treatment×periods groups were well discriminated by the 23 indicators. Burd in P0, Burd+LA in P0 and Burd+LA+NSAID in P0, P1 and P2 had low values for all indicators, likely reflecting absence of pain and discomfort. Burd in P1 and P2 and Burd+LA in P2 showed clinical signs and reduced attention, high LF/HF and high cortisol levels, reflecting acute pain. Burd and Burd+LA in P3 had high temperature, high haptoglobin, high glucose and high SAA, but no response from other pathways. These results suggest that (i) behavioral signs of pain were apparent up to 32 h post-castration, (ii) LA was partially effective, but only during its time of action (2 h) and (iii). multimodal analgesia (LA and NSAID) was effective for up to 3 days post-castration. These findings, and especially those related to sheep behavior, can help veterinarians and farmers better detect pain and refine their pain alleviation methods.

Evaluation of the plasmatic level of mepivacaine in different anatomical regions

BACKGROUND: To evaluate the serum level of the local anesthetic mepivacaine 3% without vasoconstrictor in patients who underwent procedures performed in the anterior and posterior maxilla, through a method of possible extraction to quantify it in human plasma by high performance liquid chromatography (HPLC). MATERIAL AND METHODS: This was a hybrid study consisting of 18 patients (7 females and 11 males) classified as ASA I, adults and with normal body mass index, submitted to procedures in the anterior region (group I) and posterior region of the maxilla (group II). For 40 minutes, five 6 ml blood samples were collected every 10 minutes after infiltrative injection in each region of the maxilla. Serum levels of the drug were obtained through HPLC. Blood pressure (BP) and heart rate (HR) were measured throughout the procedure. RESULTS: When compared to the general average of the concentrations of each group, significant values (p < 0.05) with greater absorption were observed for the anterior region of the maxilla (group I). There was no significant difference when comparing blood pressure (BP) and heart rate (HR) values. CONCLUSIONS: The concentrations found are safe for infiltrative anesthesia in the analyzed patients, there was a higher plasma level of the local anesthetic in the anterior region of the maxilla and there was no change in HR and BP in relation to the anesthetized area

Pharmacokinetics of 400 mg Locally Infiltrated Ropivacaine After Total Knee Arthroplasty Without Perioperative Tourniquet Use.

BACKGROUND AND OBJECTIVES: Local infiltration analgesia (LIA) with ropivacaine for total knee arthroplasty (TKA) is increasingly used. Despite the high doses of ropivacaine, LIA is considered safe, and this perception is sustained by pharmacokinetic data demonstrating that maximum concentrations of ropivacaine stay well below the toxic threshold in plasma. These pharmacokinetic studies all involve TKA procedures with the use of a tourniquet. Recently, performing TKA without the use of a tourniquet is gaining popularity, but no pharmacokinetic data exist when LIA is administered for TKA without the use of a tourniquet. The purpose of this study was to describe the pharmacokinetic profile of a single-shot ropivacaine (200 mL 0.2%) and 0.75 mg epinephrine (1000 µg/mL) when used for LIA in patients for TKA without a tourniquet. METHODS: In this prospective cohort study, 20 patients treated with LIA for TKA without a tourniquet were studied. Plasma samples were taken at 20, 40, 60, 90, 120, 240, 360, 480, 600, 720, and 1440 minutes after local anesthetic infiltration, in which total and unbound ropivacaine concentrations were determined. RESULTS: Results are given as median (interquartile range [IQR]). Median peak ropivacaine concentration was 1.16 µg/mL (IQR, 0.46); median peak unbound ropivacaine concentration was 0.05 µg/mL (IQR, 0.02). The corresponding times to reach the maximum concentration for total and unbound ropivacaine were 360 (IQR, 240) and 360 (IQR, 360) minutes, respectively. CONCLUSIONS: Although great interindividual variability in ropivacaine concentration was found, both total and unbound maximum serum concentrations remained below the assumed systemic toxic thresholds in all samples. CLINICAL TRIAL REGISTRATION: This study was registered at Netherlands Trial Registry (http://www.trialregister.nl), trial ID NTR6306.

Ultrasound-Guided Oblique Sub-Costal Transversus Abdominis Plane Block as the Principal Anesthesia Technique in Peritoneal Dialysis Catheter Implantation and Plasma Ropivacaine Concentration Evaluation in ESRD Patients: A Prospective, Randomized, Double-Blinded, Controlled Trial.

BACKGROUND: The ultrasound-guided transversus abdominis plane (TAP) block is generally used for analgesia but not for anesthesia. A TAP block has a partial analgesic effect on the parietal peritoneum in abdominal surgeries. We hypothesized that an ultrasound-guided oblique subcostal TAP block, used as the principal anesthesia technique, could provide a better anesthetic effect on peritoneum stimulation in peritoneal dialysis catheter (PDC) implantation in end-stage renal diseases (ESRD) patients than local anesthetic infiltration (LAI). METHODS: End-stage renal disease patients undergoing PDC implantation were randomized into 3 groups: LAI Group, unilateral TAP group (Uni-TAP Group) and bilateral TAP group (Bi-TAP Group). A 40-mL dose of 0.25% ropivacaine was used for the regional block (LAI or TAP). The quality of anesthesia, visual analogue scale (VAS) of pain, cumulative rescuing sufentanil consumption, and venous plasma ropivacaine concentrations were compared among the 3 groups. RESULTS: Sixty-nine patients were enrolled, and higher 'Satisfied' anesthesia rates from nephrologists and patients were recorded in the 2 TAP groups, compared with the LAI Group. Significantly lower VAS scores were observed in the Uni-TAP Group at a majority of time points compared with the LAI Group. Less cumulative rescuing sufentanil was used in the 2 TAP groups (2.5 ± 2.7 and 3.0 ± 2.8 µg, respectively) compared with the LAI Group (5.8 ± 2.6 µg, p < 0.05). The median peak venous plasma ropivacaine concentrations were below the reported toxic threshold in all 3 groups. CONCLUSIONS: As the principal anesthesia technique, an ultrasound-guided unilateral oblique subcostal TAP block with 40 mL of 0.25% ropivacaine provided better anesthetic effect in PDC implantations in ESRD patients than LAI.

Plasma Ropivacaine Concentrations Following Local Infiltration Analgesia in Total Knee Arthroplasty: A Pharmacokinetic Study to Determine Safety Following Fixed-Dose Administration.

BACKGROUND AND OBJECTIVES: The primary aim of this study was to examine the pharmacokinetics of ropivacaine in patients undergoing elective total knee arthroplasty with local infiltration analgesia as the primary analgesic method. We also sought to determine the incidence of biochemical toxicity through measurement of plasma ropivacaine concentrations over the first 24 hours postoperatively. METHODS: This was a prospective, observational study of 15 patients undergoing elective total knee arthroplasty. Local infiltration analgesia was administered by standard technique with 300 mg ropivacaine and epinephrine 5 µg/mL. Total ropivacaine concentrations were taken at specified time intervals in the 24 hours after tourniquet release and analyzed by liquid chromatography-mass spectrometry. RESULTS: Fifteen patients were enrolled into the study. The median peak ropivacaine concentration was 0.57 µg/mL, with a range of 0.32 to 0.88 µg/mL, and occurred between 6 and 24 hours. Age (P = 0.04), weight (P = 0.04), creatinine (P = 0.02), and female sex (P = 0.03) were important predictors of peak concentration. Age (P = 0.02), female sex (P = 0.01), and baseline α1 acid glycoprotein concentrations (P = 0.03) were important predictors for the area under the curve from a ropivacaine concentration versus time plot. CONCLUSIONS: The peak total ropivacaine concentration was below quoted toxic concentrations (2.2 µg/mL) in all patients. This peak occurred later than has previously been described in those undergoing neuraxial or peripheral nerve block, occurring between 6 and 24 hours. The influence of age, weight, and renal function on systemic ropivacaine concentration should be considered when planning local infiltration analgesia. Female sex is a factor that has not previously been associated with peak ropivacaine concentrations.

[Systemic toxicity of local anesthetics]. / Sistemnaia toksichnost' mestnykh anestetikov.

The paper presents characteristics of local anesthetics used in dentistry and maxillofacial surgery taking into account their effectiveness and toxicity. We described the main clinical symptoms of manifestation of systemic toxicity and measures for prevention of local anesthesia complications, as well as the detailed protocol of 'lipid rescue' and resuscitation at manifestation of systemic toxic reaction of local anesthetics with the mechanism of the fatty emulsion action.

The effects of intravenous lipid emulsion on hemodynamic recovery and myocardial cell mitochondrial function after bupivacaine toxicity in anesthetized pigs.

Local anesthetic toxicity is thought to be mediated partly by inhibition of cardiac mitochondrial function. Intravenous (i.v.) lipid emulsion may overcome this energy depletion, but doses larger than currently recommended may be needed for rescue effect. In this randomized study with anesthetized pigs, we compared the effect of a large dose, 4 mL/kg, of i.v. 20% Intralipid® ( n = 7) with Ringer's acetate ( n = 6) on cardiovascular recovery after a cardiotoxic dose of bupivacaine. We also examined mitochondrial respiratory function in myocardial cell homogenates analyzed promptly after needle biopsies from the animals. Bupivacaine plasma concentrations were quantified from plasma samples. Arterial blood pressure recovered faster and systemic vascular resistance rose more rapidly after Intralipid than Ringer's acetate administration ( p < 0.0001), but Intralipid did not increase cardiac index or left ventricular ejection fraction. The lipid-based mitochondrial respiration was stimulated by approximately 30% after Intralipid ( p < 0.05) but unaffected by Ringer's acetate. The mean (standard deviation) area under the concentration-time curve (AUC) of total bupivacaine was greater after Intralipid (105.2 (13.6) mg·min/L) than after Ringer's acetate (88.1 (7.1) mg·min/L) ( p = 0.019). After Intralipid, the AUC of the lipid-un-entrapped bupivacaine portion (97.0 (14.5) mg·min/L) was 8% lower than that of total bupivacaine ( p < 0.0001). To conclude, 4 mL/kg of Intralipid expedited cardiovascular recovery from bupivacaine cardiotoxicity mainly by increasing systemic vascular resistance. The increased myocardial mitochondrial respiration and bupivacaine entrapment after Intralipid did not improve cardiac function.

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.

Estimated Maximal Safe Dosages of Tumescent Lidocaine.

BACKGROUND: Tumescent lidocaine anesthesia consists of subcutaneous injection of relatively large volumes (up to 4 L or more) of dilute lidocaine (≤1 g/L) and epinephrine (≤1 mg/L). Although tumescent lidocaine anesthesia is used for an increasing variety of surgical procedures, the maximum safe dosage is unknown. Our primary aim in this study was to measure serum lidocaine concentrations after subcutaneous administration of tumescent lidocaine with and without liposuction. Our hypotheses were that even with large doses (i.e., >30 mg/kg), serum lidocaine concentrations would be below levels associated with mild toxicity and that the concentration-time profile would be lower after liposuction than without liposuction. METHODS: Volunteers participated in 1 to 2 infiltration studies without liposuction and then one study with tumescent liposuction totally by local anesthesia. Serum lidocaine concentrations were measured at 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, and 24 hours after each tumescent lidocaine infiltration. Area under the curve (AUC∞) of the serum lidocaine concentration-time profiles and peak serum lidocaine concentrations (Cmax) were determined with and without liposuction. For any given milligram per kilogram dosage, the probability that Cmax >6 µg/mL, the threshold for mild lidocaine toxicity was estimated using tolerance interval analysis. RESULTS: In 41 tumescent infiltration procedures among 14 volunteer subjects, tumescent lidocaine dosages ranged from 19.2 to 52 mg/kg. Measured serum lidocaine concentrations were all <6 µg/mL over the 24-hour study period. AUC∞s with liposuction were significantly less than those without liposuction (P = 0.001). The estimated risk of lidocaine toxicity without liposuction at a dose of 28 mg/kg and with liposuction at a dose of 45 mg/kg was ≤1 per 2000. CONCLUSIONS: Preliminary estimates for maximum safe dosages of tumescent lidocaine are 28 mg/kg without liposuction and 45 mg/kg with liposuction. As a result of delayed systemic absorption, these dosages yield serum lidocaine concentrations below levels associated with mild toxicity and are a nonsignificant risk of harm to patients.

Local pathology and systemic serum bupivacaine after subcutaneous delivery of slow-releasing bupivacaine microspheres.

BACKGROUND: Prolonged local anesthesia, particularly desirable to minimize acute and chronic postoperative pain, has been provided by microspheres that slowly release bupivacaine (MS-Bup). In this study, we report on the systemic drug concentrations and the local dermatopathology that occur after subcutaneous injection of MS-Bup. METHODS: Rats (approximately 300 g) were injected under the dorsolumbar skin with MS-Bup containing 40 mg of bupivacaine (base) or with 0.4 mL of 0.5% bupivacaine-HCl (BupHCl; 1.78 mg bupivacaine). Blood was drawn, under sevoflurane anesthesia, at 10 minutes to 144 hours, and the serum analyzed for total bupivacaine by liquid chromatography-tandem mass spectrometry. In different animals, skin punch biopsies (4 mm) were taken at 1, 3, 7, 14, and 30 days after the same drug injections, sectioned at 5 µm, and stained with hematoxylin-eosin. Samples from skin injected with BupHCl, with MS-Bup suspended in carboxymethyl cellulose (MS-Bup.CMC), or in methyl cellulose (MS-Bup.MC) were compared with their respective drug-free controls (placebos). RESULTS: Serum bupivacaine reached a maximal average value (n = 8) of 194.9 ng/mL at 8 hours after injection of MS-Bup (95% upper prediction limit = 230.2 ng/mL), compared with the maximal average (n = 6) serum level of 374.9 ng/mL (95% prediction limit = 470.6 ng/mL) at 30 minutes after injection of BupHCl. Serum bupivacaine decreased to undetectable levels (<3.23 ng/mL) at 8 hours after BupHCl and was detectable at approximately 20% of the maximal value at 144 hours after MS-Bup injection. BupHCl injection resulted in moderate lymphocytic infiltration of skeletal muscle at 1 and 3 days. MS-Bup.CMC and placebo-CMC caused extensive infiltration of macrophages, lymphocytes, and some neutrophils at 1 to 7 days, whereas MS-Bup.MC and placebo-MC caused only mild inflammation. CONCLUSIONS: Subcutaneous administration of microspheres releasing bupivacaine results in lower blood levels lasting for much longer times than those from bupivacaine solution.

Intraperitoneal local anesthetics have predominant local analgesic effect: a randomized, double-blind study.

BACKGROUND: It remains unclear whether analgesia from intraperitoneal local anesthetics is via local or central mechanisms. This double-blind clinical trial tests the hypothesis that intraperitoneal local anesthetic is superior to continuous IV infusion for pain management. Primary outcome was morphine consumption during 0 to 24 h. METHODS: Informed consent was obtained from 60 patients, age 30 to 75 yr, American Society of Anesthesiologists physical status I to II, undergoing abdominal hysterectomy. A computer-generated program randomized patients in parallel arms to group IV: continuous infusion of lidocaine 50 mg/h (10 ml) IV and saline 10 ml/h intermittently intraperitoneal; group IP: injection of lidocaine 50 mg/h (10 ml) once every hour intraperitoneally and continuous infusion of saline 10 ml/h intravenously; and group P (placebo): saline 10 ml/h both intravenously and intermittent intraperitoneal injection. Postoperative morphine consumption, pain intensity, recovery, home discharge, and lidocaine concentrations were measured. RESULTS: Morphine consumption during 0 to 24 h was lower in group IP versus group IV, mean difference -22.6 mg (95% CI, 11.4 to 33.8; P < 0.01). No difference was seen between group IV and group P. The total mean plasma concentration of lidocaine in group IP was significantly lower than group IV, 0 to 4.5 h postoperatively (P = 0.03) with no evidence of systemic toxicity. Pain intensity and other recovery parameters were similar between the groups. CONCLUSION: The lower supplemental morphine consumption and plasma lidocaine concentration in group IP would confirm that the effects of local anesthetics are likely to be predominant via local intraperitoneal receptors or anti-inflammatory effects and not via central mechanisms alone.

Ropivacaine plasma levels following local infiltration analgesia for primary total hip arthroplasty.

We measured total and free plasma concentrations of ropivacaine following high-volume, high-dose local infiltration analgesia in 19 patients aged 65 years or over undergoing unilateral total hip arthroplasty. The patients received 180 ml ropivacaine 0.2% (360 mg), which was injected into the deep and peri-capsular tissues, the gluteal muscles and fascia lata, and the subcutaneous tissues and skin. Patients were monitored for clinical symptoms and signs of systemic local anaesthetic toxicity. Total levels of plasma ropivacaine varied from 0.081 to 1.707 µg.ml(-1) (mean (SD) 0.953 (0.323) µg.ml(-1) ). Free levels of plasma ropivacaine varied from 0.000 to 0.053 µg.ml(-1) (mean (SD) 0.024 (0.011) µg.ml(-1) ). No samples reached the toxic threshold for venous ropivacaine concentration, although four patients exhibited mild symptoms consistent with local anaesthetic toxicity. One patient had episodes of complete heart block on ECG monitoring, but plasma ropivacaine levels were below toxic levels. We conclude that plasma levels for ropivacaine associated with toxicity in a volunteer population (total 2.2 µg.ml(-1) , free 0.15 µg.ml(-1) ) are not reached during local infiltration analgesia for hip arthroplasty in elderly patients.

Total systemic ropivacaine concentrations following aerosolized intraperitoneal delivery using the AeroSurge.

STUDY OBJECTIVE: To evaluate intraperitoneal ropivacaine delivery with the AeroSurge device in the clinical setting and to evaluate the total systemic ropivacaine levels achieved following delivery of 50 mg of aerosolized ropivacaine. DESIGN: Preliminary, prospective, nonrandomized study. SETTING: Operating room of a university hospital. PATIENTS: 5 consecutive ASA physical status 1 and 2 patients undergoing elective laparoscopic Nissen fundoplication or cholecystectomy. INTERVENTION: Five mL of 1% ropivacaine was delivered through the 10 mm port using the AeroSurge device at peritoneal insufflation. MEASUREMENTS: Venous blood samples were collected and total ropivacaine concentration was determined using liquid chromatography-mass spectrometry. MAIN RESULTS: The AeroSurge device delivered ropivacaine, visible as mist within the peritoneal cavity. Peak concentration (Cmax) was attained between 10 and 30 minutes following the end of aerosolized ropivacaine delivery. At no stage did any level approach toxic levels. CONCLUSIONS: This preliminary study confirms that aerosolized intraperitoneal local anesthetic is feasible, with ropivacaine concentrations remaining within safe levels.

Topical lidocaine enhanced by laser pretreatment: a safe and effective method of analgesia for facial rejuvenation.

BACKGROUND: Injectable forms of anesthesia for nonsurgical facial rejuvenation, although efficacious, are uncomfortable for the patient. Preclinical studies have demonstrated that laser pretreatment at low energies enhances absorption of topical lidocaine. OBJECTIVES: The authors assess the safety and efficacy of laser-assisted transdermal delivery of topical anesthetic. METHOD: Ten patients were split into 2 groups (A and B). All patients received 15 g of BLT (20% benzocaine, 6% lidocaine, and 4% tetracaine triple anesthetic cream) for 20 minutes with no occlusion. Then the cream was removed and the first blood draw taken. Group A patients were pretreated with the full ablative laser and group B patients with a fractional ablative laser to the full face. A further 15 g BLT was applied for another 20 minutes. Group A patients then underwent full ablative laser treatment, and group B received fractionated ablative laser treatment. Blood draws were taken at 60, 90, 120, 180, and 240 minutes after the initial topical anesthetic application, and the serum was analyzed for lidocaine and monoethylglycinexylidide (MEGX) levels. Patients were asked to rate the pain felt at intervals during the procedure. RESULTS: No patient required supplemental nerve blocks. Pain scores were equivalent at the end of the first pass for both groups (P = .436). Group A patients had significantly lower pain scores at the start of the second laser treatment (P = .045), but pain scores became equivalent by the end (P = .323). Combined serum lidocaine and MEGX levels were significantly higher in group A patients up to 90 minutes (peak average of 0.61 µg/mL for group A and 0.533 µg/mL for group B; P = .0253), which corresponded to greater initial analgesic effect. CONCLUSIONS: Data from this study demonstrate that topical anesthetic for facial rejuvenation can be enhanced with laser pretreatment while maintaining safe blood serum levels. Further studies should examine optimal application amount and time to allow safe multipass facial rejuvenation without the need for invasive nerve blocks.

Comparison of lidocaine metabolism for different anesthesia techniques in rabbits with liver disease.

OBJECTIVE: This study was designed to investigate the serum lidocaine concentrations (SLC) after local infiltration anesthesia (IA) and mandibular anesthesias (MA) in rabbits with carbon tetrachloride (CCl4)-induced chronic liver damage (CLD). STUDY DESIGN: Fourteen rabbits were administered CCl4 in group 1, MA (CLD-MA; n = 7); in group 2, IA (CLD-IA; n = 7); in group 3, MA (H-MA; n = 7); and in group 4, IA (H-IA; n = 6) was performed. SLC were measured. RESULTS: SLC showed difference over time. At the 10th minute, mean SLC in IA groups were higher than in MA groups. At the 120th minute, the highest mean concentration was found in the CLD-IA group. CONCLUSIONS: SLC increases in CLD, and serum lidocaine concentration after IA in the mandibular anterior region is higher than it is after MA.

The safety of peri-articular local anaesthetic injection for patients undergoing total knee replacement with autologous blood transfusion: a randomised trial.

Intra-operative, peri-articular injection of local anaesthesia is an increasingly popular way of controlling pain following total knee replacement. At the same time, the problems associated with allogenic blood transfusion have led to interest in alternative methods for managing blood loss after total knee replacement, including the use of auto-transfusion of fluid from the patient's surgical drain. It is safe to combine peri-articular infiltration with auto-transfusion from the drain. We performed a randomised clinical trial to compare the concentration of local anaesthetic in the blood and in the fluid collected in the knee drain in patients having either a peri-articular injection or a femoral nerve block. Clinically relevant concentrations of local anaesthetic were found in the fluid from the drains of patients having peri-articular injections (4.92 µg/ml (sd 3.151)). However, none of the patients having femoral nerve blockade had detectable levels. None of the patients in either group had clinically relevant concentrations of local anaesthetic in their blood after re-transfusion. The evidence from this study suggests that it is safe to use peri-articular injection in combination with auto-transfusion of blood from peri-articular drains during knee replacement surgery.

Local infiltration analgesia with levobupivacaine compared with intrathecal morphine in total hip arthroplasty patients.

BACKGROUND: Recently, local infiltration analgesia (LIA) has been promoted for pain control after total hip arthroplasty (THA). We hypothesized that LIA would offer equal analgesic efficacy but less adverse effects, e.g., nausea and vomiting, when compared with an established regimen [intrathecal morphine (it-M)] after THA. METHODS: This randomized controlled trial comprised 60 patients undergoing THA under spinal anaesthesia. For LIA, the surgeon administered levobupivacaine, ketorolac and epinephrine at the surgical site intraoperatively. LIA patients received a LIA top-up through a wound catheter on the morning of the 1st post-operative day (POD). In group it-M, 0.1 mg morphine was given together with the spinal anaesthetic. Study parameters included pain scores, vital parameters and side effects, e.g., post-operative nausea and vomiting (PONV). Besides, levobupivacaine plasma concentrations were determined in 10 LIA patients. RESULTS: The median (25th/75th percentiles) rescue oxycodone demand differed significantly with LIA 15 (10/25) mg vs. 8.5 (1.5/15) mg with it-M (P < 0.006) during the day of surgery, but not anymore on 1st or 2nd POD. The LIA top-up had no effect. However, both analgesic regimens resulted in comparable pain scores and patient satisfaction. PONV incidence and medication did not vary significantly. LIA offered certain advantages regarding early post-operative mobilization. Maximum levobupivacaine plasma concentrations (229-580 ng/ml) remained under the toxic level. CONCLUSIONS: While LIA might enable earlier mobilization after THA, it was not associated with less nausea as compared with it-M. Less rescue oxycodone was given early after it-M, but urinary retention was more common in that group.

Resuscitation strategies from bupivacaine-induced cardiac arrest.

OBJECTIVES: Local anesthetic (LA) intoxication with cardiovascular arrest is a potential fatal complication of regional anesthesia. Lipid resuscitation has been recommended for the treatment of LA-induced cardiac arrest. Aim of the study was to compare four different rescue regimens using epinephrine and/or lipid emulsion and vasopressin to treat cardiac arrest caused by bupivacaine intoxication. METHODS: Twenty-eight piglets were randomized into four groups (4 × 7), anesthetized with sevoflurane, intubated, and ventilated. Bupivacaine was infused with a syringe driver via central venous catheter at a rate of 1 mg·kg(-1)·min(-1) until circulatory arrest. Bupivacaine infusion and sevoflurane were then stopped, chest compression was started, and the pigs were ventilated with 100% oxygen. After 1 min, epinephrine 10 µg·kg(-1) (group 1), Intralipid(®) 20% 4 ml·kg(-1) (group 2), epinephrine 10 µg·kg(-1) + Intralipid(®) 4 ml·kg(-1) (group 3) or 2 IU vasopressin + Intralipid(®) 4 ml·kg(-1) (group 4) were administered. Secondary epinephrine doses were given after 5 min if required. RESULTS: Survival was 71%, 29%, 86%, and 57% in groups 1, 2, 3, and 4. Return of spontaneous circulation was regained only by initial administration of epinephrine alone or in combination with Intralipid(®). Piglets receiving the combination therapy survived without further epinephrine support. In contrast, in groups 2 and 4, return of spontaneous circulation was only achieved after secondary epinephrine rescue. CONCLUSIONS: In cardiac arrest caused by bupivacaine intoxication, first-line rescue with epinephrine and epinephrine + Intralipid(®) was more effective with regard to survival than Intralipid(®) alone and vasopressin + Intralipid(®) in this pig model.