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Brian R Davidson - One of the best experts on this subject based on the ideXlab platform.

  • intraperitoneal Local Anaesthetic instillation versus no intraperitoneal Local Anaesthetic instillation for laparoscopic cholecystectomy
    Cochrane Database of Systematic Reviews, 2014
    Co-Authors: Kurinchi Selvan Gurusamy, Myura Nagendran, Gian Piero Guerrini, Clare D Toon, Murat Zinnuroglu, Brian R Davidson
    Abstract:

    Background While laparoscopic cholecystectomy is generally considered less painful than open surgery, pain is one of the important reasons for delayed discharge after day surgery and overnight stay laparoscopic cholecystectomy. The safety and effectiveness of intraperitoneal Local Anaesthetic instillation in people undergoing laparoscopic cholecystectomy is unknown. Objectives To assess the benefits and harms of intraperitoneal instillation of Local Anaesthetic agents in people undergoing laparoscopic cholecystectomy. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Science Citation Index Expanded to March 2013 to identify randomised clinical trials of relevance to this review. Selection criteria We considered only randomised clinical trials (irrespective of language, blinding, or publication status) comparing Local Anaesthetic intraperitoneal instillation versus placebo, no intervention, or inactive control during laparoscopic cholecystectomy for the review with regards to benefits while we considered quasi-randomised studies and non-randomised studies for treatment-related harms. Data collection and analysis Two review authors collected the data independently. We analysed the data with both fixed-effect and random-effects models using Review Manager 5 analysis. For each outcome, we calculated the risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI). Main results We included 58 trials, of which 48 trials with 2849 participants randomised to intraperitoneal Local Anaesthetic instillation (1558 participants) versus control (1291 participants) contributed data to one or more of the outcomes. All the trials except one trial with 30 participants were at high risk of bias. Most trials included only low Anaesthetic risk people undergoing elective laparoscopic cholecystectomy. Various intraperitoneal Local Anaesthetic agents were used but bupivacaine in the liquid form was the most common Local Anaesthetic used. There were considerable differences in the methods of Local Anaesthetic instillation including the location (subdiaphragmatic, gallbladder bed, or both locations) and timing (before or after the removal of gallbladder) between the trials. There was no mortality in either group in the eight trials that reported mortality (0/236 (0%) in Local Anaesthetic instillation versus 0/210 (0%) in control group; very low quality evidence). One participant experienced the outcome of serious morbidity (eight trials; 446 participants; 1/236 (0.4%) in Local Anaesthetic instillation group versus 0/210 (0%) in the control group; RR 3.00; 95% CI 0.13 to 67.06; very low quality evidence). Although the remaining trials did not report the overall morbidity, three trials (190 participants) reported that there were no intra-operative complications. Twenty trials reported that there were no serious adverse events in any of the 715 participants who received Local Anaesthetic instillation. None of the trials reported participant quality of life, return to normal activity, or return to work. The effect of Local Anaesthetic instillation on the proportion of participants discharged as day surgery between the two groups was imprecise and compatible with benefit and no difference of intervention (three trials; 242 participants; 89/160 (adjusted proportion 61.0%) in Local Anaesthetic instillation group versus 40/82 (48.8%) in control group; RR 1.25; 95% CI 0.99 to 1.58; very low quality evidence). The MD in length of hospital stay was 0.04 days (95% CI -0.23 to 0.32; five trials; 335 participants; low quality evidence). The pain scores as measured by the visual analogue scale (VAS) were significantly lower in the Local Anaesthetic instillation group than the control group at four to eight hours (32 trials; 2020 participants; MD -0.99 cm; 95% CI -1.10 to -0.88 on a VAS scale of 0 to 10 cm; very low quality evidence) and at nine to 24 hours (29 trials; 1787 participants; MD -0.53 cm; 95% CI -0.62 to -0.44; very low quality evidence). Various subgroup analyses and meta-regressions to investigate the influence of the different Local Anaesthetic agents, different methods of Local Anaesthetic instillation, and different controls on the effectiveness of Local Anaesthetic intraperitoneal instillation were inconsistent. Authors' conclusions Serious adverse events were rare in studies evaluating Local Anaesthetic intraperitoneal instillation (very low quality evidence). There is very low quality evidence that it reduces pain in low Anaesthetic risk people undergoing elective laparoscopic cholecystectomy. However, the clinical importance of this reduction in pain is unknown and likely to be small. Further randomised clinical trials of low risk of systematic and random errors are necessary. Such trials should include important clinical outcomes such as quality of life and time to return to work in their assessment.

  • The Cochrane Library - Intraperitoneal Local Anaesthetic instillation versus no intraperitoneal Local Anaesthetic instillation for laparoscopic cholecystectomy
    The Cochrane database of systematic reviews, 2014
    Co-Authors: Kurinchi Selvan Gurusamy, Myura Nagendran, Gian Piero Guerrini, Clare D Toon, Murat Zinnuroglu, Brian R Davidson
    Abstract:

    Background While laparoscopic cholecystectomy is generally considered less painful than open surgery, pain is one of the important reasons for delayed discharge after day surgery and overnight stay laparoscopic cholecystectomy. The safety and effectiveness of intraperitoneal Local Anaesthetic instillation in people undergoing laparoscopic cholecystectomy is unknown. Objectives To assess the benefits and harms of intraperitoneal instillation of Local Anaesthetic agents in people undergoing laparoscopic cholecystectomy. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Science Citation Index Expanded to March 2013 to identify randomised clinical trials of relevance to this review. Selection criteria We considered only randomised clinical trials (irrespective of language, blinding, or publication status) comparing Local Anaesthetic intraperitoneal instillation versus placebo, no intervention, or inactive control during laparoscopic cholecystectomy for the review with regards to benefits while we considered quasi-randomised studies and non-randomised studies for treatment-related harms. Data collection and analysis Two review authors collected the data independently. We analysed the data with both fixed-effect and random-effects models using Review Manager 5 analysis. For each outcome, we calculated the risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI). Main results We included 58 trials, of which 48 trials with 2849 participants randomised to intraperitoneal Local Anaesthetic instillation (1558 participants) versus control (1291 participants) contributed data to one or more of the outcomes. All the trials except one trial with 30 participants were at high risk of bias. Most trials included only low Anaesthetic risk people undergoing elective laparoscopic cholecystectomy. Various intraperitoneal Local Anaesthetic agents were used but bupivacaine in the liquid form was the most common Local Anaesthetic used. There were considerable differences in the methods of Local Anaesthetic instillation including the location (subdiaphragmatic, gallbladder bed, or both locations) and timing (before or after the removal of gallbladder) between the trials. There was no mortality in either group in the eight trials that reported mortality (0/236 (0%) in Local Anaesthetic instillation versus 0/210 (0%) in control group; very low quality evidence). One participant experienced the outcome of serious morbidity (eight trials; 446 participants; 1/236 (0.4%) in Local Anaesthetic instillation group versus 0/210 (0%) in the control group; RR 3.00; 95% CI 0.13 to 67.06; very low quality evidence). Although the remaining trials did not report the overall morbidity, three trials (190 participants) reported that there were no intra-operative complications. Twenty trials reported that there were no serious adverse events in any of the 715 participants who received Local Anaesthetic instillation. None of the trials reported participant quality of life, return to normal activity, or return to work. The effect of Local Anaesthetic instillation on the proportion of participants discharged as day surgery between the two groups was imprecise and compatible with benefit and no difference of intervention (three trials; 242 participants; 89/160 (adjusted proportion 61.0%) in Local Anaesthetic instillation group versus 40/82 (48.8%) in control group; RR 1.25; 95% CI 0.99 to 1.58; very low quality evidence). The MD in length of hospital stay was 0.04 days (95% CI -0.23 to 0.32; five trials; 335 participants; low quality evidence). The pain scores as measured by the visual analogue scale (VAS) were significantly lower in the Local Anaesthetic instillation group than the control group at four to eight hours (32 trials; 2020 participants; MD -0.99 cm; 95% CI -1.10 to -0.88 on a VAS scale of 0 to 10 cm; very low quality evidence) and at nine to 24 hours (29 trials; 1787 participants; MD -0.53 cm; 95% CI -0.62 to -0.44; very low quality evidence). Various subgroup analyses and meta-regressions to investigate the influence of the different Local Anaesthetic agents, different methods of Local Anaesthetic instillation, and different controls on the effectiveness of Local Anaesthetic intraperitoneal instillation were inconsistent. Authors' conclusions Serious adverse events were rare in studies evaluating Local Anaesthetic intraperitoneal instillation (very low quality evidence). There is very low quality evidence that it reduces pain in low Anaesthetic risk people undergoing elective laparoscopic cholecystectomy. However, the clinical importance of this reduction in pain is unknown and likely to be small. Further randomised clinical trials of low risk of systematic and random errors are necessary. Such trials should include important clinical outcomes such as quality of life and time to return to work in their assessment.

  • wound infiltration with Local Anaesthetic agents for laparoscopic cholecystectomy
    Cochrane Database of Systematic Reviews, 2014
    Co-Authors: Sofronis Loizides, Kurinchi Selvan Gurusamy, Myura Nagendran, Gian Piero Guerrini, Michele Rossi, Brian R Davidson
    Abstract:

    Background While laparoscopic cholecystectomy is generally considered to be less painful than open surgery, pain is one of the important reasons for delayed discharge after day surgery resulting in overnight stay following laparoscopic cholecystectomy. The safety and effectiveness of Local Anaesthetic wound infiltration in people undergoing laparoscopic cholecystectomy is not known. Objectives To assess the benefits and harms of Local Anaesthetic wound infiltration in patients undergoing laparoscopic cholecystectomy and to identify the best method of Local Anaesthetic wound infiltration with regards to the type of Local Anaesthetic, dosage, and time of administration of the Local Anaesthetic. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Science Citation Index Expanded until February 2013 to identify studies of relevance to this review. We included randomised clinical trials for benefit and quasi-randomised and comparative non-randomised studies for treatment-related harms. Selection criteria Only randomised clinical trials (irrespective of language, blinding, or publication status) comparing Local Anaesthetic wound infiltration versus placebo, no intervention, or inactive control during laparoscopic cholecystectomy, trials comparing different Local Anaesthetic agents for Local Anaesthetic wound infiltration, and trials comparing the different times of Local Anaesthetic wound infiltration were considered for the review. Data collection and analysis Two review authors collected the data independently. We analysed the data with both fixed-effect and random-effects meta-analysis models using RevMan. For each outcome, we calculated the risk ratio (RR) or mean difference (MD) with 95% confidence interval (CI). Main results Twenty-six trials fulfilled the inclusion criteria of the review. All the 26 trials except one trial of 30 participants were at high risk of bias. Nineteen of the trials with 1263 randomised participants provided data for this review. Ten of the 19 trials compared Local Anaesthetic wound infiltration versus inactive control. One of the 19 trials compared Local Anaesthetic wound infiltration with two inactive controls, normal saline and no intervention. Two of the 19 trials had four arms comparing Local Anaesthetic wound infiltration with inactive controls in the presence and absence of co-interventions to decrease pain after laparoscopic cholecystectomy. Four of the 19 trials had three or more arms that could be included for the comparison of Local Anaesthetic wound infiltration versus inactive control and different methods of Local Anaesthetic wound infiltration. The remaining two trials compared different methods of Local Anaesthetic wound infiltration. Most trials included only low Anaesthetic risk people undergoing elective laparoscopic cholecystectomy. Seventeen trials randomised a total of 1095 participants to Local Anaesthetic wound infiltration (587 participants) versus no Local Anaesthetic wound infiltration (508 participants). Various Anaesthetic agents were used but bupivacaine was the commonest Local Anaesthetic used. There was no mortality in either group in the seven trials that reported mortality (0/280 (0%) in Local Anaesthetic infiltration group versus 0/259 (0%) in control group). The effect of Local Anaesthetic on the proportion of people who developed serious adverse events was imprecise and compatible with increase or no difference in serious adverse events (seven trials; 539 participants; 2/280 (0.8%) in Local Anaesthetic group versus 1/259 (0.4%) in control; RR 2.00; 95% CI 0.19 to 21.59; very low quality evidence). None of the serious adverse events were related to Local Anaesthetic wound infiltration. None of the trials reported patient quality of life. The proportion of participants who were discharged as day surgery patients was higher in the Local Anaesthetic infiltration group than in the no Local Anaesthetic infiltration group (one trial; 97 participants; 33/50 (66.0%) in the Local Anaesthetic group versus 20/47 (42.6%) in the control group; RR 1.55; 95% CI 1.05 to 2.28; very low quality evidence). The effect of Local Anaesthetic on the length of hospital stay was compatible with a decrease, increase, or no difference in the length of hospital stay between the two groups (four trials; 327 participants; MD -0.26 days; 95% CI -0.67 to 0.16; very low quality evidence). The pain scores as measured by the visual analogue scale (0 to 10 cm) were lower in the Local Anaesthetic infiltration group than the control group at 4 to 8 hours (13 trials; 806 participants; MD -1.33 cm on the VAS; 95% CI -1.54 to -1.12; very low quality evidence) and 9 to 24 hours (12 trials; 756 participants; MD -0.36 cm on the VAS; 95% CI -0.53 to -0.20; very low quality evidence). The effect of Local Anaesthetic on the time taken to return to normal activity between the two groups was imprecise and compatible with a decrease, increase, or no difference in the time taken to return to normal activity (two trials; 195 participants; MD 0.14 days; 95% CI -0.59 to 0.87; very low quality evidence). None of the trials reported on return to work. Four trials randomised a total of 149 participants to Local Anaesthetic wound infiltration prior to skin incision (74 participants) versus Local Anaesthetic wound infiltration at the end of surgery (75 participants). Two trials randomised a total of 176 participants to four different Local Anaesthetics (bupivacaine, levobupivacaine, ropivacaine, neosaxitoxin). Although there were differences between the groups in some outcomes the changes were not consistent. There was no evidence to support the preference of one Local Anaesthetic over another or to prefer administration of Local Anaesthetic at a specific time compared with another. Authors' conclusions Serious adverse events were rare in studies evaluating Local Anaesthetic wound infiltration (very low quality evidence). There is very low quality evidence that infiltration reduces pain in low Anaesthetic risk people undergoing elective laparoscopic cholecystectomy. However, the clinical importance of this reduction in pain is likely to be small. Further randomised clinical trials at low risk of systematic and random errors are necessary. Such trials should include important clinical outcomes such as quality of life and time to return to work in their assessment.

  • The Cochrane Library - Wound infiltration with Local Anaesthetic agents for laparoscopic cholecystectomy
    The Cochrane database of systematic reviews, 2014
    Co-Authors: Sofronis Loizides, Kurinchi Selvan Gurusamy, Myura Nagendran, Gian Piero Guerrini, Michele Rossi, Brian R Davidson
    Abstract:

    Background While laparoscopic cholecystectomy is generally considered to be less painful than open surgery, pain is one of the important reasons for delayed discharge after day surgery resulting in overnight stay following laparoscopic cholecystectomy. The safety and effectiveness of Local Anaesthetic wound infiltration in people undergoing laparoscopic cholecystectomy is not known. Objectives To assess the benefits and harms of Local Anaesthetic wound infiltration in patients undergoing laparoscopic cholecystectomy and to identify the best method of Local Anaesthetic wound infiltration with regards to the type of Local Anaesthetic, dosage, and time of administration of the Local Anaesthetic. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Science Citation Index Expanded until February 2013 to identify studies of relevance to this review. We included randomised clinical trials for benefit and quasi-randomised and comparative non-randomised studies for treatment-related harms. Selection criteria Only randomised clinical trials (irrespective of language, blinding, or publication status) comparing Local Anaesthetic wound infiltration versus placebo, no intervention, or inactive control during laparoscopic cholecystectomy, trials comparing different Local Anaesthetic agents for Local Anaesthetic wound infiltration, and trials comparing the different times of Local Anaesthetic wound infiltration were considered for the review. Data collection and analysis Two review authors collected the data independently. We analysed the data with both fixed-effect and random-effects meta-analysis models using RevMan. For each outcome, we calculated the risk ratio (RR) or mean difference (MD) with 95% confidence interval (CI). Main results Twenty-six trials fulfilled the inclusion criteria of the review. All the 26 trials except one trial of 30 participants were at high risk of bias. Nineteen of the trials with 1263 randomised participants provided data for this review. Ten of the 19 trials compared Local Anaesthetic wound infiltration versus inactive control. One of the 19 trials compared Local Anaesthetic wound infiltration with two inactive controls, normal saline and no intervention. Two of the 19 trials had four arms comparing Local Anaesthetic wound infiltration with inactive controls in the presence and absence of co-interventions to decrease pain after laparoscopic cholecystectomy. Four of the 19 trials had three or more arms that could be included for the comparison of Local Anaesthetic wound infiltration versus inactive control and different methods of Local Anaesthetic wound infiltration. The remaining two trials compared different methods of Local Anaesthetic wound infiltration. Most trials included only low Anaesthetic risk people undergoing elective laparoscopic cholecystectomy. Seventeen trials randomised a total of 1095 participants to Local Anaesthetic wound infiltration (587 participants) versus no Local Anaesthetic wound infiltration (508 participants). Various Anaesthetic agents were used but bupivacaine was the commonest Local Anaesthetic used. There was no mortality in either group in the seven trials that reported mortality (0/280 (0%) in Local Anaesthetic infiltration group versus 0/259 (0%) in control group). The effect of Local Anaesthetic on the proportion of people who developed serious adverse events was imprecise and compatible with increase or no difference in serious adverse events (seven trials; 539 participants; 2/280 (0.8%) in Local Anaesthetic group versus 1/259 (0.4%) in control; RR 2.00; 95% CI 0.19 to 21.59; very low quality evidence). None of the serious adverse events were related to Local Anaesthetic wound infiltration. None of the trials reported patient quality of life. The proportion of participants who were discharged as day surgery patients was higher in the Local Anaesthetic infiltration group than in the no Local Anaesthetic infiltration group (one trial; 97 participants; 33/50 (66.0%) in the Local Anaesthetic group versus 20/47 (42.6%) in the control group; RR 1.55; 95% CI 1.05 to 2.28; very low quality evidence). The effect of Local Anaesthetic on the length of hospital stay was compatible with a decrease, increase, or no difference in the length of hospital stay between the two groups (four trials; 327 participants; MD -0.26 days; 95% CI -0.67 to 0.16; very low quality evidence). The pain scores as measured by the visual analogue scale (0 to 10 cm) were lower in the Local Anaesthetic infiltration group than the control group at 4 to 8 hours (13 trials; 806 participants; MD -1.33 cm on the VAS; 95% CI -1.54 to -1.12; very low quality evidence) and 9 to 24 hours (12 trials; 756 participants; MD -0.36 cm on the VAS; 95% CI -0.53 to -0.20; very low quality evidence). The effect of Local Anaesthetic on the time taken to return to normal activity between the two groups was imprecise and compatible with a decrease, increase, or no difference in the time taken to return to normal activity (two trials; 195 participants; MD 0.14 days; 95% CI -0.59 to 0.87; very low quality evidence). None of the trials reported on return to work. Four trials randomised a total of 149 participants to Local Anaesthetic wound infiltration prior to skin incision (74 participants) versus Local Anaesthetic wound infiltration at the end of surgery (75 participants). Two trials randomised a total of 176 participants to four different Local Anaesthetics (bupivacaine, levobupivacaine, ropivacaine, neosaxitoxin). Although there were differences between the groups in some outcomes the changes were not consistent. There was no evidence to support the preference of one Local Anaesthetic over another or to prefer administration of Local Anaesthetic at a specific time compared with another. Authors' conclusions Serious adverse events were rare in studies evaluating Local Anaesthetic wound infiltration (very low quality evidence). There is very low quality evidence that infiltration reduces pain in low Anaesthetic risk people undergoing elective laparoscopic cholecystectomy. However, the clinical importance of this reduction in pain is likely to be small. Further randomised clinical trials at low risk of systematic and random errors are necessary. Such trials should include important clinical outcomes such as quality of life and time to return to work in their assessment.

Colin Royse - One of the best experts on this subject based on the ideXlab platform.

  • symptomatic Local Anaesthetic toxicity and plasma ropivacaine concentrations after transversus abdominis plane block for caesarean section
    BJA: British Journal of Anaesthesia, 2013
    Co-Authors: James D Griffiths, S Grant, A R Bjorksten, P Hebbard, Colin Royse
    Abstract:

    Background The transversus abdominis plane (TAP) block involves injecting a large volume of Local Anaesthetic between the muscles of the abdominal wall. Plasma concentrations of ropivacaine after gynaecological laparotomy are potentially high enough to result in systemic toxicity, and there are pharmacokinetic reasons why pregnancy may increase susceptibility to Local Anaesthetic toxicity. Methods Adult female patients (n=30) undergoing elective Caesarean section under spinal anaesthesia received bilateral ultrasound-guided TAP blocks after wound closure (2.5 mg kg−1 of ropivacaine diluted to 40 ml). Venous blood samples were collected at 10, 20, 30, 45, 60, 90, 120, 180 and 240 min following the block. Blood samples were assayed for total and free ropivacaine concentrations. Patients were assessed for symptoms of Local Anaesthetic toxicity. Results The mean [standard deviation ( sd )] peak total concentration of ropivacaine occurred at 30 min post-injection and was 1.82 (0.69) μg ml−1. The maximum detected concentration in any patient was 3.76 μg ml−1 (at 10 min post-injection). Three patients reported symptoms of mild neurotoxicity, and the mean ( sd ) peak levels were elevated in these patients, 2.70 (0.46) µg ml−1. Conclusions TAP blocks can result in elevated plasma ropivacaine concentrations in patients undergoing Caesarean section, which may be associated with neurotoxicity.

Jhijoung Wang - One of the best experts on this subject based on the ideXlab platform.

  • dextromethorphan 3 methoxymorphinan and dextrorphan have Local Anaesthetic effect on sciatic nerve blockade in rats
    European Journal of Pharmacology, 2006
    Co-Authors: Janninn Tzeng, Chiehhsien Tu, Yu Wen Chen, Jhijoung Wang
    Abstract:

    AbstractDextromethorphan has been used as an antitussive for more than 40 years and is considered a drug with a good margin of safety. The aim of thestudy was to evaluate whether dextromethorphan and its metabolites — 3-methoxymorphinan and dextrorphan— had Local Anaesthetic effects.Using a method of sciatic nerve blockade in rats, the potencies and durations of actions of dextromethorphan and its metabolites on sciatic nerveblockades of motor function, proprioception, and nociception were evaluated. Lidocaine was used as control. We found that dextromethorphanand its metabolites produced dose-related Local Anaesthetic effects on sciatic nerve blockades of motor function, proprioception, and nociception.The ranks of potencies were lidocaine>dextromethorphan>3-methoxymorphinan>dextrorphan (P<0.01 for each comparison). Under an equi-potent basis, dextrorphan and 3-methoxymorphinan had durations of actions longer than that of lidocaine (P<0.05 for each comparison). Co-administration of dextromethorphan or its metabolites with lidocaine produced an additive effect on sciatic nerve blockades. In conclusion,dextromethorphan and its metabolites — 3-methoxymorphinan and dextrorphan— had a Local Anaesthetic effect on sciatic nerve blockades ofmotor function, proprioception and nociception with durations of actions longer than that of lidocaine. Co-administration of dextromethorphan andits metabolites produced an additive effect on sciatic nerve blockades.© 2006 Elsevier B.V. All rights reserved.

  • Dextromethorphan, 3-methoxymorphinan, and dextrorphan have Local Anaesthetic effect on sciatic nerve blockade in rats.
    European journal of pharmacology, 2006
    Co-Authors: Janninn Tzeng, Chiehhsien Tu, Yu Wen Chen, Jhijoung Wang
    Abstract:

    Dextromethorphan has been used as an antitussive for more than 40 years and is considered a drug with a good margin of safety. The aim of the study was to evaluate whether dextromethorphan and its metabolites--3-methoxymorphinan and dextrorphan--had Local Anaesthetic effects. Using a method of sciatic nerve blockade in rats, the potencies and durations of actions of dextromethorphan and its metabolites on sciatic nerve blockades of motor function, proprioception, and nociception were evaluated. Lidocaine was used as control. We found that dextromethorphan and its metabolites produced dose-related Local Anaesthetic effects on sciatic nerve blockades of motor function, proprioception, and nociception. The ranks of potencies were lidocaine>dextromethorphan>3-methoxymorphinan>dextrorphan (P

J Mc G Donnell - One of the best experts on this subject based on the ideXlab platform.

  • studies on the spread of Local Anaesthetic solution in transversus abdominis plane blocks
    Anaesthesia, 2011
    Co-Authors: J Carney, Olivia Finnerty, Jassim Rauf, D Bergin, John G Laffey, J Mc G Donnell
    Abstract:

    Summary The extent of analgesia provided by transversus abdominis plane blocks depends upon the site of injection and pattern of spread within the plane. There are currently a number of ultrasound-guided approaches in use, including an anterior oblique-subcostal approach, a mid-axillary approach and a more recently proposed posterior approach. We wished to determine whether the site of injection of Local Anaesthetic into the transversus abdominis plane affects the spread of the Local Anaesthetic within that plane, by studying the spread of a Local Anaesthetic and contrast solution in four groups of volunteers. The first group underwent the classical landmark-based transversus abdominis plane block whereby two different volumes of injectate were studied: 0.3 ml.kg−1 vs 0.6 ml.kg−1. The second group underwent transversus abdominis plane block using the anterior subcostal approach. The third group underwent transversus abdominis plane block using the mid-axillary approach. The fourth group underwent transversus abdominis plane block using the posterior approach, in which Local Anaesthetic was deposited close to the antero-lateral border of the quadratus lumborum. All volunteers subsequently underwent magnetic resonance imaging at 1, 2 and 4 h following each block to determine the spread of Local Anaesthetic over time. The studies demonstrated that the anterior subcostal and mid-axillary ultrasound approaches resulted in a predominantly anterior spread of the contrast solution within the transversus abdominis plane and relatively little posterior spread. There was no spread to the paravertebral space with the anterior subcostal approach. The mid-axillary transversus abdominis plane block gave faint contrast enhancement in the paravertebral space at T12-L2. In contrast, the posterior approaches, using both landmark and ultrasound identifications, resulted in predominantly posterior spread of contrast around the quadratus lumborum to the paravertebral space from T5 to L1 vertebral levels. We concluded that the pattern of spread of Local Anaesthetic differs depending on the site of injection into the transversus abdominis plane. This may have important implications for the extent of analgesia produced with each approach.

James D Griffiths - One of the best experts on this subject based on the ideXlab platform.

  • symptomatic Local Anaesthetic toxicity and plasma ropivacaine concentrations after transversus abdominis plane block for caesarean section
    BJA: British Journal of Anaesthesia, 2013
    Co-Authors: James D Griffiths, S Grant, A R Bjorksten, P Hebbard, Colin Royse
    Abstract:

    Background The transversus abdominis plane (TAP) block involves injecting a large volume of Local Anaesthetic between the muscles of the abdominal wall. Plasma concentrations of ropivacaine after gynaecological laparotomy are potentially high enough to result in systemic toxicity, and there are pharmacokinetic reasons why pregnancy may increase susceptibility to Local Anaesthetic toxicity. Methods Adult female patients (n=30) undergoing elective Caesarean section under spinal anaesthesia received bilateral ultrasound-guided TAP blocks after wound closure (2.5 mg kg−1 of ropivacaine diluted to 40 ml). Venous blood samples were collected at 10, 20, 30, 45, 60, 90, 120, 180 and 240 min following the block. Blood samples were assayed for total and free ropivacaine concentrations. Patients were assessed for symptoms of Local Anaesthetic toxicity. Results The mean [standard deviation ( sd )] peak total concentration of ropivacaine occurred at 30 min post-injection and was 1.82 (0.69) μg ml−1. The maximum detected concentration in any patient was 3.76 μg ml−1 (at 10 min post-injection). Three patients reported symptoms of mild neurotoxicity, and the mean ( sd ) peak levels were elevated in these patients, 2.70 (0.46) µg ml−1. Conclusions TAP blocks can result in elevated plasma ropivacaine concentrations in patients undergoing Caesarean section, which may be associated with neurotoxicity.