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Lumbar transversus abdominis plane block: the role of local anesthetic volume and concentration—a pilot, prospective, randomized, controlled trial

BACKGROUND: The lumbar transversus abdominis plane (TAP) block has become an optional part of multimodal analgesia following several abdominal surgeries. There remains a lack of consensus regarding the extent of dermatomal blockade following lumber TAP block, as well as the optimal local anesthetic...

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Autores principales: Forero, Mauricio, Heikkila, Andrew, Paul, James E, Cheng, Ji, Thabane, Lehana
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5153686/
https://www.ncbi.nlm.nih.gov/pubmed/27965789
http://dx.doi.org/10.1186/s40814-015-0002-6
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author Forero, Mauricio
Heikkila, Andrew
Paul, James E
Cheng, Ji
Thabane, Lehana
author_facet Forero, Mauricio
Heikkila, Andrew
Paul, James E
Cheng, Ji
Thabane, Lehana
author_sort Forero, Mauricio
collection PubMed
description BACKGROUND: The lumbar transversus abdominis plane (TAP) block has become an optional part of multimodal analgesia following several abdominal surgeries. There remains a lack of consensus regarding the extent of dermatomal blockade following lumber TAP block, as well as the optimal local anesthetic volumes and concentrations. The objectives of this pilot trial were to assess the feasibility of conducting a similar full-scale trial and gather information on relevant clinical outcomes, namely whether greater local anesthetic volumes would lead to more cephalad dermatomal blockade. METHODS: The study was a prospective, double-blinded pilot randomized controlled trial (RCT) with three arms, each representing different local anesthetic volumes: 20 ml 0.5% ropivacaine, 30 ml 0.33% ropivacaine, and 40 ml 0.25% ropivacaine. We planned to recruit 30 females undergoing total abdominal hysterectomy for non-malignant pathology, who would then receive bilateral ultrasound-guided midaxillary TAP blocks at the completion of surgery. Randomized patients would be followed for 48 h post-block and would receive multimodal analgesia. The primary outcomes were measurements of patient recruitment and safety, to inform the feasibility of a larger trial. The main secondary outcome was the clinically pertinent endpoint of dermatomal blockade, which was assessed by loss of sensation to ice and pinprick. RESULTS: Our target sample size was reached in 8 months, and the recruitment rate was 52% (31/60). A total of 58 TAP blocks were performed among 29 patients. All but one of the patients who received interventions were successfully followed and assessed up to 48 h. No patient safety-related adverse events were reported during the study period. The mean highest dermatome blocked in each group at any time point was T8. The 20 ml 0.5% ropivacaine group achieved a T9–L1 block that lasted for 48 h. The 30 ml 0.33% ropivacaine group had a sensory block from T9–L1 that regressed to T10–T12 between 24 and 48 h. The 40 ml 0.25% ropivacaine group reported an initial sensory block from T9–T12 that regressed by 24 h to include only the T12 dermatome. CONCLUSIONS: This pilot study demonstrated that the study design is feasible and safe to be carried to a full-scale RCT. The preliminary clinical findings showed that increasing the volume, while maintaining a constant dose, of local anesthetic does not appear to extend the height of dermatomal blockade following midaxillary TAP block. This finding needs to be confirmed in future studies. TRIAL REGISTRATION: ClinicalTrials.gov registration is: NCT01307215.
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spelling pubmed-51536862016-12-13 Lumbar transversus abdominis plane block: the role of local anesthetic volume and concentration—a pilot, prospective, randomized, controlled trial Forero, Mauricio Heikkila, Andrew Paul, James E Cheng, Ji Thabane, Lehana Pilot Feasibility Stud Research BACKGROUND: The lumbar transversus abdominis plane (TAP) block has become an optional part of multimodal analgesia following several abdominal surgeries. There remains a lack of consensus regarding the extent of dermatomal blockade following lumber TAP block, as well as the optimal local anesthetic volumes and concentrations. The objectives of this pilot trial were to assess the feasibility of conducting a similar full-scale trial and gather information on relevant clinical outcomes, namely whether greater local anesthetic volumes would lead to more cephalad dermatomal blockade. METHODS: The study was a prospective, double-blinded pilot randomized controlled trial (RCT) with three arms, each representing different local anesthetic volumes: 20 ml 0.5% ropivacaine, 30 ml 0.33% ropivacaine, and 40 ml 0.25% ropivacaine. We planned to recruit 30 females undergoing total abdominal hysterectomy for non-malignant pathology, who would then receive bilateral ultrasound-guided midaxillary TAP blocks at the completion of surgery. Randomized patients would be followed for 48 h post-block and would receive multimodal analgesia. The primary outcomes were measurements of patient recruitment and safety, to inform the feasibility of a larger trial. The main secondary outcome was the clinically pertinent endpoint of dermatomal blockade, which was assessed by loss of sensation to ice and pinprick. RESULTS: Our target sample size was reached in 8 months, and the recruitment rate was 52% (31/60). A total of 58 TAP blocks were performed among 29 patients. All but one of the patients who received interventions were successfully followed and assessed up to 48 h. No patient safety-related adverse events were reported during the study period. The mean highest dermatome blocked in each group at any time point was T8. The 20 ml 0.5% ropivacaine group achieved a T9–L1 block that lasted for 48 h. The 30 ml 0.33% ropivacaine group had a sensory block from T9–L1 that regressed to T10–T12 between 24 and 48 h. The 40 ml 0.25% ropivacaine group reported an initial sensory block from T9–T12 that regressed by 24 h to include only the T12 dermatome. CONCLUSIONS: This pilot study demonstrated that the study design is feasible and safe to be carried to a full-scale RCT. The preliminary clinical findings showed that increasing the volume, while maintaining a constant dose, of local anesthetic does not appear to extend the height of dermatomal blockade following midaxillary TAP block. This finding needs to be confirmed in future studies. TRIAL REGISTRATION: ClinicalTrials.gov registration is: NCT01307215. BioMed Central 2015-03-25 /pmc/articles/PMC5153686/ /pubmed/27965789 http://dx.doi.org/10.1186/s40814-015-0002-6 Text en © Forero et al.; licensee BioMed Central. 2015 This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Forero, Mauricio
Heikkila, Andrew
Paul, James E
Cheng, Ji
Thabane, Lehana
Lumbar transversus abdominis plane block: the role of local anesthetic volume and concentration—a pilot, prospective, randomized, controlled trial
title Lumbar transversus abdominis plane block: the role of local anesthetic volume and concentration—a pilot, prospective, randomized, controlled trial
title_full Lumbar transversus abdominis plane block: the role of local anesthetic volume and concentration—a pilot, prospective, randomized, controlled trial
title_fullStr Lumbar transversus abdominis plane block: the role of local anesthetic volume and concentration—a pilot, prospective, randomized, controlled trial
title_full_unstemmed Lumbar transversus abdominis plane block: the role of local anesthetic volume and concentration—a pilot, prospective, randomized, controlled trial
title_short Lumbar transversus abdominis plane block: the role of local anesthetic volume and concentration—a pilot, prospective, randomized, controlled trial
title_sort lumbar transversus abdominis plane block: the role of local anesthetic volume and concentration—a pilot, prospective, randomized, controlled trial
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5153686/
https://www.ncbi.nlm.nih.gov/pubmed/27965789
http://dx.doi.org/10.1186/s40814-015-0002-6
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