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1.
Pain ; 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33021563

RESUMO

Phantom limb pain is thought to be sustained by reentrant neural pathways which provoke dysfunctional reorganization in the somatosensory cortex. We hypothesized that disrupting reentrant pathways with a 6-day-long continuous peripheral nerve block reduces phantom pain 4 weeks after treatment. We enrolled patients who had an upper- or lower-limb amputation and established phantom pain. Each was randomized to receive a 6-day perineural infusion of either ropivacaine or normal saline. The primary outcome was the average phantom pain severity as measured with a Numeric Rating Scale (0-10) at 4 weeks, after which an optional crossover treatment was offered within the following 0-12 weeks. Pretreatment pain scores were similar in both groups, with a median [interquartile range] of 5.0 [4.0, 7.0] for each. After 4 weeks, average phantom limb pain intensity was a mean (SD) of 3.0 (2.9) in patients given local anesthetic versus 4.5 (2.6) in those given placebo (difference (95% CI) 1.3 (0.4, 2.2), P=0.003). Patients given local anesthetic had improved global impression of change and less pain-induced physical and emotional dysfunction, but did not differ on depression scores. For subjects who received only the first infusion (no self-selected crossover), the median decrease in phantom limb pain at 6 months for treated subjects was 3.0 [0, 5.0] vs. 1.5 [0, 5.0] for the placebo group; there appeared to be little residual benefit at 12 months. We conclude that a 6-day continuous peripheral nerve block reduces phantom limb pain as well as physical and emotional dysfunction for at least 1 month.

2.
Anesth Analg ; 128(6): e104-e108, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31094804

RESUMO

We tested the hypothesis that during a continuous popliteal-sciatic nerve block, postoperative analgesia is improved with the catheter insertion point "deep" to the paraneural sheath immediately distal to the bifurcation between the tibial and common peroneal branches, compared with the traditional approach "superficial" to the paraneural sheath proximal to the bifurcation. The needle tip location was determined to be accurately located with a fluid bolus visualized with ultrasound; however, catheters were subsequently inserted without a similar fluid injection and visualization protocol (visualized air injection was permitted and usually implemented, but not required per protocol). The average pain (0-10 scale) the morning after surgery for subjects with a catheter inserted at the proximal subparaneural location (n = 31) was a median (interquartile) of 1.5 (0.0-3.5) vs 1.5 (0.0-4.0) for subjects with a catheter inserted at the distal supraparaneural location (n = 32; P = .927). Secondary outcomes were similarly negative.


Assuntos
Analgesia/métodos , Cateterismo/métodos , Bloqueio Nervoso , Manejo da Dor/métodos , Dor Pós-Operatória/tratamento farmacológico , Nervo Isquiático/efeitos dos fármacos , Adulto , Idoso , Anestésicos Locais , Cateteres , Feminino , Humanos , Injeções , Lidocaína/administração & dosagem , Masculino , Pessoa de Meia-Idade , Agulhas , Medição da Dor , Período Pós-Operatório , Estudos Prospectivos
3.
J Anesth ; 31(3): 374-379, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28364165

RESUMO

PURPOSE: Retrospective studies have associated perioperative regional anesthesia/analgesia during mastectomy for breast cancer with a decreased incidence of cancer recurrence. However, to date, no prospective data from a randomized controlled trial have been reported. In a previous study we found that extending a single-injection paravertebral block with a multiple-day perineural local anesthetic infusion improves analgesia. This follow-up study investigates the rates of cancer recurrence for the single-injection and multiple-day infusion treatments. METHODS: Patients undergoing unilateral (n = 24) or bilateral mastectomy (n = 36) were included in the study. All patients had been diagnosed with breast cancer or tumor in situ, except for six patients who were receiving prophylactic bilateral mastectomy and were excluded from analyses. Patients received unilateral or bilateral single-injection thoracic paravertebral block(s) corresponding to their surgical site(s) with ropivacaine and perineural catheter(s). Subsequently, patients were randomized to receive either ropivacaine 0.4% (n = 30) or normal saline (n = 30) via their catheter(s) until catheter removal on postoperative day 3. Cancer recurrence from the date of surgery until at least 2 years post surgery was investigated via chart review. RESULTS: Five of the 54 (9.2%) patients experienced a cancer recurrence following mastectomy-3 of 26 (11.5%) of the patients with perineural ropivacaine and 2 of 28 (7.1%) of the patients with perineural saline. CONCLUSIONS: This pilot study found no evidence that extending a single-injection paravertebral block with a multi-day perineural local anesthetic infusion decreases the risk of post-mastectomy cancer recurrence. However, due to the small sample size of this investigation, further research is needed to draw definitive conclusions.


Assuntos
Neoplasias da Mama/cirurgia , Mastectomia/métodos , Bloqueio Nervoso/métodos , Dor Pós-Operatória/tratamento farmacológico , Adulto , Amidas/administração & dosagem , Anestésicos Locais/administração & dosagem , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Projetos Piloto , Período Pós-Operatório , Estudos Prospectivos , Ropivacaina
4.
Medsurg Nurs ; 25(1): 25-30, 49, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27044125

RESUMO

Combined scientific advances in pharmaceutical agents, perineural blocks, and pump delivery capabilities such as those used with continuous peripheral nerve blocks have demonstrated advantages in pain management for patients undergoing joint arthroplasty. This report documents the incidence of falls increased after the implementation of a continuous peripheral nerve block program for patients undergoing knee and hip arthroplasty in an academic medical center.


Assuntos
Acidentes por Quedas/prevenção & controle , Acidentes por Quedas/estatística & dados numéricos , Anestésicos/efeitos adversos , Artroplastia de Quadril/efeitos adversos , Artroplastia do Joelho/efeitos adversos , Debilidade Muscular/etiologia , Bloqueio Nervoso/efeitos adversos , California , Estudos de Coortes , Feminino , Humanos , Incidência , Masculino , Músculo Esquelético/efeitos dos fármacos , Nervos Periféricos/efeitos dos fármacos , Estudos Retrospectivos , Fatores de Risco
5.
Anesth Analg ; 122(5): 1689-95, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26962712

RESUMO

BACKGROUND: Multiple studies have demonstrated that, for single-injection popliteal sciatic nerve blocks, block characteristics are dependent upon local anesthetic injection relative to the sciatic nerve bifurcation. In contrast, this relation remains unexamined for continuous popliteal sciatic nerve blocks. We, therefore, tested the hypothesis that postoperative analgesia is improved with the perineural catheter tip at the level of the bifurcation compared with 5 cm proximal to the bifurcation. METHODS: Preoperatively, subjects having moderately painful foot or ankle surgery were randomly assigned to receive an ultrasound-guided subepimyseal perineural catheter inserted either at or 5 cm proximal to the sciatic nerve bifurcation. Subjects received a single injection of mepivacaine 1.5% either via the insertion needle preoperatively or the perineural catheter postoperatively, followed by an infusion of ropivacaine 0.2% (6 mL/h basal, 4 mL bolus, and 30-min lockout) for the study duration. The primary end point was the average pain measured on a numeric rating scale (0-10) in the 3 hours before a data collection telephone call the morning after surgery. RESULTS: The average numeric rating scale of subjects with a catheter inserted at the sciatic nerve bifurcation (n = 64) was a median (10th, 25th to 75th, and 90th quartiles) of 3.0 (0.0, 2.4-5.0, and 7.0) vs 2.0 (0.0, 1.0-4.0, and 5.0) for subjects with a catheter inserted proximal to the bifurcation (n = 64; P = 0.008). Similarly, maximum pain scores were greater in the group at the bifurcation: 6.0 (3.0, 4.4-8.0, and 9.0) vs 5.0 (0.0, 3.0-8.0, and 10.0) (P = 0.019). Differences between the groups for catheter insertion time, opioid rescue dose, degree of numbness in the foot/toes, catheter dislodgement, and fluid leakage did not reach statistical significance. CONCLUSIONS: For continuous popliteal sciatic nerve blocks, a catheter inserted 5 cm proximal to the sciatic nerve bifurcation provides superior postoperative analgesia in subjects having moderately painful foot or ankle surgery compared with catheters located at the bifurcation. This is in marked contrast with single-injection popliteal sciatic nerve blocks for which benefits are afforded to local anesthetic injection distal, rather than proximal, to the bifurcation.


Assuntos
Amidas/administração & dosagem , Anestésicos Locais/administração & dosagem , Cateteres , Pé/cirurgia , Bloqueio Nervoso/instrumentação , Procedimentos Ortopédicos , Dor Pós-Operatória/prevenção & controle , Nervo Isquiático/efeitos dos fármacos , Adulto , Amidas/efeitos adversos , Anestésicos Locais/efeitos adversos , California , Feminino , Pé/inervação , Humanos , Masculino , Mepivacaína/administração & dosagem , Pessoa de Meia-Idade , Bloqueio Nervoso/efeitos adversos , Bloqueio Nervoso/métodos , Procedimentos Ortopédicos/efeitos adversos , Medição da Dor , Limiar da Dor/efeitos dos fármacos , Dor Pós-Operatória/diagnóstico , Dor Pós-Operatória/etiologia , Dor Pós-Operatória/fisiopatologia , Estudos Prospectivos , Ropivacaina , Nervo Isquiático/diagnóstico por imagem , Fatores de Tempo , Resultado do Tratamento , Ultrassonografia de Intervenção
6.
Reg Anesth Pain Med ; 40(5): 559-67, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26115189

RESUMO

BACKGROUND: We tested the hypothesis that, following unicompartment knee arthroplasty, a continuous adductor canal block decreases the time to reach 4 discharge criteria compared with a continuous femoral nerve block. METHODS: Subjects were randomized to either an adductor canal or femoral perineural catheter (2-day ropivacaine 0.2% infusion) in an unmasked fashion. The primary outcome was the time to attain 4 discharge criteria: (1) adequate analgesia; (2) intravenous opioid independence; (3) ability to independently stand, walk 3 m, return, and sit down; and (4) ambulate 30 m. RESULTS: Subjects with an adductor canal catheter (n = 15) reached all 4 criteria in a median of 35 hours (interquartile range, 24-43 hours), compared with 40 hours (interquartile range, 27-69 hours) for those with a femoral catheter (n = 15; Wilcoxon rank sum test: P = 0.46; log-rank test: P = 0.16). However, the percentages of subjects (adductor canal: femoral) who reached the 2 mobilization criteria were 27%:0% on postoperative day (POD) 0, 93%:53% on POD 1, and 100%:73% on POD 2. Of adductor canal subjects, 100% were discharge ready by POD 2, compared with only 73% of femoral subjects (P < 0.001). CONCLUSIONS: Compared with a continuous femoral nerve block, a continuous adductor canal block did not appreciably decrease the median number of hours to overall discharge readiness, yet did decrease the number of discrete days until discharge readiness. These results are applicable to only unicompartment knee arthroplasty and must be considered preliminary because of the limited sample size of this pilot study.


Assuntos
Artroplastia do Joelho/tendências , Bloqueio Nervoso Autônomo/tendências , Nervo Femoral , Dor Pós-Operatória/prevenção & controle , Alta do Paciente/tendências , Idoso , Idoso de 80 Anos ou mais , Artroplastia do Joelho/efeitos adversos , Bloqueio Nervoso Autônomo/efeitos adversos , Bloqueio Nervoso Autônomo/métodos , Feminino , Nervo Femoral/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor/métodos , Medição da Dor/tendências , Dor Pós-Operatória/diagnóstico , Dor Pós-Operatória/etiologia , Alta do Paciente/normas , Projetos Piloto , Estudos Prospectivos , Resultado do Tratamento
7.
Anesthesiology ; 123(2): 444-56, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26079800

RESUMO

BACKGROUND: The authors conducted a randomized, controlled, parallel-arm, superiority study to test the hypothesis that a continuous adductor canal block decreases the time to attain four discharge criteria compared with a continuous femoral nerve block after tricompartment knee arthroplasty. METHODS: Subjects undergoing tricompartment knee arthroplasty were randomized using computer-generated lists to either an adductor canal or femoral perineural catheter (3-day ropivacaine 0.2% infusion) in an unmasked manner. The primary outcome was the time to attain four criteria: (1) adequate analgesia; (2) intravenous opioids independence; (3) ability to stand, walk 3 m, return, and sit down; and (4) ambulate 30 m. RESULTS: Subjects with an adductor canal catheter (n = 39) reached all four criteria in a median of 55 h (interquartile, 42 to 63 h) compared with 61 h (49 to 69 h) for those with a femoral catheter (n = 41; 95% CI, -13 to 1 h; P = 0.12). The percentage of subjects who reached the two mobilization criteria on postoperative days 1 and 2 were 72 and 95% for those with an adductor canal catheter (n = 39), but only 27 and 76% in subjects with a femoral catheter (n = 41; both P < 0.001). Differences in pain scores at rest and intravenous opioid requirements were minimal, but femoral infusion improved dynamic analgesia (P = 0.01 to 0.02). CONCLUSION: Compared with a continuous femoral nerve block, a continuous adductor canal block did not appreciably decrease the time to overall discharge readiness even though it did decrease the time until adequate mobilization, primarily because both groups experienced similar analgesia and intravenous opioid requirements that--in most cases--exceeded the time to mobilization.


Assuntos
Artroplastia do Joelho/efeitos adversos , Artroplastia do Joelho/tendências , Bloqueio Nervoso Autônomo/métodos , Cateteres de Demora , Nervo Femoral/diagnóstico por imagem , Alta do Paciente/tendências , Idoso , Cateterismo/métodos , Feminino , Nervo Femoral/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor/métodos , Dor Pós-Operatória/diagnóstico por imagem , Dor Pós-Operatória/prevenção & controle , Ultrassonografia
8.
J Clin Anesth ; 27(5): 371-4, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25957529

RESUMO

BACKGROUND: The treatment of postoperative pain after mastectomy is an area of increasing interest, as this treatment option is now considered a standard of care for those affected by breast cancer. Thoracic paravertebral nerve block (tPVB) using local anesthetics administered before mastectomy can theoretically provide postoperative analgesia, thereby facilitating a more comfortable and shorter hospitalization. METHODS: In this retrospective cohort study, we aimed to determine the duration and degree to which tPVB provides postoperative analgesia in patients who underwent either unilateral or bilateral mastectomy (n = 182). We retrospectively examined the numeric rating scale (NRS) for pain scores recorded by nursing staff throughout individual patient hospitalizations, looking specifically at the following time points: arrival from the postanesthesia care unit to the surgical wards, noon on postoperative day 1 (POD1), and discharge. We also examined the number of days until patients were discharged from the hospital. RESULTS: Our results revealed a statistically significant decrease in NRS in pain scores for patients who had received a tPVB (n = 92) on arrival from the postanesthesia care unit to the surgical wards (mean NRS decrease of 1.9 points; 99% confidence interval [CI], -3.0 to -0.8; P < .001) but did not show statistically significant decreases in NRS for pain scores for patients at noon on POD1 (mean NRS decrease of 0.3 points at noon on POD1, P = .43) or at discharge (mean NRS decrease of 0.1 point at discharge, P = .65). Moreover, use of tPVB did not have an impact on time until discharge (average decrease of 0.5 hours; 95% CI, -6 to +5 hours, P = .87). CONCLUSIONS: Single-injection tPVB appears to provide meaningful postoperative analgesia in the immediate postoperative period after mastectomy but not after the first day of surgery.


Assuntos
Anestésicos Locais/administração & dosagem , Neoplasias da Mama/cirurgia , Mastectomia/métodos , Bloqueio Nervoso/métodos , Dor Pós-Operatória/tratamento farmacológico , Adulto , Idoso , Estudos de Coortes , Feminino , Humanos , Tempo de Internação , Pessoa de Meia-Idade , Medição da Dor , Estudos Retrospectivos , Fatores de Tempo
9.
Ann Surg Oncol ; 22(6): 2017-25, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25413267

RESUMO

BACKGROUND: In a previous randomized, triple-masked, placebo-controlled study, the authors demonstrated that extending a single-injection paravertebral nerve block with a multiple-day perineural local anesthetic infusion improves analgesia and decreases pain-related dysfunction during the 3-day infusion but not subsequent to catheter removal within 1 month after mastectomy. This report describes a prospective follow-up study of the previously published trial to investigate the possibility that extending a single-injection paravertebral block with a multiple-day infusion may decrease persistent postsurgical pain as well as pain-induced emotional and functional dysfunction 1 year after mastectomy. METHODS: Subjects undergoing uni- or bilateral mastectomy received unilateral (n = 24) or bilateral (n = 36) single-injection thoracic paravertebral block(s) with ropivacaine and perineural catheter(s). The subjects were randomized to receive either ropivacaine 0.4 % (n = 30) or normal saline (n = 30) via their catheters until the catheters were removed on postoperative day 3. Chronic pain and pain-related physical and emotional dysfunction were measured using the Brief Pain Inventory (BPI). RESULTS: No statistically significant difference between treatments 3 months after surgery was observed with the BPI. In contrast, after 12 months, only 4 subjects (13 %) who had received a perineural ropivacaine infusion reported pain-induced dysfunction compared with 14 (47 %) who had received saline infusion (P = 0.011). At 12 months, the mean BPI was 1.6 ± 4.6 for the subjects who received ropivacaine versus 5.9 ± 11.3 for the subjects who received saline (P = 0.007). CONCLUSIONS: Adding a multiple-day, continuous ropivacaine infusion to a single-injection ropivacaine paravertebral nerve block may result in a lower incidence of pain as well as pain-related physical and emotional dysfunction 1 year after mastectomy.


Assuntos
Neoplasias da Mama/psicologia , Neoplasias da Mama/cirurgia , Mastectomia/efeitos adversos , Bloqueio Nervoso , Dor Pós-Operatória/etiologia , Estresse Psicológico/etiologia , Adulto , Amidas/administração & dosagem , Anestésicos Locais/administração & dosagem , Neoplasias da Mama/patologia , Feminino , Seguimentos , Humanos , Infusões Parenterais , Pessoa de Meia-Idade , Medição da Dor , Dor Pós-Operatória/tratamento farmacológico , Prognóstico , Estudos Prospectivos , Ropivacaina
10.
Pain Med ; 15(11): 1957-64, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25138273

RESUMO

BACKGROUND: Single-injection transversus abdominis plane (TAP) block provides postoperative analgesia and decreases supplemental analgesic requirements. However, there is currently no evidence from randomized, controlled studies investigating the possible benefits of continuous TAP blocks. Therefore, the aim of this randomized, triple-masked, placebo-controlled study was to determine if benefits are afforded by adding a multiple-day, ambulatory, continuous ropivacaine TAP block to a single-injection block following hernia surgery. METHODS: Preoperatively, subjects undergoing unilateral inguinal (N=19) or peri-umbilical (N=1) hernia surgery received unilateral or bilateral TAP perineural catheter(s), respectively. All received a ropivacaine 0.5% (20 mL) bolus via the catheter(s). Subjects were randomized to either postoperative perineural ropivacaine 0.2% or normal saline using portable infusion pump(s). Subjects were discharged home where the catheter(s) were removed the evening of postoperative day (POD) 2. Subjects were contacted on POD 0-3. The primary endpoint was average pain with movement (scale: 0-10) queried on POD 1. RESULTS: Twenty subjects of a target 30 were enrolled due to the primary surgeon's unanticipated departure from the institution. Average pain queried on POD 1 for subjects receiving ropivacaine (N=10) was a mean (standard deviation) of 3.0 (2.6) vs 2.8 (2.7) for subjects receiving saline (N=10; 95% confidence interval difference in means -2.9 to 3.4; P=0.86). There were no statistically significant differences detected between treatment groups in any secondary endpoint. CONCLUSIONS: The results of this study do not support adding an ambulatory, continuous ropivacaine infusion to a single-injection ropivacaine TAP block for hernia surgery. However, the present investigation was underpowered, and further study is warranted.


Assuntos
Anestésicos Locais/administração & dosagem , Herniorrafia/efeitos adversos , Bloqueio Nervoso/métodos , Dor Pós-Operatória/tratamento farmacológico , Músculos Abdominais/efeitos dos fármacos , Amidas/administração & dosagem , Método Duplo-Cego , Feminino , Hérnia Inguinal/cirurgia , Hérnia Umbilical/cirurgia , Humanos , Bombas de Infusão , Masculino , Pessoa de Meia-Idade , Ropivacaina
13.
Reg Anesth Pain Med ; 39(2): 89-96, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24448512

RESUMO

BACKGROUND: We aimed to determine with this randomized, triple-masked, placebo-controlled study if benefits are afforded by adding a multiple-day, ambulatory, continuous ropivacaine paravertebral nerve block to a single-injection ropivacaine paravertebral block after mastectomy. METHODS: Preoperatively, 60 subjects undergoing unilateral (n = 24) or bilateral (n = 36) mastectomy received either unilateral or bilateral paravertebral perineural catheter(s), respectively, inserted between the third and fourth thoracic transverse process(es). All subjects received an initial bolus of ropivacaine 0.5% (15 mL) via the catheter(s). Subjects were randomized to receive either perineural ropivacaine 0.4% or normal saline using portable infusion pump(s) [5 mL/h basal; 300 mL reservoir(s)]. Subjects remained hospitalized for at least 1 night and were subsequently discharged home where the catheter(s) were removed on postoperative day (POD) 3. Subjects were contacted by telephone on PODs 1, 4, 8, and 28. The primary end point was average pain (scale, 0-10) queried on POD 1. RESULTS: Average pain queried on POD 1 for subjects receiving perineural ropivacaine (n = 30) was a median (interquartile) of 2 (0-3), compared with 4 (1-5) for subjects receiving saline (n = 30; 95% confidence interval difference in medians, -4.0 to -0.3; P = 0.021]. During this same period, subjects receiving ropivacaine experienced a lower severity of breakthrough pain (5 [3-6] vs 7 [5-8]; P = 0.046) as well. As a result, subjects receiving perineural ropivacaine experienced less pain-induced physical and emotional dysfunction, as measured with the Brief Pain Inventory (lower score = less dysfunction): 14 (4-37) versus 57 (8-67) for subjects receiving perineural saline (P = 0.012). For the subscale that measures the degree of interference of pain on 7 domains, such as general activity and relationships, subjects receiving perineural saline reported a median score 10 times higher (more dysfunction) than those receiving ropivacaine (3 [0-24] vs 33 [0-44]; P = 0.035). In contrast, after infusion discontinuation, there were no statistically significant differences detected between treatment groups. CONCLUSIONS: After mastectomy, adding a multiple-day, ambulatory, continuous ropivacaine infusion to a single-injection ropivacaine paravertebral nerve block results in improved analgesia and less functional deficit during the infusion. However, no benefits were identified after infusion discontinuation.


Assuntos
Assistência Ambulatorial/métodos , Amidas/administração & dosagem , Mastectomia/efeitos adversos , Bloqueio Nervoso/métodos , Dor Pós-Operatória/diagnóstico , Dor Pós-Operatória/tratamento farmacológico , Adulto , Método Duplo-Cego , Feminino , Humanos , Bombas de Infusão , Infusões Parenterais/métodos , Pessoa de Meia-Idade , Ropivacaina , Resultado do Tratamento
16.
Anesth Analg ; 117(5): 1248-56, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24108252

RESUMO

BACKGROUND: Currently available local anesthetics approved for single-injection peripheral nerve blocks have a maximum duration of <24 hours. A liposomal bupivacaine formulation (EXPAREL, Pacira Pharmaceuticals, Inc., San Diego, CA), releasing bupivacaine over 96 hours, recently gained Food and Drug Administration approval exclusively for wound infiltration but not peripheral nerve blocks. METHODS: Bilateral single-injection femoral nerve blocks were administered in healthy volunteers (n = 14). For each block, liposomal bupivacaine (0-80 mg) was mixed with normal saline to produce 30 mL of study fluid. Each subject received 2 different doses, 1 on each side, applied randomly in a double-masked fashion. The end points included the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle and tolerance to cutaneous electrical current in the femoral nerve distribution. Measurements were performed from baseline until quadriceps MVIC returned to 80% of baseline bilaterally. RESULTS: There were statistically significant dose responses in MVIC (0.09%/mg, SE = 0.03, 95% confidence interval [CI], 0.04-0.14, P = 0.002) and tolerance to cutaneous current (-0.03 mA/mg, SE = 0.01, 95% CI, -0.04 to -0.02, P < 0.001), however, in the opposite direction than expected (the higher the dose, the lower the observed effect). This inverse relationship is biologically implausible and most likely due to the limited sample size and the subjective nature of the measurement instruments. While peak effects occurred within 24 hours after block administration in 75% of cases (95% CI, 43%-93%), block duration usually lasted much longer: for bupivacaine doses >40 mg, tolerance to cutaneous current did not return to within 20% above baseline until after 24 hours in 100% of subjects (95% CI, 56%-100%). MVIC did not consistently return to within 20% of baseline until after 24 hours in 90% of subjects (95% CI, 54%-100%). Motor block duration was not correlated with bupivacaine dose (0.06 hour/mg, SE = 0.14, 95% CI, -0.27 to 0.39, P = 0.707). CONCLUSIONS: The results of this investigation suggest that deposition of a liposomal bupivacaine formulation adjacent to the femoral nerve results in a partial sensory and motor block of >24 hours for the highest doses examined. However, the high variability of block magnitude among subjects and inverse relationship of dose and response magnitude attests to the need for a phase 3 study with a far larger sample size, and that these results should be viewed as suggestive, requiring confirmation in a future trial.


Assuntos
Anestésicos Locais/administração & dosagem , Bupivacaína/administração & dosagem , Lipossomos/química , Bloqueio Nervoso/métodos , Sistema Nervoso Periférico/efeitos dos fármacos , Adulto , Estudos de Coortes , Preparações de Ação Retardada/administração & dosagem , Relação Dose-Resposta a Droga , Portadores de Fármacos , Feminino , Humanos , Masculino , Fatores de Tempo , Resultado do Tratamento
17.
Pain Med ; 14(6): 935-42, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23489466

RESUMO

BACKGROUND: There is currently no reliable treatment for phantom limb pain (PLP). Chronic PLP and associated cortical abnormalities may be maintained from abnormal peripheral input, raising the possibility that a continuous peripheral nerve block (CPNB) of extended duration may permanently reorganize cortical pain mapping, thus providing lasting relief. METHODS: Three men with below-the-knee (2) or -elbow (1) amputations and intractable PLP received femoral/sciatic or infraclavicular perineural catheter(s), respectively. Subjects were randomized in a double-masked fashion to receive perineural ropivacaine (0.5%) or normal saline for over 6 days as outpatients using portable electronic infusion pumps. Four months later, subjects returned for repeated perineural catheter insertion and received an ambulatory infusion with the alternate solution ("crossover"). Subjects were followed for up to 1 year. RESULTS: By chance, all three subjects received saline during their initial infusion and reported little change in their PLP. One subject did not receive crossover treatment, but the remaining two subjects reported complete resolution of their PLP during and immediately following treatment with ropivacaine. One subject experienced no PLP recurrence through the 52-week follow-up period and the other reported mild PLP occurring once each week of just a small fraction of his original pain (pretreatment: continuous PLP rated 10/10; posttreatment: no PLP at baseline with average of one PLP episode each week rated 2/10) for 12 weeks (lost to follow-up thereafter). CONCLUSIONS: A prolonged ambulatory CPNB may be a reliable treatment for intractable PLP. The results of this pilot study suggest that a large, randomized clinical trial is warranted.


Assuntos
Amidas/administração & dosagem , Bloqueio Nervoso/métodos , Dor Intratável/tratamento farmacológico , Membro Fantasma/tratamento farmacológico , Adulto , Anestésicos Locais/administração & dosagem , Humanos , Bombas de Infusão Implantáveis , Masculino , Ropivacaina , Resultado do Tratamento
18.
Reg Anesth Pain Med ; 38(3): 226-32, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23528646

RESUMO

BACKGROUND: Historically, the anterolateral interscalene block--deposition of local anesthetic adjacent to the brachial plexus roots/trunks--has been used for surgical procedures involving the shoulder. The resulting block frequently failed to provide surgical anesthesia of the hand and forearm, even though the brachial plexus at this level included all of the axons of the upper-extremity terminal nerves. However, it remains unknown whether deposition of local anesthetic adjacent to the seventh cervical root or inferior trunk results in anesthesia of the hand and forearm. METHODS: Using ultrasound guidance and a needle-in-plane posterior approach, a Tuohy needle was positioned with the tip located between the deepest and next-deepest visualized brachial plexus root/trunk, followed by injection of mepivacaine (1.5%). Grip strength and the tolerance to cutaneous electrical current in 5 terminal nerve distributions were measured at baseline and then every 5 minutes following injection for a total of 30 minutes. The primary end point was the proportion of cases in which the interscalene nerve block resulted in a decrease in grip strength of at least 90% and hand and forearm anesthesia (tolerance to >50 mA of current in all 5 terminal nerve distributions) within 30 minutes. The primary hypothesis was that a single-injection interscalene brachial plexus block produces a similar rate of anesthesia of the hand and forearm to the published success rate of 95% for other brachial plexus block approaches. RESULTS: Of 55 subjects with blocks placed per protocol, all had a successful block of the shoulder as defined by inability to abduct at the shoulder joint. Thirty-three subjects had measurements at 30 minutes following local anesthetic deposition, and only 5 (15%) of these subjects had a surgical block of the hand and forearm (P < 0.0001; 95% confidence interval, 6%-33%). We therefore reject the hypothesis that the interscalene block as performed in this study provides equivalent anesthesia to the hand and forearm compared with other brachial plexus block techniques. Block failures of the hand and forearm were due to inadequate cutaneous anesthesia of the ulnar (n = 27; 82%), median (n = 26; 78%), or radial (n = 22; 67%) distributions; the medial forearm (n = 25; 76%); and/or the lateral forearm (n = 14; 42%). Failure to achieve at least a 90% reduction in grip strength occurred in 16 subjects (48%). CONCLUSIONS: This study did not find evidence to support the hypothesis that local anesthetic injected adjacent to the deepest brachial plexus roots/trunks reliably results in surgical anesthesia of the hand and forearm.


Assuntos
Plexo Braquial/diagnóstico por imagem , Antebraço/cirurgia , Mãos/cirurgia , Bloqueio Nervoso/métodos , Ultrassonografia de Intervenção/métodos , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
20.
Anesth Analg ; 115(3): 721-7, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22745116

RESUMO

BACKGROUND: During a continuous femoral nerve block, the influence of catheter tip position relative to the femoral nerve on infusion characteristics remains unknown. METHODS: We inserted bilateral femoral perineural catheters in volunteers (ultrasound-guided, needle in-plane). Subjects' dominant side was randomized to have the catheter tip placed either anterior or posterior to the femoral nerve. The contralateral limb received the alternative position. Ropivacaine 0.1% was administered through both catheters concurrently for 6 hours (4 mL/h). Outcome measures included the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle and tolerance to cutaneous electrical current over to the distal quadriceps tendon. Measurements were performed at hour 0 (baseline), and on the hour until hour 9, as well as hour 22. The primary end point was the MVIC of the quadriceps at hour 6. RESULTS: As a percentage of the baseline measurement, quadriceps MVIC for limbs with anterior (n = 16) and posterior (n = 16) catheter tip placement did not differ to a statistically significant degree at hour 6 (mean [SD] 29% [26] vs 30% [28], respectively; 95% confidence interval: -22% to 20%; P = 0.931), or at any other time point. However, the maximum tolerance to cutaneous electrical current was higher in limbs with anterior compared with posterior catheter tip placement at hour 6 (20 [23] mA vs 6 [4] mA, respectively; 95% confidence interval: 1-27 mA; P = 0.035), as well as at hours 1, 7, 8, and 9 (P < 0.04). CONCLUSIONS: This study documents the significant (70%-80%) quadriceps femoris weakness induced by a continuous femoral nerve block infusion at a relatively low dose of ropivacaine (4 mg/h) delivered through a perineural catheter located both anterior and posterior to the femoral nerve. In contrast, an anterior placement increases cutaneous sensory block compared with a posterior insertion, without a concurrent relative increase in motor block.


Assuntos
Nervo Femoral/fisiologia , Debilidade Muscular/etiologia , Bloqueio Nervoso/efeitos adversos , Pele/inervação , Adulto , Cateterismo , Feminino , Humanos , Masculino , Estudos Prospectivos , Adulto Jovem
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