ABSTRACT
BACKGROUND: The efficacy and safety of intrathecal magnesium as analgesic adjuvant has been tested by several clinical trials in recent years. We performed a meta-analysis of the available literature. METHODS: Randomized clinical trials comparing a 50 to 100 mg dose of intrathecal magnesium sulfate versus placebo in addition to an intrathecal local anesthetic and/or opiate for a below-umbilicus procedure were included. Medline, LILACS, Cochrane Library and Google Scholar databases were searched. A random analysis was performed and heterogeneity was tested for. The size of the effect for quantitative outcomes was calculated as standard mean difference (SMD, neutral=0); and as odds ratio (OR, neutral=1) for dichotomous outcomes. RESULTS: Twelve studies totaling 817 patients were included. The "time to first analgesia request" was at least 35 minutes longer when intrathecal magnesium was included in the intervention (SDM 0.94, 95%CI 0.51 to 1.37, P<0.001). The "onset time to sensory block" (SDM 0.64, 95%CI 0.15 to 1.12, P=0.01) and the "time to maximal motor block" (SDM 0.97, 95%CI 0.28 to 1.67, P=0.006) were 2.4 minutes slower with intrathecal magnesium. There was no difference in "time to full motor recovery, incidence of pruritus, postoperative nausea and vomiting, bradicardia, low blood pressure and urinary retention". No cases of respiratory depression or neurotoxicity were recorded in these studies. CONCLUSION: The inclusion of 50 to 100 mg of intrathecal magnesium in a spinal anesthetic prolongs opiate analgesia duration; no safety concerns have been identified by the included clinical studies but additional evidence is advised.
Subject(s)
Analgesics/administration & dosage , Anesthesia, Spinal/methods , Magnesium Compounds/administration & dosage , Adjuvants, Anesthesia/administration & dosage , Anesthetics/administration & dosage , Humans , Injections, Spinal , Randomized Controlled Trials as TopicABSTRACT
Objetivo: Existen estudios en animales con cáncer de mama y estudios retrospectivos en humanos que sugieren una reducción de riesgo de metástasis tras realizar una anestesia regional en la cirugía de mama. Hemos estudiado si la realización de bloqueo paravertebral torácico (BPVT) asociado a una anestesia general comparado con una anestesia general sin BPVT reduce la incidencia de metástasis a corto plazo en las pacientes sometidas a cirugía oncológica de mama. Métodos: Se recogieron retrospectivamente 138 pacientes sometidas a cirugía de mama (bien cirugía conservadora, o bien mastectomía, en ambos casos con o sin linfadenectomía) en el periodo entre enero de 2008 hasta junio de 2009. Se consideraron las siguientes variables: edad, peso, antecedentes personales, tipo de tumor, grado histológico, TNM, índice de Nottingham, si recibió o no terapia sistémica, tipo de cirugía, tipo de anestesia, metástasis a 6 meses y a 12 meses, y la supervivencia libre de enfermedad. Resultados: En 40 pacientes se practicó un BPVT más anestesia general, y en 98 anestesia general solamente. En cuanto al grado histológico, clasificación TNM, índice de Nottingham y terapia sistémica no presentaban diferencias entre los dos grupos. La aparición de metástasis a 6 meses fue de 2,5% en el grupo de anestesia con BPVT y de un 6,1% en el grupo de anestesia general (p = 0,673), y a 12 meses, un 2,5% en el grupo de anestesia general con BPVT, y un 9,2% en el de anestesia general (p = 0,281). El consumo intraoperatorio de fentanilo y remifentanilo y de analgesia postoperatoria fue mayor en el grupo con anestesia general. Conclusiones: En este estudio retrospectivo el porcentaje de metástasis fue menor tanto a 6 como a 12 meses en las pacientes en las que se realizó un bloqueo paravertebral con respecto a las que se realizó anestesia general exclusivamente, sin que la diferencia fuera estadísticamente significativa(AU)
Objectives: A reduction in risk of metastasis after performing regional anesthesia in breast surgery has been suggested in both animal studies and retrospectives human studies with breast cancer. We studied whether thoracic paravertebral block (TPVB) associated with general anesthesia compared with general anesthesia reduces the metastases incidence in short term in patients undergoing breast cancer surgery. Methods: 138 patients undergoing breast surgery (either conservative breast surgery or mastectomy, both of them with or without lymphadenectomy) were retrospectively examined between January 2008 and June 2009. The following variables were recorded: age, weight, medical history, type of tumor, histological grade, TNM, Nottingham Index, adjuvant therapy, type of surgery, type of anesthesia, metastasis at 6 and 12 months and disease-free survival. Results: In 40 patients a TPVB combined with general anesthesia were performed, and 98 patients had general anesthesia alone. There were no differences in histological grade, TNM classification, Nottingham index and adjuvant therapy between the two groups. Metastasis at 6 months was 2.5% in the group of anesthesia combined with TPVB and 6.1% in the General Anesthesia group (p = 0.673). At 12 months was 2.5% and 9.2%, respectively (p = 0.281). The intraoperative consumption of fentanyl and remifentanil and postoperative analgesia requirements were higher in the group with general anesthesia. Conclusions: In this retrospective study, the rate of metastasis was lower at both 6 and 12 months in patients who underwent the paravertebral block combined with general anesthesia compared to general anesthesia. However, differences between both groups were not found to be significant(AU)
