Inducción con propofol: infusión controlada por objetivo o manual. Un estudio observacional / Manual vs. target-controlled infusion induction with propofol: An observational study

Background: Target-controlled infusion (TCI) systems allow the administration of drug to achieve a target blood or site-effect concentration. We determine induction and recovery times and the amount of drug used with TCI systems vs. manual induction. Objective: To determine whether the induction of propofol TCI and manual infusion are two comparable techniques. Methods: A retrospective observational study was conducted in which sixty-two ASA I-II patients scheduled for elective surgery received induction using TCI or manually. Anaesthetic induction was achieved with remifentanil (0.25 μg/kg/min) and propofol (manual bolus injection: 2 mg/kg, or target blood concentration: 5 μg/ml with the TCI system [Marsh model]) with maintenance doses of remifentanil (0.15 μg/kg/min) and propofol (manually 0.10 mg/kg/min or 2.5-4 μg/ml using the TCI system). In both groups, rocuronium bromide was used (induction and maintenance doses: 0.6 and 0.3 mg/kg, respectively) as was morphine (0.1 mg/kg) 45 min before the end of the surgery. We measured: induction, operative and recovery mean times; bispectral index, heart rate, blood pressure, costs, haemodynamic instability, and intraoperative awareness. A telephone questionnaire was administered 1 month later. Results: The mean induction time was longer in the TCI than the manual group (1.76 ± 0.94 vs. 0.9 ±0.4 min; p < 0.001), but the total dose of propofol (TCI: 112.4 ±60.9 vs. manual: 133.8 ± 80.3 ml, p = 0.241) tended to be smaller and the recovery time was significantly shorter (TCI: 7.48 ±3.1 vs. manual: 10.3 ± 4.9 min) (p = 0.008). Condusions: Induction with propofol using TCI is similar to manually delivered propofol.

Antecedentes: los sistemas de infusión controlada por objetivo (TCI) permiten la administración de fármacos para lograr una concentración en sangre de destino o sitio-efecto. Determinamos los tiempos de inducción y recuperación y la cantidad de fármacos que se usa con los sistemas TCI vs inducción manual. Objetivo: comprobar si la inducción de propofol en TCI y la infusión manual son dos técnicas comparables. Métodos: Estudio observacional retrospectivo en el que sesenta y dos pacientes ASA I-II programados para cirugía electiva recibieron inducción manualmente o usando TCI. La inducción de anestesia se logró con remifentanilo (0,25 μg/kg/min) y propofol (inyección de bolo Manual: 2 mg/kg, o concentración en sangre: 5 μg/ml con el sistema TCI [modelo de Marsh]) con dosis de mantenimiento de remifentanilo (0,15 μg/kg/min) y propofol (0,10 manualmente mg/kg/min o 2.5-1 μg/ml utilizando el sistema de TCI). En ambos grupos, se utilizó bromuro de rocuronio (dosis de inducción y mantenimiento: 0,6 y 0,3 mg/kg, respectivamente) así como la morfina (0,1 mg/kg) 45 minutos antes del final de la cirugía. Medimos: tiempos medios de inducción, mantenimiento y de recuperación; índice biespectral, la frecuencia cardíaca, la presión arterial, los costes, la inestabilidad hemodinámica y el despertar intraoperatorio. Un cuestionario telefónico se administró 1 mes después. Resultados: La media de tiempo de inducción fue mayor en el grupo TCI que en el grupo manual (1,76 ±0,94 vs. 0,9 ±0,4 min; p< 0,001), pero la dosis total de propofol (TCI: 112,4 ±60,9 vs Manual: 133,8 ± 80,3 ml, p = 0,241) tendía a ser más pequeña y el tiempo de recuperación fue significativamente más corto (TCI: 7,48 ±3,1 vs. manual de: 10,3 ± 4,9 min) (p = 0,008) en el grupo TCI. Conclusiones: inducción de propofol en TCI es comparable a la infusión manual.

Cost-effectiveness analysis of levobupivacaine 0.5 %, a local anesthetic, infusion in the surgical wound after modified radical mastectomy.

BACKGROUND AND OBJECTIVE: Effective treatment of postoperative pain contributes to decreasing the rate of complications as well as the total cost of the operated patients. The aim of this study was to analyze the costs and the efficiency of use of continuous infusion of levobupivacaine 0.5 % with the help of an infusion pump in modified radical mastectomy. METHODS: A cost calculation of the analgesic procedures (continuous infusion of levobupivacaine 0.5 % [levobupivacaine group (LG)] or saline [saline group (SG)] (2 ml/h 48 h) has been carried out based on the data of a previous clinical trial (double-blind randomized study) of patients who underwent modified radical mastectomy surgery. The measure of the effectiveness was the point reduction of pain derived from the verbal numeric rating scale (VNRS). The usual incremental cost-effectiveness ratio (ICER) was performed. RESULTS: Considering only the intravenous analgesia, overall costs were lower in LG, as less analgesia was used (EUR14.06 ± 7.89 vs. 27.47 ± 14.79; p < 0.001). In this study the costs of the infusion pump were not calculated as it was used by both groups and they offset each other. However, if the infusion pump costs were included, costs would be higher in the LG, (EUR91.89 ± 7.89 vs. 27.47 ± 14.79; p < 0.001) and then the ICER was -8.51, meaning that for every extra point of decrease in the pain verbal numerical rating score over the 2-day period, the cost increased by EUR8.51. CONCLUSION: Infiltration of local anesthetics is an effective technique for controlling postoperative pain and the associated added costs are relatively low in relation to the total cost of mastectomy, therefore providing patients with a higher quality of care in the prevention of pain. CLINICAL TRIALS REGISTRATION: clinicaltrials.gov: reference number NCT01389934. http://clinicaltrials.gov/show/NCT01389934

Postoperative analgesia by infusion of local anesthetic into the surgical wound after modified radical mastectomy: a randomized clinical trial.

BACKGROUND: There is no consensus on the efficacy of postoperative infusion of local anesthetics after radical mastectomy. METHODS: A randomized, double-blind, placebo-controlled, parallel-groups clinical trial was conducted in a tertiary hospital. Eighty consecutive women with operable breast cancer with indications for modified radical mastectomy without breast reconstruction were assigned randomly to receive infusion of levobupivacaine (0.5%) or saline at 2 ml/hour for 48 hours through a wound catheter. Seventy-three women finished the study (intervention group, n = 34; control group, n = 39). During surgery, all patients received 0.25% levobupivacaine (30 ml). RESULTS: The levobupivacaine group reported less pain (p < 0.001) than controls in the postanesthesia care unit (1.6 ± 1.3 versus 6.7 ± 1.8) and on the ward at 24 (0.8 ± 0.9 versus 4.2 ± 1.9) and 48 (0.4 ± 0.7 versus 3.3 ± 2.3) hours. In the postanesthesia care unit, the levobupivacaine group consumed less metamizole (0.4 ± 0.5 versus 0.8 ± 0.4; p < 0.001) and dexketoprofen (0.1 ± 0.3 versus 0.7 ± 0.4; p < 0.001), with differences in paracetamol use being insignificant (0.8 ± 0.4 versus 0.9 ± 0.3; p = 0.140). On the ward, the levobupivacaine group used significantly less paracetamol (0.5 ± 0.7 versus 2.0 ± 2.0; p < 0.001) and metamizole (0.2 ± 0.4 versus 1.2 ± 1.4; p < 0.001), but differences in dexketoprofen were not significant (0.03 ± 0.2 versus 0.2 ± 0.6; p = 0.074). In the postanesthesia care unit, the levobupivacaine and control groups consumed 0 ± 0 and 0.7 ± 1.2 doses of opioids (p = 0.001), respectively. The authors observed no differences in nausea and vomiting at any stage in the postanesthesia care unit (0.2 ± 0.4 versus 0.4 ± 0.5; p = 0.081) or on the ward (0.3 ± 0.5 versus 0.4 ± 0.5; p = 0.563). All participants reported high levels of satisfaction. CONCLUSION: Continuous infusion of local anesthetic reduces pain and analgesic consumption, with high satisfaction, but does not affect rates of nausea and vomiting.