RESUMEN
BACKGROUND: The alpha agonist dexmedetomidine, a sedative and analgesic, reduces heart rate and blood pressure dose-dependently. We investigated whether it also has the ability to attenuate airway and circulatory reflexes during emergence from anaesthesia. METHODS: Sixty ASA I-III patients received a standard anaesthetic. Five minutes before the end of surgery, they were randomly allocated to receive either dexmedetomidine 0.5 microg/kg (Group D) (n=30) or saline placebo (Group P) (n=30) intravenously (i.v.) over 60 s in a double-blind design. The blinded anaesthetist awoke all the patients, and the number of coughs per patient was continuously monitored for 15 min after extubation; coughing was evaluated on a 4-point scale. Any laryngospasm, bronchospasm or desaturation was recorded. Heart rate (HR) and systolic and diastolic blood pressure (SAP, DAP) were measured before, during and after tracheal extubation. The time from tracheal extubation and emergence from anaesthesia were recorded. RESULTS: Median coughing scores were 1 (1-3) in Group D and 2 (1-4) in Group P (P<0.05), but there were no differences between the groups in the incidence of breath holding or desaturation. HR, SAP and DAP increased at extubation in both groups (P<0.05), but the increase was less significant with dexmedetomidine. The time from tracheal extubation and emergence from anaesthesia were similar in both groups. CONCLUSION: These findings suggest that a single-dose bolus injection of dexmedetomidine before tracheal extubation attenuates airway-circulatory reflexes during extubation.
Asunto(s)
Analgésicos no Narcóticos/farmacología , Dexmedetomidina/farmacología , Hemodinámica/efectos de los fármacos , Intubación Intratraqueal/métodos , Reflejo/efectos de los fármacos , Mecánica Respiratoria/efectos de los fármacos , Anciano , Análisis de Varianza , Periodo de Recuperación de la Anestesia , Presión Sanguínea/efectos de los fármacos , Tos/fisiopatología , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Cloruro de Sodio , Factores de TiempoRESUMEN
BACKGROUND AND OBJECTIVE: The aim of this study was to determine the duration of onset and regression time of sensory and motor blocks, the quality of anaesthesia and postoperative analgesia by the addition of dexmedetomidine to local anaesthetic solution in intravenous regional anaesthesia (IVRA). METHODS: Forty patients scheduled for elective hand surgery participated in this prospective randomized double-blind study. The IVRA was achieved using 3 mg kg(-1) lidocaine diluted with saline to a total volume of 40 mL in the control group or 1 microg kg(-1) of dexmedetomidine + 3 mg kg(-1) lidocaine diluted with saline to a total volume of 40 mL in the dexmedetomidine group. The onset and regression times for sensory and motor blocks were recorded. Qualities of anaesthesia, intraoperative and postoperative analgesic requirements were noted. RESULTS: There was no difference between the groups with respect to sensory and motor blocks onset and regression time. The quality of anaesthesia was better in the dexmedetomidine group than the control group and the difference was statistically significant. Intraoperative and postoperative analgesic requirements were greater in the control group than in the dexmedetomidine group. CONCLUSIONS: Addition of dexmedetomidine to local anaesthetic solution in IVRA improved the quality of anaesthesia and decreased analgesic requirements, but had no effect on the sensory and motor blocks onset and regression times.