The effects of nitrous oxide on controlled hypotension during low flow anesthesia.

BACKGROUND AND OBJECTIVES: We investigated the effect of Nitrous Oxide (N2O) on controlled hypotension in low-flow isoflurane-dexmedetomidine anesthesia in terms of hemodynamics, anesthetic consumption, and costs. METHODS: We allocated forty patients randomly into two equal groups. We then maintained dexmedetomidine infusion (0.1 µg.kg(-1).min(-1)) for 10 minutes. Next, we continued it until the last 30 minutes of the operation at a dose of 0.7 µg.kg(-1).hour(-1). We administered thiopental (4-6 mg. kg(-1)) and 0.08-0.12 mg.kg(-1) vecuronium bromide at induction for both groups. We used isoflurane (2%) for anesthesia maintenance. Group N received a 50% O2-N2O mixture and Group A received 50% O2-air mixture as carrier gas. We started low-flow anesthesia (1L.min(-1)) after a 10-minute period of initial high flow (4.4L.min(-1)). We recorded values for blood pressure, heart rate, peripheral O2 saturation, inspiratory isoflurane, expiratory isoflurane, inspiratory O2, expiratory O2, inspiratory N2O, expiratory N2O, inspiratory CO2, CO2 concentration after expiration, Minimum Alveolar Concentration. In addition, we determined the total consumption rate of fentanyl, dexmedetomidine and isoflurane as well as bleeding. RESULTS: In each group the heart rate decreased after dexmedetomidine loading. After intubation, values were higher for Group A at one, three, five, 10, and 15 minutes. After intubation, the patients reached desired hypotension values at minute five for Group N and at minute 20 for group A. MAC values were higher for Group N at minute one, three, five, 10, and 15 (p<0.05). FiO2 values were high between minute five and 60 for Group A, while at minute 90 Group N values were higher (p<0.05). FiIso (inspiratuvar isofluran) values were lower in Group N at minute 15 and 30 (p<0.05). CONCLUSION: By using dexmedetomidine instead of nitrous oxide in low flow isoflurane anesthesia, we attained desired MAP levels, sufficient anesthesia depth, hemodynamic stability and safe inspiration parameters. Dexmedetomidine infusion with medical air-oxygen as a carrier gas represents an alternative anesthetic technique.

Efeitos do óxido nitroso em hipotensão controlada durante anestesia com baixo fluxo / The effects of nitrous oxide on controlled hypotension during low flow anesthesia / Efectos del óxido nitroso en la hipotensión controlada durante la anestesia con bajo flujo

JUSTIFICATIVA E OBJETIVOS: Investigamos o efeito do óxido nitroso (N2O) em hipotensão controlada durante anestesia com baixo fluxo (isoflurano-dexmedetomidina) em termos de hemodinâmica, consumo de anestésico e custos. MÉTODOS: Quarenta pacientes foram randomicamente alocados em dois grupos. Infusão de dexmedetomidina (0,1 µg.kg-1.min-1) foi mantida por 10 minutos. Subsequentemente, essa infusão foi mantida até os últimos 30 minutos de operação a uma dose de 0,7 µg.kg-1.hora-1. Tiopental (4-6 mg.kg-1) e brometo de vecurônio (0,08 0,12 mg.kg-1) foram administrados na indução de ambos os grupos. Isoflurano (2%) foi administrado para manutenção da anestesia. O Grupo N recebeu uma mistura de 50% de O2-N2O e o Grupo A recebeu uma mistura de 50% de O2-ar como gás de transporte. Anestesia com baixo fluxo (1 L.min-1) foi iniciada após um período de 10 minutos de alto fluxo inicial (4,4 L.min-1). Os valores de pressão arterial, frequência cardíaca, saturação periférica de O2, isoflurano inspiratório e expiratório, O2 inspiratório e expiratório, N2O inspiratório e expiratório, CO2 inspiratório, concentração de CO2 após expiração e concentração alveolar mínima foram registrados. Além disso, as taxas de consumo total de fentanil, dexmedetomidina e isoflurano, bem como de hemorragia, foram determinadas. RESULTADOS: A frequência cardíaca diminuiu em ambos os grupos após a carga de dexmedetomidina. Após a intubação, os valores do Grupo A foram maiores nos minutos um, três, cinco, 10 e 15. Após a intubação, os valores de hipotensão desejados foram alcançados em 5 minutos no Grupo N e em 20 minutos no grupo A. Os valores da CAM foram mais altos no Grupo N nos minutos um, três, cinco, 10 e 15 (p < 0,05). Os valores da FiO2 foram mais altos entre 5 e 60 minutos no Grupo A, enquanto foram mais altos no Grupo N aos 90 minutos (p < 0,05). Os valores de Fi Iso (isoflurano inspiratório) foram menores no Grupo N nos minutos 15 e 30 (p < 0,05). CONCLUSÃO: O uso de dexmedetomidina em vez de óxido nitroso em anestesia com isoflurano pela técnica de baixo fluxo atingiu os níveis desejados de pressão arterial média (PAM), profundidade suficiente da anestesia, estabilidade hemodinâmica e parâmetros de inspiração seguros. A infusão de dexmedetomidina com oxigênio-ar medicinal como gás de transporte é uma técnica anestésica opcional.

BACKGROUND AND OBJECTIVES: We investigated the effect of Nitrous Oxide (N2O) on controlled hypotension in low-flow isoflurane-dexmedetomidine anesthesia in terms of hemodynamics, anesthetic consumption, and costs. METHODS: We allocated forty patients randomly into two equal groups. We then maintained dexmedetomidine infusion (0.1 µg.kg-1.min-1) for 10 minutes. Next, we continued it until the last 30 minutes of the operation at a dose of 0.7 µg.kg-1.hour-1. We administered thiopental (4-6 mg. kg-1) and 0.08-0.12 mg.kg-1 vecuronium bromide at induction for both groups. We used isoflurane (2%) for anesthesia maintenance. Group N received a 50% O2-N2O mixture and Group A received 50% O2-air mixture as carrier gas. We started low-flow anesthesia (1 L.min-1) after a 10-minute period of initial high flow (4.4 L.min-1). We recorded values for blood pressure, heart rate, peripheral O2 saturation, inspiratory isoflurane, expiratory isoflurane, inspiratory O2, expiratory O2, inspiratory N2O, expiratory N2O, inspiratory CO2, CO2 concentration after expiration, Minimum Alveolar Concentration. In addition, we determined the total consumption rate of fentanyl, dexmedetomidine and isoflurane as well as bleeding. RESULTS: In each group the heart rate decreased after dexmedetomidine loading. After intubation, values were higher for Group A at one, three, five, 10, and 15 minutes. After intubation, the patients reached desired hypotension values at minute five for Group N and at minute 20 for group A. MAC values were higher for Group N at minute one, three, five, 10, and 15 (p < 0.05). FiO2 values were high between minute five and 60 for Group A, while at minute 90 Group N values were higher (p < 0.05). Fi Iso (inspiratuvar isofluran) values were lower in Group N at minute 15 and 30 (p < 0.05). CONCLUSION: By using dexmedetomidine instead of nitrous oxide in low flow isoflurane anesthesia, we attained desired MAP levels, sufficient anesthesia depth, hemodynamic stability and safe inspiration parameters. Dexmedetomidine infusion with medical air-oxygen as a carrier gas represents an alternative anesthetic technique.

JUSTIFICATIVA Y OBJETIVOS: Investigamos el efecto del óxido nitroso (N2O) en hipotensión controlada durante anestesia con bajo flujo (isoflurano-dexmedetomidina) en términos de hemodinámica, consumo de anestésico y costes. MÉTODOS: Cuarenta pacientes fueron aleatoriamente divididos en dos grupos iguales. La infusión de dexmedetomidina (0,1 µg.kg-1.min-1) se mantuvo entonces por 10 minutos. En secuencia, esa infusión se mantuvo hasta los últimos 30 minutos de operación en una dosis de 0,7 µg.kg-1.hour-1. El tiopental (4-6 mg.kg-1) y el bromuro de vecuronio (0,08 0,12 mg.kg-1) fueron administrados en la inducción de ambos grupos. El Isofluorano (2%) fue administrado para el mantenimiento de la anestesia. El Grupo N recibió una mezcla de un 50% de O2-N2O y el Grupo A recibió una mezcla de un 50% de O2-ar como gas de transporte. La anestesia con bajo flujo (1 L.min-1) fue iniciada después de un período de 10 minutos de alto flujo inicial (4,4 L.min-1). Se registraron los valores de la presión arterial, frecuencia cardíaca, saturación periférica de O2, isoflurano inspiratorio, isoflurano espiratorio, O2 inspiratorio, O2 espiratorio, N2O inspiratorio, N2O espiratorio, CO2 inspiratorio, concentración de CO2 después de la espiración y concentración alveolar mínima. Además, de determinaron las tasas de consumo total de fentanil, dexmedetomidina e isoflurano, como también la de hemorragia. RESULTADOS: La frecuencia cardíaca disminuyó en ambos grupos después de la carga de dexmedetomidina. Después de la intubación, los valores del Grupo A fueron mayores en los minutos 1, 3, 5, 10 y 15. Después de la intubación, los valores de hipotensión deseados se alcanzaron en 5 minutos en el Grupo N y en 20 minutos en el grupo A. Los valores de la CAM fueron más altos en el Grupo N en los minutos 1, 3, 5, 10 y 15 (p < 0,05). Los valores de la FiO2 fueron más altos entre 5 y 60 minutos en el Grupo A, mientras que fueron más altos en el Grupo N a los 90 minutos (p < 0,05). Los valores de Fi Iso (isoflurano espiratorio) fueron menores en el Grupo N en los minutos 15 y 30 (p < 0,05). CONCLUSIONES: El uso de la dexmedetomidina en vez del óxido nitroso en la anestesia con el isoflurano por la técnica de bajo flujo, alcanzó los niveles deseados de presión arterial promedio (PAP), profundidad suficiente de la anestesia, estabilidad hemodinámica y parámetros de inspiración seguros. La infusión de dexmedetomidina con oxígeno / aire medicinal como gas de transporte es una técnica anestésica opcional.

The effects of nitrous oxide on controlled hypotension during low flow anesthesia.

BACKGROUND AND OBJECTIVES: We investigated the effect of Nitrous Oxide (N2O) on controlled hypotension in low-flow isoflurane-dexmedetomidine anesthesia in terms of hemodynamics, anesthetic consumption, and costs. METHODS: We allocated forty patients randomly into two equal groups. We then maintained dexmedetomidine infusion (0.1 µg.kg-1.min-1) for 10 minutes. Next, we continued it until the last 30 minutes of the operation at a dose of 0.7 µg.kg(-1).hour(-1). We administered thiopental (4-6 mg. kg(-1)) and 0.08-0.12 mg.kg(-1) vecuronium bromide at induction for both groups. We used isoflurane (2%) for anesthesia maintenance. Group N received a 50% O2-N2O mixture and Group A received 50% O -air mixture as carrier gas. We started low-flow anesthesia (1 L.min(-1)) after a 10-minute period of initial high flow (4.4 L.min(-1)). We recorded values for blood pressure, heart rate, peripheral O2 saturation, inspiratory isoflurane, expiratory isoflurane, inspiratory O2, expiratory O2, inspiratory N2O, expiratory N2O, inspiratory CO2, CO2 concentration after expiration, Minimum Alveolar Concentration. In addition, we determined the total consumption rate of fentanyl, dexmedetomidine and isoflurane as well as bleeding. RESULTS: In each group the heart rate decreased after dexmedetomidine loading. After intubation, values were higher for Group A at one, three, five, 10, and 15 minutes. After intubation, the patients reached desired hypotension values at minute five for Group N and at minute 20 for group A. MAC values were higher for Group N at minute one, three, five, 10, and 15 (p < 0.05). FiO2 values were high between minute five and 60 for Group A, while at minute 90 Group N values were higher (p < 0.05). Fi Iso (inspiratuvar isofluran) values were lower in Group N at minute 15 and 30 (p < 0.05). CONCLUSION: By using dexmedetomidine instead of nitrous oxide in low flow isoflurane anesthesia, we attained desired MAP levels, sufficient anesthesia depth, hemodynamic stability and safe inspiration parameters. Dexmedetomidine infusion with medical air-oxygen as a carrier gas represents an alternative anesthetic technique.

Tabagismo e efeito de dexmedetomidina e fentanil na intubação traqueal / Cigarette smoking and the effect of dexmedetomidine and fentanyl on tracheal intubation / Tabaquismo y efecto de la dexmedetomidina y del fentanil en la intubación traqueal

JUSTIFICATIVA E OBJETIVOS: Comparar os efeitos de dexmedetomidina e fentanil sobre as alterações hemodinâmicas em fumantes crônicos do sexo masculino. MÉTODOS: Este é um estudo prospectivo, randômico e cego. Sessenta pacientes do sexo masculino, tabagistas crônicos, com idades entre 16 e 60 anos foram selecionados. Os pacientes foram alocados aleatoriamente em dois grupos: Grupo D (n = 30) recebeu 1 µg.kg-1 de dexmedetomidina e Grupo F (n = 30) recebeu 3 µg.kg-1 de fentanil em 150 mL de solução salina normal, com início 10 minutos antes da indução da anestesia. Antes da intubação, a frequência cardíaca e a pressão arterial dos pacientes foram medidas. Após a indução da anestesia para intubação endotraqueal, a frequência cardíaca e os valores da pressão arterial foram novamente medidos 1, 3 e 5 minutos após a intubação. RESULTADOS: A frequência cardíaca estava baixa no Grupo D antes da indução da anestesia, intubação e no primeiro e terceiro minutos pósintubação. A pressão arterial sistólica estava baixa no Grupo F antes da intubação. Embora a pressão arterial diastólica estivesse menor antes da indução da anestesia e aos 5 minutos após a intubação em ambos os grupos, ela já estava baixa no Grupo F antes mesmo da intubação. Enquanto a pressão arterial média estava baixa no Grupo D antes da indução anestésica, ela estava baixa no Grupo F antes da intubação. Os valores para o duplo produto (frequência cardíaca vezes pressão arterial sistólica) estavam baixos no Grupo D antes da indução e no 1º e 3º minutos após a intubação. CONCLUSÕES: A dexmedetomidina, aplicada em fumantes crônicos do sexo masculino via infusão a uma dose de 1 µg.kg-1 10 minutos antes de indução anestésica, controla melhor as elevações da frequência cardíaca e do duplo produto a 1 e 3 minutos após a intubação, comparado ao grupo que recebeu 3 µg.kg-1 de fentanil.

BACKGROUND AND OBJECTIVES: To compare the effect of dexmedetomidine and fentanyl on hemodynamic changes in chronic male smokers. METHODS: This is a prospective, randomized, blinded study. Were selected 60 chronic male smokers (aged 16 to 60 years). The patients were randomly divided into two groups: Group D (n = 30) received 1 µg.kg-1 dexmedetomidine and Group F (n = 30) received 3 µg.kg-1 fentanyl in 150 mL of normal saline, beginning 10 minutes before anesthesia induction. Before intubation, the heart rate and blood pressure of patients were measured. After anesthesia induction for endotracheal intubation, heart rate and blood pressure values were measured at 1, 3, and 5 minutes after intubation. RESULTS: Heart rate was low in Group D before anesthesia induction, intubation, and at the 1st and 3rd minutes after intubation. Systolic arterial pressure was low in Group F before intubation. Although diastolic arterial pressure was lower before anesthesia induction and at 5 minutes after intubation in both groups, it was already low in Group F before intubation. Whereas the mean arterial pressure was low in Group D before anesthesia induction, it was low in Group F before intubation. The values for rate-pressure product were low in Group D before induction and at 1 and 3 minutes after intubation. CONCLUSIONS: Dexmedetomidine, which was applied via infusion at a loading dose of 1 µg.kg-1 10 minutes before anesthesia induction in chronic male smokers, better suppressed increases in heart rate and rate-pressure product at 1 and 3 minutes after intubation compared to the group receiving 3 µg.kg-1 fentanyl.

JUSTIFICATIVA Y OBJETIVOS: Comparar los efectos de la dexmedetomidina y del fentanil sobre las alteraciones hemodinámicas en fumadores crónicos del sexo masculino. MÉTODOS: Este es un estudio prospectivo, randómico y ciego. Sesenta pacientes del sexo masculino, fumadores crónicos, con edades entre los 16 y los 60 años, fueron seleccionados. Los pacientes fueron divididos aleatoriamente en dos grupos: Grupo D (n = 30) recibió 1 µg.kg-1 de dexmedetomidina o 3 µg.kg-1 de fentanil, y el Grupo F (n = 30) que recibió 150 mL de solución salina normal, con inicio 10 minutos antes de la inducción de la anestesia. Antes de la intubación, se mensuraron la frecuencia cardíaca y la presión arterial de los pacientes. Después de la inducción de la anestesia para la intubación endotraqueal, la frecuencia cardíaca y los valores de la presión arterial fueron medidos uno, tres y cinco minutos después de la intubación. RESULTADOS: La frecuencia cardíaca estaba baja en el Grupo D antes de la inducción de la anestesia, de la intubación y en el primero y tercer minutos posintubación. La presión arterial sistólica estaba baja en el Grupo F antes de la intubación. Aunque la presión arterial diastólica fuese menor antes de la inducción de la anestesia y a los cinco minutos después de la intubación en ambos grupos, ella ya estaba baja en el Grupo F antes incluso de la intubación. Mientras la presión arterial promedio estaba baja en el Grupo D antes de la inducción anestésica, estaba baja también en el Grupo F antes de la intubación. Los valores para el doble producto (frecuencia cardíaca por la presión arterial sistólica), eran bajos en el Grupo D antes de la inducción y en el 1º y 3º minutos después de la intubación. CONCLUSIONES: Descubrimos pues, que la dexmedetomidina, que fue aplicada en fumadores crónicos del sexo masculino vía infusión a una dosis de 1 µg.kg-1 10 minutos antes de la inducción anestésica, controla mejor las elevaciones de la frecuencia cardíaca y del doble producto a uno y tres minutos después de la intubación, comparado al grupo que recibió 3 µg.kg-1 de fentanil.

Cigarette smoking and the effect of dexmedetomidine and fentanyl on tracheal intubation.

BACKGROUND AND OBJECTIVES: To compare the effect of dexmedetomidine and fentanyl on hemodynamic changes in chronic male smokers. METHODS: This is a prospective, randomized, blinded study. Were selected 60 chronic male smokers (aged 16 to 60 years). The patients were randomly divided into two groups: Group D (n=30) received 1µg.kg(-1) dexmedetomidine and Group F (n=30) received 3µg.kg(-1) fentanyl in 150mL of normal saline, beginning 10 minutes before anesthesia induction. Before intubation, the heart rate and blood pressure of patients were measured. After anesthesia induction for endotracheal intubation, heart rate and blood pressure values were measured at 1, 3, and 5 minutes after intubation. RESULTS: Heart rate was low in Group D before anesthesia induction, intubation, and at the 1st and 3rd minutes after intubation. Systolic arterial pressure was low in Group F before intubation. Although diastolic arterial pressure was lower before anesthesia induction and at 5 minutes after intubation in both groups, it was already low in Group F before intubation. Whereas the mean arterial pressure was low in Group D before anesthesia induction, it was low in Group F before intubation. The values for rate-pressure product were low in Group D before induction and at 1 and 3 minutes after intubation. CONCLUSIONS: Dexmedetomidine, which was applied via infusion at a loading dose of 1µg.kg(-1) 10 minutes before anesthesia induction in chronic male smokers, better suppressed increases in heart rate and rate-pressure product at 1 and 3 minutes after intubation compared to the group receiving 3µg.kg(-1) fentanyl.

The influence of various anesthesia techniques on postoperative recovery and discharge criteria among geriatric patients.

OBJECTIVE: We aim to compare selective spinal anesthesia and general anesthesia with regard to postoperative recovery and fast-track eligibility in day surgeries. MATERIALS AND METHOD: Sixty geriatric outpatient cases, with ASA II-III physical status and requiring short-duration transurethral intervention, were enrolled in the study. The cases were split into 2 groups: as general anesthesia (Group GA) and selective spinal anesthesia (Group SSA). Group GA (n = 30) received propofol 2 mg kg⁻¹ (until loss of eyelash reflex), remifentanil induction 0.5-1 µg kg⁻¹, and laryngeal mask. Maintenance was achieved by 4-6% desflurane in 60% N2O and 40% O2 along with remifentanil infusion at 0.05 µg /kg⁻¹ /min⁻¹. Drugs were discontinued after the withdrawal of the ureteroscope, and extubation was carried out with 100% O2. Group SSA (n = 30) received 0.5% spinal anesthesia via L4-5 space by 0.5% hyperbaric bupivacaine 5 mg. Anesthesia preparation time, time to surgical anesthesia level, postoperative fast-tracking, and time to White-Song recovery score of 12, were noted. In the operating room, we evaluated hemodynamics, nausea/vomiting, surgeon and patient satisfaction with anesthesia, perioperative midazolam-fentanyl administration, postoperative pain, and discharge time. RESULTS: Anesthesia preparation time, length of surgery, anesthesia-related time in the operating room, time to sit, and time to walk were significantly low in Group GA (p < 0.05), whereas time to fast-track eligibility, length of stay in the PACU, discharge time, and other parameters were similar in both of the groups. CONCLUSION: While anesthesia preparation time, length of surgery, start time of surgery, time to sit, and time to walk were shorter in the General Anesthesia group, time to fast-track eligibility, phase 1 recovery time, and discharge time were similar among patients subjected to selective spinal anesthesia.

The influence of various anesthesia techniques on postoperative recovery and discharge criteria among geriatric patients

OBJECTIVE: We aim to compare selective spinal anesthesia and general anesthesia with regard to postoperative recovery and fast-track eligibility in day surgeries. MATERIALS AND METHOD: Sixty geriatric outpatient cases, with ASA II-III physical status and requiring shortduration transurethral intervention, were enrolled in the study. The cases were split into 2 groups: as general anesthesia (Group GA) and selective spinal anesthesia (Group SSA). Group GA (n = 30) received propofol 2 mg kg-1 (until loss of eyelash reflex), remifentanil induction 0.5-1 µg kg-1, and laryngeal mask. Maintenance was achieved by 4-6 percent desflurane in 60 percent N2O and 40 percent O2 along with remifentanil infusion at 0.05 µg /kg-1 /min-1. Drugs were discontinued after the withdrawal of the ureteroscope, and extubation was carried out with 100 percent O2. Group SSA (n = 30) received 0.5 percent spinal anesthesia via L4-5 space by 0.5 percent hyperbaric bupivacaine 5 mg. Anesthesia preparation time, time to surgical anesthesia level, postoperative fast-tracking, and time to White-Song recovery score of 12, were noted. In the operating room, we evaluated hemodynamics, nausea/vomiting, surgeon and patient satisfaction with anesthesia, perioperative midazolam-fentanyl administration, postoperative pain, and discharge time. RESULTS: Anesthesia preparation time, length of surgery, anesthesia-related time in the operating room, time to sit, and time to walk were significantly low in Group GA (p < 0.05), whereas time to fast-track eligibility, length of stay in the PACU, discharge time, and other parameters were similar in both of the groups. CONCLUSION: While anesthesia preparation time, length of surgery, start time of surgery, time to sit, and time to walk were shorter in the General Anesthesia group, time to fast-track eligibility, phase 1 recovery time, and discharge time were similar among patients subjected to selective spinal anesthesia.