Barçın Semiha, Sahan Leyla, Ornek Dilsen, Sahin Fazilet, Kilci Oya, Deren Serpil, Erdogan Gulay, Un Canan, Gamli Mehmet, Dikmen Bayazit
Anaesthesia and Reanimation Department, Ankara Numune Training and Research Hospital, Ankara, Turkey.
Braz J Anesthesiol. 2013 Mar-Apr;63(2):170-7. doi: 10.1016/S0034-7094(13)70210-1.
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.
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.
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).
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.
我们从血流动力学、麻醉药物消耗及成本方面，研究了氧化亚氮（N₂O）对低流量异氟烷-右美托咪定麻醉中控制性低血压的影响。
我们将40例患者随机分为两组，每组20例。先持续输注右美托咪定（0.1μg·kg⁻¹·min⁻¹）10分钟，然后以0.7μg·kg⁻¹·小时⁻¹的剂量持续输注至手术最后30分钟。两组患者诱导时均给予硫喷妥钠（4 - 6mg·kg⁻¹）和0.08 - 0.12mg·kg⁻¹维库溴铵。采用异氟烷（2%）维持麻醉。N组给予50%O₂ - N₂O混合气体，A组给予50%O₂ - 空气混合气体作为载气。初始高流量（4.4L·min⁻¹）10分钟后开始低流量麻醉（1L·min⁻¹）。记录血压、心率、外周血氧饱和度、吸入异氟烷、呼出异氟烷、吸入O₂、呼出O₂、吸入N₂O、呼出N₂O、吸入CO₂、呼气末CO₂浓度、最低肺泡浓度。此外，还测定了芬太尼、右美托咪定和异氟烷的总消耗率以及出血量。
每组在输注右美托咪定负荷量后心率均下降。插管后，A组在第1、3、5、10和15分钟时的值较高。插管后，N组在第5分钟达到预期低血压值，A组在第20分钟达到。N组在第1、3、5、10和15分钟时的MAC值较高（p<0.05）。A组在第5至60分钟时的FiO₂值较高，而在第90分钟时N组的值较高（p<0.05）。N组在第15和30分钟时的FiIso（吸入异氟烷）值较低（p<0.05）。
在低流量异氟烷麻醉中使用右美托咪定替代氧化亚氮，我们达到了预期的平均动脉压水平、足够的麻醉深度、血流动力学稳定性和安全的吸入参数。以医用空气-氧气作为载气输注右美托咪定代表了一种替代麻醉技术。
