Background

The MIRUS™ (TIM, Koblenz, Germany) is an electronical gas delivery system, which offers an automated MAC (minimal alveolar concentration)-driven application of isoflurane, sevoflurane, or desflurane, and can be used for sedation in the intensive care unit. We investigated its consumption of volatile anesthetics at 0.5 MAC (primary endpoint) and the corresponding costs. Secondary endpoints were the technical feasibility to reach and control the MAC automatically, the depth of sedation at 0.5 MAC, and awakening times. Mechanically ventilated and sedated patients after major surgery were enrolled. Upon arrival in the intensive care unit, patients obtained intravenous propofol sedation for at least 1 h to collect ventilation and blood gas parameters, before they were switched to inhalational sedation using MIRUS™ with isoflurane, sevoflurane, or desflurane. After a minimum of 2 h, inhalational sedation was stopped, and awakening times were recorded. A multivariate electroencephalogram and the Richmond Agitation Sedation Scale (RASS) were used to assess the depth of sedation. Vital signs, ventilation parameters, gas consumption, MAC, and expiratory gas concentrations were continuously recorded.

Results

Thirty patients obtained inhalational sedation for 18:08 [14:46–21:34] [median 1st–3rd quartiles] hours. The MAC was 0.58 [0.50–0.64], resulting in a Narcotrend Index of 37.1 [30.9–42.4] and a RASS of − 3.0 [− 4.0 to (− 3.0)]. The median gas consumption was significantly lowest for isoflurane ([ml h⁻¹]: isoflurane: 3.97 [3.61–5.70]; sevoflurane: 8.91 [6.32–13.76]; and desflurane: 25.88 [20.38–30.82]; p < 0.001). This corresponds to average costs of 0.39 € h⁻¹ for isoflurane, 2.14 € h⁻¹ for sevoflurane, and 7.54 € h⁻¹ for desflurane. Awakening times (eye opening [min]: isoflurane: 9:48 [4:15–20:18]; sevoflurane: 3:45 [0:30–6:30]; desflurane: 2:00 [1:00–6:30]; p = 0.043) and time to extubation ([min]: isoflurane: 10:10 [8:00–20:30]; sevoflurane: 7:30 [4:37–14:22]; desflurane: 3:00 [3:00–6:00]; p = 0.007) were significantly shortest for desflurane.

Conclusions

A target-controlled, MAC-driven automated application of volatile anesthetics is technically feasible and enables an adequate depth of sedation. Gas consumption was highest for desflurane, which is also the most expensive volatile anesthetic. Although awakening times were shortest, the actual time saving of a few minutes might be negligible for most patients in the intensive care unit. Thus, using desflurane seems not rational from an economic perspective.Trial registration Clinical Trials Registry (ref.: NCT03860129). Registered 24 September 2018—Retrospectively registered.

中文翻译：

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MIRUS™在术后ICU患者中由MAC驱动的异氟醚，七氟醚和地氟烷的应用的随机对照试验

背景

MIRUS™（TIM，德国科布伦茨）是一种电子气体输送系统，可自动驱动异氟醚，七氟醚或地氟醚的MAC（最低肺泡浓度）驱动应用，并可用于重症监护室中的镇静作用。我们调查了其在0.5 MAC（主要终点）下的挥发性麻醉剂消耗量以及相应的成本。次要终点是自动达到和控制MAC的技术可行性，0.5 MAC时的镇静深度和唤醒时间。纳入大手术后机械通气和镇静的患者。到达重症监护室后，患者在使用MIRUS™和异氟烷，七氟醚，或地氟醚。至少2小时后，停止吸入镇静剂，并记录唤醒时间。多元脑电图和里士满躁动镇静量表（RASS）用于评估镇静深度。连续记录生命体征，通气参数，气体消耗，MAC和呼气浓度。

结果

30例患者在18:08 [14：46–21：34] [中位数1至3四分位数]小时内吸入了镇静剂。MAC为0.58 [0.50-0.64]，因此Narcotrend指数为37.1 [30.9-42.4]，RASS为− 3.0 [-4.0至（-3.0）]。异氟烷的平均气体消耗量最低（[ml h ^-1 ]：异氟烷：3.97 [3.61-5.70]；七氟醚：8.91 [6.32-13.76]；地氟烷：25.88 [20.38-30.82]；p  <0.001）。这相当于0.39€H平均成本^-1异氟醚，2.14€^ h ^-1七氟醚和7.54€^ h ^-1地氟烷。唤醒时间（睁眼[min]：异氟醚：9：48 [4：15–20：18]；七氟醚：3：45 [0：30–6：30]；地氟醚：2：00 [1：00–6] ：30]; p = 0.043）和拔管时间（[分钟]：异氟烷：10：10 [8：00–20：30]；七氟醚：7：30 [4：37–14：22]；地氟醚：3：00 [3： 00–6：00]；p  = 0.007）对于地氟醚而言最短。

结论

目标控制的，由MAC驱动的挥发性麻醉剂的自动化应用在技术上是可行的，并具有足够的镇静作用。地氟醚的气体消耗最高，这也是最昂贵的挥发性麻醉剂。尽管唤醒时间最短，但对于重症监护病房的大多数患者而言，实际节省的几分钟时间可能微不足道。因此，从经济角度看，使用地氟醚似乎是不合理的。试验注册临床试验注册（ref .: NCT03860129）。已注册，2018年9月24日-追溯注册。