Hobbhahn J, Funk W
Klinik für Anästhesiologie, Universität Regensburg.
Anaesthesist. 1996 Feb;45 Suppl 1:S22-7.
Sevoflurane may be an interesting substance for paediatric anaesthesia due to its combination of a very low blood-gas partition coefficient and non-pungency. This review discusses the status of sevoflurane in paediatric anaesthesia on the basis of studies published so far. The blood-gas partition coefficient of sevoflurane in children is 0.66, and hence markedly lower than those of isoflurane (1.25) and halothane (2.26) [15]. Induction of anaesthesia with sevoflurane/N2O is slightly shorter compared to halothane/N2O (Table 1) [4]. During induction of anaesthesia, sevoflurane/O2 is more often associated with excitement (35%) than sevoflurane/N2O (5%) and halothane/N2O (5%) [25]. Seizure-like movements in one case [1] and electrically generalised but clinically silent seizure activity in two cases [12] may raise the question of seizure-inducing effects of sevoflurane. However, up to now there is no clinical evidence of epileptogenic effects of sevoflurane. The MAC50 in neonates and infants 1-6 months of age is 3.3 vol% [14]; in infants 6-12 months and children 1-12 years of age it is 2.5 vol.% [14]. Sixty per cent N2O decreases the MAC50 of sevoflurane and desflurane by only 20%-25% [3, 14]. In contrast, 60% N2O decreases the MAC50 of halothane in children by 60% [16]. Thus, the MAC-reducing effect of N2O in children appears to be attenuated in the presence of less soluble inhalation anaesthetics. Sevoflurane has a similar low incidence of airway irritation as halothane and provides a smooth induction (Fig. 2) [4]. Haemodynamics during sevoflurane anaesthesia may be somewhat more stable compared to halothane. Serum fluoride levels increase rapidly when sevoflurane is administered, but decrease shortly after discontinuation [4]. Mean maximum levels reported are about 20 mumol/l and are of no concern for renal function. A study with mivacurium indicates more pronounced muscle relaxation by sevoflurane compared to halothane [9]. Sevoflurane may induce malignant hyperthermia. Emergence from sevoflurane anaesthesia is significantly more rapid than after halothane anaesthesia (Table 1); however, it is associated with more restlessness and agitation, probably due to the earlier perception of pain [4]. The incidence of postoperative nausea and vomiting after sevoflurane anaesthesia is comparable to that after halothane (Table 2). Sevoflurane may be a user-friendly alternative to halothane and is more preferred by children than halothane [32]. The status of sevoflurane in paediatric anaesthesia will depend on several factors: its own benefit/risk-ratio, a possible re-evaluation of the known risks of halothane and the financial limitations of the hospitals.
由于七氟烷具有极低的血气分配系数且无刺激性,它可能是用于小儿麻醉的一种有吸引力的药物。本综述基于目前已发表的研究,讨论七氟烷在小儿麻醉中的应用现状。七氟烷在儿童中的血气分配系数为0.66,因此明显低于异氟烷(1.25)和氟烷(2.26)[15]。与氟烷/N₂O相比,七氟烷/N₂O诱导麻醉的时间略短(表1)[4]。在麻醉诱导过程中,七氟烷/O₂比七氟烷/N₂O(5%)和氟烷/N₂O(5%)更常伴有兴奋(35%)[25]。1例出现癫痫样运动[1],2例出现电全身性但临床无症状的癫痫活动[12],这可能会引发七氟烷是否具有致癫痫作用的问题。然而,到目前为止,尚无七氟烷有致癫痫作用的临床证据。新生儿及1 - 6个月婴儿的七氟烷半数有效肺泡浓度(MAC50)为3.3体积%[14];6 - 12个月婴儿及1 - 12岁儿童为2.5体积%[14]。吸入60%的N₂O仅使七氟烷和地氟烷的MAC50降低20% - 25%[3, 14]。相比之下,吸入60%的N₂O可使儿童氟烷的MAC50降低60%[1十六条]。因此,在存在溶解度较低的吸入性麻醉药时,N₂O对儿童MAC的降低作用似乎减弱。七氟烷引起气道刺激的发生率与氟烷相似,且诱导过程平稳(图2)[4]。与氟烷相比,七氟烷麻醉期间的血流动力学可能更稳定。给予七氟烷后血清氟离子水平迅速升高,但停药后很快下降[4]。报告的平均最高水平约为20μmol/L,对肾功能无影响。一项关于米库氯铵的研究表明,与氟烷相比,七氟烷引起的肌肉松弛更明显[9]。七氟烷可能诱发恶性高热。七氟烷麻醉后的苏醒明显比氟烷麻醉后快(表1);然而,这与更多的烦躁不安有关,可能是由于更早感觉到疼痛[4]。七氟烷麻醉后术后恶心呕吐的发生率与氟烷相当(表2)。七氟烷可能是氟烷的一种使用方便的替代药物,并比氟烷更受儿童青睐[32]。七氟烷在小儿麻醉中的应用现状将取决于几个因素:其自身的效益/风险比、对氟烷已知风险的可能重新评估以及医院的经济限制因素。