Albera R, Ferrero V, Canale A, De Siena L, Pallavicino F, Poli L
Department of Clinical Physiopathology, II Chair of ENT, University of Turin, Turin, Italy.
Acta Otolaryngol. 2003 Sep;123(7):812-6. doi: 10.1080/00016480310002230.
Because it is necessary to maintain controlled hypotension during middle ear surgery in order to avoid bleeding and as it is known that cochlear blood flow (CBF) is related to blood pressure (BP), it is useful to evaluate CBF modifications induced by anaesthetics in order to prevent cochlear damage. The aim of this paper is to evaluate, using laser Doppler flowmetry, which anaesthetic drug, out of sevoflurane and propofol, has the smallest effect on CBF.
Twenty consenting adult patients scheduled for myringoplasty under general anaesthesia for simple tympanic membrane perforation were studied. Patients were divided into two groups: the first group was treated with sevoflurane and the second with propofol. For the first group, CBF measurement was carried out on three different occasions: (i) at a basal low drug dosage; (ii) having increased the drug dosage to a higher level; and (iii) having reduced the drug dosage to the basal low level again. For the second group, CBF measurement was carried out on three different occasions: (i) 10 min after injecting a bolus of propofol; (ii) immediately after a second propofol injection; and (iii) 10 min after a third injection of propofol. A probe was placed over the promontory in order to measure CBF levels.
In the subjects treated with sevoflurane, after having increased the drug dosage, BP decreased significantly while CBF did not change significantly. In the subjects treated with propofol we recorded a significant reduction in BP, as well as a decrease in CBF.
The results obtained show that sevoflurane has a hypotensive effect without modifying CBF, while propofol, although having a similar effect on BP to sevoflurane, has less of a protective effect on inner ear microcirculation.
由于中耳手术期间有必要维持控制性低血压以避免出血，且已知耳蜗血流量（CBF）与血压（BP）相关，因此评估麻醉剂引起的CBF变化对于预防耳蜗损伤很有用。本文的目的是使用激光多普勒血流仪评估七氟醚和丙泊酚这两种麻醉药物中哪一种对CBF的影响最小。
研究了20例因单纯鼓膜穿孔计划在全身麻醉下行鼓膜成形术的成年患者。患者分为两组：第一组用七氟醚治疗，第二组用丙泊酚治疗。对于第一组，在三种不同情况下进行CBF测量：（i）基础低药物剂量时；（ii）将药物剂量增加到更高水平时；（iii）再次将药物剂量降低到基础低水平时。对于第二组，在三种不同情况下进行CBF测量：（i）注射一剂丙泊酚后10分钟；（ii）第二次注射丙泊酚后立即测量；（iii）第三次注射丙泊酚后10分钟。将探头置于岬部上方以测量CBF水平。
在使用七氟醚治疗的受试者中，增加药物剂量后，血压显著下降，而CBF没有显著变化。在使用丙泊酚治疗的受试者中，我们记录到血压显著降低，同时CBF也降低。
所得结果表明，七氟醚具有降压作用而不改变CBF，而丙泊酚虽然对血压的影响与七氟醚相似，但对内耳微循环的保护作用较小。
