Jia L, Cepurna W O, Johnson E C, Morrison J C
Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health Sciences University, Portland 97201, USA.
Invest Ophthalmol Vis Sci. 2000 Oct;41(11):3415-9.
To determine the effect of several common general anesthetics on intraocular pressure (IOP) after experimental aqueous outflow obstruction in the rat.
A single episcleral vein injection of hypertonic saline was used to sclerose aqueous humor outflow pathways and produce elevated IOP in Brown Norway rats. Animals were housed in either standard lighting or a constant low-level light environment. Awake IOPs were determined using a TonoPen (Mentor, Norwell, MA) immediately before induction of anesthesia by either isoflurane, ketamine, or a mixture of injectable anesthetics (xylazine, ketamine, and acepromazine). For each anesthetic, IOPs were measured immediately after adequate sedation (time 0) and at 5-minute intervals, up to 20 minutes. RESULTS; Awake IOPs ranged from 18 to 52 mm Hg. All anesthetics resulted in a statistically significant (P: < 0.01) reduction in measured IOP at every duration of anesthesia when compared with the corresponding awake IOP. With increasing duration of anesthesia, measured IOP decreased approximately linearly for both the anesthetic mixture and isoflurane. However, with ketamine, IOP declined to 48% +/- 11% (standard lighting) and 60% +/- 7% (constant light) of awake levels at 5 minutes of anesthesia, where it remained stable. In fellow eyes, the SD of the mean IOP in animals under anesthesia was always greater than the corresponding SD of the awake mean. Anesthesia's effects in normal eyes and eyes with elevated IOP were indistinguishable.
All anesthetics resulted in rapid and substantial decreases in IOP in all eyes and increased the interanimal variability in IOPs. Measurement of IOP in awake animals provides the most accurate documentation of pressure histories for rat glaucoma model studies.
确定几种常见全身麻醉药对大鼠实验性房水流出受阻后眼压（IOP）的影响。
通过单次巩膜外静脉注射高渗盐水使棕色挪威大鼠的房水流出途径硬化并导致眼压升高。将动物饲养在标准光照或恒定低水平光照环境中。在通过异氟烷、氯胺酮或注射用麻醉药混合物（甲苯噻嗪、氯胺酮和乙酰丙嗪）诱导麻醉前，立即使用眼压计（Mentor，诺威尔，马萨诸塞州）测定清醒状态下的眼压。对于每种麻醉药，在充分镇静后立即（时间0）以及每隔5分钟直至20分钟测量眼压。结果：清醒状态下的眼压范围为18至52毫米汞柱。与相应的清醒眼压相比，所有麻醉药在每个麻醉持续时间均导致测量的眼压出现统计学显著降低（P < 0.01）。随着麻醉持续时间增加，麻醉药混合物和异氟烷的测量眼压均大致呈线性下降。然而，使用氯胺酮时，麻醉5分钟时眼压降至清醒水平的48%±11%（标准光照）和60%±7%（恒定光照），并保持稳定。在对侧眼中，麻醉动物的平均眼压标准差始终大于清醒平均值的相应标准差。麻醉对正常眼和眼压升高眼的影响无法区分。
所有麻醉药均导致所有眼的眼压迅速大幅下降，并增加了动物间眼压的变异性。在清醒动物中测量眼压可为大鼠青光眼模型研究提供最准确的眼压历史记录。
