Tamai K, Toumoto E, Majima A
Department of Ophthalmology, Nagoya City University Medical School, Japan.
Br J Ophthalmol. 1997 Sep;81(9):789-94. doi: 10.1136/bjo.81.9.789.
Hypothermic irrigating solutions were used during vitrectomy in pressure induced ischaemic eyes so that their effects on retinal function and histological changes could be investigated.
After anaesthetised albino rabbits underwent closed vitrectomy, their vitreous cavities were continuously irrigated for 30 minutes at a perfusion pressure of 140 mm Hg. The rabbits were divided into three groups according to their intraocular perfusion temperatures--8 degrees C, 22 degrees C, and 38 degrees C. Electroretinograms were taken before and after irrigation. Glutamate levels in the vitreous were examined after irrigation. Eyes were enucleated on the seventh postoperative day and examined histologically.
On the seventh postoperative day, the recovery rate of a-wave amplitudes was significantly lower in the 38 degrees C group than in the 8 degrees C group, and that of b-wave amplitudes was significantly lower in the 38 degrees C group than in either the 8 degrees C or 22 degrees C group. Retinal damage in the 38 degrees C group revealed more severe histological impairment than in either the 8 degrees C or 22 degrees C group. Oedema of the inner retinal layer was significant in both the 22 degrees C and 38 degrees C groups. Glutamates reached peak values 30 minutes after the end of ischaemia in the 38 degrees C group. However, no significant glutamate increases were detected 15 to 60 minutes after ischaemia in either the 8 degrees C or 22 degrees C group.
Local hypothermia during vitrectomy in acute ischaemic eyes appears to decrease retinal damage.
在压力诱导性缺血性眼玻璃体切除术中使用低温灌注液，以便研究其对视网膜功能和组织学变化的影响。
对麻醉后的白化兔进行闭合式玻璃体切除术，然后在140mmHg的灌注压力下对其玻璃体腔进行30分钟的持续灌注。根据眼内灌注温度将兔子分为三组——8℃、22℃和38℃。在灌注前后进行视网膜电图检查。灌注后检测玻璃体中的谷氨酸水平。术后第7天摘除眼球并进行组织学检查。
术后第7天，38℃组a波振幅的恢复率显著低于8℃组，38℃组b波振幅的恢复率显著低于8℃组和22℃组。38℃组的视网膜损伤在组织学上比8℃组和22℃组更严重。22℃组和38℃组的视网膜内层均有明显水肿。38℃组谷氨酸在缺血结束后30分钟达到峰值。然而，8℃组和22℃组在缺血后15至60分钟未检测到谷氨酸的显著增加。
急性缺血性眼玻璃体切除术中的局部低温似乎可减少视网膜损伤。
