Sørensen Nina Buus, Christiansen Anders Tolstrup, Kjær Troels Wesenberg, Klemp Kristian, la Cour Morten, Kiilgaard Jens Folke
Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
Department of Neurology, Zealand University Hospital, Roskilde, Denmark.
Transl Vis Sci Technol. 2017 Mar 21;6(2):6. doi: 10.1167/tvst.6.2.6. eCollection 2017 Mar.
The time-dependent effect of anesthetics on the retinal function is debated. We hypothesize that in anesthetized animals there is a time-dependent decline that requires optimized multifocal electroretinogram (mfERG) recording procedures.
Conventional and four-frame global-flash mfERG recordings were obtained approximately 15, 60, and 150 minutes after the induction of propofol anesthesia (20 pigs) and isoflurane anesthesia (nine pigs). In six of the propofol-anesthetized pigs, the mfERG recordings were split in 3-minute segments. Two to 4 weeks after initial recordings, an intraocular injection of tetrodotoxin (TTX) was given and the mfERG was rerecorded as described above. Data were analyzed using mixed models in SAS statistical software.
Propofol significantly decreases the conventional and global-flash amplitudes over time. The only significant effect of isoflurane is a decrease in the global-flash amplitudes. At 15 minutes after TTX injection several of the mfERG amplitudes are significantly decreased. There is a linear correlation between the conventional P1 and the global-flash DR mfERG-amplitude ( = 0.82, slope = 0.72, < 0.0001). There is no significant difference between the 3-minute and the prolonged mfERG recordings for conventional amplitudes and the global-flash direct response. The global flash-induced component significantly decreases with prolonged mfERG recordings.
A 3-minute mfERG recording and a single stimulation protocol is sufficient in anesthetized pigs. Recordings should be obtained immediately after the induction of anesthesia. The effect of TTX is significant 15 minutes after injection, but is contaminated by the effect of anesthesia 90 minutes after injection. Therefore, the quality of mfERG recordings can be further improved by determining the necessary time-of-delay from intraocular injection of a drug to full effect.
General anesthesia is a possible source of error in mfERG recordings. Therefore, it is important to investigate the translational relevance of the results to mfERG recordings in children in general anesthesia.
麻醉药对视网膜功能的时间依赖性效应存在争议。我们假设在麻醉动物中存在时间依赖性下降，这需要优化多焦视网膜电图（mfERG）记录程序。
在丙泊酚麻醉（20头猪）和异氟烷麻醉（9头猪）诱导后约15、60和150分钟，进行传统和四帧全视野闪光mfERG记录。在6头丙泊酚麻醉的猪中，mfERG记录被分成3分钟的片段。在初次记录后2至4周，进行眼内注射河豚毒素（TTX），并按上述方法重新记录mfERG。使用SAS统计软件中的混合模型分析数据。
丙泊酚随时间显著降低传统和全视野闪光幅度。异氟烷的唯一显著效应是全视野闪光幅度降低。在TTX注射后15分钟，几个mfERG幅度显著降低。传统P1与全视野闪光DR mfERG幅度之间存在线性相关性（ = 0.82，斜率 = 0.72， < 0.0001）。对于传统幅度和全视野闪光直接反应，3分钟和延长的mfERG记录之间没有显著差异。全视野闪光诱导成分随mfERG记录延长而显著降低。
在麻醉猪中，3分钟的mfERG记录和单次刺激方案就足够了。记录应在麻醉诱导后立即进行。TTX注射后15分钟效应显著，但注射后90分钟被麻醉效应干扰。因此，通过确定眼内注射药物至完全起效的必要延迟时间，可进一步提高mfERG记录的质量。
全身麻醉是mfERG记录中可能的误差来源。因此，研究这些结果与全身麻醉下儿童mfERG记录的转化相关性很重要。
