Drolet C, Pinard C, Gaitero L, Monteith G, Bateman S
Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
J Small Anim Pract. 2021 Dec;62(12):1070-1078. doi: 10.1111/jsap.13403. Epub 2021 Jul 15.
To investigate the effects of anaesthetic duration and serial anaesthetic events on optic nerve sheath diameter in a population of dogs without intracranial disease using point-of-care ultrasonography.
Client-owned dogs requiring advanced head imaging were prospectively enrolled. Exclusion criteria included signs of elevated intracranial pressure, glaucoma and optic nerve disease. Using a transpalpebral technique, two optic nerve sheath diameter measurements were recorded for each eye at three timepoints: following premedication, after induction within 7 minutes and before discontinuing isoflurane. Mixed model analysis was used to characterise optic nerve sheath diameter behaviour and investigate the effects of anaesthetic duration, bodyweight and anaesthetic protocol, age and sex.
Fourteen dogs of various ages, breeds and bodyweights were enrolled. A positive linear relationship was detected between body weight and optic nerve sheath diameter. In 12 of 14 dogs, the optic nerve sheath diameter increased from measurements taken after premedication when compared to measurements taken after induction within 7 minutes. In a subset of patients, measurements subsequently decreased when anaesthetic duration exceeded 120 minutes. Age, side, sex, final body temperature, blood pressure and anaesthetic protocol did not significantly affect optic nerve sheath diameter. No significant association was noted between optic nerve sheath diameter and end-tidal carbon dioxide after induction and before discontinuing isoflurane.
When using point-of-care ultrasound, a transient increase in optic nerve sheath diameter occurs between premedication and within 7 minutes following induction, regardless of bodyweight. This should be taken into consideration when serial monitoring is performed.
使用即时超声检查法，研究麻醉持续时间和连续麻醉事件对无颅内疾病犬群视神经鞘直径的影响。
前瞻性纳入需要进行高级头部成像的客户拥有的犬只。排除标准包括颅内压升高、青光眼和视神经疾病的体征。采用经睑技术，在三个时间点对每只眼睛记录两次视神经鞘直径测量值：用药前、诱导后7分钟内以及停用异氟烷前。使用混合模型分析来描述视神经鞘直径的变化情况，并研究麻醉持续时间、体重、麻醉方案、年龄和性别的影响。
纳入了14只不同年龄、品种和体重的犬只。体重与视神经鞘直径之间检测到正线性关系。在14只犬中的12只中，与诱导后7分钟内的测量值相比，用药前测量的视神经鞘直径增加。在一部分患者中，当麻醉持续时间超过120分钟时，测量值随后下降。年龄、侧别、性别、最终体温、血压和麻醉方案对视神经鞘直径没有显著影响。诱导后和停用异氟烷前，视神经鞘直径与呼气末二氧化碳之间未发现显著关联。
使用即时超声检查时，无论体重如何，用药前至诱导后7分钟内视神经鞘直径会出现短暂增加。进行连续监测时应考虑到这一点。
