Christley R M, Hodgson D R, Evans D L, Rose R J
Department of Veterinary Clinical Sciences, University of Sydney, New South Wales, Australia.
Equine Vet J. 1997 Jan;29(1):6-10. doi: 10.1111/j.2042-3306.1997.tb01629.x.
The relationship between different grades of laryngeal function, as assessed by endoscopy at rest, and the measurements of indices of gas exchange and exercise capacity was assessed during a standardised treadmill exercise test in 149 horses. Horses with abnormalities other than idiopathic laryngeal hemiplegia (ILH) were excluded from the study and laryngeal function was graded according to an established system. There were no significant differences in age, weight, maximum oxygen uptake, maximum carbon dioxide production, maximum respiratory exchange ratio, maximum oxygen pulse and run time between the grades. Blood lactate concentration at 10 m/s was greater (P < 0.01) in horses with grade 5 laryngeal function than other grades. Minimum PaO2 (P < 0.001) and SaO2 (P < 0.01) were lower and maximum PaCO2 (P < 0.001), higher in horses with grades 4 and 5 laryngeal function than other grades. Horses with grade 4 function had a lower minimum CaO2 (P < 0.01) than horses with other grades. Minimum PAO2 decreased from grades 1 and 2 to grades 4 and 5 (P < 0.05). The minimum alveolar ventilation was lower (P < 0.05) in horses with grades 4 and 5 laryngeal function compared to other grades. The results of this study indicate that endoscopic assessment of laryngeal function at rest, using a simple grading system, provides an indication of dynamic changes in ventilation and the effects on blood gases during exercise. From the data, we suggest that horses that have some movement of the left arytenoid cartilage but are unable to achieve full abduction have similar ventilatory effects and blood gas responses during maximal exercise to those with complete paralysis. Some horses with grade 3 laryngeal function had blood gas results similar to those of horses with grades 4 and 5 laryngeal function, indicating that discrepancies may occur between the resting assessment and laryngeal function during strenuous exercise.
在149匹马的标准化跑步机运动试验中，评估了静息状态下通过内窥镜检查所评定的不同等级喉功能与气体交换指标及运动能力测量值之间的关系。除特发性喉偏瘫（ILH）以外存在其他异常的马匹被排除在研究之外，喉功能根据既定系统进行分级。各等级之间在年龄、体重、最大摄氧量、最大二氧化碳产量、最大呼吸交换率、最大氧脉搏和跑步时间方面均无显著差异。喉功能为5级的马匹在速度10米/秒时的血乳酸浓度高于其他等级（P<0.01）。喉功能为4级和5级的马匹，其最低动脉血氧分压（P<0.001）和动脉血氧饱和度（P<0.01）低于其他等级，而最高动脉血二氧化碳分压（P<0.001）则高于其他等级。喉功能为4级的马匹，其最低动脉血氧含量（P<0.01）低于其他等级的马匹。最低肺泡氧分压从1级和2级到4级和5级呈下降趋势（P<0.05）。喉功能为4级和5级的马匹，其最低肺泡通气量低于其他等级（P<0.05）。本研究结果表明，使用简单分级系统对静息状态下的喉功能进行内窥镜评估，可显示运动过程中通气的动态变化及对血气的影响。根据数据，我们认为左杓状软骨有一定活动但无法完全外展的马匹，在最大运动时的通气效果和血气反应与完全麻痹的马匹相似。一些喉功能为3级的马匹的血气结果与喉功能为4级和5级的马匹相似，这表明在静息评估和剧烈运动时的喉功能之间可能存在差异。
