Sleutjens Janneke, Smiet Esmee, van Weeren René, van der Kolk Johannes, Back Willem, Wijnberg Inge D
Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
Am J Vet Res. 2012 Apr;73(4):522-8. doi: 10.2460/ajvr.73.4.522.
To evaluate the effect of various head and neck positions on intrathoracic pressure and arterial oxygenation during exercise in horses.
7 healthy Dutch Warmblood riding horses.
The horses were evaluated with the head and neck in the following predefined positions: position 1, free and unrestrained; position 2, neck raised with the bridge of the nose aligned vertically; position 4, neck lowered and extremely flexed with the nose pointing toward the pectoral muscles; position 5, neck raised and extended with the bridge of the nose in front of a vertical line perpendicular to the ground surface; and position 7, neck lowered and flexed with the nose pointing towards the carpus. The standard exercise protocol consisted of trotting for 10 minutes, cantering for 4 minutes, trotting again for 5 minutes, and walking for 5 minutes. An esophageal balloon catheter was used to indirectly measure intrathoracic pressure. Arterial blood samples were obtained for measurement of Pao(2), Paco(2), and arterial oxygen saturation.
Compared with when horses were in the unrestrained position, inspiratory intrathoracic pressure became more negative during the first trot (all positions), canter and second trot (position 4), and walk (positions 4 and 5). Compared with when horses were in position 1, intrathoracic pressure difference increased in positions 4, 2, 7, and 5; Pao(2) increased in position 5; and arterial oxygen saturation increased in positions 4 and 7.
Position 4 was particularly influential on intrathoracic pressure during exercise in horses. The effects detected may have been caused by a dynamic upper airway obstruction and may be more profound in horses with upper airway disease.
评估马匹运动期间各种头颈部姿势对胸内压和动脉氧合的影响。
7匹健康的荷兰温血骑乘马。
对马匹进行评估时，使其头颈部处于以下预定义姿势：姿势1，自由无约束；姿势2，颈部抬起，鼻梁垂直对齐；姿势4，颈部降低并极度弯曲，鼻子指向胸肌；姿势5，颈部抬起并伸展，鼻梁位于垂直于地面的垂直线前方；姿势7，颈部降低并弯曲，鼻子指向腕关节。标准运动方案包括小跑10分钟、慢跑4分钟、再次小跑5分钟和步行5分钟。使用食管气囊导管间接测量胸内压。采集动脉血样以测量动脉血氧分压（Pao₂）、动脉血二氧化碳分压（Paco₂）和动脉血氧饱和度。
与马匹处于无约束姿势时相比，在第一次小跑（所有姿势）、慢跑和第二次小跑（姿势4）以及步行（姿势4和5）期间，吸气时胸内压变得更负。与马匹处于姿势1时相比，姿势4、2、7和5的胸内压差增加；姿势5的动脉血氧分压增加；姿势4和7的动脉血氧饱和度增加。
姿势4对马匹运动期间的胸内压影响尤为显著。检测到的这些影响可能是由动态上呼吸道阻塞引起的，并且在上呼吸道疾病的马匹中可能更为明显。
