Boesch Jordyn M, Gleed R D, Buss Peter, Hofmeyr Markus, Tordiffe Adrian, Zeiler Gareth, Meyer Leith
J Zoo Wildl Med. 2018 Dec 13;49(4):849-855. doi: 10.1638/2017-0120.1.
The effects of etorphine on the pulmonary vascular system of white rhinoceros ( Ceratotherium simum) have not been described and could play a role in the severe hypoxemia that develops after immobilization with etorphine-based drug combinations. Characterization of these effects requires measurement of pulmonary vascular pressures and cardiac output (CO). To refine a technique for pulmonary arterial catheterization, five boma-habituated white rhinoceros (three females and two males weighing 1,012-1,572 kg) were immobilized by remote injection with etorphine plus azaperone followed by butorphanol. This afforded the opportunity to perform a pilot study and acquire preliminary measurements of pulmonary arterial pressure (PAP) and CO before and after supplemental etorphine given intravenously. Ultrasonographic guidance was used to insert a sheath introducer into a linguofacial branch of a jugular vein. A 160-cm-long pulmonary artery catheter with a balloon and thermistor was then passed through the introducer and positioned with its tip in the pulmonary artery. It was not long enough to permit wedging for measurement of pulmonary artery occlusion pressure. Mean PAP was 35 mm Hg (minimum, maximum 32, 47 mm Hg) and increased ( P = 0.031) by 83% (28, 106%) after supplemental etorphine. Thermodilution CO was 120 L/min (92, 145 L/min) and increased 27% (3, 43%) ( P = 0.031). Heart rate was 100 (88, 112) beats/min and increased 20% (4, 45%) ( P = 0.031), whereas arterial partial pressure of oxygen was 35 mm Hg (30, 94 mm Hg) and decreased 47% (20, 72%) ( P = 0.031). The cardiovascular observations could result from etorphine-induced generalized sympathetic outflow, as has been reported in horses. Further studies of etorphine in isolation are needed to test this suggestion and to discern how the changes in pulmonary vascular pressures and blood flow might relate to hypoxemia in etorphine-immobilized white rhinoceros.
埃托啡对白犀（白犀属）肺血管系统的影响尚未见报道，可能在使用基于埃托啡的药物组合进行麻醉后出现的严重低氧血症中起作用。对这些影响的特征描述需要测量肺血管压力和心输出量（CO）。为完善肺动脉插管技术，对5头习惯圈养的白犀（3头雌性，2头雄性，体重1012 - 1572千克）进行远程注射埃托啡加阿扎哌隆，随后注射布托啡诺进行麻醉。这为开展一项初步研究并获取静脉注射补充埃托啡前后的肺动脉压（PAP）和CO的初步测量值提供了机会。使用超声引导将鞘管导入器插入颈静脉的舌面分支。然后将一根带有气囊和热敏电阻的160厘米长的肺动脉导管穿过导入器，并将其尖端置于肺动脉中。导管长度不足以进行楔入操作以测量肺动脉闭塞压。平均PAP为35毫米汞柱（最小值、最大值分别为32、47毫米汞柱），补充埃托啡后升高了83%（28、106%）（P = 0.031）。热稀释法测得的CO为120升/分钟（92、145升/分钟），升高了27%（3、43%）（P = 0.031）。心率为100（88、112）次/分钟，升高了20%（4、45%）（P = 0.031），而动脉血氧分压为35毫米汞柱（30、94毫米汞柱），降低了47%（20、72%）（P = 0.031）。心血管方面的观察结果可能是由埃托啡诱导的全身性交感神经兴奋引起的，正如在马身上所报道过的那样。需要进一步单独研究埃托啡，以验证这一推测，并弄清楚肺血管压力和血流的变化与使用埃托啡麻醉的白犀低氧血症之间可能存在的关系。
