Iff Isabelle, Larenza M Paula, Moens Yves P S
Clinic for Anaesthesiology and Perioperative Intensive Care, Clinical Department of Small Animals and Horses, Veterinary University, Vienna, Austria.
Vet Anaesth Analg. 2009 Mar;36(2):180-5. doi: 10.1111/j.1467-2995.2008.00436.x.
To measure the extradural pressures in goats before and after extradural injection, and to investigate the occurrence of extradural pressure waves.
Prospective experimental trial.
Nine healthy adult goats weighing 59.4 +/- 6.4 kg, scheduled for stifle arthroscopy.
The goats were pre-medicated with midazolam and anaesthesia was induced with propofol and maintained with sevoflurane. The goats were placed in lateral recumbency and extradural puncture was performed via the lumbosacral space. Correct placement of the needle was assessed by lack of resistance to the injection of saline. The needle was connected to an electronic pressure transducer to record extradural pressure. Measurements were taken before and after extradural injection of methadone (0.1 mg kg(-1), diluted to a total volume of 0.2 mL kg(-1)) and 10 minutes later. Contrast medium was injected and correct extradural needle placement confirmed by radiography.
Lack of resistance to injection of saline occurred in all goats, but there were no pressure waves observed before injection in any animal. Radiography indicated incorrect needle placement in four animals and one had pressure waves synchronous with the arterial pulse after methadone injection. Correct needle placement was confirmed in the remaining five animals which exhibited pressure waves after extradural methadone injection. In the five goats with successful needle placement the baseline extradural pressure ranged from 0.4 to 2.5 kPa (3-19 mmHg), increasing to 4.4-39.9 kPa (33-300 mmHg) after injection. Ten minutes after injection, extradural pressure remained elevated and ranged from 2.5 to 17.3 kPa (19-130 mmHg).
Extradural pressure waves were not useful to confirm correct extradural needle placement in laterally recumbent goats. The presence of such waves after injection of 0.2 mL kg(-1) may be indicative of correct placement but even here we saw one of nine animals with extradural pressure waves where we failed to confirm correct needle placement. Extradural pressure increases after extradural injection.
测量山羊硬膜外注射前后的硬膜外压力，并研究硬膜外压力波的发生情况。
前瞻性实验性试验。
9只体重为59.4±6.4千克的健康成年山羊，计划进行膝关节镜检查。
山羊术前用咪达唑仑预处理，丙泊酚诱导麻醉，七氟醚维持麻醉。山羊侧卧，经腰骶间隙进行硬膜外穿刺。通过注射生理盐水时无阻力来评估针头的正确位置。将针头连接到电子压力传感器以记录硬膜外压力。在硬膜外注射美沙酮（0.1毫克/千克(-1)，稀释至总体积0.2毫升/千克(-1)）之前、之后及10分钟后进行测量。注入造影剂，并通过X射线确认硬膜外针头的正确位置。
所有山羊注射生理盐水时均无阻力，但任何动物在注射前均未观察到压力波。X射线显示4只动物针头位置不正确，1只动物在注射美沙酮后出现与动脉搏动同步的压力波。其余5只动物针头位置正确，在硬膜外注射美沙酮后出现压力波。在5只针头放置成功的山羊中，硬膜外基线压力范围为0.4至2.5千帕（3至19毫米汞柱），注射后增至4.4至39.9千帕（33至300毫米汞柱）。注射10分钟后，硬膜外压力仍升高，范围为2.5至17.3千帕（19至130毫米汞柱）。
硬膜外压力波对确认侧卧山羊硬膜外针头的正确位置无用。注射0.2毫升/千克(-1)后出现此类波可能表明位置正确，但即便如此，我们在9只出现硬膜外压力波的动物中仍有1只未确认针头位置正确。硬膜外注射后硬膜外压力升高。
