Okutomi T, Watanabe S, Goto F
Department of Anaesthesiology, School of Medicine, Kitasato University, Kanagawa, Japan.
Can J Anaesth. 1993 Nov;40(11):1044-8. doi: 10.1007/BF03009475.
The purpose of this study was to measure thoracic epidural pressure at the time of insertion of an epidural needle. The pressure was measured using a closed pressure measurement system after insertion of a Tuohy needle at the T7-8 intervertebral level. This system is unique because it has a pressure transducer equipped with a device which regulates flow through the transducer and prevents the heparinized saline in the system from being evacuated into the epidural space due to sudden pressure change. As reported previously, high negative epidural pressures, up to -60 mmHg, were observed at the moment of epidural puncture. However, the pressure became positive in about 30 sec in 12 of the 13 patients, and stabilized at +3.7 +/- 3.2 mmHg (mean +/- SD) within 90 sec. Similar results were observed when the procedure was repeated within a few minutes to the same patients. This suggests that negative epidural pressures at the moment of epidural puncture are artifacts induced by tenting of the dural membrane. Subsequent adaptation of the surrounding tissue results in restoration of the normal positive epidural pressure.
本研究的目的是在硬膜外穿刺针插入时测量胸段硬膜外压力。在T7 - 8椎间隙水平插入Tuohy针后，使用封闭压力测量系统测量压力。该系统独特之处在于它有一个配备了调节通过换能器流量装置的压力换能器，可防止系统中的肝素化盐水因压力突然变化而排入硬膜外间隙。如先前报道，在硬膜外穿刺瞬间观察到高达 - 60 mmHg的高负性硬膜外压力。然而，13例患者中有12例的压力在约30秒内变为正压，并在90秒内稳定在 + 3.7 +/- 3.2 mmHg（平均值 +/- 标准差）。在几分钟内对同一患者重复该操作时观察到类似结果。这表明硬膜外穿刺瞬间的负性硬膜外压力是由硬膜膜帐篷状突起引起的伪像。周围组织随后的适应性变化导致正常的正性硬膜外压力恢复。
