| 摘要 |
A method for detecting probe penetration of human (i) target tissue having predetermined internal pressure and (ii) epidural space having essentially negative gauge pressure relative to atmosphere pressure and enlarging the epidural space in the neighborhood of said probe which includes inserting a hollow probe into the human body towards the internal target tissue and gradually increasing pressure in a closed volume defined by the probe interior and a conduit communicating therewith until a moveable piston slideably resident within the conduit and having a passageway therethrough connecting the portion of the conduit interior communicating with the hollow probe with an orifice in a laterial surface of the moveable piston slideably contacting said conduit interior, moving in response to pressure within the conduit opposing predetermined bias force applied to the moveable piston, reaches a predetermined position, at which the laterial surface orifice of the moveable piston communicates with ambient air via a passageway through the wall of the conduit, corresponding to pressure in the closed volume equaling the predetermined internal pressure. Apparatus for detecting probe penetration of human (i) target tissue having predetermined internal pressure and (ii) epidural space and for enlarging said epidural space away from said probe which includes: an elongated hollow probe, a valve having first and second orifices with the first orifice communicating with the hollow probe, a conduit communicating with the second orifice of the valve, a piston movable resident within the conduit in response to conduit pressure, for limiting pressure within the conduit to the predetermined internal pressure and providing visible indication upon pressure within the conduit reaching the predetermined internal pressure and has a hand squeezable bulb communicating with the conduit intermediate the movable piston and the valve, for increasing pressure within the conduit and the probe until the movable piston limits pressure within the conduit to the predetermined pressure.
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