Non-invasive monitoring method and apparatus of central venous pressure, and improved transducer used in this

摘要

A method and apparatus for measuring central venous pressure (CVP) is disclosed, along with an improved transducer (50) for measuring CVP in infants. Changes in CVP may also be monitored by employing the method and apparatus of the invention. The apparatus comprises a pair of transducers (12a, 12b) disposed in spaced parallel relation about the neck (14) of the subject (16). Each transducer (12a, 12b) comprises an extensible electrically conductive loop (18) supported by an elastic tube (20). The transducers (12a, 12b) are responsive to changes in the volume or circumference of the neck. Waveform recordings from the transducers (12a, 12b) are evaluated as the subject's positioning is varied until a transition point is reached wherein the vertical distance (d) from the phlebostatic axis (26) to a point (28) on the lower transducer (12b) provides a good approximation of CVP. For infant measurements of CVP, a transducer (50) is placed about the head.