Intracranial pressure monitor and drainage catheter assembly

Abstract

A monitor-driven intracranial catheter assembly including dual lumen catheter for monitoring intracranial pressure via a pressure sensor located in one lumen while simultaneously draining cerebrospinal fluid through another lumen. A third lumen can also be provided with a side port for receiving a stylet. The stylet is used as a stiffening agent to aid in advancing the catheter into the patient's brain. The pressure sensor is preferably a spectral modulation sensor that communicates with a photodetector apparatus by means of a single optical fiber, thus minimizing the diameter of the catheter. The photodetector is self-correcting for signal errors caused by temperature change, changes in intensity of the input light, and transmission losses within the optical apparatus. Moreover, the photodetector operates off the output voltage of the standard hospital monitor by 'scaling' the signal from the monitor to provide a pressure measurement signal that emulates the output of a piezoresistive strain gauge sensor or Wheatstone bridge. Therefore, the entire catheter assembly is designed to be used with any of the common types of hospital monitors. The pressure monitoring catheter assembly can be used in any situation requiring very sensitive pressure measurements and can be zeroed and calibrated in situ.