Device and Method for Needle/Catheter Location Utilizing Correlation Analysis

Abstract

An apparatus and method to enable clinicians to verify needle or catheter location within an anatomic site by relying upon combined sensing of two signals, such as a pressure signal and a heart rate pulse signal, in which the detection of a correlation between both signals is identified to confirm location of the needle or catheter.

Description

FIELD OF THE INVENTION[0001]The present invention relates generally to devices and methods for determining needle or catheter location in a patient utilizing a correlation analysis, and more particularly, but not exclusively, to correlation analysis, such as comparison of beats-per-minute or cross-correlation of waveforms, of objective pressure in the needle or catheter and the patient's heart rate pulse.BACKGROUND OF THE INVENTION[0002]Currently, when measuring pressure within a needle or catheter, there is no ability to identify false-positives of a cardiac pulsewave detected in the needle or catheter as opposed to pressure changes which truly represent the cardiac pulsewave. As used herein cardiac pulsewave is defined to mean a pressure waveform which contains a signal which originates from the contraction of the heart or vessels, and therefore contains information representing, the cardiac pulse. It is conceivable that a needle or an indwelling catheter can detect a non-cardiac ...

AI Technical Summary

Benefits of technology

[0008]Positive verification of the cardiac pulsewave in the needle or catheter may establish both the correct position of the needle or catheter and its patency. As a result, devices and methods of the present invention can allow clinicians to more easily assess in real-time proper needle or catheter placement with confidence, due to the verified detection of the cardiac pulsewave. These may be presented to the clinician as a signal or an alert confirming proper needle or catheter placement. As a result, with the verified real-time detection of the cardiac pulsewave in the needle or catheter the clinician may use a manual syringe rather than an automated mechanical pump such that the clinician can personally position the needle and control the delivery of medication or aspiration of fluid and the accompanying physical force applied to the syringe. More precise control of the physical force by the clinician can also prevent catheter movement from excessive pressures. Excessive pressure during medication delivery could cause the dislodgement of the needle or catheter from a site as uncontrolled fluid pressures produce a “jet-stream” at the tip of the catheter or needle.

[0009]In another of its aspects, devices of the present invention may provide a clinician with an objective (i.e. measured) pressure value in the needle or catheter during the flushing stage. Knowing the objective pressure as a medication is injected can also assist the clinician in avoiding excessive force, preventing excessive pressures. For example, the present invention may alert the clinician when a pressure value has been exceeded. The alert can be audible, visual, haptic or the like.

[0010]Exemplary uses of devices and methods of the present invention may include locating a needle within the body to a specific target site, such as that of an epidural procedure or peripheral nerve block. In particular the identification of the epidural space, the determination of needle proximity to a neurovascular bundle in regional peripheral nerve blocks, and other medical procedures which require a needle or catheter tip to be positioned at a specific location (e.g., intrathecal, intravenous, intra-arterial, organ of the body) where the cardiac pulse is present, all can benefit from devices and methods of the present invention. Accordingly, the use of devices and methods of the present invention at such exemplary target sites can with greater reliability replace the current Loss-of-Resistance technique (LOR-technique). Further to its advantages, devices and methods of the present invention may be used for all types of needles and catheters that are placed into patients at anatomic sites at locations that emit a rhythmic pulsation of the arterial system, and may be provided as an inexpensive and portable system.

[0011]In still further of its aspects the present invention may achieve a number of objectives. For example, an objective of the invention may be to detect a pulsatile waveform of a catheter which is verified for the presence of a cardiovascular pulse by comparing a first input to a second input from the cardiovascular system, such as a heartbeat detected from a second input source. The redundant nature of these two sources may be identified and confirmed electronically and produce an alert to the operator. A further objective of the present invention may be to provide an inexpensive device to determine an objective pressure value that is generated when a drug is injected through a catheter using a manual syringe to prevent excessive pressure production at the tip of a catheter that might dislodge the catheter from a target position. Devices of the present invention can enable an audible alert to be set for a maximum pressure value to alert the operator if they have exceeded a specific pressure value. In addition, a further objective may be to detect and display a pulsatile pressure waveform corresponding to the pulse of the cardiac-vascular system to determine the position of a catheter. A further objective of the invention may be to provide a method and device that can detect the pulsatile pressure waveform that is present in the epidural space or intrathecal space of the central nervous system and detecting a pulsatile waveform or the proximity to the neurovascular bundle of nerve. A further objective may be to observe an objective pressure and graph an objective pressure value over time to monitor the response to an injection performed with a manual syringe to determine the patency of a catheter. Another objective may be to correlate an objective pressure value with a pulsatile pressure waveform to determine the patency and position of a catheter by simultaneously viewing the pressure / time graph and the pulsatile pressure waveform to determine catheter function. A further objective may be to provide a mean value of a pulsatile pressure waveform from an intravenous catheter to determine the patency of said catheter before, after and during an infusion.

Problems solved by technology

Excessive pressure during medication delivery could cause the dislodgement of the needle or catheter from a site as uncontrolled fluid pressures produce a “jet-stream” at the tip of the catheter or needle.

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