Patent ID: 9592029
Date: 2017-03-14
CPC Classifications: A61B,A61M

Claim:
1. A monitoring device for continuously monitoring the presence of an unattended skin piercing vascular access device, the monitoring device comprising: an ultrasonic transmitter configured to transmit an ultrasound signal pulse; a sensing section having an ultrasonic receiver configured to receive a reflected ultrasound signal; attachment means for attaching the monitoring device to a patient adjacent a vascular access point such that, in use, a vascular access device entering the patient at the vascular access point passes underneath the sensing section of the monitoring device; and control electronics configured so that, in use, the control electronics activate the transmitter to transmit the ultrasound signal pulses, and monitor an amplitude of the reflected ultrasound signal received by the receiver to determine whether the received reflected ultrasound signal was reflected only by the patient's body tissue or, alternatively, was reflected by both the patient's body tissue and the vascular access device that has been inserted underneath the sensing section; wherein, when the vascular access device is underneath said sensing section, the ultrasound signal pulses transmitted by said transmitter pass through the patient's skin and are reflected by the patient's body tissues and by the vascular access device, and when the vascular access device is not underneath said sensing section, the ultrasound signal pulses transmitted by said transmitter pass through the patient's skin and are reflected by the patient's body tissue only; wherein the determination by the control electronics of whether the ultrasound signals received by the receiver were reflected only by the patient's body tissue consists essentially of comparing the amplitude of the reflected ultrasound signals across a frequency spectrum received by the receiver to a control signal, and detecting whether there is a difference in amplitude between the reflected ultrasound signals received by the receiver and the control signal; and wherein, if the difference is detected, the control electronics automatically take appropriate action as a consequence of dislodgement of the vascular access device; and wherein the appropriate action comprises at least one of generating a warning signal that the vascular access device has become dislodged and stopping a medical procedure using the vascular access device.