Isis Innovation Limited

Oxford Biosignals Limited

Neil William Townsend

Lionel Tarassenko

James David Price

A method for combining measurements from two or more independent measurement channels, particularly physiological measurements such as heart rate. Independent measurements of heart rate, for instance by ECG and pulse oximetry, can be combined to derive an improved measurement eliminating artefacts on one channel. A model of the process generating the physiological parameter, e.g., the heart rate, is constructed and is run independently for each channel to generate predictions of the parameter. The measured values are compared with the predicted values and the differences are used as an indication of the confidence in the measurement. The measurements from the two channels are ombined using weights calculated from the respective differences.

Combining measurements from different sensors

Data from a plurality of sensors representing a patient's condition, including measurement signals and also secondary parameters derived from the measurement signals, are displayed in a simple way by calculating a novelty index constituting a one-dimensional visualization space. The novelty index is based on the distance of the current data point in a multi-dimensional measurement space, whose coordinates are defined by the values of the measurement signals and secondary parameters, from a predefined normal point. This may be achieved by using a suitably trained artificial neural network to sum the distance between the current data point in the measurement space and a plurality of prototype points representing normality.

Patient condition display

A system for acquiring, and displaying, data such as physiological data, from a plurality of data connection devices, each of which monitor one or more different parameters and output data at different sampling frequencies based on their own system clocks. The system receives the data signals at different sampling frequencies and associates each sample of each signal with a time stamp derived from a single master clock. Low rate and high rate data are treated differently. Low rate data is associated with the current value of the master clock, where as high rate data is time stamped by giving the first sample a time stamp equal to the current value of the current master clock, subsequent samples being given an estimated time stamp based on the expected interval between samples derived from the sampling frequency of the data collection device, and the timescale given to the first example. The estimated time stamp may be periodically corrected, and the estimation calculation can be improved by correcting the value used for the interval between samples. The different signals can be displayed together on a display aligned with respect to a time axis. The system can display, the data in two different timescales, one showing a few seconds of data and one showing a few hours of data. The data traces are scrolled across the time axis, new data being added to one end of the trace.

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Oxford, United Kingdom

Neil William Townsend