Monitoring device and method
A monitoring device arranged to display a level of consciousness and hemodynamic parameters of a patient for simultaneous viewing. A dependence of changes in the hemodynamic parameters of the patient on the level of consciousness of the patient may be more easily observed using the monitoring device. Correlations between the patient's level of consciousness and the patient's hemodynamic parameters may further be determined and displayed to aid clinicians in estimating any improvement in hemodynamic parameters that may be achieved through manipulation of the patient's level of consciousness, fluid status and drugs.
1. A monitoring device comprising:
a part for acquiring a signal indicating a level of consciousness, wherein said signal is a biopotential signal, based on a biopotential signals or a bispectral index signal;
a part for acquiring an arterial blood pressure signal;
a display; and
a processor or processors arranged to record a series of data sets over a period of time, each data set at least comprising a value of said signal indicating a level of consciousness applicable at a time point and a value of said arterial blood pressure signal at the time point;
wherein the processor or processors are further arranged to determine, based on the series of data sets, a characteristic of one or more of a change in mean arterial blood pressure, in systemic vascular resistance, in cardiac output, in stroke volume, in stroke volume variation and in pulse pressure variation and pleth variability index dependent on the level of consciousness.
2. The device of claim 1 , wherein the processor or processors are further arranged to cause the display to display one or more of the said characteristics and an indication of a change in blood pressure and/or another hemodynamic parameter that is to be expected, based on the characteristics, for a unit change in the level of consciousness.
3. The device of claim 1 , wherein the processor or processors are arranged to cause the display to display, in one operating mode and for simultaneous viewing, an image showing the blood pressure signal over time, an image showing cardiac output or stroke volume over time, an image showing systemic vascular resistance over time and an image showing the level of consciousness over time based on the signal indicating the level of consciousness.
4. The device of claim 3 , wherein the processor or processors are further arranged to, in another operating mode, replace the display of one of the said images with the display of an image showing a response of a hemodynamic parameter to an intervention.
5. The device of claim 3 , wherein the processor or processors are arranged to cause the display to display an indication of a current value of a parameter or parameters that is or are displayed in one or more of the images in number format alongside the images.
6. The device of claim 3 , wherein the processor or processors are further arranged to display one or more of the images in a time synchronised fashion.
7. The device of claim 1 , wherein the device is arranged to store a base line of one or more of the level of consciousness, a value of a blood flow/oxygen delivery signal and the arterial blood pressure signal; and
wherein the processor or processors are arranged to display a current and/or past indication of the level of consciousness and/or current and/or past level of one or more of the arterial blood pressure, the cardiac output, the oxygen delivery, the stroke volume and the systemic vascular resistance with reference to a said stored base line or to a base line determined from a said stored base line.
8. The device of claim 1 , wherein the data set further comprises one or more of the cardiac output at the time point, the stroke volume at the time point and the systemic vascular resistance at the time point.
9. The device of claim 1 , wherein the processor or processors are further arranged to facilitate interpolation between the series of data sets.
10. The device of claim 9 , wherein the processor or processors are arranged to fit a curve to said series of data sets.
11. The device of claim 10 , wherein the processor or processors are configured to cause the display to display the curve or, if the curve is a linear function, an indication of the gradient of the function.