| 摘要 |
A non-invasive device and method for continuously monitoring concentration levels of blood constituents utilizes a polychromatic light source that emits light over a broad spectrum of wavelenghts. The light is passed through, or reflected from, a part of the subject. That light is then separated into its various components by means of a grating, or prism, and the near infrared band is focussed onto a linear array detector. A microprocessor uses the output of the array detector to measure the light transmitted (T), calculate the absorbance (log 1/T) and calculate the second derivative of the absorbance. A calibration equation is used for each constituent to be monitored to convert the absorbance second derivative measurements to a concentration level for that constituent. The device is programmed to take measurements between heart beats and to adjust for the temperature of the sample being taken. The memory in the microprocessor can be used to assist with record keeping and with dosage calculations. |
