| 摘要 |
Several techniques are provided for aiding in the discrimination of detected bilogical signals indicative of blood pressure from detected signals not indicative of blood pressure (e.g., noise). A threshold, based predominantly on a level of noise, is developed and used in the discrimination. A second threshold, based predominantly on levels of previously detected biological signals, is developed and additionally used to help discriminate the biological signals from noise. The biological signals are detected during a selected portion of a cardiac cycle, and additional signals detected outside of the selected portion of the cycle are applied to the detected signals. Another threshold may be developed based predominantly on a level of signals sensed by a transducer positioned to preferentially sense noise; the transducer is positioned so that the noise that it detects is related to noise that is detected during the detection of the bilogical signals. Blood pressure is measured during periodically scheduled measurement cycles, and a measurement cycle is suspended if noise exceeds a predeteremined level. The times at which the detected signals (i.e., the signals indicative of blood pressure and the signals not indicative of blood pressure) are processed during a given cardiac cycle are selected based at least in part on the pressure of the cuff. The biological signals indicative of blood pressure that are detected during a current measurement cycle are used to at least in part determine the times at which the detected signals will be processed during a succeeding measurement cycle. |
