To provide a method in which the presence or absence of pressure waveform caused by pulses is judged in the various kinds of pressure waves and the pressure waveforms including mixed with outer disturbances obtained by measuring the pressure of a liquid moving through a blood vessel access, an abnormality caused in the blood vessel access of a medical apparatus can be surely observed, by the disappearance of the pressure waveform caused by pulses, and to provide the medical apparatus using the above method.
The abnormality of the blood vessel access such as the coming off of a vessel cannula can be surely detected by detecting the presence of the direct current ingredient within the waveform by multiplying the pressure waveform, caused by the pulses independently measured, and the waveform of the blood or infusion including various kinds of pressure waveforms.
YAMAZAKI HIROMI
Sadayoshi Igarashi
Susumu Kitano
Akio Ishii