Biological state monitoring system

A biological state monitoring system for monitoring a biological state of a subject on a bed over a predetermined monitoring period, the system comprising:

• plurality of load detectors each configured to detect a load of the subject on the bed;
• and
• a controller configured to:
• obtain a respiratory waveform of the subject based on the temporal variation of the detection value of each of the plurality of load detectors;
• successively obtain and output estimated values of a respiratory rate of the subject, based on the respiratory waveform of the subject;
• and
• determine whether or not the subject has the body motion based on the temporal variation of the detection value of at least one of the plurality of load detectors,
• wherein the monitoring period includes a body motion period in which the subject has a body motion, and a resting period in which the subject merely performs a respiration,
• wherein, in a case that the monitoring period shifts from a first resting period to the body motion period and then from the body motion period to a second resting period, the controller is configured to outputs, in the body motion period and a period after shifting from the body motion period to the second resting period, a last estimated value which is the latest among the estimated values obtained successively in the first resting period, and
• wherein the controller is configured to:
• obtain an interpeak distance between two peaks of the respiratory waveform of the subject, the two peaks being firstly and secondly exhibited peaks of the respiratory waveform in the second resting period;
• obtain the estimated value of the respiratory rate of the subject by using the equation of R=60/t, provided that t[s] is the inter-peak distance and R is the estimated value of the respiratory rate in one minute of the subject;
• and
• output the obtained estimated value instead of the last estimated value which is the latest among the estimated values obtained successively in the first resting period.