A new intelligent bed care system for hospital and home patients.

An intelligent bed-care system has been developed for monitoring patient movements and behavior in the hospital and at home in order to prevent injuries from falls, a major problem in health care facilities. Falls, as well as patient activity immediately preceding falls (i.e. exiting the bed), are especially dangerous when infusion extubation also occurs. This new system detects in-bed infusion fluid leaks, bleeding due to infusion-tube pullout, and urine resulting from incontinence. It employs stainless steel tape and wire noncontacting electrodes, several linear integrated circuits, and a low-power, 8-bit single-chip microcomputer The electrodes are installed between the bed mattress and sheet to record changes in an always-present alternating current (AC) voltage, which is induced on the patient's body by electrostatic coupling from a 100-V, 60-Hz alternating current power line around the bed. The microcomputer uses changes in the induced alternating current voltage to detect the patient's movements before and after leaving the bed, as well as any fluid leakage. The microcomputer alerts the nursing station, via the nurse call system or personal handy phone (PHS), that the patient is in an active state; has a dangerous posture on the bed; is contaminating the sheet due to leaking, bleeding or incontinence; or is out of bed.

A system for monitoring heart pulse, respiration and posture in bed.

A non-invasive system has been developed to monitor cardiac vibrations, respiration and posture of inbed hospitalized patients and elderly people who need constant care. These physiological variables are recorded by four 2 x 28 cm piezoelectric film acceleration sensors, eight 2 x 2 cm small pressure sensors and a 5 x 100 cm long pressure sensor. The piezoelectric sensors, attached to the chest over the heart during bed sleep or rest, detect the movements produced by the heartbeat and respiration. The eight small pressure sensors are attached at various positions on the upper and lower body. A longer pressure sensor, to detect the patient leaving the bed, is attached to the side of the bed. These sensor outputs are digitized at a sampling rate of 200 Hz using a 12-bit A/D converter and stored on a personal computer. The computer detects cardiac vibrations and respiration from upper chest movements and posture from the pressures recorded by small and long pressure sensors.