Unconstrained respiration measurement and respiratory arrest detection method by dynamic threshold in transferring patients by stretchers

General anesthesia used for surgical operations may cause unstable conditions of the patients after the operations, which could lead to respiratory arrests. Under such circumstances, nurses could fail in finding the change of the conditions, and other malpractices could also occur. It is highly possible that such malpractices may occur while transferring a patient from ICU to the room using a stretcher. Monitoring the change in the blood oxygen saturation concentration and other vital signs to detect a respiratory arrest is not easy when transferring a patient on a stretcher. Here we present several noise reduction system and algorithm to detect respiratory arrests in transferring a patient, based on the unconstrained air pressure method that the authors presented previously. As the result, when the acceleration level of the stretcher noise was 0.5G, the respiratory arrest detection ratio using this novel method was 65%, while that with the conventional method was 0%.