The objective of this research is to build and test a novel scale to improve the accuracy and resolution of measuring patient weight in bed. The proposed system consists of four piezoelectric load cells mounted in series with the bed posts and uses a unique dynamic technique to measure patient-bed weight. The dynamic measurement technique provides a means to include self-diagnostics for the sensors and electronics. This system has the potential of improving the accuracy of measuring patient weight by as must as a factor of 50 when compared to commercial patient-bed weighting systems. The proposed weighting system will have a number of applications in patients who are temporarily or permanently incapacitated and cannot be moved easily or comfortably. It's precision, sensitivity and dynamic range will be useful in the early detection and treatment of fluid imbalances; and it's accuracy, in the management of nutritional problems. This system can also be used to measure patient weight in dialysis units; premature nurseries; regular pediatrics or adult hospital beds; heavy, extensively instrumented intensive care beds; and stryker frames. A team consisting of a technical manager,a physician, and several design and test engineers will combine their expertise to (1) design, construct and test a low-cost precision piezoelectric load cell, (2) formulate a suitable design for the pneumatic lift system and (3) fabricate and test a prototype unit. In phase one research, the prototype system will be tested using a commercial hospital bed. The proposed piezoelectric scale system represents a significant advancement in high capacity, high resolution, rugged patient-bed weighting systems. This system can be retrofitted to any commercial hospital bed. It does not interfere with patient care or the operation of the bed.
About 1.261 million hospital beds [Source: American Hospital Association, Hospital Statistics, 19881 are in use in the United States. The proposed system can be retrofitted to many types of existing hospital beds. A commercial precision patient-bed scale system would cost about $2000, equivalent to state-of-the-art electronic platform scales. Instrumenting one percent of the existing hospital beds with the proposed scale system represents a $25.000,000 market. We believe the world market is an additional $50,000,000 to $75,000,000. Instrumenting dialysis chairs and incubators would probably develop into an equivalent market.
