New MinimallyInvasive Bed Ridden Patient Weighing System Amy

New Minimally-Invasive Bed. Ridden Patient Weighing System Amy Rosenthal, Nicole Typaldos, Emily Jaeger Mentor: Dr. Frank CP Yin

Background �Patient’s weight is critical to care �Uncomfortable for patients to be weighed �Difficult and time consuming for nurses to move patients �Nurses often estimate weight to avoid the hassle �May become unsafe to weigh certain patients �Obesity has increased to over 35% of the population 1 1. United States. Center for Disease Control and Prevention. Department of Health and Human Services. Prevalence of Obesity in the United States, 2009 -2010. By Cynthia L. Ogden, Margaret D. Carroll, Brian K. Kit, and Katherine M. Flegal. Vol. 83. Hyattsville, MD: National Center for Health and Statistics, 2012. CDC. Web. 23 Sept. 2012.

Problem �Patients can be lifted � Uncomfortable � Unsafe for patient and nurse � Difficult � Complicated �Scale built into bed � Nurses forget to tare � Poor repeatability � Nurses are expected to do calculation �Bed can be weighed � Difficult to move the bed � Uncomfortable for patient to move � Large weight of the bed must be subtracted off causing less accuracy

Scope � Design a device for weighing bedridden patients within 0. 23 kg (0. 5 lbs) and with minimal movement of patient to avoid the discomfort for patients and hassle for nurses. � A single user with no additional training will be able to operate the device and determine the weight of the patient within 5 minutes of seeking the information so weighing can be done efficiently without taking the current 15 -20 minute standard. � The device design will not interfere with normal patient care. � Adults and obese patients weighing 22. 7 kg to 453. 6 kg (50 lbs to 1000 lbs) should be able to remain comfortable while weight is monitored. � Some automatic capabilities will be added to ease continual patient weight monitoring including an automatic readout for use in hospitals. � The device will cost a maximum of $10, 000.

Current Patents �Attached to the bed �Design raises bed on a leg attached to a force transducer that takes weight 1 1. Neuman, Eli. Weighting Device for Bedridden Patients. Tedea-Huntleigh Intl. Ltd. , assaignee Patent 5747745. 05 May 1998

Current Patents �Mobile scale �Design slides under hospital bed and then weighs both bed and patient and then the bed weight is subtracted 1 �Design has scale wheeled against patient bed, but still requires moving patient 2 �Design goes under bed mattress to give reading 3 1. Ashpes, Adam T. , Rynd, Richard. Mobile Hospital Bed Scale. EZE Weigh, LLC. , assignee. Patent 5990423. 23 Nov. 1999 2. Stultz, Frederick L. , and Clark, George C. Scale for Weighing Hospital Patients in their Horizontal Position. Acme Sclae Company, assignee. Patent 4006789. 08 Feb 1997 3. Hasty, Byron E. and Carbona, John A. Portable Scale. CH Administration Inc. , assginee. Patent 5393935. 28 Feb. 1995.

Current Patents �Veterinary scales �Design pulls cables taught when table is in lowest position, letting force transducer measure weight 1 �Design has a platform suspended at four corners with tensile load cells that give signal proportional to force 2 1. Rosenberg, Philip M. , and Rosenberg, Alexander J. Veterinary Examination Table. Animal Veterinary Products, Inc. , assignee. Patent RE 32052. 24 Dec. 1985. 2. Schneider, H. Allen. Animal Scale. Weigh Right Electronic Systems, Inc. , assignee. Patent 4286679. 01 Sept. 1981

Stryker Hospital Beds �Bariatric Hospital Beds �Model: Bari 10 A � In bed scale standard with 453. 6 kg (1000 lb) range �Critical Care Beds �Models: In. Touch, Epic II � Integrated scale only comes standard in In. Touch model � Maximum weight capacity of only 228 kg (500 lb) �Med/Surge Beds �Models: S 3, Go. Bed II � Integrated one-touch scale optional in both models � Ability to weigh patient in any position Stryker. http: //www. stryker. com/enus/products/Patient. Handling. EMSand. Evacuation. Equipment/Beds/index. htm

Hill-Rom Hospital Beds �Bariatric Beds �Tri. Flex II-Optional In-bed scale � Maximum capacity 453. 6 kg (1000 lb) capacity �Excel Care ES – In-bed scale standard � Accuracy of 1% of patient weight when sleep deck in supine position � Maximum capacity of 453. 6 kg (1000 lb) capacity �Total. Care Bariatric Plus – Integrated scale standard � Accuracy of 1% of patient weight up to 181. 4 kg (400 lb) � Functional up to 227 kg (500 lb) Hill-Rom. http: //www 2. hill-rom. com/usa/index. asp

Hill-Rom Hospital Beds �Non-Bariatric Beds �Versa. Care – In-bed scale standard � Accuracy of 1% of patient’s weight, even with head elevated �Care. Assist ES – optional integrated scale � Accuracy within 1 kg (2. 2 lb) or 1. 1% of patient’s weight, whichever is greater � Repeatability is within 2% of patient’s weight � Functional up to 227 kg (500 lb) Hill-Rom. http: //www 2. hill-rom. com/usa/index. asp

Hoyer Lift Scales �Variety of models with capacities ranging around 500 to 700 lbs �Need to buy the lift and the scale separately �Lift slings can be either a chair or a stretcher lift �Commonly used �Portable

Design Specifications: Force �Range: 22. 68 kg 453. 59 kg (50 lbs to 1000 lbs) �Sensitivity: 0. 23 kg (0. 5 lbs) �Repeatability: Variance of less than 0. 25 kg �Force transducers linear over 44 N to 5000 N

Design Specification: Safety �Shockproof �Waterproof �Can be sterilized �Current leakage of less that 100 microamp

Design Specifications: Device �Size: fit within normal bed dimensions (91 x 213 cm) �Portable: May be carried by a single nurse, less than 35 lbs �Digital readout of weight �Option to remove or add the object’s weight (i. e. to account for removal or addition blankets) �Interface with computer or standalone device �Display output in units of kg or lbs �Efficient: less than 5 minutes to operate and single output for easy reading �Made for adults and obese patients �Power source: 120 V AC or convert to DC �Temperature range: Perform in 10°C to 37°C (50°F to 100°F)

Design Specifications �Minimal movement of patient �No change to patient’s comfort

Load Cell Equations �Converts force into an electrical signal. �Force deforms a strain gauge which measures the strain as an electrical signal, as a strain causes a change in the electrical resistance �Strain gauge in form of Wheatstone bridge

Load Cell Equation �Electrical signal output must be amplified by instrumentation amplifier

Mass Equation �Weight = mass x acceleration due to gravity �g = 9. 81 m/s 2 = acceleration due to gravity

Current Nurse Calculations for Weight by Bed Freitag, Elke, et al. "Determination of body weight and height for critically ill patients admitted to the intensive care unit: A quality improvement project. " Australian Critical Care 23 (2010): 197 -207.

Team Organization Amy Nicole Emily First Presentation Second Presentation Third Presentation Computer Programming Hospital Contact Client Contact Designs Electrical Component Mechanical Aspect

1 2 3 4 5 6 7 8 9 10 Initial Process Background Research Literature Patents Social Impact Interviews Problem Definition Project Scope Specifications Metrics Concept Generation Brainstorming Comination Table Design Alternatives Project Choice Design Requirements Design. Safe Project Development Draft Due Timeline to work on project 11 12 13 14

Due Dates Course Assignments 1 st Preliminary Report Preliminary Presentation Progress Report Progress Presentation Final Report Final Presentation Design Webpage Poster Presentation 2 nd 3 rd 4 th 5 th 6 th 7 th 8 th 9 th 10 th Final Due Date Initial Draft Timeline to work on project 11 th 12 th 13 th 14 th 15 th

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