Group 16Members: Emily Jaeger, Amy Rosenthal and Nicole Typaldos Presented by: Nicole Typaldos29 October 2012

PROGRESS REPORT PRESENTATIONSENIOR DESIGN BME 401

A NEW MINIMALLY-INVASIVE BEDRIDDEN PATIENT WEIGHING SYSTEM

BRIEF OVERVIEW OF DESIGN

Weigh bedridden patients within 0.23 kg (0.5 lb) and with minimal movement of patient.

A single user with no additional training to operate the device and obtain patient weight in less than 5 minutes.

Device will not interfere with normal patient care.

Adult and obese patient weighing 22.7 kg to 453.6 kg (50 lb to 1000 lb) should remain comfortable.

Automatic readout to display screen.

The device will cost a maximum of $10,000.

DESIGN ALTERNATIVES

Location

breakdown of

design alternatives

Above Patient

Directly Under Patient

Beneath Bed

Below Bed Deck

DESIGN ALTERNATIVES UNDER CONSIDERATION

1) Four Scales under bed

2) Two Slats under bed

3) Lift mattress

4) Single Fluid Filled Bladder

5) Legs with load cells

6) Capacitance load sensor

7) Above bed deck four load cells

8) Double lift device

9) Measurement of string tension

10) Spring partition mattress, displacement measurement

11) Current inducing magnet mattress

12) Compartmental fluid filled bladder

ABOVE PATIENT

Double Lift Device Alternative to a single patient lift device, device has two structures

which connect above the patient’s bed to form a stable lifting apparatus.

Does involve displacement of the patient without repositioning.

Uses a typical sling lift, hydraulic lifts and attaching mechanism.

Wireless communication between the two sides.

Minimal tare capabilities.

BENEATH BED

Four Scales under bed Improvement on currently available full bed weigh scales

Hospital bed is positioned on all four floor scales with patient remaining in bed

Compounding error unavoidable in this design

Use four load cells

Expanded force range to include bed weight, approximately 200 lb.

DIRECTLYUNDER PATIENT

Capacitance load sensor Does allow patient to remain on device during entire stay.

Linear voltage output with respect to applied force.

Multiple measuring units necessary to acquire accurate readings.

Several variables to control design process to meet needs.

Unable to provide repeatability of readings in environment.

Embodiment Force

Support

Mobile Plate Fixed Plate with Dielectric

ANALYSIS PERFORMED TO CHOSE DESIGN

Research of current components available that would be needed in the device manufacturing.

Benefits and Compromises that would be necessary for each device.

Review of current patient care practices and procedures.

Review of each design for potential patient and nurse safety issues within the hospital setting.

Pugh Chart with 25 variables for comparison of each design alternative.

Focus on patient safety and meeting design specifications.

CHOSEN DESIGNCOMPARTMENTAL FLUID FILLED

BLADDER

Several compartments that measure the absolute pressure within the fluid filled bladder.

Single compartment did not offer repeatability necessary for informative weights.

Number and distribution of compartments will be determined in next stage of design.

Device is able to withstand necessary force range while maintaining linearity.

Directly below the patient and mattress

Patient is weighed undisturbed.

Medical staff will have access to weight during patient stay.

GENERAL DESIGN

Single measurement unit Embodiment of Chosen DesignFluid Filled Bladder

Pressure Sensor

Hospital Bed

Compartment Representation

Top Surface

Base Surface

NECESSARY EQUATIONS

Absolute Pressure

Weight of Patient

where a= base area of bladder

Compartment dimensions, solve to determine sensitivity to weight error, bladder fill conditions (h=height of bladder, A=total surface area, V=volume)

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Background ResearchLiterature

PatentsConcept Generation

DesignSafe

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Design Webpage

Initial Processes

BrainstormingCombination Table

Project ChoiceDesign Requirements

Combination Table

Project Development

Course Assignments

Poster Presentation

Progress ReportProgress Presentation

Final ReportFinal Presentation

SCHEDULE FOR DESIGN COMPLETION

Final Due Date

Initial Draft

Timeline to work on project

RESPONSIBILITIES Emily Jaeger

Presentation of Final Design

Device embodiment design

Amy Rosenthal

AutoCAD and website design

Materials for Design

Nicole Typaldos

DesignSafe and contacting manufacturers

Program GUI for device

Group 16Members: Emily Jaeger, Amy Rosenthal and Nicole Typaldos Presented by: Nicole Typaldos29 October 2012

QUESTIONS?

A NEW MINIMALLY-INVASIVE BEDRIDDEN PATIENT WEIGHING SYSTEM