Digital Human Modeling in Ergonomics Assessment of Patient Lifting by Paramedics

Excellence Through Innovative Research

www.wise.binghamton.edu

Digital Human Modeling for Ergonomics Assessment of Patient Lifting by Paramedics

Akiev Samson

Graduate Research AssociateDepartment of Systems Science and Industrial Engineering

Binghamton University (State University of New York) Binghamton, NY 13902

Feb 27th, 2009

http://www.wise.binghamton.edu/

2Binghamton University | February 2009www.wise.binghamton.edu

Agenda

• Ergonomics

• Work-Related Musculoskeletal Disorders (WMSDs)

• Patient Handling

• Paramedic Profession, Statistics

• Conventional Ergonomics vs Digital Human Modeling (DHM)

• Research Objectives and Outline

• Uniqueness and Significance

• Experiments

• Validation, Anthropometric Effect, Adjustment, Postural Effect

• Results

• Recommendations

• Conclusions and Future Work



Ergonomics

Ergonomics



Work-Related Musculoskeletal Disorders (WMSDs)

WMSDs

ConstructionManufacturingMining Office Work

Repetitive Motion Injuries

Repetitive Strain Injuries

Cumulative Trauma Disorders

Occupational Cervicobrachial

Disorders

Overuse Syndrome

Regional Musculoskeletal

Disorders

Soft Tissue Orders



Cost of WMSDs

2 Million Lost

Workdays

Highest Risk for

WRMSDs 1 in 5 Reported WRMSDs

Rate of Injuries

Twice the Working

Population

$1 in $3 Spent on WRSMDs

Healthcare Domain

“Increase in Ergonomic

Injuries, Worker Compensation

Claim..” Washington

State

Construction:

$1,000,000,000

Manufacturing:$500,000,000

Administrative: $200,000,000

Educational: $75,000,000

Healthcare: $340,000,000

50,000 Claims

45,000 Claims

20,000 Claims

8,000 Claims

36, 000 Claims

“Just for Washington State”

Center for Occupational and Environmental Medicine, 2003. Safety and Health Assessment and Research for Prevention (SHARP), 2005



Motivation

Du, 2005



Patient Handling in Healthcare

“Paramedics do not have the option of Time”



Paramedic Profession

Occupational Fatalities

Back Injuries

Sickness

Ambulance Crashes

Shootings

Fire BreakoutPatient Lifting

Repetitive Bending

Awkward Bending Hazardous

Material

Treating the Diseased

Excessive Work

“More than half have some form of WMSD”

“Many devices and many injuries”

“Complex and challenging” “Lack of

documentation of data”

“Many EMTs were volunteers”

“Less emphasis on patient lifting

training”



Paramedics: Statistics

Okada et al. (2005)



Conventional Ergonomics vs DHM

• Postural

Angles

• 3DSSPP

LMM

• Muscle

Activity

• Electrodes

EMG

• Stress

Perception

• Survey

BORG’s

Scale

DHM TechnologyLower Back

Analysis

Static Strength Prediction

Metabolic Energy Expenditure

Fatigue Analysis

Animation

Digital Humans Never

Say ‘No’ !!

TSB SimulationReach Zone

Analysis

Vision Analysis Collision Detection

“Lumbar Motion Monitor”

“Electromyography”



Research Objectives

• To demonstrate the effectiveness of DHM software for ergonomics assessment of paramedic patient handling

• To study the influence of anthropometry of paramedics on lower back stress

• To study the influence of postural variables on lower back stress during patient lifting



Research Outline

Quantifying Lower Back Stress: Validation

Defining Team Roles through Anthropometry

Adjustment of Stretcher and GurneyPostural Variables

DHM Software

“Challenging Environment”



Uniqueness and Significance

“Innovative Technology to Study

Healthcare Ergonomics”

“Implementation of a Cost Effective Solution

to Study Healthcare Ergonomics that will Benefit Healthcare Professionals in the

long term”



Research Methodology




Validation of DHM Software as a Tool to Study Patient Lifting



Validation

Replication of Images from Previous Research

10 Male Paramedics

Variable Anthropometry

48 Kilogram Patient

Average Postural Angles

Difference in Back Stress between Teams

Lavender et al. (2000a, 2000b)



Results: Validation

Bed Stretcher

Bed-side

Paramedic:

Standing

Stretcher- Side

Paramedic

Patient

Bedside

Paramedic:

Kneeling

Stretcher- Side

Paramedic

Stretcher Bed

Patient

Follower

Leader

Patient

Backboard

Follower

Leader

Stairs

Patient

Backboard

Follower

Leader

Stairs

Patient

Stairchair

Follower

Leader

Stairs

Patient

Stairchair

Gurney Side

Paramedic

Stretcher Side

Paramedic

Patient

Gurney

Stretcher



Results: Validation (Contd.)

“Paramedics will experience > 3400 N at least once during a complete transfer task”

48 Kg Patient




Effect of Anthropometry



Methodology for Simulating Postures

Get Anthropometries

Identify Grip Points

Identify Dimensions which are (can be) Fixed

Height of Stretcher Height

of Gurney

Distance between Grips (Stretcher, Backboard &

Stairchair)

Height of Bed

A



A

Distance between Hands (Gripping a

Bed Sheet)

Identify Dimensions

(angles) which can be Varied

Wrist Angles

Trunk Flexion

Shoulder Abduction

Position Body with Respect to Grip Points

Validate Postures

Analyze

Repeat for Other Digital

Humans

Paramedic Height

Patient Weight5th 50th 95th 5th 50th 95th

Methodology for Simulating Postures (Contd.)



Results: Effect of Anthropometry – Paramedic Height

“




Influence of Stretcher and Gurney Height Adjustment on Lower Back Stress for

Paramedics with Different Heights



Methodology for Simulating Tasks

Paramedic Height

Paramedic Weight

Patient Weight

Stretcher and Gurney Height

5th 50th 95th

5th 50th 95th

5th 50th 95th

53 cm

72.5 cm

92 cm



Results: Stretcher Side Paramedic

3750 N

2870 N

3200 N

4900 N



Main Effects: Stretcher Side Paramedic

3000 N

4200 N



Contour Plot: Stretcher Side Paramedic



Results: Gurney Side Paramedic

5750 N

6050 N

6500 N

7600 N

5900 N

5550 N



Contour Plot: Gurney Side Paramedic



Stretcher vs Gurney Side




Postural Variables



Different Postural Variables



Results: Trunk Flexion vs Shoulder Rotation



Results: Trunk Flexion vs Shoulder Separation



Results: Trunk Flexion vs Shoulder Elevation



Results: Trunk Flexion vs Elbow Angle



Summary of Results

• Team Role

• Leader in a safer role compared to follower

• Gurney Side role strenuous

• Standing safer than kneeling

• Anthropometry of Paramedic

• Shorter paramedics encounter lower back stress

• Could influence lower back stress of team member

• Height Adjustment is Crucial

• Degree of adjustment more for stretcher side than gurney side

• Postural Variables

• Stress trends at 0 , 10 , 20 and 30 , 40 and 50



Proposed Solutions

Recruitment

• Ideal: Shorter Paramedics

• Not the Most Effective: Shortage of Paramedics

Pre-planning

• Less Strength: Less Strenuous Task

• Equal Strength: Alternate between Tasks

Equipment

• Handles as Close as Possible to Patient Body

• Use of DHM to Evaluate Equipment

“Effort from Upper Management to Invest in Patient Lifting Equipment”



Limitations



Conclusions and Future Work

Stryker, 2007




Health & Medicine

Digital Human Modeling in Ergonomics Assessment of Patient Lifting by Paramedics