A biomechanical and subjective comparison of two powered ambulance cots

This study investigated biomechanical effects of different leg folding/unfolding mechanisms used for loading/unloading two powered cots (Cots A and B) into and from a simulated ambulance. Sixteen experienced emergency medical service (EMS) workers loaded and unloaded cots with weights of 45, 68 and 91 kg placed on the cots to simulate patients. Peak back and shoulder/arm muscle activity was reduced 52–87% when using Cot A in comparison to Cot B. Peak ground reaction force (PGRF) was reduced by 74% with Cot A. Adding weight resulted in increased muscle activity and PGRF when using Cot B, but had little effect when using Cot A. Task time was longer with Cot A, though was not perceived unfavourably by participants. This study confirmed that it is possible to substantially reduce physical stress imposed on EMS workers when loading and unloading a cot to and from an ambulance through improvements in cot design. Practitioner Summary: This study compared two powered ambulance cots, one that lifts/lowers the front and rear wheels independently and one that lifts/lowers the four wheels simultaneously during ambulance loading and unloading. Measured muscle activity, ground reaction forces and operator perceptions support using cot designs that lift/lower the front and rear wheels independently.

[1]  Larry L Jackson,et al.  Occupational injuries among emergency responders. , 2009, American journal of industrial medicine.

[2]  Jonathan R Studnek,et al.  Evaluation of occupational injuries in an urban emergency medical services system before and after implementation of electrically powered stretchers. , 2012, Applied ergonomics.

[3]  E. Heath.  Borg's Perceived Exertion and Pain Scales , 1998 .

[4]  Susan Furber,et al.  Injuries to ambulance officers caused by patient handling tasks , 1997 .

[5]  David G. Behm,et al.  Reliability of electromyographic and force measures during prone isometric back extension in subjects with and without low back pain. , 2008, Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme.

[6]  S A Lavender,et al.  Biomechanical analyses of paramedics simulating frequently performed strenuous work tasks. , 2000, Applied ergonomics.

[7]  Steven A Lavender,et al.  A biomechanical and subjective assessment and comparison of three ambulance cot design configurations , 2012, Ergonomics.

[8]  W S Marras,et al.  A stochastic model of trunk muscle coactivation during trunk bending. , 1993, Spine.

[9]  J. Ruser.  Allegations of Undercounting in the BLS Survey of Occupational Injuries and Illnesses , 2010 .

[10]  Helmut Strasser,et al.  Ergonomics in the rescue service—Ergonomic evaluation of ambulance cots , 2006 .

[11]  C. Jensen,et al.  The influence of electrode position on bipolar surface electromyogram recordings of the upper trapezius muscle , 2004, European Journal of Applied Physiology and Occupational Physiology.

[12]  G Cooper,et al.  Risk assessment of patient handling with ambulance stretcher systems (ramp/(winch), easi-loader, tail-lift) using biomechanical failure criteria. , 2007, Medical engineering & physics.

[13]  Katherine L Hunting,et al.  Occupational Injuries among Emergency Medical Services Personnel , 2005, Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors.

[14]  Steven A Lavender,et al.  Designing ergonomic interventions for EMS workers, Part I: transporting patients down the stairs. , 2007, Applied ergonomics.

[15]  A Garg,et al.  Revised NIOSH equation for the design and evaluation of manual lifting tasks. , 1993, Ergonomics.

[16]  C. Ogden,et al.  Anthropometric reference data for children and adults: United States, 2007-2010. , 2012, Vital and health statistics. Series 11, Data from the National Health Survey.