Recommendations on Standards for the Design of Medical Diagnostic Equipment for Adults with Disabilities, Advisory Committee Final Report

2.4.2 Considerations of Manufacturers in Accessible MDE Design

MDE plays a central role in ensuring the health and well-being of all individuals by supporting the detection of diseases and disorders – essential information for developing treatments or therapeutic regimens to cure, control, or significantly palliate a wide range of health problems across the life span. Therefore, an immutable core attribute of MDE must be its ability to effectively support accurate and timely diagnoses. Other key factors that guide MDE manufacturers in their equipment design include: the nature of the specific diagnostic objective; safety requirements; FDA regulations (specifically 21CFR Part 820 – Quality Systems Regulations) and processes (Section 2.5); expected patient and user demographics; international standards for safety, essential performance, and usability; ergonomic guidelines; and ultimately, validation with representative customers to help establish the safety and effectiveness of the medical devices. MDE manufacturers believe that their usability requirements should include some measure of accessibility.

As detailed in Section 2.5.2.1, the most common standard used by manufacturers to guide the design of medical equipment is ANSI/AAMI ES60601-1:2005^K, which is the U.S. version of the larger scope of the International Electrotechnical Commission’s IEC 60601 series of standards for basic safety and essential performance of medical electrical equipment which also must be met. Imaging equipment that utilizes ionizing radiation must also comply with 21CFR Subchaper J. As detailed further in Section 2.5, all medical devices must adhere to FDA quality system regulation (21CFR820), applicable pre-market notification or approval processes, and risk management performed in accordance with ISO 14971.

These standards, regulations, and recommended practices provide details concerning the elements supporting the basic safety and essential performance of MDE. Standards with particular relevance to accessibility considerations include:

• Instability hazards: including the risk of the equipment tipping. Avoiding dangerous tipping is particularly important as patients transfer onto or off of MDE or reposition themselves upon it. As the width of MDE, such as examination tables and chairs increases, equipment may require redesign to address changes in tipping hazards. To mitigate tipping risks, the size of table and chair bases can be increased. This increase in base size can affect lift capability, reduce the open areas around equipment in the examination room, and require significant product redesigns (e.g., to ensure lift compatibility).

• Patient support safety factors: Patient support devices must meet applicable safety factors as delineated in IEC 60601-1. These factors typically range from 4x to 8x. This means a patient table labeled to support a 500 lb. patient must actually be designed and tested at up to 4,000 lbs. This has significant implications for adjustable height table design as many designs lose mechanical advantages as they go lower.

To guide their design efforts, manufacturers rely on anthropometric information,^L such as the specific measurements of men and women from the 5th to 95th percentiles. They also must consider the use of the MDE for the operator, including accessibility for the operator, topics which are not addressed in the NPRM. For example, accessibility standards could define operator requirements for communication (M306) and operable parts (M307). This is particularly important regarding standards for proper ergonomics for lifting and bending, which should meet Occupational Safety and Health Administration (OSHA) Standards (Section 2.3).^M

For clinical personnel, as the size of the transfer surface increases, the likelihood rises of putting clinical personnel into an unfavorable ergonomic position as a result of increasing their need to reach, lean or stretch. OSHA standards speak directly to this issue of ergonomic hazards within health care, including specific concerns about awkward postures and patient handling.^N

Another critical factor that must be considered is the ability of clinical staff to access the patient during a diagnostic imaging exam to ensure proper positioning, administer imaging agents or other drugs, monitor the patient, respond to patients’ requests, and so on. Additionally, because in most cases, the tables on diagnostic imaging equipment move during the exam; tables may have both moveable and stationary parts. Therefore, design consideration must be given to avoid tubing and other such items that are attached to the patient from getting caught in a tableside support and pulled out of a patient with the potential for injuring patients, compromising image quality, or necessitating another imaging procedure.

Notes

^K Association for the Advancement of Medical Instrumentation. ANSI/AAMI ES60601-1:2005 (R) 2012. Medical Electrical Equipment—Part 1: General Requirements for Basic Safety and Essential Performance. Approved 9 February 2006 by American National Standards Institute, Inc. Revised 2012.

^L Tilley, Alvin R. The Measure of Man and Woman: Human Factors in Design. New York: Wiley, 2002.

^M U.S. Department of Labor. OSHA Technical Manual, Section VII, Chapter 1, Back Disorders and Injuries. OSHA website: http://www.osha.gov/dts/osta/otm/otm_vii/otm_vii_1.html (visited May 17, 2012).

^N U.S. Department of Labor. Hospital eTool: Healthcare Wide Hazards – Ergonomics. OSHA website: http://www.osha.gov/SLTC/etools/hospital/hazards/ergo/ergo.html (visited May 17, 2012).