Clinical Engineering Bank

  Be inspired by your Profession  



What do we mean by Safety?

Safety would be
1. The condition of being safe; freedom from danger, risk, or injury.
2. A device designed to prevent accidents, as a lock on a firearm preventing accidental firing.

Another definition of Safety is the state of being "safe" (from French sauf), the condition of being protected against physical, social, spiritual, financial, political, emotional, occupational, psychological, educational or other types or consequences of failure, damage, error, accidents, harm or any other event which could be considered non-desirable. Safety can also be defined to be the control of recognized hazards to achieve an acceptable level of risk. This can take the form of being protected from the event or from exposure to something that causes health or economical losses. It can include protection of people or of possessions.

Health and Safety at Work

Hospitals are still potentially dangerous sites; they are very worthy areas for contamination. Personnel are strictly have to conform the safety procedures and precautions for their own and others safety.

These are the Golden Rules in medical environment:

  1. Good hygiene plus common sense.
  2. Learn to be cautious or slightly suspicious.

These safety procedures in general terms for new biomedical professionals entering the health care facilities for the first time and do not have adequate knowledge about safety at work within the healthcare environment. It is not intended to be comprehensive notes:

  • It shall be the duty of every employee while at work to take reasonable care for the health and safety of him and of other persons who may be affected by his acts or omissions.
    • Any job that has to be left incomplete and that presents a safety hazard MUST be clearly marked as such.
    • Protective clothing, including gloves, goggles, ear muffs, industrial footwear, overalls, hard hats, aprons etc., is available for use and should be worn wherever the nature of work demands it. Failure to use appropriate protective clothing not only exposes to unnecessary risk of injury, but also may influence any claim made against industrial insurance.
    • Employees working on live electrical circuits, flammable explosive or harmful chemicals, exposed to unguarded machine hazards and at a height where there may be a danger of falling must never work alone.
    • An employee in the above circumstances who may unexpectedly be left alone should be aware that his own safety is at risk, and should highlight this exposure to his manager or supervisor as soon as possible.

    They must be in sight or calling distance of another employee who has the following qualifications:

    • Shall be familiar with the means of removing power from any equipment involved.
    • Shall know how to apply artificial respiration and/or how quickly to obtain medical aid.
    • Shall be familiar with emergency measures, first aid locations and fire extinguishers.
    Risks and responses

    Safety is generally interpreted as implying a real and significant impact on risk of death, injury or damage to property. In response to perceived risks many interventions may be proposed with engineering responses and regulation being two of the most common.

    Probably the most common individual response to perceived safety issues is insurance, which compensates for or provides restitution in the case of damage or loss.

    System safety and reliability engineering

    System safety and reliability engineering is an engineering discipline. Continuous changes in technology, environmental regulation and public safety concerns make the analysis of complex safety-critical systems more and more demanding.

    A common fallacy, for example among electrical engineers regarding structure power systems, is that safety issues can be readily deduced. In fact, safety issues have been discovered one by one, over more than a century in the case mentioned, in the work of many thousands of practitioners, and cannot be deduced by a single individual over a few decades. A knowledge of the literature, the standards and custom in a field is a critical part of safety engineering. A combination of theory and track record of practices is involved, and track record indicates some of the areas of theory that are relevant. (In the USA, persons with a state license in Professional Engineering in Electrical Engineering are expected to be competent in this regard, the foregoing notwithstanding, but most electrical engineers have no need of the license for their work.)

    Safety is often seen as one of a group of related disciplines: quality, reliability, availability, maintainability and safety. (Availability is sometimes not mentioned, on the principle that it is a simple function of reliability and maintainability.) These issues tend to determine the value of any work, and deficits in any of these areas are considered to result in a cost, beyond the cost of addressing the area in the first place; good management is then expected to minimize total cost.

    Safety measures

    Safety measures are activities and precautions taken to improve safety, i.e. reduce risk related to human health. Common safety measures include:

    • Chemical analysis
    • Destructive testing of samples
    • Drug testing of employees, etc.
    • Examination of activities by specialists to minimize physical stress or increase productivity
    • Geological surveys to determine whether land or water sources are polluted, how firm the ground is at a potential building site, etc.
    • Government regulation so suppliers know what standards their product is expected to meet.
    • Industry regulation so suppliers know what level of quality is expected. Industry regulation is often imposed to avoid potential government regulation.
    • Instruction manuals explaining how to use a product or perform an activity
    • Instructional videos demonstrating proper use of products
    • Root cause analysis to identify causes of a system failure and correct deficiencies.
    • Internet safety or Online Safety, is protection of the user's safety from cyber threats or computer crime in general.
    • Periodic evaluations of employees, departments, etc.
    • Physical examinations to determine whether a person has a physical condition that would create a problem.
    • Safety margins/Safety factors. For instance, a product rated to never be required to handle more than 200 pounds might be designed to fail under at least 400 pounds, a safety factor of two. Higher numbers are used in more sensitive applications such as medical or transit safety.
    • Self-imposed regulation of various types.
    • Implementation of standard protocols and procedures so that activities are conducted in a known way.
    • Statements of ethics by industry organizations or an individual company so its employees know what is expected of them.
    • Stress testing subjects a person or product to stresses in excess of those the person or product is designed to handle, to determining the "breaking point".
    • Training of employees, vendors, product users
    • Visual examination for dangerous situations such as emergency exits blocked because they are being used as storage areas.
    • Visual examination for flaws such as cracks, peeling, loose connections.
    • X-ray analysis to see inside a sealed object such as a weld, a cement wall or an airplane outer skin.

    Occupational health and safety

    Occupational health and safety is concerned with protecting the safety, health and welfare of people engaged in work or employment.

    The enjoyment of these standards at the highest levels is a basic human right that should be accessible by each and every worker.

    Regardless of the nature of their work, workers should be able to carry out their responsibilities in a safe and secure working environment, free from hazards.

    These rights are set out in legislation to ensure that employers are clear about the obligations and the consequences for neglecting them. "Safe at Work"

    What is a hazard?

    The meaning of the word hazard can be confusing. Often dictionaries do not give specific definitions or combine it with the term "risk". For example, one dictionary defines hazard as "a danger or risk" which helps explain why many people use the terms interchangeably.

    There are many definitions for hazard but the more common definition when talking about workplace health and safety is:

    A hazard is any source of potential damage, harm or adverse health effects on something or someone under certain conditions at work.

    Basically, a hazard can cause harm or adverse effects (to individuals as health effects or to organizations as property or equipment losses).

    Sometimes a hazard is referred to as being the actual harm or the health effect it caused rather than the hazard. For example, the disease tuberculosis (TB) might be called a hazard by some but in general the TB-causing bacteria would be considered the "hazard" or "hazardous biological agent".

    Environment Hazards:

    The environment within the hospital includes such elements as solid wastes, noise, utilities (natural gas, water, etc.), and building structures which must be carefully controlled and managed to reduce hazards ranging from the spread of infection to injury from physical objects.

    Biological Hazards:

    Infection control is a major factor in hospital safety today, because infection threatens the safety of staff members as well as that of patients. Infection control is accomplished by setting up and managing programs that identify exposures to and eliminate sources of infection. Isolation, decontamina tion, sterilization, and appropriate methods of biological waste disposal are the primary tools of infection control.

    Infection results when microorganisms capable of causing disease have gained access to the tissues established themselves, multiplied and caused some adverse effect upon the host.

    • General, to avoid infections:
      • Pay strict attention to personal hygiene,
      • Wear clean protective clothing,
      • Make sure that any cuts and injuries receive prompt medical attention, and
      • Keep vaccinations up to date.
    • Staff working within the operating rooms must wear protective clothing, i.e. face masks, rubber disposable gloves, gowns and head covering.
    • All electro-medical and laboratory equipment identified as a possible infection risk must be satisfactorily disinfected before it is serviced or repaired.
    • Written notification that a disinfection process has been carried out by Laboratory personnel must be obtained from the chief MLSO prior to undertaking replacement of HEPA filters in microbiological safety cabinets.
    • Maintenance and servicing within the Aseptor must only be done after the completion of a disinfection/sterilization cycle and subsequent exhausting of the formaldehyde vapour. Equipment awaiting disinfection in the Aseptor must not be touched.
    • Receiver vessels of vacuum plants, and their pipe system. Particularly Medical Vacuum, accumulate a variety of substances of unknown potential to cause injury and infection. When opened for protective measures against inhaling and skin contact.

    [When In Doubt Whether A Particular Hazard Exists - Assume that it does]

    Mechanical Hazards:

    Mechanical devices used for clinical purposes in the modern hospital include mobility aids, transfer devices, prosthetic devices, mechanical-assist devices, and patient-support equipment. Since each of these devices embodies numerous threats to patients as well as to hospitals staff, they must be subjected to careful design review and failure indication, and specifications for safe use must be established.

    Electrical Hazards:

    Patients are surrounded by and often connected to electrical devices where they are exposed to low-level electrical hazards. An electrical shock is any undesired physiological response to an electrical current applied to the body. The physiological responses of an electrical current in the body begin at the cellular level. A current passing in the proximity of a single cell will depolarize it if it is above threshold.

    If the current applied to the body is large enough, it can cause the cell to get hot and ultimately to vaporize. This form of an electrical shock would be manifested as tissue injury. In summary, a shock appears as unwanted tissue stimulation, unwanted muscle contraction, or tissue injury.

    The danger of an electrical shock increases as the current level increases. Shock is measured in terms of current rather than voltage because the physiological responses of the body are consistently related to current intensity. Shocks of current confined to the limbs may cause injury but are less dangerous than shocks to the vital regions of the heart and the respiratory centers. Currents passing through the heart or brain stem can cause death.

    Microshock and Macroshock:

    A much subtler electrical shock situation than macroshock is microshock (figure 2.2). It is sometimes more dangerous because it is difficult to detect. The two situations differ as indicated by the following definitions:

    Macroshock a physiological response to a current applied to the surface of the intact skin of the body that produces unwanted or unnecessary stimulation, muscle contractions, or tissue injury.“

    Microshock a physiological response to a current applied to the surface or in the close vicinity of the heart that produces unwanted stimulation, muscle contractions, or tissue injury.”

    High Current Risk with current above 100 mA. The actual danger to life is related to the magnitude of the electric current passed through the body. The main high current risk is that of burns at the site of contact.

    Low Current Risk with current below 100 mA. The low current risks can be divided into three categories:

    a) Muscular Stimulation where the threshold for momentary contact with a live object at about 200 microA at 50 Hz. For gripping contact is at 500 microA. The threshold of current above which a subject can not normally let go is on average 6 - 10 mA at 50 Hz. An even more dangerous form of tetanisation is that affecting the respiratory muscles known as thoracic tetanus which can cause death by suffocation.

    b) Neuronal Damage: This is damage to the central nervous system that occurs without cardiac arrest. It could temporary or permanent damage.

    c) Cardiac Arrest and Microshock: If the heart receives a stimulus of sufficient magnitude during the 100 msec or so either side of T-wave in the electrocardiogram which corresponds to the ventricular repolarisation then an unsynchronised contraction and relaxation of ventricular muscle fibers occurs with consequent cessation of cardiac pumping action. This is ventricular fibrillation, which has thresholds of 30 mA for currents applied across the chest for two-year-old children and of 60 - 120 mA for adults have been suggested. In case of intracardiac measurements the ventricular fibrillation thresholds may be as low as 60 - 100 microA .

    What is risk?

    Risk is the chance or probability that a person will be harmed or experience an adverse health effect if exposed to a hazard. It may also apply to situations with property or equipment loss.

    For example: The risk of developing cancer from smoking cigarettes could be expressed as "cigarette smokers are 12 times (for example) more likely to die of lung cancer than non-smokers". Another way of reporting risk is "a certain number, "Y", of smokers per 100,000 smokers will likely develop lung cancer" (depending on their age and how many years they have been smoking). These risks are expressed as a probability or likelihood of developing a disease or getting injured, whereas hazards refer to the possible consequences (e.g., lung cancer, emphysema and heart disease from cigarette smoking).

    Factors that influence the degree of risk include:

    • how much a person is exposed to a hazardous thing or condition,
    • how the person is exposed (e.g., breathing in a vapour, skin contact), and
    • how severe are the effects under the conditions of exposure. "ccohs"
    What is a risk assessment?

    Risk assessment is the process where you:

    • identify hazards,
    • analyze or evaluate the risk associated with that hazard, and
    • determine appropriate ways to eliminate or control the hazard.

    The OSH Answers Risk Assessment has details on how to conduct an assessment and establish priorities.

    What types of hazards are there?

    A common way to classify hazards is by category:

    • Biological - bacteria, viruses, insects, plants, birds, animals, and humans, etc.,
    • Chemical - depends on the physical, chemical and toxic properties of the chemical.
    • Ergonomic - repetitive movements, improper set up of workstation, etc.,
    • Physical - radiation, magnetic fields, pressure extremes (high pressure or vacuum), noise, etc,
    • Psychosocial - stress, violence, etc.,
    • Safety - slipping/tripping hazards, inappropriate machine guarding, equipment malfunctions or breakdowns

    Please use OSH Answers to find information about specific hazards and their control. If you are unable to find the information you are looking for, please consider using our subscription products, or contacting our free Inquiries Service for more assistance.

    What is a risk assessment?

    Risk assessment is the process where you:

    • Identify hazards.
    • Analyze or evaluate the risk associated with that hazard.
    • Determine appropriate ways to eliminate or control the hazard.

    In practical terms, a risk assessment is a thorough look at your workplace to identify those things, situations, processes, etc that may cause harm, particularly to people. After identification is made, you evaluate how likely and severe the risk is, and then decide what measures should be in place to effectively prevent or control the harm from happening.

    For definitions and more information about what hazards and risks are, please see the OSH Answers document Hazard and Risk.

    How do you do a risk assessment?

    Assessments should be done by a competent team of individuals who have a good working knowledge of the workplace. Staff should be involved always include supervisors and workers who work with the process under review as they are the most familiar with the operation.

    In general, to do an assessment, you should:

    • Identify hazards.
    • Evaluate the likelihood of an injury or illness occurring, and its severity.
    • Consider normal operational situations as well as non-standard events such as shutdowns, power outages, emergencies, etc.
    • Review all available health and safety information about the hazard such as MSDSs, manufacturers literature, information from reputable organizations, results of testing, etc.
    • Identify actions necessary to eliminate or control the risk.
    • Monitor and evaluate to confirm the risk is controlled.
    • Keep any documentation or records that may be necessary. Documentation may include detailing the process used to assess the risk, outlining any evaluations, or detailing how conclusions were made.

    When doing an assessment, you must take into account:

    • the methods and procedures used in the processing, use, handling or storage of the substance, etc.
    • the actual and the potential exposure of workers
    • the measures and procedures necessary to control such exposure by means of engineering controls, work practices, and hygiene practices and facilities

    By determining the level of risk associated with the hazard, the employer and the joint health and safety committee can decide whether a control program is required.

    It is important to remember that the assessment must take into account not only the current state of the workplace but any potential situations as well. See a sample risk assessment form.

    Risk based maintenance decisions

    Are you a risk-aware (neutral decision maker) or a risk-averse EBME manager?

    When considering maintenance applications, CE managers often face complicated decisions. These complications increase when they have to reflect on conflicting objectives such as clinical need, technical resources, cost, risk, and customer expectations. Maintenance work should consider repairable systems subject to random failures and analyse trade-offs between the costs and the benefits of the maintenance activities.

    This article aims to assist with decision making on planning maintenance for electro-medical devices that are in everyday use.  Continue reading at Risk based maintenance decisions

    Useful Resources

    • ISO 14971 – Application of risk management to medical devices

    • FDA Guidance – Incorporating human factors into risk management

    • FDA Guidance – Premarketing Risk Assessment

    • ISO 14971, Risk Management - Application of Risk Management to Medical Devices, International Standards Organization, 2000. Defines several risk management terms and provides a framework for an effective risk management process.

    • IEC 60601-1-4, Medical Electrical Equipment, Part 1: General Requirements for Safety and Essential Performance, Collateral Standard: Programmable Electrical Medical Systems; ed. 1.1, International electrotechnical Commission, 2000. IEC 60601-1-4. Defines many basic principles of risk management, including the definition of risk as the combination of probability and severity.

    • ANSI/ISO/AAMI 13485, Medical Devices —Quality Management Systems— Requirements for Regulatory Purposes, International Standards Organization, 2003. Provides the framework for a quality system for medical device manufacturers and requires establishing a risk management process based on ISO 14971 and using it throughout the product realization process.

    • ANSI/AAMI SW68, Medical Device Software, Software Life-Cycle Processes, Association for the Advancement of Medical Instrumentation, 2001. Defines requirements for a software development life cycle and requires that manufacturers implement risk management throughout the life cycle on the basis of ISO 14971.

    • AAMI TIR32, Medical Device Software Risk Management, Assoc. for the Advancement of Medical Instrumentation, 2004. Provides guidance on ways to interpret and apply the ISO 14971 requirements for software-based medical devices.