Hospital beds and lifts require the use of electric linear actuators to position hospital patients to optimal comfort and health levels.
There are multiple factors to consider when selecting an appropriate actuator for hospital environment:
- Medical Design Standards / Certifications.
- Ability to react in emergencies.
- IP Rating.
Electrical Medical Design Standards
There is a technical standard for medical electrical equipment — IEC 60601. This is a series of technical standards for the safety of electrical equipment which ensures reliability and effectiveness in hospitals and medical environments.
When selecting an actuator for a hospital environment, they must have the following certifications:
- Basic Safety and Essential Performance.
Additional certifications will assist in the FDA approval process:
- Requirements for Basic Safety and Essential Performance specifically for Hospital Beds.
- Mandatory Compliance for the manufacturing of hospital beds.
- Enforced starting April 1st, 2013.
- Requirements and test methods only for hoists and body-support units. intended for the transfer of disabled persons.
Progressive Automations offers IEC 60601-1 compliant actuators for your hospital bed manufacturing process which will result in the approval process and compliance with IEC 60601-2-52.
IEC 60601 has its own criteria for mandatory requirements for hospital beds and patient lifts – however, when selecting one, there are your own discretionary measures.
Electric linear actuators have their own duty cycle, voltage input rating, life cycle and operation safety measures.
The majority of our linear actuators have a duty cycle of 25%. This is typically quite enough for the hospital industry. Our duty cycles are based on the IEC S2 motor class of short-term duty. This duty cycle is based on a 20-minute time frame. Based on the 25% duty cycle, the patient or hospital staff controlling the bed or lift can potentially operate for 5 minutes every 20 minutes, or 15 minutes for every hour – that’s more than enough.
Lifecycle is also a large factor. When selecting an actuator for a hospital environment, you want to ensure that they will last a long time – replacing components can be time-consuming and impact the day-to-day operation and efficiency.
One cycle for linear actuators is defined as one extension + one retraction. Let’s say that a patient adjusts their bed frame a total of 12 times a day. That equals approximately 6 full actuator cycles. A lifecycle count of 60,000 cycles, for 6 cycles a day, equals to a life span of approximately 27.4 years!
Force, Speeds, and Feedback
Let’s review the basic actuator’s metrics in detail.
When designing a hospital bed you must account for a wide range of patients, and therefore, the weight of the patients using the beds. Let’s assume the max weight of a patient to be 400LBS.
The force imposed on the actuator will vary based on the angle of the patient.
Let’s assume a degree of patient mobility to be from 0 degrees (or 180 degrees) to 45 degrees*. At an incline of 45 degrees, a patient that is 400lbs will require a force of approximately 565lbf. This means that the actuator will need to be able to handle at least 565lbf* when the patient needs to be moved to a 45-degree angle.
*This will need to be calculated on your end of the project and the values displayed here are merely an example.
We recommend applying at least a 20% safety factor to the force required to ensure that there are no complications when unexpected imposed forces are experienced by the bed system.
Next is the speed. The speed of the actuator isn’t a large factor when selecting an appropriate model for hospital beds. Force and reliability are more important – but it is necessary to select a speed that will not frustrate the patient. You must select an option that provides a happy medium for the patient.
Choose an actuator that is too fast, and it will be difficult for the patient to adjust the bed to their “perfect” comfort level as overshoot and undershoot of the stroke can occur. Choose an actuator that is too slow, and the patient will have to wait “too long” to get to their desired position.
Feedback options are available on Progressive Automations actuators. Typically, HALL sensors or potentiometer feedback will be used for positioning.
A useful option to offer clients would be a positioning system that lets users select their optimal positions without having to constantly re-adjust. With this system, we offer the FLTCON series of control boxes that require HALL sensor feedback. We offer some remotes that have multiple memory presets. These presets can be programmed in by the patient and can be reset when a new patient uses the bed.
Situations will arise when patients in hospital beds will experience life-threating emergencies that rely on the quick decisions and actions of medical staff for survival.
Actuators have a fixed no load and full load speed. However, if a scenario presents where a patient is coding (in cardiac arrest), and the patient is in a sitting/partially sitting position, they must be placed in a lying position in order for medical staff to perform CPR and/or use a defibrillator.
This will require the actuator to be ‘quick released’ as the actuator will take time to move to a fully flattened position – every second count when saving a life.
Progressive Automations manufactures actuators that provide quick-release functionality that will provide precious time to save a person’s life.
Depending on the location of the hospital, certain spills and exposure to liquids and debris will occur. Sanitizing the beds, bodily fluids, or general exposure to liquids requires the ingress protection (IP) of the actuator to be enough to prevent liquids from penetrating the electrical components.
Progressive Automations offer actuators that have IP ratings up to IP69K! Typically, IP-66S should be sufficient, but IP-69K is fully submersible indefinitely.
For hospital beds, we recommend our PA-04 linear actuator. This model has an IP-66S rating, can be customized to have up to 900lbf of force and the necessary IEC 6061-1 compliance to be used in hospital environments.