Real-Time Location Systems (RTLS) in Healthcare: Optimizing Operational Efficiency
Real-Time Location Systems (RTLS) have emerged as a valuable technological tool in healthcare. By providing real-time tracking of patients, staff, and assets, these systems contribute to workflow optimization and greater operational efficiency. Additionally, to enable even more valuable use cases, Real-Time Location Systems can be integrated with other healthcare systems such as Electronic Medical Records (EMR) systems, Enterprise Resource Planning (ERP) systems, Computerized Maintenance Management Systems (CMMS), Bed Management software, and Nurse Call systems.
There are now many different enabling technologies that power RTLS and many different vendors. There are myriad combinations of technologies, integrations, and use cases. This has made it important for healthcare organizations to establish a basic understanding of the underlying technologies.
Definition and Purpose of RTLS
Real-Time Location Systems (RTLS) are technologies that enable the tracking of objects or people within a defined area in real time or near real time. This is useful in healthcare settings for monitoring patients, locating critical assets, and enhancing staff workflow. This is becoming especially useful as integrations between healthcare systems are becoming more possible and prevalent.
Overview of Main Components
A Real-Time Location System is typically comprised of three fundamental components:
- Tags: These are mobile specialized devices and/or labels that are attached to objects or worn/carried by people. These are the devices that will be located and may include battery-powered RTLS tags, passive RFID labels, mobile computers/phones, and other similar devices.
- Fixed Infrastructure Devices: These are specialized fixed-position devices that send and/or receive signals to and/or from tags to calculate tag locations. These devices include network access points, specialized RTLS fixed devices, RFID readers/antennas, and other similar devices.
- Software: This is the software that calculates, processes, and displays the real-time location information of Tags as determined by the Fixed Infrastructure. This software may be hosted locally on an on-premises server (“on-prem”) or on a cloud server off-premises (“off-prem”).
Different RTLS technologies and vendors require different types of hardware components. While these various hardware components differ in functionality (and terminology), typically those various components can be categorized into one of the latter categories.
The Right RTLS for the Right Job
There are different technologies that enable Real-Time Location Systems (RTLS), and one size does not fit all.
Some use cases require a high degree of room-level accuracy – certainty that a Tag is within a space bounded by four walls (such as an operating room or an inpatient room).
Other use cases require a high degree of accuracy in free space – certainty that a Tag is in a specific position not bounded by four walls (such as a chair in an infusion center or a bed in a PACU).
Other use cases do not require a high level of accuracy and instead require a minimal optimal cost of ownership.
Still other use cases demand a low Tag cost where tens or hundreds of thousands of assets & supplies need to be tracked.
Sometimes these requirements may conflict with one another and sometimes not, which is why RTLS experts can help hospitals weigh these decisions.
Different Types of RTLS Technologies
In the following sections, we’ll delve into the diverse landscape of Real-Time Location Systems (RTLS) technologies, each offering unique advantages and limitations. We’ll explore the high-level basics of how these technologies function and how they can best be utilized in healthcare settings.
The most widely deployed RTLS-enabling technologies include:
- Infrared (IR)
- Ultra-Wideband (UWB)
- RFID (Radio-Frequency Identification)
- Bluetooth/BLE(Bluetooth Low Energy)-based
- Active vs. Passive RTLS Systems
- Choosing the Right System for Healthcare
Infrared (IR) systems use infrared signals to determine the location of a tagged object or person. They operate on the principle of line-of-sight (LoS), which makes them especially suited for high room-level accuracy in controlled environments. It is important to note that modern infrared systems do not have strict line-of-sight limitations.
- High room-level accuracy with line-of-sight (LoS) technology.
- Difficult to interfere with or to eavesdrop on.
- Best performance requires line-of-sight between the tag and the sensor.
- Infrastructure can be expensive due to the high density of sensors needed.
Ideal Healthcare Use Cases
- Patient Tracking & Workflows (especially where room-level accuracy is important)
- Staff Tracking & Workflows, and Staff Safety/Duress
- Tags: Tags are battery-powered devices that are equipped with infrared (IR) sensors, wireless radios for communication, and any additional sensors that may augment location accuracy (in hybrid systems).
- Fixed Infrastructure Devices: Fixed-position devices are installed that have at least infrared (IR) sensors and may be either battery-powered or line-powered.
Understanding Infrared RTLS: The Importance of Line-of-Sight and Controlled Environments
Infrared (IR) systems use infrared signals—part of the electromagnetic spectrum with wavelengths longer than those of visible light but shorter than microwaves—to determine the location of a tagged object or person. These signals are emitted from tags and captured by receivers. An IR system may calculate the distance based on the time it takes for the infrared signal to travel from the tag to the receiver, thus providing the tagged object’s or person’s location.
The IR system operates at least in part on the principle of line-of-sight. This means that the tagged object must be visible to the sensor for a precise measurement. Because of this line-of-sight (LoS) requirement, infrared signals can be used to accurately and precisely locate a Tag within a given room, allowing for a high level of certainty that an object or person is located within a room – especially when compared to other, non-LoS technologies.
IR systems thrive in a “controlled environment,” meaning spaces where the conditions are stable and predictable such as individual hospital rooms, as opposed to larger, more open areas with more variables that could impact signal integrity. In such controlled environments, the line-of-sight (LoS) requirement can be more reliably met, leading to higher accuracy in tracking.
Obstructions to the line-of-sight in an infrared system can include a variety of physical and environmental barriers. Some examples are:
- Walls: Traditional walls, partitions, or even temporary structures like screens can block the infrared signals.
- Furniture: Large furniture items like cabinets, desks, and beds could potentially interfere with the direct path between the tag and the receiver.
- People: In busy environments like hospitals, the movement of healthcare providers, patients, and visitors can momentarily obstruct the signal.
- Medical Equipment: Large pieces of medical equipment like diagnostic machines, mobile workstations, or medical carts could also act as obstructions.
- Doors: Closed or even partially open doors can impede the line-of-sight for infrared systems.
- Curtains or Drapes: Soft obstructions like curtains, blinds, or other window coverings could also interfere with infrared signals if they are positioned between the tag and the receiver.
- Plants: Although less common in healthcare settings, large potted plants could potentially obstruct the line-of-sight.
Understanding these potential obstructions is essential for the effective deployment of infrared RTLS, especially in a complex and dynamic environment like healthcare facilities. Obstructions are not necessarily bad and can in fact help bound spaces (e.g., walls bounding a room); however, system design must be intentional and thoughtful by considering how the environment may change.
Ultrasound systems utilize sound waves to measure the time it takes for a signal to travel between the tag and the receiver. Because they rely on sound rather than light or radio waves, they offer unique advantages in accuracy and resistance to electronic interference but also come with their own set of environmental constraints.
- Provides precise location information.
- Not impacted by electronic interference.
- Can interfere with lighting control systems when ultrasound motion sensors are used
- Infrastructure can be expensive due to the high density of sensors needed (similar but often less than infrared)
Ideal Healthcare Use Cases
- Patient Tracking and Workflows
- Staff Tracking, Safety/Duress, and Workflows
Ultrasound RTLS Systems: The Power and Limitations of Sound-Based Tracking
Ultrasound RTLS systems function by emitting sound waves from a tagged object, which are then picked up by a receiver. The time it takes for the sound wave to travel from the tag to the receiver allows the system to calculate the distance between them. Unlike systems that use light or radio waves, sound waves offer some distinct advantages but also come with unique environmental constraints.
Sound waves are mechanical waves that travel through a medium like air or water, whereas light and radio waves are electromagnetic and can travel through a vacuum. This fundamental difference makes sound waves less susceptible to electronic interference. Sound waves can offer more precise location tracking in certain environments because they are not easily interfered with by electronic devices or Wi-Fi signals. However, this precision can come at a cost, as sound waves are also more affected by environmental factors.
It is also important to note that ultrasound RTLS can interfere with lighting control systems when ultrasound motion sensors are used.
Understanding environmental considerations is essential for the effective deployment of ultrasound RTLS, especially in a complex and dynamic environment like healthcare facilities. As with infrared RTLS, system design must be intentional and thoughtful by considering how the environment may change.
Wi-Fi-based RTLS systems leverage existing and additional Wi-Fi infrastructure to locate and track assets or individuals. These systems can be beneficial for large healthcare facilities due to their scalability and compatibility with existing networking equipment. To benefit from existing equipment, the Wi-Fi network needs to have capacity to handle the additional RTLS systems.
- Potentially cost-effective due to leveraging existing Wi-Fi infrastructure.
- Good coverage across larger areas.
- Can be augmented with other RTLS technologies to achieve better accuracy (e.g., infrared and ultrasound)
- Less accurate compared to other RTLS types when not augmented.
- Dependent on the reliability and coverage of the Wi-Fi network.
- Frequently requires new licenses and often new access points.
Ideal Healthcare Use Cases
- Asset Tracking and Management
Wi-Fi-Based RTLS Systems: Bridging Scalability and Compatibility in Healthcare Settings
Wi-Fi-based systems utilize existing Wi-Fi networks within healthcare facilities to locate and track assets or individuals. Generally, Wi-Fi-based RTLS systems measure the signal strength of Wi-Fi signals sent between access points and tags. The received signal strength indicator (RSSI) values are used in a multiliterate calculation to approximate the location of tags. Wi-Fi-Based systems hold the advantage of leveraging existing infrastructure, making them particularly appealing for large healthcare environments in terms of scalability and compatibility with network access points already in place.
It is important to note that while many RTLS vendors promise their systems will use “existing WiFi networks,” systems often require additional software licenses, access point upgrades, and/or additional access points.
Wi-Fi-based RTLS systems can cover large areas effectively when access points are strategically placed. They often use high transmission power and advanced antenna designs. The use of repeaters and mesh networks can further extend this coverage, which can increase the effectiveness of Wi-Fi-based solutions.
Wi-Fi signal strength can fluctuate widely and unevenly due to physical obstacles like walls and furniture, as well as electronic interference from other devices. Additionally, certain building materials such as metal and concrete can weaken or block the signals. Locating tags using signal strength based multiliterate algorithms can be subject to wide variations in accuracy and precision. Often, when better accuracy or precision is required, Wi-Fi-based RTLS is augmented with other RTLS technologies (e.g., ultrasound and infrared).
Challenges with Integration
- Network Capacity: Not all existing Wi-Fi systems have the bandwidth to handle the added load of an RTLS system, which may require an upgrade to the network infrastructure.
- Security Concerns: Merging RTLS with existing Wi-Fi systems could potentially expose vulnerabilities, necessitating additional security measures.
- Software Compatibility: RTLS software must be compatible with the existing network management software to function correctly.
Utilizing Existing Coverage
- Use of Existing Access Points: The system can utilize current Wi-Fi access points, avoiding the need for specialized infrastructure.
- Wide Range: Wi-Fi signals can cover a large area, making them suitable for expansive healthcare facilities.
- Signal Fluctuations: Wi-Fi signals can fluctuate due to environmental factors or electronic interference, affecting accuracy.
- High Traffic: Wi-Fi networks often serve many functions; the added traffic can introduce latency, affecting real-time tracking capabilities.
- Multiple Devices: Wi-Fi networks generally support multiple devices. This multiplicity can cause ‘noise,’ making it harder to isolate the specific signal from an RTLS tag, thereby affecting accuracy.
Ultra-Wideband (UWB) RTLS systems use low-power digital radio signals for precise location tracking. These systems are known for their high accuracy and low latency, but they require dedicated infrastructure that can be costly.
- Very high accuracy and precision.
- Penetrates walls and floors well without losing accuracy.
- Requires the installation of dedicated infrastructure.
- Typically much more expensive compared to other systems.
Ideal Healthcare Use Cases
- Not widely deployed in healthcare due to the high cost.
Ultra-Wideband (UWB) RTLS Systems: A Detailed Overview
Understanding Signal Types and Positioning Techniques
Ultra-Wideband (UWB) RTLS systems employ low-power digital radio signals, operating in the frequency range between 3.1 and 10.6 GHz for precise location tracking. Unlike infrared or ultrasonic systems, which operate on the principles of line-of-sight or sound wave propagation, these digital radio signals use Time-of-Arrival (ToA) and/or Time Difference of Arrival (TDoA) techniques to calculate position. These methods contribute to high accuracy and precision.
Signal Penetration and Environmental Constraints
Ultra-Wideband (UWB) systems generally do not suffer from obstructions to the same degree as infrared systems. Unlike infrared, which requires a direct line-of-sight (or at least near line-of-site) between the tag and the sensor, UWB radio signals can penetrate walls and other solid objects to some extent. While they are less susceptible to physical barriers, the signals can still be attenuated or weakened by certain materials like metal or concrete. Thus, while UWB systems offer more flexibility in terms of placement and are less hindered by physical obstructions, their performance may still be affected by the composition of the environment they are deployed in.
The Importance of Low Latency
The term ‘low latency’ refers to the minimal time delay in the transmission of data between the tag and the reader, which is typically in the range of microseconds to milliseconds for UWB systems. This low latency makes the system responsive and real-time, allowing for immediate action based on the location data.
Cost Considerations for UWB Systems
In terms of cost, UWB systems generally require the installation of dedicated infrastructure, including multiple fixed infrastructure devices and specialized software, which can make them more expensive than other RTLS systems that leverage existing infrastructure like Wi-Fi-based systems. Costs can range from a few thousand dollars for smaller deployments to hundreds of thousands for larger, more complex environments.
RFID (Radio-Frequency Identification)
Passive RFID systems utilize electromagnetic fields to identify and track tags attached to objects or individuals. These systems are versatile and can be easily integrated into existing healthcare processes like inventory management and patient check-in where users are likely already printing tags/labels which can be easily upgraded to RFID-enabled tags/labels.
- Passive tags do not require a power source.
- Easily integrated with other systems like barcode printers.
- Low-cost passive tags (many less than $1/tag).
- Line-of-sight may be needed for certain types.
- Variable accuracy and range based on tag type.
- Higher cost for retrofitting infrastructure.
Ideal Healthcare Use Cases
- Asset Tracking and Management
- Inventory Management
- Specimen Tracking
- Patient Tracking and Workflows
RFID (Radio-Frequency Identification) in RTLS: A Comprehensive Look
In RFID systems, RFID readers and their attached RFID antennas (the fixed infrastructure) emits an electromagnetic field that powers battery-free passive tags when the tags comes into range, allowing tags to transmit identification information back to the reader. This makes passive tags more cost-effective and easier to manage, as they can last indefinitely without requiring a battery change. Additionally, these tags can be printed by the user from similar printers (and sometimes even the same printers) that may already be used in their workflow to create barcode labels or patient wristbands.
Easy Integration with Existing Systems
The versatility of RFID systems makes them easily integrable into existing healthcare processes, such as inventory management and patient check-in systems. This is in part because the RFID tags can share the same form factor as barcodes, making it easy to replace or augment barcode systems with RFID capabilities. Also, RFID readers can often be integrated into existing IT frameworks.
Read Range in RFID Systems
While RFID systems do not have strict line-of-sight constraints, they are subject to a similar constraint of read range. Dense materials like metal or water can interfere with the electromagnetic fields, preventing effective reading of tags. This can pose challenges in complex environments like hospitals, where numerous electronic devices, fluids, and metallic structures are present.
High Infrastructure Costs
One of the major drawbacks of RFID systems can be the initial cost of infrastructure, particularly if a high level of accuracy is required (which equates to more fixed infrastructure). While the total cost of ownership (on a long-term basis) is often lower than active RTLS systems (especially when a high volume of tags are tracked), the initial expense is typically higher than most other RTLS modalities (excluding UWB RTLS, which is often the most expensive option).
Bluetooth (including BLE – Bluetooth Low Energy)
Bluetooth RTLS, including its low-energy variant BLE, uses radio signals to determine the location of tagged objects or individuals. These systems are easily scalable and compatible with existing devices like smartphones and tablets, making them versatile for a range of healthcare applications.
- Compatible with many existing devices like smartphones.
- BLE is more energy-efficient than other active RTLS solutions, leading to longer battery life for tags.
- Scalable and can cover larger areas without significant additional costs, particularly when BLE is in access points, lighting and other controls.
- Dependent on the density of Bluetooth beacons for accuracy.
- Susceptible to signal interference from other electronic devices.
- Less accurate compared to other RTLS types (without augmentation with other technologies)
Ideal Healthcare Use Cases
- Asset Tracking and Management
Bluetooth and BLE in RTLS: A Deep Dive into Scalability and Energy Efficiency
BLE-based RTLS often is similar to Wi-Fi-based RTLS in that it measures the signal strength of BLE signals sent between fixed infrastructure and tags. The received signal strength indicator (RSSI) values are used in a multiliterate calculation to approximate the location of tags. However, newer BLE-based systems are starting to incorporate other approaches such as angle of arrival (AoA) which is more accurate than RSSI-based calculations.
While simplistic, it is not unreasonable to consider BLE-based RTLS a newer, better version of Wi-Fi-based RTLS, which is why major access point vendors are adding the capability to their networking technology.
The Energy Efficiency of BLE
Bluetooth Low Energy (BLE) is designed to provide significantly lower power consumption compared to traditional Bluetooth technology. It achieves this by maintaining a sleep mode and only becoming active when a connection is initiated, thereby extending battery life. This makes it ideal for applications where constant, real-time tracking is not necessary, such as asset tracking in healthcare settings. BLE-based RTLS holds a distinct power advantage over its Wi-Fi-based RTLS counterpart.
Scalability and Coverage
BLE-based systems are highly scalable because they can easily integrate with existing devices like smartphones and tablets. This eliminates the need for specialized tracking devices or tags in many cases. BLE also uses a mesh networking topology, allowing devices to relay signals between each other, effectively extending the system’s range without requiring additional infrastructure. It is important to note that mileage varies on the accuracy that can be achieved tracking devices not specifically designed as RTLS tags (e.g., smartphones).
Density of Beacons: A Double-Edged Sword
To achieve high accuracy, Bluetooth RTLS often requires a high density of beacons, which can be a disadvantage in terms of both cost and complexity. The more beacons you have, the more accurately you can pinpoint a device’s location. However, the need for multiple beacons can increase infrastructure costs and make the system more difficult to manage.
Susceptibility to Signal Interference
As with Wi-Fi-based RTLS, BLE-based RTLS is susceptible to signal interference from other and subject to environmental impacts to signal strength. As with Wi-Fi-based RTLS, the BLE signals are prone to environmental factors like walls and human bodies, which can cause signal attenuation and multi-path effects. These factors result in a less precise location calculation compared to systems that use other technologies.
Active vs. Passive RTLS Systems
Active and passive RTLS systems differ mainly in the type of tags they use and how those tags interact with the rest of the system. Active RTLS systems use battery-powered tags to transmit real-time location and additional data, making them ideal for complex tracking needs. Passive RTLS systems rely on unpowered tags that draw energy from the reader’s field, offering a cost-effective solution for simpler tracking applications.
These systems use battery-powered tags that emit signals regularly.
- Offers real-time tracking.
- Higher accuracy can be achieved with less infrastructure than passive.
- Can cover larger distances with fewer infrastructural needs.
- Tags can store and transmit additional data, such as sensor data and button-presses.
- Tags are generally larger due to the battery.
- Higher cost due to complexity and battery replacements.
- Systems require specialized maintenance.
Tags do not have their own power source; they reflect or absorb and re-emit signals from a reader.
- Tags are cheaper and smaller.
- Long-lasting due to no battery requirements.
- Many tags available with interoperable standards.
- Lower range compared to active tags, requiring more infrastructure.
- Less accurate, and may be unsuitable for real-time tracking without higher-density infrastructure.
- Infrastructure is more expensive (especially for retrofit)
Choosing the Right RTLS for Healthcare
Selecting an RTLS for healthcare involves balancing several factors. It is important to consider your facility’s specific needs, size, and existing infrastructure. There are various RTLS technologies available—each with its own set of advantages, limitations, and ideal use-cases.
Factors to Consider
- Specific needs and use cases.
- Number of people and/or assets to track.
- Size of the facility(ies).
- Whether RTLS will be added to an existing facility(ies) (retrofit) or whether it will be incorporated into a new facility(ies).
- Existing RTLS-relevant infrastructure (e.g., existing Wi-Fi access points, lighting controls, legacy RTLS systems, existing RFID infrastructure, etc.).
- Budget constraints.
- Integration capabilities with existing systems.
Hybrid RTLS Technology Solutions
When it comes to real-time location systems (RTLS), there is no one-size-fits-all solution. Different technologies come with their own sets of advantages and disadvantages. However, combining different types of RTLS can potentially mitigate the weaknesses of each, while maximizing their strengths. This is becoming increasingly common.
The Synergy of Combining Technologies
When you merge two or more RTLS technologies, the resulting system can offer more than the sum of its parts. For example, Wi-Fi might provide extensive coverage but lacks in pinpoint accuracy. Pairing it with ultrasound can remedy this issue by adding a layer of high room-level accuracy where needed.
Common RTLS Combinations
- Infrared + Wi-Fi
Infrared offers high room-level accuracy but can be obstructed easily. Wi-Fi, on the other hand, provides a broader range. By combining these two, you can achieve comprehensive coverage and high accuracy where you most need it.
- Ultrasound + Wi-Fi
Ultrasound excels in accuracy and resistance to electronic interference. When paired with Wi-Fi’s extensive range and existing infrastructure, you get a system that is both precise and expansive.
- Infrared + Bluetooth
This combination harnesses infrared’s high room-level accuracy and Bluetooth’s flexibility and scalability. Bluetooth can fill in the gaps when line-of-sight for infrared is obstructed, providing a more robust system.
- Ultrasound + Bluetooth
The high accuracy of ultrasound and the scalability of Bluetooth make this combination ideal for facilities that need precise tracking but also require a system that can easily expand as needs evolve.
- Passive RFID + Active RTLS
Passive RFID has many advantages that stem from tags not having batteries to manage – however, the required infrastructure may be cost prohibitive to put in all areas, and it may be beneficial to pair with other active RTLS technologies such as Wi-Fi based RTLS.
Why Combine RTLS Technologies?
The ideal use cases for multi RTLS solutions depend on the specific challenges your facility faces. If you need high accuracy in certain sensitive areas (like surgical suites or intensive care units) but also need to cover a large campus, a combined solution could be your best bet. It allows you to customize your tracking capabilities according to the diverse needs of different hospital zones, thus offering a tailored solution.
The Future of RTLS in Healthcare
Advancements in AI and machine learning are set to improve RTLS accuracy, while increased interoperability between different healthcare systems and RTLS technologies in a unified software system is a promising trend.
Selecting the right RTLS is crucial for healthcare institutions aiming to improve efficiency and patient care. Keeping abreast of technological advancements will further enhance these objectives.
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