Critical Care Medical Devices and Sensors

As the most important dynamic in patient care, providing effective treatment means using tools and equipment that are as accurate as they are immediately responsive. In this guide, we dive into sensor technology’s role in critical care devices and providing effective patient treatment:

(click text to jump to section)

1. Patient Care Metrics That Matter: Pressure & Temperature
2. Pressure and Temperature Sensor Applications
3. How Temperature Sensors Are Reshaping Surgery
4. Sensor Selection: Custom Sensors Vs. Off-the-Shelf Sensors
5. Medical Sensor Design to Their Environments
6. Custom Miniature Sensors & Critical Care
7. Critical Care in the Field

There's no denying the important relationship between medical devices and sensors.

While accurate, robust, and responsive sensor technology matters in all levels of medicine, there’s arguably nowhere it’s more important than in patient critical care.

Often used in scenarios where precision and response time must be matched with patient condition, the sensors used in critical care medical devices can leave nothing to chance. The last thing caregivers should worry about is sensor technology impacting device functionality or decision-making.

Though among the smallest components of many medical devices used across the gamut of patient critical care, medical sensors do some of the most important work in patient care. Without their performance and data, delivering patient care to the level that it’s expected today would be nearly impossible for doctors, nurses, and other medical professionals.

In many respects, a medical device is only as good as the technology comprising it. With medical sensors – especially those custom-made for their intended application – patient care and its respective outcomes meet benchmarks for precision, efficacy, and safety.

Patient Care Metrics That Matter: Pressure & Temperature

In critical care, the smallest details in a patient’s condition are often the biggest indicators of a potential issue. The same goes for certain elements monitored during medical procedures or of medical device functionality.

Both key metrics in patient care, temperature and pressure monitoring are vital for maintaining physiological stability and delivering appropriate treatments & interventions regardless of the scenario. These seemingly "small details" are often the front line of defense in recognizing and addressing larger, more complex medical issues.

On one hand, pressure is an indicator of a patient’s level of wellness in several respects, be it their cardiovascular or respiratory conditions. During surgical procedures or certain treatments with medical devices, monitoring pressure serves two purposes: improving patient safety and treatment efficacy.

Changes in patient temperature can be the first sign of a more serious change in their condition – for instance, an infection starting to spread. At the same time, keeping temperatures consistent – whether it’s during a laser ablation procedure or dialysis – can mean the difference in delivering effective treatments or improved patient outcomes.

How Temperature Sensors Are Reshaping Surgery

Compared to traditional surgeries of just a few decades ago (which relied on incisions with scalpels and sutures to close the wound) laser technology is changing how surgeries are performed and their impact of a procedure on a patient. In short, surgical lasers allow for minimally invasive procedures with fewer risks of complications and reduced recovery times.

However, the concentrated beam of light that is the laser generates an intense amount of heat – something the human body cannot withstand extended and unchecked exposure to.

In fact, surgical lasers can reach temperatures of up to 1,000℃. Even brief exposure to extremely high temperatures can be life-threatening to the patient. The same goes for the medical professional using the laser surgical device.

Temperature sensors make laser surgery a viable, safe option. Whether it’s during laser ablation in cancer treatment or an endarterectomy, this sensor type allows those delivering treatment to keep a close eye on temperatures and make sure they stay within safe thresholds.

In a general sense, body temperature medical devices used in laser-assisted surgeries fall into two categories: contact and non-contact, each representing a variety of temperature sensor types.

Contact Temperature Sensors

Thermistor – a type of resistor that exhibits a large and predictable change in resistance in response to changes in temperature. They are often used in temperature measurement and control circuits because they are highly sensitive to small changes in temperature, but can be susceptible to self-heating effects.
Thermocouples – temperature sensors that are made up of two wires of different metals that are welded together at the sensing end. When this junction is exposed to a temperature differential, it produces a voltage that is proportional to the temperature difference. Thermocouples are often used in high-temperature applications because of their durability and accuracy.
Resistance Temperature Detectors (RTDs) – made of a metal wire, usually platinum, that changes resistance as its temperature changes. They are very accurate and stable over time, but are generally slower to respond to changes in temperature compared to thermocouples and thermistors.

Non-Contact Temperature Sensors

Infrared Temperature Sensors – Using infrared light to measure the temperature of an object or surface without making direct contact, this sensor works by detecting the thermal radiation emitted by the object and converting it into an electrical signal.
Fiber Optic Temperature Sensors – With optical fibers these sensors monitor changes in the physical properties of their fiber optic cable as temperature changes. The fiber optic cable is typically coated with a material that changes its refractive index as temperature changes, which alters the way light is transmitted through the fiber. This change in light transmission can be measured to determine temperature. Fiber optic medical temperature sensors are often used in harsh environments because they are immune to electromagnetic interference.

MEdical Devices And Sensor Selection: Custom Sensors Vs. Off-the-Shelf Sensors

When it comes to the medical device and sensor selection, there are essentially two choices: an off-the-shelf sensor or one that’s custom-made.

There’s nothing inherently wrong with an off-the-shelf sensor – a one-size-fits-all option of sorts, they’re designed to measure a certain metric and are usually immediately available. In your daily life, you probably use plenty of off-the-shelf products all the time with no issue.

However, there is a difference between a product that is meant for general use vs. one that’s designed specifically for an application. This is especially true with sensors, and having sensor technology developed for your device can be worth its weight in gold.

With a custom-designed sensor for your medical device, there’s little worry about it meeting the rigors of application or even something as basic as fitting where it needs to. Simply put, the sensor is designed to your device, for your medical device and its function.

Custom Medical Sensor Design Considerations

Regardless of a sensor’s function or application, there are some universal design considerations that its manufacturer should dig deep into as the medical device and sensor technology is initially conceptualized. Their checklist should go over:

Defining Environmental Requirements: An important first step is to clearly define the environmental requirements the sensor needs to withstand – be it temperature, pressure, or any other factor. This also includes materials the sensor is in direct contact with within its housing. (We’ll dig into this a bit more in the next section)
Material Selection: Based on the defined environmental requirements, the manufacturer evaluates different materials to identify those that can withstand specified conditions or even repeated sterilizations.
Material Testing & Validation: Once potential materials are identified, the manufacturer conducts material testing and validation to ensure their suitability for the intended application. This may involve subjecting the materials to environmental stressors such as temperature cycling, humidity exposure, or mechanical stress to evaluate its performance and stability under specific environmental conditions.
Shape, Size, & Housing: The manufacturer incorporates design features that protect the sensor's ability to withstand environmental demands. This may include elements such as protective enclosures, sealing mechanisms, insulation layers, and shock-absorbing structures. The design should also consider ease of cleaning, sterilization, and maintenance for reusable devices.
Device Validation & Testing: Custom sensors undergo rigorous validation and testing to ensure they meet the defined environmental requirements. This includes performance testing under simulated environmental conditions, such as temperature and humidity chambers, exposure to chemicals, and mechanical stress testing. The sensors are evaluated for accuracy, reliability, and durability to confirm they can withstand the intended environment.
Compliance and Certification: Depending on the specific application and regulatory requirements, the manufacturer ensures the custom sensor complies with relevant standards and regulations. This may involve obtaining certifications or approvals from regulatory bodies to ensure the sensor's safety and effectiveness.

Medical Devices & Sensors Design to Their Environments

In general, medical devices and their sensors face some of the most challenging environments to function in. In addition to the potential to be exposed to harsh chemicals or sudden changes in the medium, they also have to contend with temperature shifts. In other words, the environment they’re used in has the potential to be very dynamic, which can affect several key factors of the device:

Overall performance
Longevity
Accuracy
Reliability

In a grand sense, when working with a sensor manufacturer to create sensors that are accurate and robust, design should:

Recognize the myriad environmental factors the sensor will likely face
Preserve precision for the device's entire useful life

When it comes to the minutiae of medical device and sensor design for their operating environment(s), the checklist of factors and corresponding questions to consider should include:

Temperature: What temperature range will the sensor operate in? How frequently will temperatures change? How drastic will temperature changes be?
Pressure: How intense is the pressure in the environment the sensor will operate in? Will external pressures change? What degree of accuracy are pressure measurements needed within?
Chemicals & Fluids: While in use, what chemicals or fluids will the sensor be exposed to? In the case of reusable sensors, what cleaners are used to sterilize the device or equipment it's installed in?
Electrical Interference & Noise: Will the device be exposed to electrical interference? If so, how severe is it and what kind of compensation should the sensor have for accuracy when this occurs?
Physical Stress: Will the device be subject to shock or vibration while installed in a medical device? How intense will these mechanical stresses be, and how can they best be mitigated?
Humidity: Will the sensor be exposed to humidity? If so, in what humidity ranges will the sensor operate? Will external conditions change frequently, or will the environment remain fairly consistent?
Space Constraints: This is two-fold and we'll use a catheter as an example: How big a space will the medical sensor be operating in (e.g., is the sensor inside a catheter that will be fed into an artery)? Does the medical device have limited space for the sensor itself (i.e., how small does the sensor need to be to fit inside a catheter)? Does the sensor need to be miniaturized?

Thermal runaway is one of the most damaging EV battery thermal events. As the transportation and industrial markets embrace the use of lithium-ion battery power, the needs for diagnostics are evolving as well. Current Li-ion battery technology utilizes volatile electrolytes and metals that under certain extreme and rare conditions, can fail to control internal electrolytic reactions, resulting in the cell venting, and in severe cases evolving into a thermal runaway at temperatures that can result in a cascade failure of the pack in a deflagration event.

Medical devices have always been getting smaller and more sophisticated. Look in any medical textbook from the 1950s, and you’re sure to notice the difference in size between equipment then and equipment now. Even think back 20 years – there’s a size difference, too.

The same applies to the sensor technology used in them.

While it might seem like a natural next step for medical devices and sensors to “shrink,” those used in critical care are getting small for several reasons that go beyond trends. The need for miniaturized custom sensors in medicine is being driven by several factors that aren't changing anytime soon:

• Rapid Advancements in Medical Technology: As medical care devices are becoming more sophisticated and more compact, the need for smaller sensors has followed suit. But not all medical devices are the same, and thus the sensors needed for them require a level of specific design that off-the-shelf alternatives can't provide.
• Increasing Demand for Personalized Patient Care: Patient care has always been a personalized pursuit. But thanks to technology and new treatment methodologies, it's now possible for doctors and physicians to deliver care that's more individualized to the patient than ever before, and for better outcomes.
• Real-Time Monitoring: The more precise data medical professionals have about their patients, the better. In a critical care setting, small changes in a patient's condition can have significant consequences. Understanding those changes as they occur can make a major difference in providing effective treatment. (
(Hover cursor over image for more information)

Smaller Sensors = Bigger Design Challenges

Making a custom miniature sensor for critical care medical devices isn't a simple job. It’s not as easy as taking an existing sensor’s design and scaling down the dimensions.

Designing smaller requires a high level of expertise and experience – something not all OEM sensor manufacturers have.

On the technical side, making a smaller sensor means designing it so that – aside from size – there's virtually no difference from its standard-sized predecessors without compromising accuracy, reliability, or lifespan.

Compounding matters, not all custom miniature sensors are created for brand-new medical devices, and thus, require adaptation. In other words, the miniature sensor is essentially being retrofitted to the application. This kind of integration isn't always simple – it requires an even higher level of design work where tolerances are unforgiving. That's not to say it's impossible, either.

Take pressure sensors, for instance. In a perfect world, adding a custom sensor would be as simple as removing the old component and plugging in the new one. However, pressure sensors have their own unique footprint in a device, and a custom medical instrument design and development (regardless of size) must accommodate this.

Like all components of a medical device, custom miniature sensors have to meet regulatory compliance measures for both performance and safety. For critical care applications, these standards are even more stringent. Remember: all it takes is one part of a device not meeting standards to render it out of compliance.

Critical Care in the Field

While medical devices and sensors are getting smaller, they’re also becoming more mobile.

In a way, patient treatment is no longer tethered to a single physical location.

Just like those made smaller in part to sensor technology, medical devices such as respiratory or heart rate monitors, and even dialysis machines, are not only available for field care, but also do not lack in accurate and reliable readings.

Vital sign monitoring
Communication with EMS
Remote patient monitoring

1. Improved Vital Sign Monitoring

Mobile medical devices with integrated sensor technology allow for continuous monitoring of vital signs just like in, say, a hospital. Through the duration of treatment regardless of location, caregivers are able to identify immediate changes in a patient’s:

Heart rate
Respiratory rate
Blood pressure
Oxygen saturation levels

2. Enhanced Communication Between EMS

In more serious scenarios of critical care in the field, data collected on a patient's condition by first responders with emergency medical devices becomes a real-time window into the patient's care.

With traditional record keeping, data collected on a patient in emergency transport was presented to receiving medical personnel when they arrived at the ER.

Through the combination of advanced sensors and smart technology, that same information can be collected while en route to an ER and transmitted to care providers waiting at the hospital for the patient. Essentially, information on the patient and their condition arrives before EMS is even on the property.

3. Reliable Remote Patient Monitoring

Sensors can be integrated into wearable devices, medical equipment, and other healthcare devices to monitor patients' health conditions and provide real-time data to healthcare providers.

This approach enables healthcare providers to monitor patients continuously and closely from a distance. Patients can go about their daily lives while wearing a device that collects data on their vital signs, activity levels, and other important metrics. This data is transmitted to healthcare providers who can use it to diagnose and treat patients remotely.

Using sensors in remote patient care also improves patient outcomes. Providers can use the data collected by sensors to identify changes in a patient's condition early and intervene before the condition worsens. This proactive approach to care can prevent hospitalizations and reduce the risk of complications.

Prefer an eBook to Peruse at Your Leisure?

Patient Care Metrics That Matter: Pressure & Temperature

APPLICATIONS FOR PRESSURE AND TEMPERATURE SENSORS

Pressure Sensors

Hello, world!

TEMPERATURE SENSORS