Portable Wearable Devices: Advanced Monitors Are Now in the Palm of Your Hand!

Point-of-care ultrasound (POCUS) refers to diagnostic and therapeutic ultrasonography (USG) at the patient’s bedside (N Engl J Med 2011;364:749-57). The anesthesiologist’s ability to have ultrasound capabilities as readily available as their stethoscope elevates one’s ability to make diagnoses in real time to positively impact patient care. The perioperative space offers endless opportunities to integrate ultrasound into daily routine. Whether it be to perform nerve blocks in the OR, as an aid to I.V. access and epidural placement, or critical procedures such as thoracocentesis, a spot diagnosis of pneumothorax or even evaluation of left ventricular function for tamponade or regional wall motion abnormalities, “Pocket POCUS” is increasing in popularity and becoming an invaluable aid. Newer devices that no longer cause a deep rift in our pockets are on the verge of becoming an essential addition to our armamentarium.

Most of these devices feature a 190 piezoelectric crystal array or capacitive micromachined ultrasonic transducers (CMUT). Some reviewers felt the former gives much better clarity than the latter but is more expensive. Additionally, native software and artificial intelligence (AI) features vary from device to device, affecting ease of use. This article outlines some of the most popular devices available in the market.

A compact device, the Sonoque USG probe does not need internet to operate and is water-resistant, and thus can be very useful in the field and nonoperative settings as well. Unlike many of its competitors, it is completely wireless and connects to mobile phones over its Wi-Fi connection. It has a dual head for a wide range of frequencies and can therefore be used for musculoskeletal, nerve and vascular as well as abdominal and breast ultrasounds. It is cheaper than its competitors, and technical support is free without a monthly subscription. It is compatible with iOS devices but not android devices. Color and pulse wave doppler features are used for plotting vascular anatomy. Limitations include a lack of AI-based automatic labeling, no reference images for comparison of anatomy, and no archival support.

This is a compact handheld device that has undergone many modifications since its introduction more than five years ago. According to the company, it boasts multiple unique software features such as Needle vViz®, a technology targeted at increasing needle visualization during peripheral nerve blocks and biplane visualization, whereby both longitudinal and cross-sectional axes can be simultaneously visualized. Enterprise software enables clinician credentialing, documentation, billing, and image archiving across multiple departments in the same institution. The technology also offers resident and medical school education programs in POCUS through the “Butterfly Academy” program and “Compass platform” for image integration and archiving. A dedicated client experience division helps support a school’s USG program and student image archiving. However, a subscription is required for many of these support services. It is still wired unlike several of its competitors. Most importantly, the device uses CMUT and not PZ crystals, which reviewers caution could affect image quality.

Clarius offers a completely wireless probe with high-definition imaging and support for iOS and android devices. Cloud storage of images is marketed as comparably low-cost. It offers online USG classes, personal ultrasound training on how to use the device, and advanced specialty packages targeted at specific departments. AI aids in-app diagnosis, image comparison, and archiving. Reviewers noted that there are multiple “scanner” probes available to purchase, which can be confusing for perioperative anesthesiologists, and there is no “one size fits all” type of probe.

Medical giant Philips has also entered the fray with the “Lumify,” a multiprobe device with simplier features than its larger cousin, the bedside ultrasound. Frequencies range from 1-12 MHz. Features include 2D, Color Doppler, M-mode, advanced, XRES, and multivariate harmonic imaging. The transducer has a USB-C interface that supports compatibility with many devices. According to the company, it is one of the few devices with a center line marker. Our review team found that The Lumify boasts excellent image quality and archiving and EMR compatibility.

The KOSMOS ultrasound by EchoNous is a handheld ultrasound device reported to contain all the features and power of a large ultrasound unit. EchoNous uses piezoelectric crystals to generate their images, as opposed to CMUT, in order to produce HD clarity. Additionally, it is compatible with EMR/PACS for uploading and saving clinical images. It supports multiple probes, but the linear probe covers most frequencies for nerve block and emergent chest USGs.

What we think sets KOSMOS apart is AI, which not only optimizes the image but actually labels anatomy in both the heart and abdomen. The AI also instructs users on moving the probe to obtain the image. Very few of us in anesthesia are trained to do an emergent transthoracic echo. It appears that with this system, even a novice can quickly learn to see two or four chambers and get an EF, SV, or pressure across valves. Our review team believes this could be a game changer in an emergent situation in the OR with limited access to a TEE probe.

EchoNous is also set to release nerve identification AI. In those patients where the nerve is tough to visualize, this could be a nice tool to help confirm if what the user suspects is a nerve actually is a nerve. The KOSMOS also offers PW and CW doppler, a feature of Butterfly and Lumify as well.

Another medical giant, GE, has two strong contenders in the field, Vscan and Vscan air, both of which claim high image clarity due to use of PZC, compatibility with GE’s Centricity PACS (widely used in many hospitals), cloud archiving, and dedicated tech support. What we think sets it apart is the ability to securely connect remotely with colleagues and educators for real-time sharing of images and video while scanning. An optional subscription offers user-centric digital tools. AI helps with obtaining images and aids with diagnosis.

Unfortunately, the race is too close to call. Ming Phuong et al. compared four of these handheld ultrasound devices, namely the Butterfly iQ+™ by Butterfly Network Inc., Kosmos™ by EchoNous, Vscan Air™ by General Electric, and Lumify™ by Philips Healthcare, and quantified ease of use, image quality, and overall satisfaction.

A group of 24 POCUS experts utilized four handheld devices to obtain three ultrasound views on the same standardized patients using high- and low-frequency probes (Ultrasound J 2022;14:27). Their image quality report showed Lumify emerging as the winner, while Vscan Air scored top marks in ease of use. Not surprisingly, all of the devices that scored high on image quality used high-density PZC arrays.

In the end, the “best” device is a matter of opinion and practice priorities. Some reviewers preferred strong image quality over features; others found value in service support, but some felt subscription fees were too high. Luckily, most models offer free trials so you can choose the device that’s best for your needs. Whatever may be the limitations, ultrasound-guided procedures have become the norm, and these devices have become exciting and increasingly enticing additions to our armamentarium.