Editorial
Franzen MH, Krishnamurthy G, Gálvez JA. Augmenting the Anesthesiologist's Cockpit with Head-mounted Displays for Image-guided Procedures: Are We There Yet? Anesthesiology. 2021 Oct 1;135(4):562-563. PMID: 34499094
Original Article
Jang YE, Cho SA, Ji SH, Kim EH, Lee JH, Kim HS, Kim JT. Smart Glasses for Radial Arterial Catheterization in Pediatric Patients: A Randomized Clinical Trial. Anesthesiology. 2021 Oct 1;135(4):612-620. PMID: 34352073
Many years ago, I (Myron) was studying the molecular biology of chronic pain using the classic Chun model. In this mouse model, part of the sciatic nerve is dissected, crushed, and tied off. The procedure involved delicate work under a microscope to visualize the animal’s sciatic nerve and necessary instruments. Each working session requires looking up from the microscope to position hands and instruments followed by looking in the microscope to identify them in the field. If anything moved, the whole process would be repeated: look up, reposition, look down. Over and over again. Does this sound familiar?
Anesthesiologists are applying ultrasonographic imaging in many aspects of their practice such as for peripheral nerve blocks and vascular access procedures. Learning to use the ultrasound to provide image guidance during procedures can be challenging due to the need for precise hand-eye coordination as well as interpretation of the images on the screen, which invariably takes your eyes away from the field where the procedure is taking place. This process can be even more challenging because of the ergonomic challenges that we experience in the operating room every day of our lives.
Wouldn’t it be great if instead of looking at the screen in front (or gasp behind) you, you could keep your eyes in the field and have a head’s up display to guide you? Imagine if the ultrasound display was not affected by glare from the operating room lights!
The article by Jang and his colleagues as well as the accompanying editorial present a hint of the future, or perhaps the present.(1,2) It is reminiscent of earlier attempts to introduce augmented reality such as Google Glass.(3) Today’s PAAD is co-authored with a team of experts in clinical applications of immersive reality technologies in pediatric perioperative medicine: Dr. James Thomas from the Children’s Hospital of Colorado and one of the editorial’s authors, Dr Jorge A. Gálvez from the Children’s Hospital & Medical Center in Omaha and the University of Nebraska Medical Center.
In this prospective, randomized controlled study (ClinicalTrials.gov NCT04329026), patients less than 2 years of age who required an insertion of an arterial line were randomized to have placement with and without a head mounted display (binocular Moverio BT-35E (V11H935051, Seiko Epson Co., Japan) connected to the ultrasound machine with a HDMI cable). Arterial cannulation was percutaneously performed with a 24 gauge catheter using a thru and thru, transfixing, puncture technique. Of note, the arterial lines were placed while the patient was already under surgical drapes. Cutting to the chase: it worked! Those using the head-mounted display had a greater first-attempt success rate, shorter times to cannulation, and lower rates of catheter malfunction compared to the control group that relied on conventional ultrasound use. They also reported greater ergonomic comfort compared to the control group.
The head mounted display studied offer an elegant solution to the challenge of incorporating ultrasound image guidance for vascular access procedures. A process that requires frequent head and eye movements between the procedure field and the ultrasound image. The head mounted display described in the paper essentially functions as a secondary display for the ultrasound device. The operator is able to visualize the procedure field and ultrasound display without needing to adjust their head position to alternate between the two. At the ASA meeting, Jorge and Myron checked all of the commercially available ultrasound machines and found that all of them have HDMI slots to allow the use of this technology.
This is not a new concept in modern operating rooms. Video displays from laryngoscopes and fiberoptic bronchoscopes can be displayed in the integrated operating room monitors. In contrast to the operating room displays, the head mounted display is portable and can move with an ultrasound device. The article demonstrates value in the specific application of image guidance during technically challenging procedures. How many other areas of our practice could benefit from this type of technology? Can you imagine using a heads up display to visualize the echocardiogram and vital signs monitors while coming off bypass? Can you imagine managing an operating room with instantaneous access to the status board via a head mounted display?
Graduate medical education curriculum is incorporating point of care ultrasound imaging for more applications than we ever imagined. Imagine the potential impact of guiding a trainee with the assistance of augmented reality displays. The instructor could navigate a pointer in the ultrasound image to guide the trainee in real time. The sky is the limit and the imagination of the educators of our field will undoubtedly take advantage of these emerging technologies to optimize education programs and advance our field. WOW!
There are lots of issues that still need to be worked out for implementing head mounted displays into practice. Will commercially available head mounted displays be sufficient to connect to ultrasound devices or will medical device manufacturers develop their own options? Being tethered to the ultrasound device with the wired HDMI connection may not be a problem since the ultrasound probe is also tethered to the ultrasound machine. Wireless devices may be more appealing but introduce new challenges such as the potential for lag in image display as well as the duration of the battery. We have all experienced the ultrasound device running out of battery and shutting off in the middle of a procedure. Will you buy your own head mounted display to go with your stethoscope or will these be supported and managed at an institutional level? The cost of the devices themselves is not the rate-limiting step today. There are many devices available for use today, including the ones described in the study. It is important to consider how much technical support will be required to integrate and maintain the device in optimal functioning conditions. The innovation and technology development cycle in augmented reality systems is staggeringly fast. Investing in new technologies may seem risky at times. The good news is that the longer that one waits, the better and cheaper that this technology becomes.
Adoption of emerging technologies always carries a risk. Early adopters may be willing to take a risk in terms of cost, time and resources for a solution that may not work. “Failed” projects pave the way for new ideas that eventually reshape our world. Thomas Edison said “I have not failed. I've just found 10,000 ways that won't work.“
It is worthwhile to pause and consider whether augmented reality technology should be embraced in clinical practice. In 2003, Nick Bostrom argued that there is a significant chance that we are living in a computer simulation. How much of a role does the element of immersion play in creating focus when using a head mounted display for procedures and what other important issues within a clinical setting might be missed by the distraction caused by this application. What necessary skills might we be sacrificing (such as the inability to navigate our city without GPS) by relying on these new technologies? Setting aside the consumer applications of head mounted displays to further disconnect ourselves from others, we applaud Jang and his colleagues for this work. The article is important contribution to a growing body of literature demonstrating value of augmented reality technology in clinical practice with improvements in patient care and outcomes.
When GPS became widely available in smartphones, many people were quick to say “who needs GPS, I can read a map!” History speaks for itself as GPS plays an integral role in many aspects of our daily lives. Head mounted displays will undoubtedly become more widely available. So, our feelings are best summed up Marty McFly (Michael J. Fox) from Back to the Future: “I guess you guys aren’t ready for that yet, but your kids are gonna love it.” [Back to the Future, Universal Pictures, 1985]
References
1. Franzen MH, Krishnamurthy G, Gálvez JA: Augmenting the Anesthesiologist's Cockpit with Head-mounted Displays for Image-guided Procedures: Are We There Yet? Anesthesiology 2021; 135: 562-563
2. Jang et al . Smart Glasses for Radial Arterial Catheterization in Pediatric Patients: A Randomized Clinical Trial. Anesthesiology 2021.
3. https://www.investopedia.com/articles/investing/052115/how-why-google-glass-failed.asp accessed 10/11/2021