Physician anesthesiologist at Stanford at Associated Anesthesiologists Medical Group
Richard Novak, MD is a Stanford physician board certified in anesthesiology and internal medicine.Dr. Novak is an Adjunct Clinical Professor in the Department of Anesthesiology, Perioperative and Pain Medicine at Stanford University, the Medical Director at Waverley Surgery Center in Palo Alto, California, and a member of the Associated Anesthesiologists Medical Group in Palo Alto, California.

A South Korean group led by Dr. Y.E. Jang published a study in this month’s issue of Anesthesiology describing the use of a head-mounted smart glasses display during radial arterial line placement in patients younger than 2 years. Placing a catheter into the tiny radial artery in a child’s wrist is one of the most difficult procedures in our specialty. The average internal diameter of the radial artery is 1.2 ± 0.3 millimeter in children aged less than 2 years. Wearing smart glasses improved the anesthesiologist’s first-attempt success rate, and reduced the procedure time and complication rates. This was an important study, and important information.

In the control group of this study, each anesthesiologist would use a traditional ultrasound screen to visualize the artery. 

The anesthesiologist must look up to see the ultrasound machine, while he is working on the patient’s wrist.

In the smart glasses group, the ultrasound machine was located behind the operator, and the smart glasses were paired with the ultrasound machine. The smart glasses used were a binocular Moverio BT-35E unit,  connected to an ultrasound machine by a HDMI cable. The smart glasses displayed a simultaneous replica of the ultrasound screen image in front of the anesthesiologist’s eyes, so the operator could easily see both the procedure field (the radial artery at the wrist) and the ultrasound screen simultaneously without any head and eye movement. 

The anesthesiologist can see the ultrasound image while he is looking at the patient’s wrist

One hundred sixteen children were included in the study. The smart glasses group had a higher first-attempt success rate than the control group: 87.9% (51 of 58) vs. 72.4% (42 of 58) in the control group, with p = 0.036. The smart glasses group also had a shorter first-attempt procedure time (median 33 seconds) than the control group (median 43 seconds), with p = 0.007.

An accompanying editorial in the same issue of Anesthesiology stated, “This elegant prospective trial offers objective insight into the potential impact of head-mounted displays on the overall success and provider ergonomics in anesthetic care during technically complex procedures. Head-mounted displays and augmented reality devices have been evaluated in various settings, including placement of ultrasound-guided peripheral nerve blocks, for use in intraoperative patient monitoring and placement of central venous catheters.”

What will be the role of smart glasses in medicine? We all remember the original hype surrounding the 2013 release of Google Glass, a product which failed to capture a significant market of users. 

Google Glass

Problems with Google Glass included: “The unit overheated frequently with use and shut itself down, the battery life wasn’t long enough (less than an hour), the apps were great demos but limited in scope, and the user interface — tapping, swiping, blinking, head gestures, and the voice recognition after saying ‘Ok Glass’ — was not always smooth.” 

A 2014 study looked at using Google Glass to aid central venous catheter insertion in adults. This study failed to show any positive effects on success rate, procedure time, or number of attempts. These results most likely were due to the fact that larger central blood vessels in adults are easier to locate than the diminutive radial artery in the pediatric population.

Smart glasses are being studied in aviation. Both anesthesiologists and pilots have occupations where the slightest miscalculation or mistake can cost lives. Any step which enhances safety can be seen as a valuable change. A new product called AEROGLASS (Augmented reality aerial navigation for a safer and more effective aviation) attempts to put augmented reality in front of pilots’ eyes.

AEROGLASS in aviation

A recent review states, “The AEROGLASS turnkey smart glass solution provides general aviation pilots a true 3D, 360° view of navigation and safety features. One of the largest challenges for aviation professionals is accurately and safely navigating an aircraft. Current studies show that pilot error accounts for up to 70 % of all aviation accidents. Piloting an aircraft requires translating complex readings from the control panel displayed in 2D into a 3D environment and 360° reality. Accessing this information also requires pilots to take their eyes off the sky, thereby making them more prone to errors and increasing their stress levels. With a headset on, pilots will now be able to have digital 3D information appearing naturally in their field of vision, helping them make faster and better decisions. ‘Our product is an AR solution based on smart glasses. When pilots wear them, they will continue to see the scenery around them, but in addition to that, relevant safety and navigation information will be overlaid transparently within their field of view. . . . At first, the newly developed technology targets professional general aviation, but after some time AEROGLASS plans to utilize its technology in other transportation domains such as automotive and maritime or even for passengers.”

There are two potential uses for smart glasses in anesthesiology. The first is for performing invasive procedures which require ultrasound technology, such as the placement of peripheral nerve blocks or the placement of catheters into arteries and veins. This use makes sense, because it can make some procedures easier, as shown in the Jang study. But the placement of pediatric arterial lines, as in the Jang study, is a small marketplace (e.g. including pediatric open heart surgery, and pediatric surgery involving major blood loss). Ultrasound imaging for the placement of peripheral nerve blocks would be a bigger market, but to date there is no data supporting the use of smart glasses in the placement of peripheral nerve blocks.

Anesthesia vital signs monitor display

A second and more compelling use for smart glasses would be the display of a patient’s vital sign monitoring in real time on the smart glass screen, so that an anesthesiologist is in constant contact with the images of the vital sign electronic monitors. In 2021 a nurse anesthetist publication looked at the use of Google Glass by seven nurse anesthetists for display of the vital signs monitor, but there were no quantitative data to examine the significance of the technology. The physician medical literature has not studied the issue. 

Advantages of using smart glasses for real time patient vital signs monitoring would include:

  • The electrocardiogram, oximeter, and end-tidal CO2 waveforms would be displayed front and center in the anesthesiologist’s sight. The vital signs of heart rate, blood pressure, oxygen saturation, end-tidal gas values, and temperature would be constantly visualized no matter where the anesthesiologist was looking. 
  • This is a futuristic technology, and its use may connote that the hospital or surgery center is at the cutting edge of monitoring and safety equipment (despite the lack of any data to confirm this advantage at this time).

Disadvantages of using smart glasses for patient vital signs real time monitoring would include:

  • The cost of the head-mounted display (Moverio BT-35E, glasses in the current study) is approximately $800. This is not a large amount of money, but multiplied times every anesthetizing site, the expense rises.
  • The requirement for reliable and constant Bluetooth connection between the smart glasses and the electronic monitor.
  • The weight of the smart glasses (119 grams, or 0.43 pounds) is 4 – 8 times heavier than usual glasses (25 – 50 grams, or 0.05 – 0.1 pounds). Many individuals may object to wearing this product. 
  • If an anesthesiologist wears prescription glasses of his or her own, there would be two pairs of glasses needed.
  • The question of whether smart glasses are necessary in every routine anesthetic.

Let’s look at this last point. During most routine anesthetics the constant beep-beep-beep note and tone of the pulse oximeter gives the anesthesiologist real-time audible monitoring of both the heart rate and the ballpark oxygen saturation, without having to look at the display. The anesthesiologist still has to look up at the vital signs screen intermittently to note the blood pressure, end-tidal gas values, and temperature, but this intermittent look is part of the vigilance all anesthesiologists must do anyway. A left-to-right scanning gaze at the patient, the surgical field, the IV lines, any IV infusions, the airway tubing, the anesthesia machine, and the vital signs monitor screen is standard procedure in anesthesiology. If adopted, the use of smart glass technology for routine vital signs monitoring would indeed be a large market. Would the addition of smart glasses for routine monitoring be an overdose of technology in the operating room cockpit? Does excessive technology distract us from the actual patient?

Let me give you a historical perspective. As recently as the year 2000 there were zero computers in the anesthesia workstation. Our equipment included an anesthesia gas machine, a vital signs monitor, and carts which contained breathing tubes, airway equipment, syringes, needles, and drugs. Now we are encumbered by an electronic medical record (EMR) system screen + keyboard, and a narcotic-dispensing computerized drug cart in every hospital anesthetizing location. 

EPIC anesthesia electronic medical record (EMR) computer
Anesthesia drug cart
Anesthesia bar code reader/label printer computer

Add in some smart glasses with Bluetooth connection, and you’ve got an armada of gadgets to both aid the anesthesiologist and to distract him or her from the actual patient, who is three feet away and in need of vigilant care. Is anesthesia care any safer with all the computers: the EMR, and the narcotic-dispensing computerized drug cart? There is no data that these devices have made anesthesia any safer—it is only more complicated.

If smart glasses are ever to become a standard of care, I believe it would require data and proof that anesthesia complications were reduced and anesthesia outcomes were improved with such a device.

Technology in medicine tends to come between the patient and his or her doctor, a theme explored in my 2019 editorial, and in my novel Doctor Vita. View the future of medical technology with care. Think of that computer terminal between you and your doctor during a clinic visit. Now imagine a parallel situation with that computer terminal between you and your anesthesiologist, between you and your emergency room doctor, or between you and your ICU nurse. Will adding more electronic devices lead to safer care or more convoluted care? 

Put it another way: Do we need smart glasses, if we have smart anesthesiologists?



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