SPIRO ROBOTICS: THE FUTURE OF DIFFICULT INTUBATION MANAGEMENT

I’ve seen the future of difficult intubation management, and I’ve held that future in my hands. The Spiro Robotics device—a combination video laryngoscope and fiberoptic endoscope in one unit—is a marked advance in anesthesiology, as well as a harbinger of how Artificial Intelligence can one day make difficult endotracheal intubation easier for all clinicians.

Disclosure: I have no financial interest or ownership stake in Spiro Robotics. I’m writing this review to inform anesthesia providers and laypersons regarding developments in the field of anesthesiology.

Vladimir Nekhendzy, Clinical Professor of Anesthesiology and Otolaryngology, Stanford University School of Medicine, and Past President of the Society for Head and Neck Anesthesia, is the inventor of the Spiro device. In Dr. Nekhendzy’s words, “Spiro-VISTA (Video Intubation System for Total Access) combines the power of video laryngoscopy, flexible endoscopy, and robotic precision into one handheld, easy-to-use device, setting a new standard for difficult airway management.”

The advantage of using a Glidescope plus a fiberoptic scope at the same time was demonstrated by Mazzarini et al in the 2019 Anesthesia and Analgesia publication Effect of Dynamic Versus Stylet-Guided Intubation on First-Attempt Success in Difficult Airways Undergoing Glidescope Laryngoscopy: A Randomized Controlled Trial. One hundred sixty adult patients with predicted difficult airways were randomly assigned to a conventional Glidescope intubation or a combined Glidescope + fiberscope intubation. The first-attempt intubation success was higher in the Glidescope + fiberscope group than in the standard Glidescope group (91% vs 67%; P = .0012). The median time to successful tracheal intubation was shorter in the Glidescope + fiberscope group than in the standard Glidescope group (50 vs 64 seconds; P = .035), and the airway injury rate was lower in the Glidescope + fiberscope group than in the standard Glidescope group (1% vs 11%; P = .035).

To date the Spiro device has been tested with a 100% success rate in intubating the trachea in 70+ cadavers in less than one minute per case. The device will now undergo a phase of safety and efficacy testing on difficult intubation human subjects, in its path toward expected eventual FDA approval.

THE DEVICE:

The heart of the Spiro device is the robotic base:

 

Two disposables attach to the base unit. The first disposable attachment contains the joystick and control buttons, and resembles the clear sleeve one slides over a video laryngoscope:

The second disposable attachment contains the fiberoptic scope and clips on to the robotic base via two blue clamps.

The completed device, with both disposables attached, looks like this:

 

The next step involves threading the fiberoptic laryngoscope (FOL) through the lumen of an endotracheal tube (ETT), and sliding that FOL-ETT assembly into the channel of the Spiro device.

 

The sleeve disposable contains a joystick and the control buttons, which the operator moves with his/her left thumb. Depressing the joystick moves the FOL distally, out of the tip of the ETT. Once the tip of the FOL is extended into the airway, the operator manipulates the direction of the FOL tip by maneuvering the joystick.

HOW TO USE THE DEVICE:

When the operator attaches the robotic base to the monitor, two images appear on the video screen which is attached to a wheeled base much like a Glidescope stand. The left half of the video screen shows the image from the Spiro video endoscope camera, and the right half of the video screen shows the image from the camera at the tip of the fiberoptic laryngoscope.

Initially the operator retracts the fiberoptic laryngoscope tip so that it is approximately 10 millimeters short of the beveled tip of the endotracheal tube. The Spiro device is then inserted into the patient’s mouth in the same manner that a videolaryngoscope is inserted.

The left half of the video screen will show the inside of the patient’s mouth, and the operator advances the device until the epiglottis is visualized. The operator then presses down on the joystick button until the FOL extends out from the endotracheal tube. The operator then maneuvers the joystick to direct the FOL tip under the epiglottis until the larynx is visualized. The operator once again pushes down on the joystick button, which advances the FOL into the trachea. At this point the operator manually advances the endotracheal tube over the FOL into the lumen of the trachea, and withdraws the FOL from the tube. The cuff of the endotracheal tube is then inflated. After 10–15 minutes of practicing with the Spiro device, I was able to easily utilize the technology and intubate the trachea of a difficult airway mannequin in less than 40 seconds.

I see the Spiro device as a definite advance over videolaryngoscopy alone, because it equips you with not just a videolaryngoscope, but also a fiberoptic laryngoscope aimed directly at the epiglottis and larynx. Spiro’s technology is backed by seven patents, including 1) dual cameras, 2) disposable controls, and 3) Al use in intubation.

ARTIFICIAL INTELLIGENCE:

A fascinating feature of the Spiro device is the potential of Artificial Intelligence/machine learning with this invention. In a demonstration of future AI capacity, the Spiro device was inserted into the mannequin’s airway and then the software for AI intubation was activated. The software controlled the motion of the tip of the FOL. Based on the digital images of the airway from the tip of the FOL, the device guided the FOL around the epiglottis and into the trachea without any input from the operator. This technology, once it’s perfected and approved for use in humans, will do what I once thought was all but impossible—it enables a device to intubate the trachea without any anesthesiologist input. AI may likely replace medical professionals in the interpretation of digital images in specialties such as pathology, dermatology, and radiology, but I never imagined AI replacing an anesthesiologist’s ability to intubate the trachea. Because Spiro’s AI software can reduce endotracheal intubation to the interpretation of digital images, it can make endotracheal intubation possible without an MD. I’ve written about robotics in anesthesia in a previous column.  Academics have previously invented an impractical robot to place an endotracheal tube, and have invented a robot that can perform regional blocks, but the previous inventions showed little promise for widespread application.

America is currently faced with a significant shortage of anesthesiology providers, which is projected to become an even bigger problem in the future. Closed-loop devices exist which can infuse maintenance doses of propofol and remifentanil without anesthesiologist input, with the rate of the infusions guided by a bispectral (BIS) monitor of EEG (electroencephalography) activity, but there has been little progress in machines to replace an anesthesiologist’s hands. With a bit of science fiction imagination, one can imagine a solitary attending anesthesiologist manning multiple operating rooms via a panel of video monitors, with each general anesthetic beginning with airway management by the Spiro placement of an endotracheal tube, and then AI technology controlling the depth of anesthesia by feedback loops gained from BIS-monitoring of a patient’s electroencephalogram (EEG) score.

Sound unbelievable? The tech advances of the past thirty years would have sounded unbelievable to an individual in 1994, but the advances arrived, and progress will continue.

THE MARKET:

How big is the market for the Spiro device? In a video featuring Spiro CEO Dimitri Sokolovd, he quotes the number of expected and unexpected difficult intubations as 6 million per year in American operating rooms, emergency rooms, and intensive care units. Each difficult intubation runs the risk of complications, including at the worst, anoxic brain damage, when an airway management is botched and oxygenation is lost for over five minutes. The current standard of care for difficult intubation is videolaryngoscopy. Videolaryngoscopy is not foolproof and can be unsuccessful.

The ASA Difficult Airway Algorithm contains instructions for a surgical airway (cricothyrotomy) should laryngoscopy be unsuccessful. No anesthesiologist wants to resort to cricothyrotomy to save a patient’s life. The need for a technology superior to videolaryngoscopy is real.

Each difficult intubation currently costs a hospital more than $14,000.  A 2021 study in ClinicoEconomics and Outcomes Research highlighted the significant costs associated with difficult intubation patients. This was a retrospective observational cohort study, conducted using three years of data (2016–2018) from more than 600 hospitals in the United States. The study compared the difficult intubation (DI) group to the non-DI group, and discovered that for the DI group the hospital cost was $14,468 more, and the length of hospital stay was 3.8 days longer than for the non-DI group. Use of the Spiro device is touted to pay for itself, as the increased cost for complications of difficult intubation is reduced or eliminated. What are the costs of the Spiro technology? While still investigational, the Spiro Robotics base unit, including the video screen, are expected to sell for $15,000. The two disposables, including the videolaryngoscope sleeve, the joystick and buttons, and the fiberoptic laryngoscope, will likely sell for about $350 per case. A hospital is likely to own a small number of base units, from one to three, which would be made available in the operating rooms suites, the emergency room, and the intensive care units. The total costs of using Spiro would depend on the utilization of the disposables for single patient use.

MY COMMENTS:

As a hybrid private practice/academic clinician who has practiced anesthesiology since the 1980s, I’ll make the following observations on the Spiro Robotics product I was allowed to demo:

1. When faced with a difficult intubation in the future, would an anesthesia professional choose to use a videolaryngoscope device alone, or a videolaryngoscope + fiberoptic laryngoscope combined device, i.e. the Spiro device? After having my hands on the Spiro Robotics device, I would rather have the extra technology of the FOL in my hands when faced with a difficult airway, particularly if it was an emergency setting in which the time of adequate oxygenation to the brain was waning.
2. What will be the marketplace utilization of videolaryngoscopy vs Spiro? The acquisition costs of a Spiro unit versus a Glidescope are not significantly different. The costs of the disposables are higher with a Spiro unit, because the disposables include a joystick controller and a fiberoptic laryngoscope.This increased cost may drive practitioners to use a Glidescope first, instead of the Spiro, for all but the most difficult airways, with Spiro available as backup. It’s possible that using videolaryngoscopy alone instead of Spiro for the first look on a difficult intubation patient will be unwise. If the delay in utilization of the Spiro device leads to anoxic brain damage, death, and/or a massive lawsuit, the medical center administration and the practitioner will wish they had not pinched pennies and had used the Spiro first.
3. In the future the AI aspect of the Spiro unit may be the slickest airway management imaginable. Can the AI version of Spiro be used by lesser trained professionals to intubate the trachea, making the undersupply of anesthesia providers less of a crisis? Time will tell.