ASA Meeting Exhibits Sharpen Patient Safety Focus

John H. Eichhorn, MD

While patient safety certainly persisted as a general theme of the 2007 ASA Annual Meeting exhibits which incorporated many engaging presentations, the specific topics of airway management techniques and ultrasound-guided needle placement received more than the usual attention.

Among the Scientific Exhibits, 20 of the 63 represented programs (several involved with simulation as a teaching tool), groups or causes, leaving 43 original exhibits. Eleven of these concerned airway management techniques.

Reinforcing the adage “everything that’s old is new again,” Drs. T. Wu and H. Chou from Kaiser in California reinforced with an elaborate display a concept first published in 1993 that many difficult direct laryngoscopies are due to the “tongue-in-the-neck” phenomenon in which the base of tongue is large and low in the hypopharynx (with a long mandibular-hyoid distance). Multiple X-rays, photos, and case reports made the point dramatically. The conclusion is a recommendation to incorporate into every preoperative airway assessment an evaluation of the distance from the hyoid bone directly cephalad to the inferior edge of the mandible with longer distances, e.g., greater than about 3 cm, suggesting possible difficult mask ventilation and/or direct laryngoscopy that can be anticipated and thus more easily overcome.

As often stated in this report, the induction of deep unconsciousness and muscle relaxation before genuine confirmation that a patient’s airway can be managed and accessed is still one of the least improved and most dangerous things anesthesia professionals do. While the actualization of a simple routine real-time preoperative image and analysis of airway anatomy is still a Star-Trek type fantasy, a team from the Cleveland Clinic presented a very compelling exhibit of virtual reality 3-D reconstruction of airway anatomy in patients who have preop CT/MRI of the head and neck (often ENT or trauma patients with airway questions). Because the image is digitized and online it can be accessed and processed by specific (open source) software (for MAC) to yield a truly remarkable and strikingly detailed virtual image of the airway that can be fully manipulated and explored. It is thus possible to view this virtual airway exactly as the patient would appear through a fiberoptic scope and verify airway access or plan specifically a fiberoptic intubation in situations of distorted anatomy. Creation of such plans has allowed many patients who otherwise would have had awake intubations to have pre-mapped asleep fiberoptic intubation.

Continuing the theme of airway issues, making the process of extubation safer, particularly by doing a “reversible” extubation leaving a stylet in place, was the focus of one exhibit. Another showed a new device that removes the stylet from a just-placed endotracheal tube automatically, without any assistance and without compromising the line of sight into the larynx. A new angled laryngoscope blade (which fits a traditional handle) with a lens and an insufflation port was offered as another approach to managing difficult airways where the larynx is not seen with standard blades. Likewise, a new pair of devices involving a supraglottic airway through which a rigid intubating stylet is fitted was suggested as an improved approach to otherwise difficult or impossible airways. One other popular exhibit allowed visitors to compare 3 different video-assisted laryngoscopes side by side on an intubation mannequin. There was an exhibit of a teaching device developed in Wales, UK, that measures force and direction of the laryngoscope blade being used (in a conventional manner) to intubate a simulation mannequin; results suggested faster learning curves for trainees exposed to this teaching regime.

The other significant recurrent theme was the utility of ultrasound guidance (various makes and models) for correct needle placements—both for blocks (neuraxial, plexus, and peripheral) and for cannulation of veins (particularly the internal jugular and subclavian via a supraclavicular approach) and even peripheral arteries in difficult circumstances when intra-arterial monitoring is needed but difficult to obtain. Models and videos were presented in several exhibits and one included a simulator used at New York University to teach the use of ultrasound to guide peripheral block needles.

A large team from Robert Wood Johnson in New Jersey presented a simple concept for use during monitored anesthesia care when the patient needs supplemental oxygen for safety and has nasal cannulae placed. In essence, a plastic bag is used to make a tent over the patient’s face in a specific manner to specifically prevent CO2 rebreathing but that raises the enclosed FiO2 to over 40%.

Finally, while not traditional direct patient safety topics, 2 Scientific Exhibits presented applications of classic Oriental medicine, one from Japan involving the use of acupressure to resolve intractable pain and the other from Virginia Commonwealth University to enhance preoperative evaluation by palpation of certain arteries and acupuncture points as well as observation of the patient’s tongue.

In the Technical Exhibits, many manufacturers followed themes similar to those in the Scientific Exhibits. Also, information management/technology systems were numerous, each implying, either directly or indirectly, positive patient safety implications. Each of the simulator manufacturers had an elaborate display with opportunities to try the product.

Airway tools were ubiquitous. Intubating and video laryngoscopes of various shapes and sizes permeated the displays. A new model of micro video camera is intended to fit to the forehead of an anesthesia trainee (or dental student) so that the supervising faculty can see exactly what the trainee sees and thus tailor teaching and suggestions to exactly what the trainee is doing. The system looks much like a standard surgical headlight common in all ORs and it attaches to the same type of light source. The video image, however, is transmitted wirelessly to a receiver that is connected to any available monitor. In the equipment exhibits, a new airway device is an endotracheal tube stylet that protrudes 2 cm out the distal end of the tube and has a soft, somewhat flexible tapered point that will smoothly traverse the larynx—the purpose of which is to avoid trauma to the vocal cords from the edges at the tip of a regular tube. Another new shape was a brand of oral airway that is wide and flat and offered as particularly helpful with mask ventilation.

Ultrasound devices to facilitate correct needle placement in all applicable circumstances were prominent in the exhibit hall, each touting its particular features and advantages. On another tack, 2 manufacturers exhibited new systems to diagnose obstructive sleep apnea at home in the preoperative period. When a patient gives a suggestive history or has anatomic likelihood, such a system of sensors and a recorder can be sent home with the patient. Ventilatory patterns from either chest plethysmography or expired breath are sensed and recorded in a computer memory along with pulse oximetry measurements. Then, when the patient arrives for preoperative preparation prior to an anesthetic, the computer files can be downloaded and analyzed in real time—within a few minutes—providing a report that includes evaluation for sleep apnea/airway obstruction.

Patient warming devices again seemed to receive less emphasis from exhibitors. The singular exception was the expanded presentation of an air- and noise-free patient warming system that uses a radiant fabric that can adapt easily to various sized patients in various positions (and can also be connected to a vest to be worn by chilled anesthesia providers). Cited advantages are increased energy efficiency and decreased risk of infection transmission to anesthetized patients. Also, intraoperative medication error prevention was the emphasis of exhibit
s from services providing pre-filled syringes and/or bar-code readers to help insure 100% correct medication administration.

Interestingly, a new emphasis on concern for dangerous risks from postoperative pain medication, especially opioid PCA, appeared this year. Apparently, cases of excessive ventilatory depression and resulting hypoxemia associated with aggressive narcotic pain management, even starting in the PACU but usually associated with general care floors and often at night, are being much more widely recognized. Seven systems in which patient monitoring (usually oximetry and/or capnography) were integrated with PCA pumps were shown as exhibits. Most are interlocked so that alarm signals from the patient monitor(s) not only call for help but will automatically prevent additional PCA doses from being administered.

Overall, patient safety persisted as a key focus of both types of exhibits at the ASA Annual Meeting. This continued emphasis recognizes both the current success in improving patient safety and also the significant challenges yet remaining.

Dr. John Eichhorn, Professor of Anesthesiology at the University of Kentucky, founded the APSF Newsletter in 1985 and was its editor until 2002. He remains on the Editorial Board and serves as a senior consultant to the APSF Executive Committee.