ABCs of dentistry: Airway, breathing, and circulation

“Z is for zebras and other dental surprises” appeared in the July 2022 issue of dvm360^®, culminating a 5-year project highlighting dentistry topics from each letter of the alphabet. Now the journey begins again, starting with A, B, and C (airway, breathing, and circulation), which are essential monitoring parameters for every professional oral prevention, assessment, and treatment visit. Note that prevention is first because it is most important.

Safe anesthesia usage is a critical aspect of a dental procedure. Administering anesthesia safely boils down to 3 crucial actions:

1. Ensuring the patient can handle anesthesia through a physical and laboratory test examination.
2. Tailoring the anesthetic protocol to the patient’s American Society of Anesthesia score:
   • Normal healthy patient
   • Patient with mild systemic disease
   • Patient with severe systemic disease
   • Patient with severe systemic disease that is a constant threat to life
   • Moribund patient not expected to survive without the operation

3. Monitoring anesthesia closely during procedure.

Clients worry about oral hygiene procedures because of the risks associated with their pet under general anesthesia for scaling, polishing, irrigating, probing, radiographs, and treatment. Attention to the airway, breathing, and circulation are critical to mitigate these risks. In the past, if a patient was breathing and the mucous membranes were pink, we surmised that all was good, confirmed by placing our stethoscope to the patient’s chest. Fortunately, there are monitors that can let us know within a breath if the dog or cat on our table is safe. With hundreds of monitors available, what should you pay attention to when choosing one?

How to select a monitor

The marketplace is flooded with available monitors, making it feel almost impossible to choose the perfect one for your practice. Use these parameters to help find your best fit:

Figure 1

• Choose a veterinary-specific monitor instead of one manufactured for humans. Veterinary-specific monitors will account for differences in patient types and sizes. (Figure 1: Patient size/type screen)

Figure 2

• Look for veterinary-specific monitors that incorporate ECG processes adjusted for the animal’s QRS complex, which differs from humans. For example, Digicare’s VetECG modules use algorithms based on signal spectrum analysis developed using ECG data from numerous recordings at general practices, universities, and zoos. Systems are optimized for veterinary QRS detection and classification to prevent conditions such as double counting and inaccurate readings. This veterinary-specific 3 Lead ECG module, AnimalEKG, is a high heart rate module that will read up to 999 beats per minute (BPM), making this monitor the perfect solution for any type of procedure, including exotics patients. (Figure 2: Image of high-quality ECG monitor board)

Figure 3

• Look for a monitor that measures and continuously displays pulse oximetry, end tidal carbon dioxide (ETCO₂), inspired carbon dioxide PaCO₂, wave-form capnography, blood pressure, temperature, and ECG. Consistently viewing all these parameters is important to ensure safety. The carbon dioxide readings will give breath-to-breath information on how your patient is ventilating and allow troubleshooting the anesthesia machine, including levels of expired soda lime. Since the mainstream sensor is placed in the endotracheal tube very close to the mouth, the tube will be sprayed constantly with moisture throughout the procedure, making mainstream sensors less desirable for dental work. Sidestream CO₂ sensors use a disposable sample line, keeping the module far from the patient inside of the monitor. In addition, the sample line includes a filter to better protect against water ingression. This makes Sidestream sensors more desirable for dental procedures. (Figure 3: Sidestream CO₂)

Figure 4

• Check for pulse oximetry. Masimo’s SET pulse oximetry has been the leading technology for veterinarians around the world and has been proven in more than 150 independent clinical studies. Masimo SET’s accurate SpO₂ readings are even proven during challenging conditions such as low perfusion, motion, and the use of drugs that are alpha-2 agonists. Pulse oximetry in these machines provides PVi, a continuous noninvasive measure of relative plethysmograph variability on mechanically ventilated patients and is used as an indicator of fluid responsiveness. (Figure 4: Pulse oximeter board and peripherals)
• Determine if the monitor displays parameter value trends (graphic, histogram, and numerical readings) on 1 page for easy viewing in real time. This is important to analyze changes in the patient’s vitals over time. (Figure 5: Graphic display of multiple contemporaneous readings; 5a: Tabular display, 5b: histogram display)

Figure 5

Figure 5a

Figure 5b

Figure 6

• Think about your patients’ blood pressure. Noninvasive blood pressure (NIBP) is often procured while the patient is not under anesthesia for preoperative testing, medication monitoring, and as part of the semiannual wellness exam. For NIBP, SunTech’s VetBP module uses an animal-specific algorithm designed with motion-tolerant technology. High-quality components and cuffs that can sustain the rigors of an animal hospital are critical when choosing a monitor. (Figure 6: Non-invasive blood pressure board and cuffs)

Figure 7

• Choose a monitor with a display that is bright and easy to view from different angles, easily differentiating all the numbers and waveforms. Each parameter should be displayed in a different color to make information eye-catching and accessible. This greatly enhances the monitoring experience. Touch screen adjustment should be intuitive and featured. (Figure 7: Visually pleasing screen with large, colorful numerals and waveforms)

Figure 8

• Find visual and auditory alarms that give an alert when any of the vital parameters are either too high or low. Alarms should be easy to set initially and adjust during a procedure. (Figure 8: Alarm limits)
• Select a monitor that will automatically prepare an anesthesia report that can be attached to the medical record and/or saved to a PDF or Excel document for future reference.

Figure 9

• Confirm the monitor manufacturer has ISO 13485 certification. The International Organization for Standardization is an independent, nongovernmental international association with a membership of 162 national standards bodies. ISO 13485 is an international standard that sets out the requirements for a quality management system specific to the medical devices industry. ISO 13485 enables an organization to consistently provide safe and effective medical devices and fulfill customer and regulatory requirements. (Figure 9: Device and company certifications)
• Talk to the sales representative and ask questions about customer support, training programs, and whether there are certified veterinary technicians on staff who understand veterinary anesthesia. Too many monitors are sold without the veterinary technicians and assistants understanding how to adjust and tailor the display. Finding a manufacturer that will work with your staff to make sure they are trained in operating the monitor quickly boosts its effectiveness and your patients’ safety.
• See if there is a monitor loaner program. The leading monitor vendors provide loaners for life at no charge if the monitor needs to be serviced in another location.

How to pay for the best monitor

Obviously, it is expensive for the monitor manufacturer to provide a product that checks all the boxes above. Consider a line-item charge for patient anesthesia monitoring either by the quarter hour, full hour, or a set fee. With the number of anesthetic procedures most practices perform, not only will the impact of the additional cost be spread among clients, but the monitor will help the practice bring in more revenue.

We cannot perform dentistry without a patent airway, a breathing patient, and supportive circulation. Having a great monitor that fits the criteria for your practice ensures we can protect all 3 and keep the risks associated with anesthesia and your stress levels as low as possible.

If you are still unsure about which machine is correct for you and your team, call your local specialty hospitals and veterinary universities to see which monitors they like and use. If possible, speak to the doctor or nurse in charge of anesthesia for recommendations.

Jan Bellows, DVM, DAVDC, DABVP, FAVD, received his undergraduate training at the University of Florida and his doctorate in veterinary medicine from Auburn University. After completing an internship at the Animal Medical Center in New York, New York, he returned to Florida, where he practices companion animal medicine surgery and dentistry at All Pets Dental in Weston. He has been certified by the American Board of Veterinary Practitioners (canine and feline) since 1986 and the American Veterinary Dental College (AVDC) since 1990. He was president of the AVDC from 2012 to 2014 and is president of the Foundation for Veterinary Dentistry.