As procedures grow more complex and patient risk increases, continuous CO2 monitoring gives clinicians a clearer, faster picture of respiratory status – helping them intervene before complications arise.
By Pete Mercer
In ambulatory surgery centers, patient safety and efficiency are the top priorities as surgical volumes and case complexity continue to rise. One technology playing a growing role in advancing both is capnography – the continuous monitoring of a patient’s exhaled carbon dioxide. Capnography is being recognized as an invaluable tool within ASCs for enhancing airway management, improving sedation safety, and enabling earlier detection of respiratory compromise. By integrating capnography into routine perioperative monitoring, ASCs can strengthen their commitment to high-quality, patient-centered care while meeting evolving clinical standards and regulatory expectations.
Repertoire Magazine spoke to Paul Mountford, the medical affairs program manager for Microstream™ Capnography at Medtronic, and Shayna Jackson, the senior principal marketing manager for Microstream™ Capnography at Medtronic, to discuss what capnography is, the role that it plays in an ambulatory surgery setting, and how the Medtronic Microstream™ Luer capnography sampling lines can integrate into the ambulatory workflow.
What is capnography?
Capnography is a medical monitoring technique that measures the concentration of carbon dioxide in the patient’s exhaled breath. This is used as another form of patient monitoring to improve the patient’s safety and overall health outcomes while undergoing a procedure in an ASC.
“Capnography is not directly measuring oxygenation, but rather the ventilation status of the patient,” Mountford said. “The way it does that is it samples and measures exhaled end-tidal carbon dioxide content from the patient’s breath, providing a respiratory rate, which is just how many times you’re breathing. The reason you want capnography is it’s the fastest indicator of ventilatory status.”
With capnography, you can immediately detect any changes in breath, which tells you more about a patient’s respiratory status faster than relying on pulse oximetry or other monitoring methods. This provides a much fuller picture of respiration compared to pulse oximetry, which measures blood oxygen saturation.
Oxygenation is a latent indicator of a patient’s respiratory function because oxygen will remain in your blood even after you stop breathing. When you breathe in, that oxygenated air goes into your lungs, through the alveoli, and into your blood system, which is where the pulse oximeter captures the oxygen levels. This doesn’t account for the carbon dioxide being produced and then circulated back into the lungs and out of the body on exhalation.
Jackson said, “When patients are undergoing cases where we need to monitor respiratory levels, they’re on supplemental oxygen as well. They have elevated oxygen levels, which will cause an extended delay even in those times of respiratory depression. We need to be able to capture that gas. The capnography reading is truly a breath-by-breath waveform analysis that’s going to be able to detect any of those changes, whether it be through partial airway obstruction, complete apneas, or even episodes of hypopnea that patients sometimes go through.”
Enhancing patient safety in the ASC setting
Due to the nature of the procedures and the speed with which they’re performed in an ASC, patient safety is paramount. Hypoventilation, or when the body cannot effectively remove carbon dioxide from the body, is a common challenge in these settings, where the medication slows down the respiration rate, and can also decrease the depth of ventilation. For this reason, capnography is an incredibly valuable tool to enhance respiratory monitoring.
“A lot of times, these patients are not intubated,” Jackson said. “Anywhere from mild to deep sedation, their airway is unprotected, and the medications being used have respiratory depressive properties. Things like propofol, fentanyl, and midazolam. Every patient is different, and how they respond to these medications is different.”
Even when the patient meets a certain height, weight, or age requirement, that doesn’t mean that physicians can count on a specific response to these medications. This can leave the airway compromised, and the patient may not breathe sufficiently on their own. Being able to capture the ventilation through capnography can help the physician to determine how they can proceed with their case.
Mountford likens capnography to an added layer of protection for the patients, despite the level of sedation expertise in the ASC setting. “We step into these ASC settings, whether it’s spine or gastroenterology, and we don’t always have the anesthesia expert in the room. Capnography is just an early onset indicator so that you can intervene sooner in the case of respiratory depression.”
The growing case for capnography
The practice of capnography is readily available to use in most sedation suite monitors. Most anesthesia carts are equipped with the required connections, so it comes down to ensuring that the team knows how available the tools are and having the right one at your disposal.
Capnography is not only a versatile tool to monitor patient’s respiratory functions; it can also act as a sort of warning system for when facilities are busy. Mountford said, “There are less sedation nurses, less CRNAs, less anesthesiologists, and less gastroenterologists if we consider GI-focused facilities. Everyone’s working more, which may mean things are going to get missed. The more people are overworked, the more advantageous it is to have a warning indicator like capnography.”
There is a growing case for capnography in healthcare settings – more complex procedures are being pushed to ASCs, which means that more high-risk patients are being treated in ASCs. As the patient population grows older, heavier, and sicker, the risk of operating on these patients increases.
Mountford said, “As you go up in patient risk, you really want to be looking at capnography because they are at a higher risk for respiratory depression. The case is growing because we have a growing number of high-risk patients.” He explained further that capnography is important to use with younger patient populations as well, because it will detect any adverse reactions to any of the sedative agents being used.
Medtronic Microstream Luer capnography sampling lines
Medtronic Microstream Luer capnography sampling lines are compatible with most sidestream monitors, making it a flexible option for use with patients in an ASC setting. This is an easy-to-implement technology that supports practitioners who may not have the anesthesia expert in the room with them.
“Because the technology is already integrated into most of these monitors, our Luer lines come equipped with both a male and female adapter,” Jackson said. “It’s very versatile as far as what connection point you have on that monitor. That versatility combined with the dual-nare sampling versus the split-nare sampling that most of the other options in the market have today is where the Microstream Luer capnography sampling lines really shine, providing powerful insights with every breath.”
Microstream Luer capnography sampling lines are designed to capture samples from the mouth and both nostrils, referred to as dual-nare, which is important because approximately 80% of patients experience nasal cycling, where the airflow alternates between nostrils. On top of that, Jackson said that is “extremely common for patients to transition between nasal and oral breathing.” Without the dual-nare sampling and the oral sampling lines, it’s much easier to miss exhalations for patients who are nasal cycling as well as switching between nasal breathing and mouth breathing.
“Just having that technology there to be able to serve as a guardrail to those early warning signs of hypoventilation is an added measure of protection, especially for ASC spaces that might not be tied to an acute care facility right next door. Practitioners need to have that level of confidence to be able to complete the procedure and send the patient home,” Jackson said.
1 Marshall SG, Henry NR, Russian, CJ. Right Versus Left Prong Nasal Cannula, Flow Delivery and the Effects of Nasal Cycling on Inspired FiO2 in an Adult, Anatomic Model. Respiratory Care April 2016, Vol 61, No 4, 397-404.