#318 Air Embolism Alert

Air embolism is one of those complications that feels impossible right up until it happens fast, quietly, and with life-altering consequences. We walk through the FDA’s 2025 Early Alert on the Watchman access system for left atrial appendage occlusion (LAAO) procedures and connect the dots between device exchange steps, transseptal puncture, and the anesthetic choice that can put patients at risk.

We talk about why the shift toward sedation and spontaneous ventilation in structural heart procedures can increase risk when an access system is open or imperfectly sealed. Negative intrathoracic pressure may create a suction gradient that favors air entry into the left atrium, where even small volumes can lead to coronary air embolism or cerebral air embolism. We also review what the FDA reported, including known cases of serious injury and death, and why registry rates may underestimate true events.

From there, we translate guidance into practical anesthesia patient safety moves you can use in the interventional cardiology suite: when to consider controlled positive pressure ventilation and PEEP, what to watch during sheath manipulation, and how to set clear roles for sheath control, flushing, and line management. We cover prevention details like keeping components below the level of the heart, slow flushing to maintain a continuous fluid column, and performing exchanges under saline or water baths. We also outline an immediate response plan: recognize quickly, support hemodynamics, consider Trendelenburg positioning, aspirate air if indicated, and activate perfusion support early when available.

If this topic touches your practice, share this with your cardiology and anesthesia team, then subscribe, leave a review, and send the episode to a colleague who does transseptal cases. What does your team do to prevent air entrainment during exchanges?

For show notes & transcript, visit our episode page at apsf.org: https://www.apsf.org/podcast/318-air-embolism-alert/

© 2026, The Anesthesia Patient Safety Foundation

Transcript

FDA Alert And Key Takeaways

Alli 0:00

If you provide anesthesia care for patients undergoing structural heart interventions, then it's time to turn up the volume because we are talking about the FDA's 2025 early alert for the risks of air embolism associated with the Watchman access system used for left atrial appendage occlusion procedures. There are important concerns directly related to the type of anesthetic used during this procedure. With more procedures being done under sedation, the negative intrathoracic pressure during spontaneous ventilation has been implicated in catastrophic error embolism events, especially with transeptal procedures. Hello and welcome back to the Anesthesia Patient Safety Podcast. I'm your host, Ellie Bechtel. Here are the big takeaways from today's show to support periprocedural safety for anesthesia professionals during minimally invasive heart procedures with a risk of air embolism. Number one, for a ventilation strategy, consider controlled positive pressure ventilation for high-risk patients to avoid negative intrathoracic pressure using PEEP as appropriate. Number two, remain vigilant during sheath manipulation, monitor airway pressures, hemodynamics, and echocardiographic views. Number three, establish clear roles for sheath control, flushing, and line management before starting the procedure. Number four, be prepared to recognize and treat air embolism immediately with Trendellenberg positioning, hemodynamic support, aspiration if indicated, and activation of perfusion support teams if available. And finally, for continuous improvement, stay current with FDA alerts, registry data, and device updates, participate in multidisciplinary reviews, and simulation of rare events.

Sponsor Support And Thanks

Alli 1:54

Before we dive further into the episode today, we'd like to recognize Nihon Coden, a major corporate supporter of APSF. Nihon Coden has generously provided unrestricted support to further our vision that no one shall be harmed by anesthesia care. Thank you, Nihon Coden. We wouldn't be able to do all that we do without you.

Featured Article And How To Find It

Alli 2:19

Our featured article is Air Embolism during left atrial appendage occlusion procedures, lessons from the FDA Early Alert by Daniel McGrail and colleagues. This is an APSF newsletter article that was published online April 1st, 2026. To follow along with us, head over to apSF.org and click on the newsletter heading. The first one down is newsletter articles. Then you can scroll down until you get to our featured article today, and I will include a link in the show notes as well. And now let's get into the article, and we're starting with some background information.

Structural Heart Anesthesia Shifts

Alli 2:56

Structural heart disease procedures like transcatheter aortic valve replacement, transcatheter edge-to-edge repair, and left atrial appendage occlusion have come a long way in the last 10 years, with advanced technology leading to shorter hospital length of stay and no increase in complications or mortality. The anesthesia for these procedures has evolved as well, moving from general anesthesia with an endotracheal tube to monitored anesthesia care with mild or moderate sedation. The decision between sedation and general anesthesia depends on many factors, including proceduralist experience and patient comorbidities. But there are additional considerations, including availability of anesthesiology resources, operating room block times, or the use of transesophageal echocardiography. Recent studies have evaluated the differences between general anesthesia and sedation and have found no differences for sedation when it comes to hospital length of stay and mortality. Sedation may be associated with faster recovery time and decreased resource use, but there are special physiologic and procedural safety risks associated with spontaneous ventilation during sedation when air may be introduced into the heart. Now, let's look at the left atrial appendage occlusion procedure that seals off the left atrial appendage for patients with non-valvular atrial fibrillation who can't take long-term anticoagulants. The stroke risk reduction from this procedure has been shown to be comparable to warfarin in all major trials. For the six months following the procedure, the all-cause risk of stroke and death is 1.2 and 4%, respectively.

What The FDA Early Alert Found

Alli 4:44

We are talking about this procedure as a threat to patient safety because in August 2025, the United States Food and Drug Administration, the FDA, issued an early alert that highlights a serious hazard associated with the excess system for one of the left atrial occlusion devices, the Watchmen. There were multiple cases of catastrophic air embolism during watchmen procedures that were performed under sedation with spontaneous ventilation. The alert includes important considerations to help reduce the risk of air entrainment and air embolism. This is a call to action for all anesthesia professionals providing anesthesia care for patients undergoing watchmen procedures. Check out Figure 1 in the article for a picture of a proceduralist holding the delivery sheath connected to a Tui Borst hemostatic valve with side port stopcock. There is a pigtail catheter going through the valve to access the left atrium. During the device exchange, the connection is kept submerged under sterile water in a basin while the system is briefly disconnected to attach the watchman delivery device. You can also watch the supplementary video to see this happen live. Here are the key findings from the FDA early alert. There were 120 known cases of serious injury and 17 deaths related to air embolism during left atrial appendage occlusion watchman procedures. In the National Registry, the rates of air embolism during Watchman procedures ranges between 0.03% and 0.06%. We also need to keep in mind that many air embolism events may be undetected. The watchman procedures and any percutaneous heart procedure with transeptal puncture to access the left atrium are particularly high risk for air embolism when you have a spontaneously ventilating sedated patient, leading to an increased risk of negative pressure in the left atrium and subsequent air entrainment. Risk factors for intracardiac air entrainment during these procedures include the following spontaneous ventilation, upper airway collapse or obstructive sleep apnea, hypovolemia predisposing to lower left atrial pressures, inadequate de-airing of the excess system, and accidental injection of air. The important steps when air can be introduced into the left atrial appendage occlusion access system are if the sheath or valve system is exposed to open air, inadequately de-aired, or positioned above the level of the heart during spontaneous ventilation. In order to access the left atrium, a transeptal puncture is made with a 14-French catheter, and if air is entrained through this device, it has a direct path to the left atrium. Patients are at risk for coronary air embolism, and you may see ST segment changes, hemodynamic instability, and wall motion abnormalities, as well as cerebral air embolism leading to stroke.

Risk Factors And How Air Enters

Alli 7:46

Let's turn our attention to table one and some suggestions provided by the FDA for risk mitigation to help prevent air entrainment during minimally invasive cardiac procedures. And this is especially important when there is a transeptal puncture. Number one, hemodynamic optimization and maintenance of euvolemia before puncture to avoid negative left atrial pressures. Number two, device handling with all sheaths, stopcocks, and access valves kept below the level of the heart and filled with fluid. Number three, careful de-airing of all access systems by flushing lines slowly and maintaining a continuous fluid column during device exchanges. Number four, exchange protocol with all sheath and wire exchanges performed under a saline or water bath, slow device withdrawal, and made during expiration for spontaneously ventilating patients. And number five, system readiness with confirmation of air elimination and valve seals before insertion. Clear communication between cardiology and anesthesia professionals is a vital step prior to each exchange as well. Now we're going to run through a list of safety principles for anesthesia professionals involved in minimally invasive heart procedures with a risk of air embolism. The next time you're providing anesthesia care in the interventional cardiology suite,

FDA Mitigation Steps And Team Roles

Alli 9:11

we hope that these principles will help guide your management as well as provide insights for important system-level considerations that are needed to help keep patients safe and continuing to keep patients safe in the future. For ventilation strategy, consider controlled positive pressure ventilation for high-risk patients, including those with obstructive sleep apnea, to avoid negative intrathoracic pressure and use PEEP as appropriate for the patient. For monitoring and awareness, maintain situational awareness during sheath manipulation, monitor airway pressures, hemodynamics, and echocardiographic views. For team communication, establish clear role assignments for sheath control, flushing, and line management before starting the procedure. For immediate response preparedness, be ready to recognize and treat air embolism with Trendellenberg positioning, hemodynamic support, air aspiration if indicated, and activation of the perfusion support team. And for continuous improvement, it is important to stay current with FDA alerts, registry data, and device updates. It is important for your team to participate in multidisciplinary reviews and insight-to simulation of rare events. We can see that there is a risk of air embolism during these procedures, but what is it about sedation that increases this risk? During sedation and spontaneous ventilation, negative intrathoracic pressure creates a suction gradient that favors air entry into open or inadequately sealed vascular systems. Plus, we are talking about the left atrium here, and even small amounts of air can produce serious cerebral or coronary embolic events. This suction force is not produced when patients are under general anesthesia with positive pressure ventilation. The positive pressure helps to create a protective outward pressure gradient to help decrease the risk for air embolism. Just like many things in anesthesia, though, we need

Why Spontaneous Ventilation Matters

Alli 11:12

to weigh the risks and benefits. The benefit of positive pressure ventilation and decreasing the risk for air embolism compared to the risks of general anesthesia, procedural, and other patient risk factors. There is a call to action for awareness of the physiology and closed loop communication with the procedural team anytime there is a transeptal puncture and the mode of ventilation changes the pressure gradient across the open cardiac access system. Air embolism during interventional cardiac procedures is not new and has been studied in the electrophysiology lab or EP lab.

Lessons From EP Lab Literature

Alli 11:50

So let's head next door and see what the literature from EP and pulmonary vein isolation for the treatment of atrial fibrillation reveals. Catheter ablation for pulmonary vein isolation may involve cryoballoon ablation, radiofrequency ablation, or pulse field ablation, and may be performed under general anesthesia or sedation. There was a prospective multi-center study of about a thousand patients comparing sedation with general anesthesia and showed no difference in neurological events. In addition, a recent meta-analysis compared recurrence of atrial tachyarrhythmias with sedation or general anesthesia and found no differences in the recurrence rate or the complication rate. The rates of air embolism during atrial fibrillation ablation procedures may be as high as 1.5% with air entrainment during ablation and mapping catheter utilization. Contributing factors include sheath or catheter size mismatch, catheter tip shape, design of the hemostatic valve. Pulse field ablation sheets now have clear shafts so that air bubbles can be visualized by operators. Mitigation strategies during these EP procedures include monitoring all infusion lines for bubbles and slow removal of all catheters with simultaneous aspiration. Other techniques may include using sheath-in-sheath, which involves leaving a smaller inner sheath inside the transeptal sheath at all times during exchanges with a continuous saline drip to prevent air entry during catheter exchange. Decreasing the risk for air entry may also be accomplished with slow flushing of sheath, temporary balloon inflation prior to insertion, or carrying out all sheath access under a water bath. I'll include the citations for this EP literature review in the show notes too.

Checklists Reporting And Closing Actions

Alli 13:46

As we wrap up for today, here are some important takeaways and action items. Establish clear sedation and general anesthesia criteria that account for patient and physiologic risk due to the procedure. Oversight and competency training may be required for any updated procedural steps. Consider implementation of procedural checklists, you know we love checklists, for D-airing and sheath positioning to improve reliability over time. Enable and empower all healthcare professionals to speak up about compliance with these new safety procedures. And report any adverse outcomes or device failures to the FDA for all suspected device-related adverse events. We made it to the end of the article. And if you have any questions or comments from today's show, please email us at podcast atapsf.org. Please keep in mind that the information in this show is provided for informational purposes only and does not constitute medical or legal advice. We hope that you will visit apSF.org for detailed information and check out the show notes for links to all the topics and citations that we discussed today. Remember, anesthesia professionals can help identify physiologic and procedural hazards before harm occurs. Any cardiac procedure with transeptal puncture carries serious risk for air embolism, and keeping patients safe depends on multidisciplinary collaboration and teamwork. And now, calling all researchers.

Research Grants And Final CTA

Alli 15:18

Applications are now open for the Foundation for Anesthesia Education and Research Fall 2026 grant cycle. Now through August 15th, 2026. Grants available include the Mentored Research Training Grant, Research and Education Grant, and Research Fellowship Grant. The transition to independent grant is also available on a rolling basis. Head over to FAIR.org slash grants for more information or check out the link in the show notes. Thanks for joining us for another episode of Anesthesia Patient Safety Podcast. We hope today's conversation has given you practical insights to help make anesthesia even safer for every patient in the interventional cardiology suite, EP lab, or just the general operating rooms, and given you the inspiration to apply for one of the grants that we just talked about. If you enjoyed this episode, please take a moment to like, subscribe, and share the podcast with your colleagues. Your support helps us reach more clinicians who are passionate about improving patient safety. Until next time, stay vigilant and stay informed so that no one shall be harmed by anesthesia care.