Difficult Airway Response Team Tackles ACE Inhibitor Angioedema

When it comes to intubation, every second counts, and difficult airways can quickly become life-threatening situations.

At Johns Hopkins Hospital, in Baltimore, any concern for a difficult airway can trigger activation of the difficult airway response team (DART), which brings together a multidisciplinary group of physicians that can quickly and effectively manage the most challenging airway presentations. According to a recent analysis, the program has been a critical success, especially when it comes to managing angiotensin-converting enzyme (ACE) inhibitor–induced angioedema.

“It’s extremely important to know the stages of angioedema so that management can be both appropriate and timely,” said Julie Wyrobek, MD, currently a cardiothoracic fellow at Brigham and Women’s Hospital, in Boston, who completed her residency training at Johns Hopkins. “If intubation needs to take place in these patients, we recommend an awake nasal fiber-optic intubation, preferably in the operating room, if feasible. Utilizing a multidisciplinary team of clinicians like we do with the DART program brings together different skill sets, which can be critical in managing difficult airways.”

As Dr. Wyrobek explained, the increasing popularity of ACE inhibitors has led to a corresponding increase in ACE inhibitor–associated angioedema, a rare but life-threatening condition that requires prompt recognition and differentiation from anaphylaxis for appropriate management. Populations at high risk for ACE inhibitor–induced angioedema include blacks, women and patients with a history of cardiac or renal transplant.

“At our institution, the DART program is comprised of attending and senior resident anesthesiologists, otolaryngologists, trauma surgeons, emergency medicine physicians and designated personnel to bring a DART cart, which consists of emergency airway equipment,” Dr. Wyrobek said. “This multidisciplinary team is available 24/7, to identify, risk-stratify and mobilize resources for patients with a suspected difficult airway.”

To characterize the presentation and intervention of severe cases of ACE inhibitor–associated angioedema, Dr. Wyrobek and her colleagues performed a retrospective analysis of the DART database from 2008 to 2015. Of the 45 patients with angioedema managed by DART during this time period, 18 were found to have had angioedema induced by ACE inhibitors. The investigators prospectively collected data for patients, including demographics, presentation, location, risk factors, response time and interventions.

The DART Approach To Angioedema

As Dr. Wyrobek reported at the International Anesthesia Research Society 2017 annual meeting (abstract 1544), the majority of patients presented to the emergency department with their first symptoms, and the average DART response time was 5.17 minutes. Of the 18 patients who triggered DART activation, 14 (83%) were intubated and three (17%) were monitored in the ICU with serial nasal endoscopic evaluation and did not require intubation. Of those requiring intubation, 60% were brought to the operating room, three were intubated in the ICU, two were intubated on the floor unit, and one was intubated in the emergency department. According to Dr. Wyrobek, the most successful first-time method of intubation was via an awake nasal fiber-optic intubation. No patients required a surgical airway and no patients had a loss of airway.

“Approximately 80% of our patients had stage III angioedema or higher,” Dr. Wyrobek said. “The more severe the airway gets, the more likely patients were to be brought up to the operating room to be intubated.”

As opposed to anaphylaxis, Dr. Wyrobek emphasized that angioedema presents with a slightly different picture. Angioedema usually occurs over a series of hours rather than seconds or minutes, and these patients usually have focal swelling rather than diffuse swelling. Angioedema patients are also typically hemodynamically stable, Dr. Wyrobek added. They may complain of shortness of breath, but they usually don’t need supplemental oxygen. The most important distinction, however, is that the treatment for anaphylaxis has no role in the time course or evolution of an angioedema patient.

“Even if these patients are given epinephrine or antihistamines, treatment or management should not be delayed,” Dr. Wyrobek said. “Our data, supported by the literature, suggest that any patient with a stage III or IV airway should either be intubated or brought up to the ICU where they can be monitored with serial oral airway exams.”

Moderator of the session, Sylvia Wilson, MD, associate professor at the Medical University of South Carolina, in Charleston, lauded Johns Hopkins’ approach to difficult airways and asked which member of the team directs the procedure.

“It’s usually the dynamic of the team that dictates the intubation,” Dr. Wyrobek said. “Sometimes it’s anesthesia. Other times it’s otolaryngology. Teamwork can be a challenge when you have several attendings gathered, but that’s the mentality with a DART—it’s about working together, not in a hierarchy.”

“Medications have been identified for acute airway angioedema that may prevent intubation,” Dr. Wilson said. “Have you started to incorporate these into your response?”

“These medications are not readily available at most institutions because they are expensive, and many are still in their research phase, but there have been case studies about medications that may prevent intubations,” Dr. Wyrobek said. “Case series have also suggested the benefits of administering two units of fresh frozen plasma to treat acute angioedema and prevent intubation, but this exposes patients to transfusion reactions.”