Consider the Following Case…
A 70 year-old male underwent an ablation for a past medical history of atrial fibrillation. His past medical history includes Congestive Heart Failure (CHF), Chronic Obstructive Pulmonary Disease (COPD), Type II Diabetes, and Rheumatoid Arthritis (RA) for which he takes Humira. He was discharged home without incident. Three days later, he was complaining of chest pain and weakness. His wife found him down in the bathroom where he was responsive but short of breath, weak and unable to get up (of note, the wife reported the patient was not ambulatory for the last 3 days, post ablation).
An ambulance (EMS) was called and transported him to a local emergency department (ED). He presented to the ED hypotensive in the 70s/40s range, tachypneic in the upper 20s, and hypoxic with a room air pulse oximetry reading of 75%. The ED decided to perform a “crash airway” procedure secondary to his acute unresponsive state, profound respiratory distress and predicted clinical course. He continued to decompensate hemodynamically with Norepinephrine and Dopamine infusions initiated. Central venous access was obtained femorally as was an arterial line.
The patient’s initial laboratory studies were significant for an elevated white blood cell count, elevated renal markers, mild hyperkalemia, hypomagnesmia, an elevated Beta Natriuretic Peptide (BNP), elevated D-Dimer, grossly elevated troponin, and an elevated serum lactate. His arterial Blood Gas (ABG) showed an uncompensated respiratory acidosis with an initial pH of 7.13. Blood cultures were drawn and he was started on broad-spectrum antibiotics. A Chest CT was completed and our critical care transport team was called to move the patient by air to a tertiary care facility (flight time was 30 minutes).
When in Doubt, Start with the Assessment…
As initial patient information was not available at the time that the team launched, the history of present illness (HPI) and the following physical assessment allowed the team to make some treatment and transport decisions…
Head: Normocephalic with a secured airway, central cyanosis, severe blue discoloration of the nose and ears. Pupils 3mm, equal, round, sluggish in response to light.
Trachea: Midline, with no crepitus or along the neck. No JVD appreciated
Chest/Lung findings: Dual chamber pacemaker palpated, with minimal, but symmetrical chest rise with assisted RR. Bilateral Coarse lung sounds auscultated. Volume control ventilation on 0.5 FiO2 resulted in 11 liters/minute of Minute Ventilation.
Abdomen: Slightly firm and round with hypoactive bowel sounds.
Pelvis/Genitourinary: Temperature sensing urinary catheter in place with a core temperature of 99.1F. Patient has been anuric since arrival to the ED.
Lower extremities: Right lower extremity: dusky with blue/blackish toes, Doppler pulses noted, cool to touch, capillary refill severely delayed with 2+ pitting edema. Left lower extremity: dusky, absent pedal pulses, blue/blackish toes, capillary refill severely delayed with 2+ edema.
Vital signs included a heart rate of 140 (atrial fibrillation), blood pressure of BP 96/49 (65), a respiratory rate of 26 bpm and shallow, unreadable pulse oximetry and a GCS of 1/1/1.
Let’s Talk Differentials
The FINDINGS…Air in the Where???
The CT of the chest showed a large volume of gas predominantly in the right ventricle with a small volume extending into the pulmonary outflow tract and pulmonary artery, as well in central veins and right upper extremity veins. No pericardial effusion. No pulmonary emboli.
Let’s Talk About Anatomy, Let’s Talk About The Things To See
The esophagus lies very close to the left atrium and pulmonary vein ostia. It slides behind the left atrial wall and overlaps in the area of the pulmonary vein ostium [2]. Additionally, the posterior wall of the left atrium is at its thinnest just where the esophagus passes by [2]. Radiofrequency (RF) ablation is done by creating lesions that are circumferential on the left atrium and/or pulmonary vein ostia for treatment of atrial fibrillation [3]. One can see why one of the complications of an ablation would be an atrioesophageal (AE) fistula. The exact mechanism of injury post ablation is still debatable. Current theories secondary thermal injury with impaired healing, infection, and acid reflux with an unknown weakness to the esophagus at the time of the ablation [2]. The incidence of AE fistulas is reported to be about 1 in 2,000 cases with a mortality rate of 40-100% [2]. The delay in diagnosis and clinical awareness contributes to the high mortality [2].
To Manage Or Not To Manage…That Is The Key
Early recognition is key…
Symptoms can be very vague and include malaise, fever, chest discomfort, dyspnea, nausea, vomiting, hematemesis [3]. A high index of suspicion should be the constellation of the above symptoms mentioned with past medical history of GERD as well [3]. To add to the confusion, 69% of patients with AE fistulas present neurological deficits due to air emboli [4]. EKG findisngs may show tachycardia, ST segment changes, or even evidence of right heart strain [5]. 24% of patients will present to the ED with odynophagia and hematemesis and the usual algorithm of action is a esophaogastroscopy [4]. This invasive esophageal procedure involves the insufflation of air into stomach, in which case has immediate, devastating sequela for the patient with an undiagnosed AE fistula.
What NOT to do…
Again, we want to refer back to basic anatomy. When a AE fistula is suspected, avoidance of endoscopy, transesophageal echocardiograms, or any other type of esophageal probe or monitoring device should be avoided for obvious reason [2].
The Vagus nerve can also be damaged during an ablation [2]. The nerve runs along the posterior left atrium and through the abdomen, controlling not only the heart, but the pyloric sphincter, and gastric motility, all of which can be affected when damaged [2].
Management…
- Early surgical repair
Mortality rate of 100% without surgical repair [3]. The repair involves stenting of the esophagus and placing a biological barrier between the esophagus and atrium [3]. Broad spectrum antibiotics are essential for septic shock modalities.
- Perform the Durant Maneuver… Do the what?
Place the patient in the left lateral decubitus and Trendelenburg position. This helps prevent the air emboli from traveling through the right side of the heart into the pulmonary arteries, which can lead to right ventricular outflow obstruction aka air lock. This position also prevents an air embolus that may be on the arterial side from traveling to the brain leading to an ischemic stroke [5].
So Back To The Lesson At Hand…
The Durant maneuver was performed based on the interpretation of the OSH CT which was believed to show air in the right atrium and ventricle. With this maneuver established the patient was safely transferred via helicopter by the critical air transport team. Transfer of care was complete at the accepting hospital and all was made well and good in the world.
Except…… at the accepting hospital, the repeated CT revealed… No aterioesophageal fistula and the air was resolved….
For The Moral Of This Blog Shall Be…
Don’t judge a transport by what you hear, but rather proceed with what you see. In other words, don’t allow yourself to be pulled down into the rabbit hole of someone’s initial interpretation. Instead take a moment to confirm or deny the information that has been given to you. It’s easy to allow yourself to be locked into tunnel vision when you’re confident and subsequently take someone’s word at face value. I believe I can safely say that we’ve all done it at one time or another. Our training and critical thinking skills can serve our patients through expanding our knowledge and learning such things as the Durant maneuver and applying it to those outlier cases. However, I think Albert Einstein said it best, “Education is not the learning of facts, but the training of the mind to think”. So go forth and THINK!
References
- Lanfranco, Julio & Legro, Ivan & Freire, Amado & Nearing, Katherine & Ratnakant, Sanjay. (2017). Pulmonary Air Embolism: An Infrequent Complication in the Radiology Suite. American Journal of Case Reports. doi: 18. 80-84. 10.12659/AJCR.901098.
- Muzammil, K., Mamoon, R., Hammad, Z., Wagas, U., Abu, K. (2020). A Rare Complication of Cardiac Ablation: Atrial-esophageal Fistula Presenting as Odynophagia. Cureus. 12(2). Available from: https://doi.org/10.7759/cureus.6871
- Kapur, S., Barbhaiya, C., Deneke, T., Michaud, G. Esophageal Injury and Atrioesophageal Fistula Caused by Ablation for Atrial Fibrillation. (2017). Circulation. 136(13). Available from: https://www.ahajournals.org/doi/full/10.1161/circulationaha.117.025827
- Siegel, M., Parenti, D., Simon, G. Atrial-Esopheal Fistula afer Atrial Radiofrequency Catheter Ablation. (2010). Clinical Infectious Diseases. 51(1). Available from: https://academic.oup.com/cid/article/51/1/73/299194
- McCarthy CJ, Behravesh S, Naidu SG, Oklu R. Air Embolism: Practical Tips for Prevention and Treatment. J Clin Med. 2016;5(11):93. Published 2016 Oct 31. doi:10.3390/jcm5110093. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5126790/