CARDIAC ARREST CAUSED BY IATROGENIC AIR EMBOLISM FOLLOWING COMPUTED TOMOGRAPHY

Abstract

SESSION TITLE: Medical Student/Resident Imaging Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: The presence of air within the circulatory system is a rare event that is typically iatrogenic in origin and often follows invasive or diagnostic procedures. CASE PRESENTATION: An 85-year-old male with a past medical history significant for hypertension, hypothyroidism, and osteoarthritis was admitted to the hospital for acute decompensated congestive heart failure. The etiology of his heart failure was determined to be due to severe aortic stenosis, based on a transthoracic echocardiogram. Once the patient was stabilized, he underwent a CT scan of his chest to determine if he would be a candidate for a trans-catheter catheter aortic valve replacement (TAVR). After the patient was returned to his room, he suffered PEA arrest while being assisted from the gurney to his bed. A code was called and the patient was intubated and received CPR. Return of spontaneous circulation was quickly obtained and he was transferred to the medical ICU. The patient was weaned from the ventilator and suffered no neurological consequences of the arrest. Images from the CT scan showed that his arrest was caused by acute right heart failure from a large air embolism occluding the right ventricle and pulmonary arteries. The patient was discharged home in stable condition. As an outpatient, he completed the rest of the TAVR work-up and successfully had his aortic valve replaced without complication. DISCUSSION: One of the most common causes of the introduction of air into the venous system occurs after contrast medium is injected for a CT scan. Based on previous case reports, the volume of air necessary to cause a fatality ranges from 200-300 mL, but symptoms have been reported with amounts as low as 50mL. Lethal air emboli are large enough to cause obstruction of the right ventricular outflow tract causing a drop in cardiac preload, which then leads to falling blood pressure, myocardial infarction and cerebral ischemia. The treatment of a symptomatic air embolus is to perform the Durant maneuver, which involves placing the patient in the left lateral decubitus position with the head down and the legs raised, which will alleviate the obstruction by having the air rise to the apex of the right ventricle. CONCLUSIONS: In this case, the patient was initially protected from the injected air due to his remaining supine until he returned to his room and sat upright. At that point, all of the air which had been pressed against the anterior portion of the right ventricle ascended and occluded the right ventricular outflow tract, triggering his cardiac arrest. The prevention of air emboli during CT scan typically involves constant monitoring of the pressure infusion devices to ensure that only contrast is injected into the patient. Reference #1: Durant TM, Oppenheimer MJ, Webster MR, Long J. Arterial air embolism. American Heart Journal. 1949;38(4):481-500. Reference #2: Malik N, Claus PL, Illman JE, Kligerman SJ, Moynagh MR, Levin DL et al. Air embolism: diagnosis and management. Future Cardiology. 2017;13(4):365-378. DISCLOSURES: No relevant relationships by Karl Andersen, source=Web Response No relevant relationships by Amanda Kamar, source=Web Response No relevant relationships by Arvey Stone, source=Web Response