Air embolism secondary to endoscopy in hospitalized patients: results from the National Inpatient Sample (1998-2013)

BACKGROUND: Air embolism is a rare, but potentially catastrophic complication of endoscopic procedures. We herein evaluated the overall incidence of air embolism after endoscopy. We also measured mortality outcomes after air embolism. METHODS: Patients who underwent endoscopy as an index procedure during hospitalization were selected from the National Inpatient Sample from 1998-2013. The primary outcome of interest was the incidence of air embolism after endoscopy. All-cause mortality after endoscopy was measured as a secondary outcome and the Charlson Comorbidity Index was calculated. Binary logistic regression was used to explore the effect of air embolism on inpatient mortality, using P<0.05 as level of significance. RESULTS: A total of 2,245,291 patients met the inclusion criteria. Mean age at the time of procedure was 62.5 years. Esophagogastroduodenoscopy (EGD) was the most common endoscopic procedure, accounting for 80% of endoscopic procedures. Air embolism occurred in 13 cases, giving a rate of 0.57 per 100,000 endoscopic procedures. Air embolism was most common after endoscopic retrograde cholangiopancreatography (ERCP), occurring in 3.32 per 100,000 procedures, compared with 0.44 and 0.38 per 100,000 procedures for EGD and colonoscopy, respectively. The case fatality rate for post endoscopic air embolism was 15.4%. After adjusting for covariates, air embolism after endoscopy was independently associated with higher odds of inpatient mortality: odds ratio 10.35, 95% confidence interval 1.21-88.03 (P<0.03). CONCLUSIONS: Air embolism is most common after ERCP. It is frequently associated with disorders involving a breach to the gastrointestinal mucosa or vasculature. Though rare, it is an independent predictor of inpatient mortality.