EXTRACORPOREAL MEMBRANE OXYGENATION (ECMO) CANNULA MALPOSITION IDENTIFIED THROUGH POINT-OF-CARE ULTRASOUND

Abstract

TOPIC: Critical Care TYPE: Medical Student/Resident Case Reports INTRODUCTION: In adult ECMO, veno-venous (VV) dual lumen intrajugular (IJ) cannula placement is verified intra-procedurally with echocardiogram and monitored with daily chest radiography (CXR) while bi-femoral lines are verified with pelvic films. Worsening ECMO support prompts evaluation for cannula malposition. Radiographs may suggest proper cannula placement despite malposition, which is associated with complications such as insufficient venous drainage, vessel obstruction/occlusion, and trauma to surrounding anatomic structures. In these cases, ultrasound remains a portable, fast and inexpensive tool to identify and correct malposition. We report three cases of malpositioned VV ECMO cannulas identified through bedside POCUS despite appearing appropriately positioned radiographically. CASE PRESENTATION: 27-year-old female with Hodgkin's lymphoma and suspected bleomycin induced lung injury. Cannulated via dual lumen IJ for VV ECMO for progressive and refractory hypoxemia, with line verified intraoperatively. Daily CXR commented "ECMO cannula in appropriate position". Developed increasing evidence of recirculation, and POCUS showed outflow jet positioned distally in the hepatic vein. Recirculation improved with retraction of the cannula under ultrasound guidance. 30-year-old male with rapidly progressive interstitial lung disease, intubated and cannulated for VV ECMO as a bridge to transplant. After dual lumen IJ cannulation, he showed evidence of recirculation and low flows (SpO2 88%, ScVO2 82%, flow 2.1 Lpm). CXR commented "dual lumen IJ ECMO cannula with side hole in the right atrium, distal tip in the IVC". POCUS showed the outflow jet positioned in the hepatic vein. Support immediately improved once cannula retracted under ultrasound guidance. 41-year-old male with ARDS and refractory hypoxemia underwent bi-femoral VV ECMO cannulation. On day three of hospitalization, he began cutting out flow and had marginal support despite fluids, CXR on day 1 and 3 both commented "ECMO cannula terminating in the cavo-atrial junction". POCUS showed the tip of the return cannula distal to the hepatic vein with the return jet partially entering the hepatic vein when it had been in the RA on days 1-2 ultrasonographically. DISCUSSION: Cannulas are anchored by sutures to prevent displacement. Any change in the position may be noted on follow-up radiographs. However, radiographs are static images, and discerning minor changes in cannula position may be challenging. Each of these malpositions were missed on radiography. Currently there are no guidelines for daily ultrasonographic monitoring of cannula position. Further investigation into the benefits of daily ultrasonographic monitoring over the course of ECMO support is warranted. CONCLUSIONS: Daily complete ultrasound evaluation may help to reduce complications from malpositioning in the monitoring phase of ECMO support. REFERENCE #1: Douflé G, Roscoe A, Billia F, Fan E. Echocardiography for adult patients supported with extracorporeal membrane oxygenation [published correction appears in Crit Care. 2016;20:34]. Crit Care. 2015;19:326. Published 2015 Oct 2. doi:10.1186/s13054-015-1042-2 REFERENCE #2: Lee S, Chaturvedi A. Imaging adults on extracorporeal membrane oxygenation (ECMO). Insights Imaging. 2014;5(6):731-742. doi:10.1007/s13244-014-0357-x REFERENCE #3: Victor K, Barrett N, Glover G, Kapetanakis S, Langrish C. Acute Budd-Chiari syndrome during veno-venous extracorporeal membrane oxygenation diagnosed using transthoracic echocardiography. Br J Anaesth. 2012 Jun;108(6):1043-4. doi: 10.1093/bja/aes161. PMID: 22593140. DISCLOSURES: No relevant relationships by Taylor Becker, source=Web Response No relevant relationships by Charles Rappaport, source=Web Response No relevant relationships by Roger Struble, source=Web Response