The ELSO Maastricht Treaty for ECLS Nomenclature: abbreviations for cannulation configuration in extracorporeal life support - a position paper of the Extracorporeal Life Support Organization

Background The Extracorporeal Life Support Organization (ELSO) Maastricht Treaty for Nomenclature in Extracorporeal Life Support (ECLS) established consensus nomenclature and abbreviations for ECLS to ensure accurate, concise communication. Methods We build on this consensus nomenclature by layering a framework of precise and efficient abbreviations for cannula configuration that describe flow direction, number of cannulae used, any additional ECLS-related catheters, and cannulation sites. This work is a consensus of international representatives of the ELSO, including those from the North American, Latin American, European, South and West Asian, and Asian-Pacific chapters of ELSO. Results The classification increases in descriptive capability by introducing a third (cannula tip position) and fourth (cannula dimension) level to those provided in the previous consensus on ECLS cannulation configuration nomenclature. This expansion offers the simplest level needed to convey cannulation information yet allows for more details when required. Conclusions A complete nomenclature for ECLS cannulation configurations accommodating future revisions was developed to facilitate ability to compare practices and results, to promote efficient communication, and to improve quality of registry data. Electronic supplementary material The online version of this article (10.1186/s13054-019-2334-8) contains supplementary material, which is available to authorized users.

• V-Ad venoarterial configuration with a distal perfusion cannula. "d" carries a flow and therefore is not indexed. V-Ad indicates use of an arterial cannula with an in situ port for distal perfusion.
• (dl)Vf-V venovenous configuration that uses a DLC placed via a femoral vein.
• (bc19)Vcep-V 19Fr dual-lumen bi-caval cannula with a cephalad draining catheter (cep is written in lower case, not indexed, because it is a genuine draining catheter but with lesser flow). "cep" can only be on the same side as the DLC.
• V29fsvc-V17ja venovenous configuration with a femoral 29 Fr drainage cannula passing through the right atrium with the tip in the superior vena cava for return via a jugular cannula with tip in right atrium.
• P-Afrdp draining via cannula in the pulmonary artery for venoarterial ECMO with return via the right femoral artery and distal perfusion applied at the foot.
• V27/50fsvc-A19f venoarterial femoro-femoral configuration that uses a 27Fr long drainage cannula placed via a femoral vein with the tip in the SVC and a 19Fr return cannula via a femoral artery. Note that no distal perfusion cannula is reported.
• V25/38ja-A19/18fd venoarterial configuration, atrio-femoral flow direction through a 25Fr/38 cm cannula placed via the right jugular, tip in upper right atrium for drainage, and a 19Fr/18 cm return cannula via a femoral artery with a distal perfusion cannula.
• V12a-A10carr venoarterial configuration atrio-carotid flow direction in an infant using a 12Fr cannula for draining from the right atrium and a 10Fr arterial cannula for return of oxygenated blood via the right carotid artery.
• Vivc-AfldtVj (V-AV) venoarterial configuration in femoro-femoral flow direction with an additional return cannula of oxygenated blood placed via the right jugular vein. A distal perfusion cannula is used for the leg (left side). Vivc-AdflVj would be the same configuration but the arterial cannula has the in situ port for distal perfusion.
• Vvntal-A the simple form to indicate VA configuration with a left atrial vent drainage catheter.
• V25/38javntal-A19/18frdt indicates the same as the previous configuration but with the added specifics: venous draining cannula 25Fr, 38 cm placed via the right jugular, tip in upper right atrium for drainage, and a venting catheter placed in the left atrium. Further, an arterial 19Fr, 18 cm return cannula and a distal perfusion cannula are placed via the right femoral artery.

B. Examples of central cannulation
• LV-AO central cannulation with the drainage cannula in the left ventricle and the reinfusion cannula in the aorta. The hyphen indicates that an ML is present in conformity to nomenclature for peripheral cannulation.
• RA-AO right atrium drainage via an ML and return to the aorta.
• RV-PA central cannulation with the drainage cannula in the right ventricle, the reinfusion cannula in the pulmonary artery, and an ML in the circuit.
• RA-PA\LVAO central dual cannulation: a first assist device with ML is placed with the drainage cannula in the right atrium and reinfusion into the pulmonary artery; a second assist device without ML is placed with the drainage cannula in the left ventricle and the reinfusion cannula in the aorta.
• RVPA\LV-AO central dual cannulation: a first assist device without ML is placed with the drainage cannula in the right ventricle and reinfusion into the pulmonary artery; a second assist device with ML is placed with the drainage cannula in the left ventricle and the reinfusion cannula in the aorta.
• RVvntal-PA central cannulation with the drainage cannula in the right ventricle and the reinfusion cannula in the pulmonary artery; a ML is present combined with a left atrial vent.
• plRV-LACO2R pumpless central cannulation with the drainage cannula in the right ventricle and the reinfusion cannula in the left atrium for decarboxylation.
• oxyLVAD left ventricular assist device with ML in circuit for oxygenation.

C. Examples of hybrid cannulation
• V-A/TVLS V-A ECMO with a transvalvular axial pump device applied (before or during ECMO).
• Vja-/IA drainage via jugular cannula with tip in right atrium and return to the innominate artery • V-A/LVAD V-A ECMO with a left ventricular assist device applied (before or during ECMO).

• (bc31)Vjr-V/LVAO
Bi-caval 31Fr DLC via right jugular promoting oxygenation with a concomitant central cannulation, drainage from the left ventricle, and return into the aorta without ML.
• (dl)VxP/oxyLVAD DLC for percutaneous atrio-pulmonary arterial right ventricular support (before or during ECMO) with an ML in the LVAD circuit for oxygenation.
• PA/Vfa-Af drainage via one centrally placed cannula in the pulmonary artery and one percutaneous cannula placed via a femoral vein with tip in right atrium. Return is to femoral artery.
• Vfa-Af/PAjr drainage via femoral vein with the tip in the right atrium and return to the pulmonary and femoral artery.
• Vfa-PA/TVLS Bi-ventricular ECLS with a concomitant venovenous ECMO and right ventricular support (femoral vein cannula in the right atrium, return to the pulmonary artery cannula, and a transvalvular axial pump device applied (before or during ECMO) for left ventricular support.
• V-A/IABP V-A ECMO with concomitant use of intra-aortic balloon pump.
• V(25/55)fa-V(19)jr/LVAO V-V ECMO over a 25Fr/55 cm cannula via unspecified femoral vein (tip in right atrium); the return cannula enters the SVC via the right jugular vein. A central cannulation is applied from the left ventricle to the ascending aorta without ML.