Measurements of Recirculation during Neonatal Veno-Venous Extracorporeal Membrane Oxygenation: Clinical Application of the Ultrasound Dilution Technique

Abstract

Recirculation during dual lumen veno-venous (DLVV) extracorporeal membrane oxygenation (ECMO) is a dynamic event that results in a fraction of the oxygenated blood exiting the arterial lumen and immediately shunting back into the venous lumen. Excessive recirculation will result in suboptimal oxygen delivery to the patient. Ultrasound dilution is a technology that has been shown to rapidly quantify recirculation in veno-venous (VV) ECMO animal models. This manuscript reports the first clinical application of ultrasound dilution in quantifying recirculation during neonatal VV ECMO. A 2.8-kg neonate with congenital diaphragmatic hernia was placed on VV ECMO using a single DLVV cannula inserted into the right atrium through the internal jugular vein. Ultrasound sensors were clamped to the arterial and venous lines near the dual lumen cannula and 3- to 5-mL bolus injections of isotonic saline were used proximal to the circuit heat exchanger to make the recirculation measurements. Recirculation measurements were made after initiation and periodically thereafter. During the 12-day ECMO period, 86 recirculation measurements were performed. The average recirculation was 34.3% (range, 15–57%). Reproducibility of paired measurements was 5.6%. Changes in patient positioning resulted in significant changes in recirculation. Measurements using platelet injections were compared with those made with saline. The two were found to closely correlate (mean difference, .25% ± 2.8%). Ultrasound dilution measurements of recirculation provided rapid monitoring data during a clinical VV ECMO procedure. Application of this technique could provide early data that will assist the clinician in guiding interventions to minimize recirculation.

Quantification of Recirculation During Veno-Venous Extracorporeal Membrane Oxygenation: In Vitro Evaluation of a Thermodilution Technique

“…9 Unfortunately, this technique has never been evaluated in an experimental setting with a known RF. 10 In 2000, a conventional thermodilution technique was employed by Sreenan et al 11 in rabbits on vv-ECMO. Because of the specific experimental setting, the Canadian group was able to compute only 0% and 100% of RF.…”

Therapeutic Hypothermia for Refractory Hypoxemia on Venovenous Extracorporeal Membrane Oxygenation: An In Silico Study

“…34 Recirculation has been reported to vary from 2% to 57%. [35][36][37] There is no experimental or in silico data about the effect of temperature on recirculation, so it can only be inferred from known effects of temperature on parameters that determine recirculation, such as cardiac output.…”

Extracorporeal Membrane Oxygenation Blood Flow and Blood Recirculation Compromise Thermodilution-Based Measurements of Cardiac Output

“…The recirculation fraction (Rf) was measured with the ultrasound dilution technique (UDT, Transonic ELSA Monitor, Extracorporeal Life Support Assurance; Transonic Systems Inc., Ithaca, NY) as described previously. [8][9][10][11] The UDT is based on measuring a change in ultrasound velocity after injecting 20 ml 0.9% saline with two ultrasound sensors. One sensor was placed around the return tubing of the ECMO circuit while the other sensor was placed around the drainage tubing.…”

“…But, S v O 2 cannot be measured correctly in case of VV ECMO since reoxygenated blood from the ECMO return cannula inevitably mixes with central venous blood. We measured Rf with the UDT which does not depend on S v O 2 2,[8][9][10][11].…”