Recirculation in Double Lumen Catheter Veno-Venous Extracorporeal Membrane Oxygenation Measured by an Ultrasound Dilution Technique

Abstract

Recirculation is a limiting factor for oxygen delivery in double lumen catheter veno-venous extracorporeal membrane oxygenation (DLVV-ECMO). This study compares three different methods for the determination of the recirculation fraction during double lumen catheter veno-venous ECMO at ECMO flow rates of 150, 125, 100, 75, and 50 ml/kg.min in nine lambs: (1) an ultrasound dilution method, in which the change in ultrasound velocity in blood after injection of a saline bolus as a marker is used for determination of recirculation; (2) an SvO2 method using real mixed venous blood oxygen saturation, the gold standard, for determination of recirculation fraction; and (3) the CVL method, in which oxygen saturation of a blood sample of the inferior vena cava is considered to represent mixed venous oxygen saturation. In all methods, the recirculation fraction increased with increasing ECMO flow rate. The correlation coefficient between the ultrasound dilution method and the SvO2 method was 0.68 (p < 0.01); mean difference was -2.4% (p = 0.6). Correlation coefficient between the ultrasound dilution method and the CVL method was 0.48 (p < 0.01); mean difference was -18.1% (p < 0.01). The correlation coefficient between the SvO2 method and the CVL method was 0.51 (p < 0.01); mean difference was -15.7% (p < 0.01). The ultrasound dilution method is a useful method for measurement of the recirculation fraction in DLVV-ECMO and is easier to use than the other methods.

Preliminary Experiment with a Newly Developed Double Balloon, Double Lumen Catheter for Extracorporeal Life Support Vascular Access

“…This is a factor that limits oxygen delivery to the patient and does not contribute to the oxygenation of the patient. 7 Recirculation has been found to be 53% at a bypass flow of 400 ml/min. Generally, as recirculation increases, the efficacy to the systemic circulation decreases in terms of oxygen delivery.…”

“…2,5 Recirculation during VVECLS had previously been measured and quantified by various methods to achieve a reduction. 7,8 In this preliminary experiment, we calculated the recirculation by the gold standard method.…”

Recirculation in Venovenous Extracorporeal Membrane Oxygenation

“…[8][9][10] Sreenan et al 10 demonstrated recirculation rates ranging from 30% to 70% with pump flows of 200-500 ml/min in a venovenous circuit via a unicaval dual-lumen cannula. In a study comparing different methods of calculating recirculation, consistent relationships with high correlation coefficients were identified for each of the ultrasound dilution, SvO 2 , and central venous line (CVL) methods (% recirculation = 1.88 + 0.23 × ECMO flow, r = 0.99; 1.42 + 0.32 × ECMO flow, r = 0.99; and 6.66 + 0.36 ×ECMO flow, r = 0.96, respectively).…”

“…In a study comparing different methods of calculating recirculation, consistent relationships with high correlation coefficients were identified for each of the ultrasound dilution, SvO 2 , and central venous line (CVL) methods (% recirculation = 1.88 + 0.23 × ECMO flow, r = 0.99; 1.42 + 0.32 × ECMO flow, r = 0.99; and 6.66 + 0.36 ×ECMO flow, r = 0.96, respectively). 8 The relationship between ECMO blood flow rates and recirculation may, in part, be explained by an increase in negative venous pressures within the venous drainage limb that occurs at higher flow rates. 11 Relatively larger drainage cannulae may allow for comparable blood flow rates at lower pump speeds with less negative venous pressure, potentially mitigating the amount of recirculation (Figures 3 and 4).…”

“…Methods that have been proposed to estimate the SvO 2 include the CVL method and the SvO 2 method. 3,8 The CVL method consists of measuring the venous saturation of blood from either the SVC or the IVC via a central venous catheter. 3,8,18 Although this measurement can easily be obtained, the value will not accurately reflect the mixed venous saturation of blood from both the SVC and the IVC.…”