Transpulmonary thermodilution during extracorporeal organ support (ECOS): is it worth it?A brief commentary on the effects of the extracorporeal circuit on TPTD-derived parameters

Abstract

In modern ICUs, critically ill patients with multiple organ dysfunction syndrome (MODS) may be adequately supported by different extracorporeal organ support (ECOS) devices [1]. Improvements in technology have made extracorporeal membrane oxygenation (ECMO) safer and easier to use, allowing potential more widespread application in patients with advanced respiratory failure [2, 3]. Similarly, kidney support can be provided by different intermittent and continuous blood purification techniques (Intermittent Hemodialysis, Slow Low-Efficiency Daily Dialysis, Continuous Veno-Venous Hemofiltration, Hemodialysis, or Hemodiafiltration). Hemodynamic monitoring is essential in these conditions but, while transpulmonary thermodilution (TPTD) methods are well-accepted tools to guide goal direct therapy in critically ill patients, they remain poorly investigated during extracorporeal treatment. The main advantage of transpulmonary thermodilution is the ability to provide a full cardiovascular evaluation [4, 5]: continuous measurement of the cardiac output (CO) using pulse contour analysis is combined with intermittent volumetric measurement of cardiac preload like global end-diastolic volume (GEDV) and extravascular lung water (EVLW). The consequence of adding an extracorporeal circuit on the accuracy of the TPTD technique is poorly understood and the literature on the topic is scarce (see Table 1). Therefore, we have read with great interest the paper by Herner et al. on the potential loss of indicator into the extracorporeal circuit during veno-venous extracorporeal membrane oxygenation [6].