72 T. Benedict et al.: J Extra Corpor Technol 2026, 58, 65--72 each trial. Additionally, it simulated the dissipation of microemboli within the patient shortly after initiating CPB.
Limitations
Emphasis was placed on standardization between trials, and attempts were made to replicate real clinical conditions using the resources available. However, certain elements of the study differ from the clinical setting. Specifically, 0.9 % normal saline was the selected solution for all trials. Although this solution has some osmolar resemblance to human plasma, it does not account for changes in blood viscosity in relation to patient hematocrit. As a non-Newtonian fluid, whole blood maintains a higher viscosity than plasma due to blood cells, platelets, and other clotting factors, but can vary as concentrations change. The higher a patient’ s hematocrit, the more viscous their blood becomes. Theoretically, the use of a less viscous fluid allowed for more microemboli formation in the circuit due to air-fluid dynamics.
The use of only one type of extracorporeal circuit, using a centrifugal head versus a roller head arterial pump, and an oxygenator-arterial filter limits the ability to generalize these findings to any given circuit and its components. More research must be conducted to determine if differences exist between extracorporeal devices. Additionally, a built-in arterial filter may have different air-handling capabilities than external arterial line filters, which are still used in some adult clinical practices. Using an arterial roller head as opposed to a centrifugal head may also have affected GME creation. Some movements of the proximal arterial line caused by the roller head motion likely caused more artifact detection than if a centrifugal head were used. Further research on this subject should stipulate the use of whole blood and incorporate a variety of modern extracorporeal circuit equipment.
Conclusions
The intended use for a dry venous line is to limit the amount of hemodilution that a patient experiences when going on cardiopulmonary bypass. While there is a reservoir present, which theoretically provides protection against air traveling to the patient, the use of a dry venous line combined with vacuumassisted venous drainage causes an increase in air emboli traveling to the patient. It is important to note that the amount of air observed in this study was very small, but there is no clear answer to the question of“ how much air is too much air?”. With that in mind, clinicians should limit patient exposure to GME.
According to published recommendations, there are multiple safe and effective alternatives to limit hemodilution. If a center chooses to practice using a dry venous line, our data suggests that the most effective way to limit GME transmission is to initiate bypass with a reduced vacuum level and a“ delayed” initiation approach as detailed above. Further research should be conducted to understand the impact of equipment, disposables, and fluid types. Funding The authors received no funding to complete this research.
Conflicts of interest The authors declare no conflict of interest.
Data availability statement
The authors confirm that the data supporting the findings of this study are available within the article and its supplementary material. Raw data that support the findings of this study are available from the corresponding author, upon reasonable request.
Author contribution statement
Tristan Benedict, Robert Brownlee, Christopher Foley, and Nathan Hoyer conducted the research itself. Further guidance, support, and edits by Laura Dell’ Aiera, Mary Dooley, and Dave Fitzgerald.
Ethics approval
This study did not involve human subjects data or animal investigation and therefore did not require ethics approval.
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Cite this article as: Benedict T, Brownlee R, Foley C, Hoyer N, Dell’ Aiera L, Dooley M & Fitzgerald D. Initiating cardiopulmonary bypass using a dry venous line: implications and analysis. J Extra Corpor Technol 2026, 58, 65--72. https:// doi. org / 10.1051 / ject / 2025034.