J Extra Corpor Technol 2026, 58, 65--72 Ó The Author( s), published by EDP Sciences, 2026 https:// doi. org / 10.1051 / ject / 2025034
Available online at: ject. edpsciences. org
ORIGINAL ARTICLE
Initiating cardiopulmonary bypass using a dry venous line: implications and analysis Tristan Benedict( MS, CCP), Robert Brownlee( MS, CCP), Christopher Foley( MS, CCP), Nathan Hoyer( MS, CCP), Laura Dell’ Aiera( DHSc, CCP) *, Mary Dooley( PhD), and Dave Fitzgerald( DHA, CCP)
Medical University of South Carolina, College of Health Professions, 179 Ashley Ave., Charleston, SC 29425, USA Received 8 April 2025, Accepted 17 June 2025
Abstract – Background: Autologous priming of the cardiopulmonary bypass( CPB) circuit is a critical technique for reducing hemodilution during cardiac surgery. Vacuum-assisted venous drainage( VAVD) offers access to an alternative method using a dry venous line, aiming to reduce hemodilution associated with crystalloid priming. Methods: This study investigates the impact of initiating CPB with a dry venous line on gaseous microemboli( GME) production, compared to a traditional primed venous line in an adult CPB circuit. Using a controlled experimental setup with an oxygenator featuring an integrated arterial filter, we examined GME counts and sizes throughout the circuit under varying VAVD pressures and initiation techniques. Results: Results show that higher VAVD pressures and the immediate initiation of CPB correlate with increased GME production post-oxygenator. Statistical analysis reveals significant differences in GME counts and sizes between control and experimental groups. Conclusion: The statistical differences in GME size and count observed between initiation types and pressures emphasize the importance of optimal CPB initiation strategies to minimize GME transmission. These findings underscore the need for further research to refine CPB techniques and enhance patient safety in cardiac surgery.
Key words: Cardiopulmonary bypass, Gaseous microemboli, Dry venous line, VAVD, Vacuum-assisted venous drainage, Initiation.
Introduction
* Corresponding author: dellaier @ musc. edu
Since the advent of cardiopulmonary bypass( CPB), venous return to the reservoir upon initiation of the bypass has been accomplished through a gravity siphon with a primed( typically via a crystalloid solution) venous line [ 1 ]. Vacuum-assisted venous drainage( VAVD) has made the initiation of bypass with a dry venous line possible. A dry venous line technique is utilized prior to initiation, where crystalloid in the venous tubing is drained into the reservoir, and then shuttled into a bag where it would not reach the patient. The decision to utilize a primed or dry venous line is largely based on surgeon preference, and each method has benefits and drawbacks. One concern with a primed venous line is the increase in hemodilution, which is known to decrease hematocrit and increase the risk of allogeneic red blood cell( RBC) transfusion [ 2 ]. Venous tubing with ½ inch Inner Diameter( ID) is most utilized in adult patients, and for every foot of venous tubing, a patient will receive about 40 mL of crystalloid. Reducing prime volume in the circuit as an indication for blood conservation is a Class I, Level B recommendation by the Society of Thoracic Surgeons( STS), Society of Cardiovascular Anesthesiologists( SCA), American Society of Extracorporeal Technology( AmSECT), and Society for the Advancement of Blood Management( SABM) [ 3 ]. Dickinson and colleagues performed a study where 20,000 patients had their net prime volumes indexed to their body surface area and found that patients with a greater indexed prime volume( 4th quartile) were 2.9 times more likely to receive RBC transfusions compared to patients with lower indexed prime volume( 1st quartile) [ 2 ].
Utilizing a dry venous line, which requires VAVD, eliminates the hemodilution that results from a primed venous line. However, this technique has drawbacks as well, most notably an increase in gaseous microemboli( GME). Hudacko and colleagues performed a laboratory study to compare the detection of GME in a pediatric circuit utilizing a primed venous line and a dry venous line with varying levels of VAVD pressures( �10, �20, and �40 mmHg) [ 4 ]. Their results found that a primed venous line resulted in the least amount of GME production. However, the significant increase in GME post-arterial line filter was only found in the �40 mmHg VAVD group. Microemboli, including GME, delivered to patients are known to have adverse effects such as neurological deficits. Pugsley and colleagues performed a randomized controlled trial on patients
This is an Open Access article distributed under the terms of the Creative Commons Attribution License( https:// creativecommons. org / licenses / by / 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.