J Extra Corpor Technol 2024 , 56 , 65 – 70 Ó The Author ( s ), published by EDP Sciences , 2024 https :// doi . org / 10.1051 / ject / 2024007
Available online at : ject . edpsciences . org
TECHNIQUE OR APPLICATION
Quantifying potential fluid transfused through pressure monitoring and circuit flushes in pediatric ECMO patients
Steven Robertson ( BS , CCP ) * and Katherine White ( MS , CCP )
Children ’ s Heart Center of Nevada , Las Vegas , NV , USA Received 22 September 2023 , Accepted 22 March 2024
Abstract – Pressure monitoring on pediatric Extracorporeal Membrane Oxygenation ( ECMO ) circuits is used to aid in the evaluation of patient hemodynamics and circuit health . Extracorporeal Life Support Organization ( ELSO ) recommends monitoring pressures on the venous line , pre- , and post-oxygenator . In order to keep pressure ports patent , crystalloid can be used as a flush . The fluid transfused to the patient through these lines can be challenging to quantify accurately due to variance in clinician practice . Currently , there is no published data or practice suggestions on this topic . In Vitro experiments using Edwards True Wave transducers and pressure bags were constructed , allowing for common negative and positive pressures to be simulated . Passive volume infused through the transducer as well as intermittent active flushing by pulling the snap tab were measured and the volumes were recorded . When the pressure transducer and associated tubing are kept patent by using a pressurized IV bag , per the instructions for use , the daily volume transfused was found to be 319.6 mL or close to a typical neonate ’ s total blood volume . Rather than using passive or active flushing , the use of automated syringe pumps can reduce the transfused volume to 24 mL per day . Further study is recommended to develop and publish best practices .
Key words : Neonate , Pediatric , ECMO , Pressure Transducer , Pressure Monitoring .
Overview
Extracorporeal Membrane Oxygenation ( ECMO ) is a wellestablished , life-saving therapy for critically ill patients in the neonate and pediatric populations who are in cardiac or respiratory distress [ 1 ]. Even though it is not an industry standard , some form of pressure monitoring has become a common practice with ECMO in adherence with the Extracorporeal Life Support Organization ( ELSO ) literature [ 2 ]. According to a 2011 survey involving ELSO centers , negative pressure monitoring on the venous line was used by 83 % of neonatal ECMO programs using centrifugal pumps [ 3 ]. Negative pressure from the venous cannula and positive pre-membrane and post-membrane oxygenator pressures can be monitored in order to aid in the evaluation of circuit health [ 4 ]. This includes but is not limited to , measuring circuit pressure in order to determine the pressure drop across the oxygenator , clot formation , and the siphon effect in the venous line . ECMO circuit pressures are also frequently monitored in order to evaluate patient hemodynamics , volume status , and they function as safety devices .
Circuit pressure monitoring is handled in a myriad of ways across the world . ECMO disposables like Cardiohelp ( Getinge ,
* Corresponding author : bro . ro @ icloud . com
Rastatt , Germany ) use internal pressure monitoring that does not require flushing . While this device is intended for the adult population , off-label use in pediatrics has been studied and deemed safe [ 5 ]. Some centers refrain from pressure monitoring entirely in an effort to simplify circuits , thus reducing the chances of line separations , air entrainment , and blood spillage . Although not well documented outside of institutional protocols , it is an accepted practice to flush external pressure transducers frequently with fluid in order to reduce areas of stagnation and keep pressure monitoring ports patent . This practice aids in preventing the development of thrombus formation which can lead to an adverse event in the mechanical components , or even a sentinel patient event [ 6 ]. However , this protective measure can also contribute to fluid overload in the pediatric patient [ 7 ]. Because of this and the safety concerns listed previously , some centers choose to simply not flush transducers in any capacity .
ECMO pressure transducers may be flushed in a number of ways . Syringe and IV pumps can be used to supply constant rates of flush-through transducers to circuit connection points . A crystalloid bag pressured to 300 mmHg can be used to passively flush through the transducer as well as manually by pulling on the snap tab . Similarly , a crystalloid-filled syringe may be manually pushed with a desired amount of volume at the pressure ports .
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