Automated Neonated Exchange Transfusion

Neonatal jaundice, or hyperbilirubinemia, is a common condition in newborns caused by high levels of bilirubin in the blood. Bilirubin is produced when red blood cells break down, and in newborns, the liver may not be fully developed to break it down efficiently. When bilirubin levels rise too high, it can lead to serious complications, including brain damage, neurological problems, or even death. Severe cases of hyperbilirubinemia often require exchange transfusion, a procedure in which aliquots (small amounts) of the neonate’s blood are gradually removed and replaced with fresh donor blood to lower bilirubin levels and stabilize the infant’s blood chemistry. While this procedure is life-saving, it is delicate, time-consuming, and traditionally performed manually by healthcare workers, making it prone to human error and stressful for both the neonate and the clinician. Even slight mistakes in timing or blood volume can have serious consequences, which makes automation a critical improvement for neonatal care.

The Automated Neonatal Exchange Transfusion (ANET) device was developed to make this procedure safer, more controlled, and less dependent on manual operation. The device assists clinicians by automating the withdrawal and infusion of blood, providing consistent and precise control over volumes while allowing healthcare workers to monitor the process.

The ANET prototype includes two main hardware systems: the Plunger Drive System and the Valve Control Segment. The Plunger Drive System consists of a stepper motor connected via a coupler to a ball lead screw with guiding rods, which is attached to the syringe plunger. The stepper motor rotates to move the ball lead screw, converting rotational motion into linear motion to control the plunger. Clockwise rotation of the motor pulls the plunger back, withdrawing blood from the neonate, while counter-clockwise rotation pushes the plunger forward, infusing blood. This mechanism ensures precise and repeatable control of the amount of blood withdrawn and infused.
The valve control segment consists of two three-way valves mounted on top of two servo motors. The rotation of the servo motors directs the opening and closing of the valves in a specific sequence to direct blood flow correctly during each stage of the procedure.

The current prototype operates in 52 cycles, each consisting of four phases followed by a 15-second wait period to allow blood to mix before the next cycle begins. Phase one withdraws blood from the neonate, phase two discards it to waste, phase three draws fresh donor blood, and phase four infuses the donor blood back into the neonate. This sequence is repeated automatically, providing a safe and controlled exchange transfusion process.

In addition to hardware improvements, the device incorporates a PID (Proportional-Integral-Derivative) control algorithm, which is used to maintain precise control of the syringe plunger and blood flow. In this context, the PID algorithm continuously monitors the position and speed of the plunger and makes small adjustments to the motor’s motion to reduce any deviation from the desired movement. This ensures smooth, accurate sucking and infusion cycles, compensating for variations in resistance, tubing friction, or mechanical load, which is critical when dealing with tiny volumes of blood in a neonate.

The ANET device has been iteratively improved over several years, addressing technical challenges such as valve operation, plunger stability, flow accuracy, and overall safety. The current focus is on fine-tuning the prototype for consistent performance and preparing it for controlled testing in a biological setting (animal testing).

The ANET device represents a practical solution to a critical neonatal health problem. By automating exchange transfusion, it reduces human error, decreases the physical workload on healthcare workers, and ensures more predictable and safe outcomes for newborns. With its functional prototype, ongoing fine-tuning, PID control integration, and preparation for animal testing, ANET is moving closer to becoming a reliable, efficient, and accessible device for hospitals, especially in low-resource settings where neonatal care resources are limited but the need for effective interventions is high.