Miniaturization of Artificial Lungs toward Portability

Abstract Artificial lungs support patients undergoing open‐heart surgery, organ transplantation, and in serious lung injury by providing oxygenation support through an extracorporeal circuit. Some patients require partial support for durations of a few weeks or months even after the surgery. Therefore, a portable or wearable lung assist device which can be operated for several weeks with minimum maintenance would be ideal. Miniaturization of blood oxygenators, using microfluidic technology, is a promising avenue for the realization of such portable artificial lungs. The microfluidic blood oxygenators (MBOs) are also suitable for neonates with respiratory failure due to their low priming volume and pressure drop. Herein, the history of microfluidic oxygenator development and recent progress in miniaturized artificial lungs are discussed. The MBOs have made significant advances in 1) reducing device size, 2) providing biomimetic blood flow paths, 3) enabling operation in room air, and 4) operating without the need of an external pump. Recent work has demonstrated throughput of up to 150 mL min^‐1 of blood and oxygen transfer rate of 60 mL O₂ per L of blood. The challenges faced by this technology in practical applications as well as future improvements to meet the requirements for older neonates and even adults are also presented.