Microplastics in cardiopulmonary bypass: quantification and characterisation of particles across systems

Objectives: This study determines the microplastic (MP) levels, dimension, shape, and chemical composition generated from conventional cardiopulmonary bypass and minimal invasive extracorporeal circulation (MiECC) circuits. Methods: In vitro conventional and MiECC circuits, mimicking realistic setups with 2L of Hartmann’s solution were run for 90 minutes (n=3 circuit runs each), filtered, and analysed using micro-Fourier-transform infrared spectroscopy alongside procedural blanks (n=5). Results: Conventional circuits produced 60.4 ± 7.6 MPs L-1h-1 (77.0% of the total particles). MiECC circuits produced 48.4 ± 31.3 MPs L-1h-1 (45.3% of total particles). MP levels in each circuit type were significantly elevated compared with procedural blank (n=5) samples (5.6 ± 10.4 MPs L-1h-1) but did not differ with respect to the other. Twenty different MP polymer types were detected whereby polydimethylsiloxane, polydecylmethacrylate, and poly N-butylmethacrylate represented the most MPs within conventional circuits. For MiECC, the most abundant were polypropylene, polyethylene, and polyamide. Average MP lengths differed significantly: 93.5 ± 98.6 mm (conventional) versus 62.0 ± 54.4 mm (MiECC) (p<0.001), although widths did not differ. Film particles (48.2%) were the predominant shape for conventional circuits and fragments (50.5%) for MiECC. Conclusions: Significant levels of MP particles were produced across the two systems. Future studies can determine the time points at which they are produced in machine use, to mitigate their production, as well as inform cell/tissue culture investigations into the clinical significance of their introduction into patients undergoing cardiac surgery.