The second tier of market taxonomy classifies cardiopulmonary oxygenators by type, a critical dimension of Cardiopulmonary Oxygenator segmentation. Membrane oxygenators dominate with an estimated 70 % share, owing to their superior gas‑exchange efficiency, lower priming volume, and reduced risk of plasma damage; within this class, microporous and hollow‑fiber membranes are the principal sub‑technologies, each capturing distinct clinical niches based on flow rates and durability requirements. Bubble oxygenators, once the industry standard, now account for roughly 20 % of sales; they persist in low‑resource settings because of their simpler construction and lower acquisition cost, despite higher hemolysis potential. Hybrid oxygenators, integrating membrane and bubble principles, represent the remaining 10 % and are positioned for specialized procedures that demand rapid priming combined with high‑precision gas control. The proportional weight of each type directly influences R&D allocation, supply‑chain complexity, and pricing structures, thereby shaping the overall market size and competitive landscape. Consequently, manufacturers prioritize membrane development to capture the majority of growth, while maintaining niche production lines for bubble and hybrid units.