Oxygenator

An oxygenator comprising:

• a housing having a cylindrical shape and including a blood inflow port and a blood outflow port;
• and
• a hollow fiber membrane layer formed by winding a hollow fiber membrane and accommodated in the housing,
• the oxygenator in which blood flowing in from the blood inflow port flows from one end toward an other end in a longitudinal direction of the housing and flows out from the blood outflow port,
• wherein the housing includes:
• a plurality of raised portions that is raised radially inward from an outer surface of an annular inner peripheral portion toward a surface of an innermost layer of the hollow fiber membrane layer and extends from a distal end toward a proximal end of the housing;
• and
• a recess adjacent to a downstream end of the raised portions in a blood circulation direction and continuously extending in a circumferential direction of the inner peripheral portion so as to face an outflow portion of the blood in a blood flow path communicating with the blood outflow port;
• and
• wherein the raised portions are formed continuously from the distal end to the proximal end of the housing.

An oxygenator comprising:

• a housing having a cylindrical shape and including a blood inflow port and a blood outflow port;
• and
• a hollow fiber membrane layer formed by winding a hollow fiber membrane and accommodated in the housing,
• the oxygenator in which blood flowing in from the blood inflow port flows from one end toward an other end in a longitudinal direction of the housing and flows out from the blood outflow port,
• wherein the housing includes:
• a plurality of raised portions that is raised radially inward from an outer surface of an annular inner peripheral portion toward a surface of an innermost layer of the hollow fiber membrane layer and extends from a distal end toward a proximal end of the housing;
• and
• a recess adjacent to a downstream end of the raised portions in a blood circulation direction and continuously extending in a circumferential direction of the inner peripheral portion so as to face an outflow portion of the blood in a blood flow path communicating with the blood outflow port;
• and
• wherein the raised portions are formed discontinuously from the distal end to the proximal end of the housing.