Catheter tip pressure transducer

A catheter tip pressure transducer comprising:

• a needle tube having a pressure inlet hole opened in a side wall thereof proximate an end thereof;
• a support member disposed within said needle tube said support member being positioned opposite said pressure inlet hole of said catheter;
• a pressure sensor disposed within said needle tube, said pressure sensor comprising a semi-conductor block, said block including a recess located opposite to said support member, a thinner flat portion defined by said recess and being a pressure-sensitive diaphragm and located opposite to said pressure inlet hole, and a remaining thicker portion formed integrally with said thinner flat portion, said thicker portion of said pressure sensor being seated on said support member without being rigidly attached thereto and said diaphragm being located below the outer surface of said side wall of said needle tube;
• and
• at least one strain gauge disposed on a surface of said pressure-sensitive diaphragm opposite to a face of said diaphragm facing said recess, said at least one strain gauge having lead wires, whereby the pressure at said inlet hole acts on said diaphragm and said at least one strain gauge to change the electrical characteristics of said at least one strain gauge in proportion to said pressure, and
• said pressure sensor is unaffected by thermal stresses in said support member because of said unrigid attachment.