Cannula introducer

Claim 1

A surgical device for insertion of aortic cannula of the type including an elongate, thin rod member, a blade member integrally formed with said rod member, disposed at the distal end of said rod member, an elongate housing member, an elongate bore formed in said housing member, substantially centrally thereof, wherein said rod member is slideably disposed interiorly of said bore and movably mounted therein between a blade member-extended position and a blade member-retracted position, a bias means disposed at the proximal end of said rod member for retaining said blade member in its retracted position in the absence of external, longitudinally directed forces imparted against said rod member, and an elongate, flexible cannula member having said housing member slideably disposed therein, wherein the improvement comprises: a trigger-operated means for effecting the longitudinal displacement of said cannula member into an aorta through a cut made by said blade member, said trigger-operated means comprising a hollow, longitudinally disposed base member, an elongate rack gear member slideably disposed interiorly of said blade member, a pawl member operatively disposed relative to said gear member and operable to allow unidirectional movement of said base member when said pawl member engages said gear member, a trigger member operatively secured to said pawl member, a longitudinally disposed second bias means having a stationary distal end and a proximal end fixedly secured to said base member so that sliding said base member in a distal-to-proximal direction loads said second bias means, a clamping member for securing said cannula member to said base member, a hook member associated with said clamping member, said trigger member operatively connected to said hook member, whereby said cannula member is prepared for aortic insertion by manually retracting said base member, thereby retracting said cannula member, said retraction loading said second bias means, and said pawl member, co-acting with said gear member, operable to prevent untimely unloading of said second bias means, and whereby manual activation of said trigger member is operative to disengage said pawl member from said gear member and is further operative to disengage said hook member from said bias member to the end that such trigger activation allows said second bias means to unload, thereby driving said cannula member in a proximal-to-distal direction so that said cannula is thrust through the cut made in said aorta prior to activation of said trigger member.