Patent ID: 8038664

Claim:
A method for delivering a quantity of fluid to bone marrow comprising: compressing a spring associated with a plunger operating assembly slidably disposed in a longitudinal bore of a drive housing, the plunger operating assembly comprising a piston and a plunger shaft coupled to the piston, the plunger shaft extending from a cartridge assembly filled with a fluid; inserting the fluid filled cartridge assembly into a cavity located in the plunger operating assembly; releasably engaging one end of the fluid filled cartridge assembly with a first end of the drive housing; inserting a bone penetrating needle extending from an opposite end of the fluid filled cartridge assembly into bone marrow at a target site by rotating the drive housing and the fluid filled cartridge assembly releasably engaged to the first end of the drive housing; contacting portions of a patient's skin proximate the target site with a first end of a retractable sleeve slidably disposed over exterior portions of the drive housing; sliding the retractable sleeve longitudinally relative to a pawl latch assembly wherein the pawl latch assembly is releasably engaged to hold the plunger operating assembly in a cocked position; contacting portions of the pawl latch assembly with a ramp formed on an inner surface of the retractable sleeve in response to rotating the driving housing and sliding the retractable sleeve longitudinally in order to release the spring and move the plunger operating assembly from the cocked position to a released position; and injecting a quantity of fluid from the fluid filled cartridge assembly into the bone marrow through a longitudinal bore in the bone-penetrating needle.