A safety needle device and positive flush mechanism for use with a vascular access port. In one embodiment, the combination needle assembly includes a needle, a body and a base, the body being collapsible to expunge fluid therefrom as the needle is withdrawn from a vascular access port. In another embodiment, the combination needle assembly includes a needle, a housing and a reservoir, the housing squeezing the reservoir to expunge fluid therefrom as the needle is withdrawn from the port. In another embodiment, the needle assembly includes a compression plate and balloon extension, the compression plate forcing fluid out of the balloon extension as the needle is withdrawn from the port. In all embodiments, the needle assembly is configured to provide a positive flush to overcome negative pressures in the vascular access port, while also providing a locking mechanism to prevent accidental needle sticks.