needle deadspace, which is accurate?

When you draw up the dose draw up to the marking on the syringe no matter what type of needle you are using. When you push the fluid out of the syringe there will be some fluid left in the deadspace, which should not be counted (and isn't counted) if you use the markings on the syringe.

If you dilute a med in a syringe after drawing it up the med in the deadspace will become part of the dose. Usually it's not a factor but if you are worried about it (like with pediatric patients) change to a fresh needle before you draw up the dilutent and all the med that was in your old needle (and not measured) will be in the trash.

Thanks for the reply canoehead. The reason why I am looking for some answers on this is because I am the one highlighted by other shift nurses for drawing up inaccurate dose. I was the one to open the 4 ml ampule stock and dose to be given is 2 ml of that ampule. The remaining dose is to be given by receiving shift A. I drew up the med using the first method: using syringe markings and then push out some of the fluid into needle deadspace. Calibrated the dose including the needle deadspace in this one. Second day, I opened another stock, this time calibrated the dose without including the needle deadspace. With the first method, they said the remaining stock was a tad short, something like 1.6 ml or 1.5 ml. With the second method, they said the remaining stock , was 3 ml!!! I’ve done some research on my own today using the same syringe and gauge needle, the deadspace in the needle is something like 0.1 ml. Just can’t believe something like that is left from the ampule with the second method.

No you wouldn't have a problem of missing volume like that due to deadspace.