Question about butterfly needles?!
Question: Question about butterfly needles!?
When the nurse draws blood with the butterfly, they wait until they see a flash of blood before they insert the vacuum tube!. My question is, why will blood flow in the needle before the tube is inserted!? The needle is too thin so how is blood guided to it!? Also, in vautainer needles, is there also a place where the flash can be seen before the tube is inserted!? If not, how do they know they hit a veinWww@Answer-Health@Com
Answers:
Capillary action!. Surface tension of the blood against the inside the needle helps it to be drawn into the needle!. There is also a needle covered by a latex seal that punctures the Vacutainer!. I think this is what you mean by the Vacutainer needle!. The blood doesn't travel down that far until the Vacutainer is inserted, which pulls the blood into the Vacutainer tube by negative pressure!.Www@Answer-Health@Com
The butterfly cannula it is very thin cannula with tow wing es on both sides it is mainly use in newborn and infant !. see the blood to know in or out of the scalp vein !.the blood pass to the needle because needle act as vacuum the blood pass from area of high pressure to negative pressure and the maneuver need experience!.Www@Answer-Health@Com
negative pressure!.Www@Answer-Health@Com