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-----Original Message----- From: Michael Bjarkoy <[log in to unmask]> To: [log in to unmask] <[log in to unmask]> Date: 14 June 1999 17:06 Subject: RE: Size Matters?? >Hi Stephen > >I have similar attitude and experiances as you have with cannula sizes. I >was just trying a bit of lateral thinking - not sure if it worked. > >Would you consider 18g for fluid therapy? If not, why not? > Yes I would, if I thought I couldn't get a 14g in. However, even if I can't see or feel the vein in the fossa, I know it is there somewhere and can have a paddle around for it enroute. The veins in the elbow are pretty large and will generally take a 14g. That being said, the study in Pre-Hospital Immediate Care this issue says we can infuse a bag of Hartmanns through a 16g cannula in 72 seconds if we squeeze the bag manually, which is pretty quick. With the trend towards controlled hypotension, this will probably be quite quick enough to dribble through the teacupful we will now be giving. :-) Use of a 14g brings another problem, though. If the fluid is going through very quickly and you are very busy with the patient, it is very easy to allow the drip to run dry, so to speak. Once or twice I have seen the line of air almost start down the IV line before I can turn it off. Comes with being alone with the patient in the back of an ambulance for 20-30 minutes without hot and cold running nurses on tap. ;-) >I am sure we are right in continuing 14g cannula's but need to justify to >myself why? > Because when they get to A&E, and they start pouring in the blood, I'm sure it will go in much faster through a 14g than an 18g, blood being thicker than water. All the flow rates for cannulae are given for water. I believe there may also be the question of damage to blood cells by turbulence and high pressure in the small cannula. I wonder if there has been a study of that? regards Stephen Dolphin Paramedic %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%