Monday September 28, 2009
Bedside tip

Q: Why it is not advisable to draw blood from Cordis (introducer) for blood sampling?

Answer: Given their large diameters, accurate lab draws would be difficult considering the amount of waste that needs to be withdrawn even to get a good blood sample (not visibly diluted) is substantial.

On other hand, Cordis is preferable for resuscitation. The flow rates are incredible. Technically Central line (TLC or PICC line) is not ideal for resuscitation due to longer length and smaller radius. 2 Large bore (say 18 gauge) peripheral IVs or one large bore central IV (cordis) are real placements for aggressive resuscitation, due to bigger radius and shorter length.

Remember as per Hagen-Poiseuille equation just 2 fold increase in radius increase flow by 16 fold but on the other hand, just 2 fold increase in length decrease flow by 50%.