Last week we asked, what venous access is the LEAST effective for fluid resuscitation? The options were:
A. 16G antecubital peripheral IV
B. 8.5F Cordis
C. Medial port of a triple lumen central line
D. Intraosseus line
Before we get into the answer with some numbers to back it up; take a second t go back to undergrad physics.. remember Poiseuille’s Law?
What it says is that the highest amount of flow is achieved when the conducting vessel is a) short, b)large, and d) has a high pressure gradient across it.
Now thinking about our options:
A) a 16G PIV has a relatively large lumen and is a short catheter
B) An 8.5F cordis has a huge lumen and is not very long
C) The medial port of a central line has a smaller lumen (18G) and can be upto 25cm long
D) An intraosseus needle is 16G and relatively short
So the answer is C.. a central line is NOT an effective way to provide massive fluid resuscitation.
Interestingly there are some numbers for those wondering just how fast fluids go through these vessels..
A) 16G PIV – 220ml/min
B) 8.5F cordis 126 ml/min, 333 ml/min under pressure bag at 300 mmHg
C) Medial port of triple lumen – 26 ml/min
D) IO – 80 ml/min, 150 ml/min under pressure *reference*
The take home message here is when you want to fluid resuscitate a patient, good peripheral IVs are your best option and if you can’t get them, consider an IO. While a triple lumen central venous catheter is an important line throughout an ICU stay; it is not a priority in initial resuscitation.
Thanks for participating!