Intravenous fluid resuscitation: and Poiseuille law

Q: 18-gauge (G) peripheral is considered a large-bore intravenous line.

A) True

B) False

Answer: B (False)

A large bore IV line for active resuscitation should be at least 16 G or preferably 14 G. Said that 18 G is considered standard as in trauma and other emergent situations, and provides a good balance of flow rate and ease of insertion. Additionally, it is suitable for blood transfusions.

The objective of this question is to remind students of the Poiseuille's law which states that: "The flow rate is directly proportional to the pressure difference and the fourth power of the radius, and inversely proportional to the viscosity and length of the tube  the flow rate is directly proportional to the pressure difference and the fourth power of the radius, and inversely proportional to the viscosity and length of the tube."

A mere 2-point increase in the G size of the IV line can significantly increase the flow.

#hemodynamic

References:

1. Reddick AD, Ronald J, Morrison WG. Intravenous fluid resuscitation: was Poiseuille right? Emerg Med J. 2011 Mar;28(3):201-2. doi: 10.1136/emj.2009.083485. Epub 2010 Jun 26. PMID: 20581377.

2. Rajkumar JS, Chopra P, Chintamani. Basic Physics Revisited for a Surgeon. Indian J Surg. 2015 Jun;77(3):169-75. doi: 10.1007/s12262-015-1308-6. PMID: 26246696; PMCID: PMC4522253.

3. Traylor S, Bastani A, Butris-Daut N, Christensen M, Marsack P, Rodgers L, Todd B. Are three ports better than one? An evaluation of flow rates using all ports of a triple lumen central venous catheter in volume resuscitation. Am J Emerg Med. 2018 May;36(5):739-740. doi: 10.1016/j.ajem.2017.09.058. Epub 2017 Oct 4. PMID: 29079377.