Triple Lumen Catheters Are Not Volume Lines
Posted by Clark Venable on 1/12/2005
I brought a patient to the operating room recently who had a Type A ascending thoracic aneurysm dissection. She was bleeding into her pericardium and was in tamponade on arrival. She had a radial arterial line that wasn't (in an artery), and two triple lumen central lines--one in a femoral vein and one in an internal jugular vein.
I immediately thought back to my medical school days when I would see patients in the ICU with a GI bleed being transfused with cold, undiluted packed red blood cells through a triple lumen central line....and they were on vasoactive drips for 'hypotension.'
What's my point? Triple lumen catheters are long and narrow (especially compared to Cordis introducer sheaths or products like them made by other manufacturers such as Arrow). Remember the Poiseuille-Hagen equation shows that flow rate is directly proportional to the fourth power of the radius, to the viscosity of the fluid being transfused, and to the pressure gradient established and inversely proportional to the length of the tube. A 9 French introducer sheath can infuse fluid at about 1000 cc/min. Compare that to about 250 cc/min for the 14 gauge lumen of a triple lumen catheter. So it follows, then, that if you need to give someone fluid (like blood) fast, you infuse it through a fat catheter that is short, reduce the viscosity by diluting it and warming it (in the case of packed red blood cells), and apply some pressure by elevating it well above the patient or putting a pressure bag on it. Got it? Good! This might come in handy when you next see a hypovolemic patient...
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