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Do Catheter Side Holes Provide Better Blood Flows?
Author(s) -
Wachter Dirk S. De,
Weijmer Marcel C.,
Kaušylas Mantas,
Verdonck Pascal R.
Publication year - 2002
Publication title -
hemodialysis international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.658
H-Index - 47
eISSN - 1542-4758
pISSN - 1492-7535
DOI - 10.1111/hdi.2002.6.1.40
Subject(s) - medicine , catheter , coaxial , volumetric flow rate , blood flow , surgery , biomedical engineering , thrombus , cardiology , mechanics , physics , electrical engineering , engineering
Four catheters (Ash Split Cath, Tesio, Duo‐Split, and Duo‐‐Flow; Medcomp, Harleysville, PA, U.S.A.) were tested in a temperature‐controlled in vitro setup filled with 50% aqueous glycerin solution to determine hydraulic resistance at different flow rates. All these catheters have side holes; hydraulic resistance was determined with these holes open and closed. Due to extra pressure losses near the catheter tip, the pressure–flow relationship deviates from Poiseuillian theory and is generally quadratic in nature. An equivalent diameter was derived from the data. This equivalent diameter can be used to evaluate performance using a single number. Permanent catheters can easily deliver 300 mL/minute under optimal circumstances, but acute catheters are, in practice, limited to 200 mL/minute, and even somewhat less in the coaxial Duo‐Flow type. Permanent catheters have larger equivalent internal diameters (1.8 vs 1.45 mm). Covering the side holes does not influence hydraulic resistance to a great degree, except in the arterial limb of acute catheters. These results indicate that, especially in acute catheters, obstruction of the side holes or fibrin sleeve/thrombus formation over the inlet holes may severely impact the available blood flow rate during dialysis. On the other hand, side holes in permanent catheters or venous limbs seem to be superfluous for performance reasons.