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Critically ill patients often require frequent laboratory analysis for monitoring purposes but repeated venipuncture can lead to hematoma development, iatrogenic anemia, infection, and patient discomfort.1 A sampling catheter may be placed through a peripheral vein in hospitalized patients to facilitate repeated blood collection. In addition, access to the central (venous) circulation allows administration of hyperosmotic substances, parenteral nutrition, and measurement of central venous pressure.

Related Article: A New Technique for Emergency Vascular Access

If the catheter is used for repeated blood sample collection, this should be the catheter’s sole purpose. This is important to avoid sample errors that may result from administration of IV fluids and drugs through the same catheter lumen; some studies have shown that this may cause inaccurate diagnostic results, particularly with glucose, potassium, and venous blood gas analysis.2,3

A peripheral sampling catheter may be selected when frequent sampling is necessary, but a contraindication to true central venous catheterization via the jugular vein exists. Contraindications to jugular catheter placement include injury, infection, pain, or edema within the cervical region, coagulopathy, increased intracranial pressure, or cervical disk disease.

Lateral or medial saphenous veins are most commonly used for sampling catheter placement in canine and feline patients. Through-the-needle catheters are typically used, as they are small enough to pass through a peripheral vein and are longer (8–12 in) than over-the-needle catheters; this allows more central placement into the vessel and, in smaller patients, access to the caudal vena cava.

Related Article: Intravenous Catheterization

The catheters come in a variety of sizes and are appropriate for use in most patients (Table). As peripheral sampling catheters obtain closer proximity to the central circulation and are intended for longer term use, maintaining aseptic technique is important to decrease the risk of contamination, phlebitis, and catheter-associated infection or sepsis.

Table: Central Sampling Catheters Overview
Catheter Type    Placed Through Advantage Disadvantage
Single lumen (short)    Peripheral vein    Inexpensive, easy to place
  • No central venous access*
Single lumen (long) Peripheral vein Inexpensive, central venous access*   
  • Catheter occlusion, may be difficult to maintain (prone to dislodgement, occlusion)
Multilumen Peripheral vein Central venous access*   
  • Difficult to place through smaller peripheral vessels
  • Expensive
Multilumen Jugular vein Central venous access*
  • May be contraindicated with coagulopathies or cervical disease
  • Expensive

*Lack of central venous access implies that (1) administration of hyperosmotic solutions should not be performed as it may result in phlebitis, (2) central venous pressures cannot be performed as an indirect assessment of intravascular volume, and (3) blood samples are difficult or impossible to obtain.

Thrombosis is a potential risk associated with long-term catheter use.4 Other disadvantages to this type of catheter include catheter shearing by the introducer needle, need for a bulky bandage to secure it in place, and small lumen size (limited by the needle), which may cause catheter occlusion. The potential for hemolysis exists when obtaining samples via these catheters (as opposed to venipuncture); however, recent studies of blood samples obtained via venipuncture versus through a peripheral catheter have shown no significant difference between the methods.5,6

Catheter Management

Management of the catheter is important, to ensure patency and minimize catheter-related complications, such as phlebitis, infection, and thrombosis.4 The catheter should be flushed with 0.9% NaCl (with or without heparin) every 4–6 hours to ensure it remains patent. The bandage should be evaluated every 4–6 hours as well and replaced if soiled or wet. The bandage should be removed/replaced every 24–48 hours in as sterile a manner as possible so the limb and catheter insertion site can be evaluated. Evidence of phlebitis, infection, displacement, leakage, thrombosis, or a fever may prompt the clinician to remove the catheter.

Related Article: Placement of Central Venous Catheters

Peripheral sampling catheters are a short-term option for  vascular access; previous recommendations included catheter replacement every 72–96 hours, however, because of limited peripheral venous access sites and lack of evidence to support such frequent replacements, recent recommendations suggest that as long as appropriate catheter care is performed and no complications noted, peripheral catheters need only be replaced when clinically indicated, rather than on a scheduled basis.

What You Will Need

  • Clippers
  • 5% chlorhexidine scrub
  • Sterile drape
  • Sterile gloves
  • Through-the-needle catheter kit
  • Injection cap or T-set
  • Saline flush
  • 1-inch tape
  • Bandage material

KAYLA HANSON, DVM, is an emergency and critical care resident at Lakeshore Veterinary Specialists in Glendale, Wisconsin. She is currently working on a research project evaluating the efficacy of prazosin in preventing recurrent feline urethral obstruction. Dr. Hanson obtained her DVM from Iowa State University, where she also completed a small animal rotating internship before entering residency.

References Show
  1. Complications occurring from diagnostic venipuncture. Galena HJ. J Fam Pract 34:582-584, 1992.
  2. Venipuncture versus peripheral catheter: Do infusions alter laboratory results? Hambleton VL, Gómez IA, Andreu FA. J Emerg Nurs 40:20-26, 2014.
  3. Comparison of laboratory values obtained by means of routine venipuncture versus peripheral intravenous catheter after a normal saline bolus. Zlotowski SJ, Kupas DF, Wood GC. Ann Emerg Med 38:497-504, 2001.
  4. Peripheral venous catheterization. Davis H. In Silverstein D, Hopper K (eds). Small Animal Critical Care Medicine—St. Louis: Saunders-Elsevier, 2009, pp 260-263.
  5. Blood sampling through peripheral venous catheters is reliable for selected basic analytes in children. Berger-Achituv S, Budde-Schwartzman B, Ellis MH, et al. Pediatrics 126:179-186, 2010.
  6. A cross-sectional study to compare two blood collection methods: Direct venous puncture and peripheral venous catheter. Ortells-Abuye N, Busquets-Puigdevall T, Diaz-Bergara M, et al. BMJ Open 4:e004250, 2014.
  7. Clinically-indicated replacement versus routine replacement of peripheral venous catheters. Webster J, Osborne S, Rickard CM, New K. Cochrane Database Syst Rev 4:CD007798, 2013.

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