SUPPOSE YOUR patient's I.V. treatment plan calls for a hospital stay of 6 to 10 days and he has limited venous access. He could need restarts due to complications associated with the drug's pH or osmolarity. A midline catheter may fit neatly into this patient's care plan.
Although considered a peripherally inserted catheter, a midline catheter is inserted in a larger vein than those used for standard I.V. therapy: The recommended insertion site is the basilic, cephalic, or median vein in the antecubital fossa. The catheter, which is 8 inches (20 cm) long for adults, is advanced until the distal tip rests in the upper arm, at or below the axillary line. A larger arm vessel provides better drug hemodilution than the smaller vessels used for standard peripheral catheters, reducing phlebitis and infiltration risks.
Infusion Nurses Society standards of practice place the same restrictions on pH and osmolarity for midline catheters as for peripheral catheters. But midline catheters have a longer dwell time: up to 6 weeks, compared with 96 hours for short peripheral catheters, according to Centers for Disease Control and Prevention guidelines.
When are midline catheters used?
Consider these factors when debating whether to use a midline catheter:
- Type of I.V. drug. Vesicants, including dopamine and some chemotherapy drugs, and highly irritating drugs such as vancomycin are best administered via a central line. You can safely use a midline catheter for hydrating solutions and drugs that aren't vesicants, have a pH level near blood plasma (5 to 9), or have low osmolarity (below 500 mOsm). Examples of such drugs include heparin and cephalosporins.
- Length of I.V. therapy. Midline catheters are appropriate for patients who need I.V. therapy for more than 5 but fewer than 28 days, so the typical medical/surgical patient hospitalized for less than 5 days probably isn't a good candidate for midline placement. Barring complications, he'll need just one peripheral I.V. site rotation, so a midline catheter, which costs about the same as three peripheral catheters, isn't cost-effective unless he has limited venous access.
- Patient age. Midline catheters are good for older adults, who may have limited venous access or medical conditions that contribute to increased length of stay.
How do I manage a midline catheter?
Follow your facility's protocol, training and competency requirements, and the midline catheter manufacturer's guidelines for routine care and maintenance.
My facility's protocol calls for changing the dressing 24 hours after catheter insertion, to check for moisture or bleeding underneath the dressing. After that, change the dressing at least weekly, or whenever it's soiled, wet, or loose. Monitor for catheter migration by measuring and documenting the external catheter length at each dressing change. Use a site-stabilizing device to help prevent catheter migration.
Follow your facility's protocol and the manufacturer's directions for flushing a locked midline catheter. My facility flushes midline catheters every 8 hours with 1 ml of heparin (100 units/ml). Before and after administering drugs through the catheter, whether via I.V. push or an infusion, we flush with 10 ml of sterile 0.9% sodium chloride solution, followed by 1 ml of heparin.
Use 10-ml or larger syringes to administer I.V. push drugs or flushes; smaller syringes may exert too much pressure and rupture the catheter if it's occluded.
Change the extension set and male adapter according to facility protocol—at least weekly and no more often than every 72 hours.
N. Richard Anderson is clinical coordinator of I.V. therapy at Evangelical Community Hospital in Lewisburg, Pa.
Hankins J, et al. Infusion Nurses Society: Infusion Therapy in Clinical Practice
, 2nd edition. Philadelphia, Pa., W.B. Saunders Co., 2001.
Infusion Nurses Society. Infusion nursing standards of practice. Journal of Intravenous Nursing
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O'Grady NP, et al. Guidelines for the prevention of intravascular catheter-related infections. Centers for Disease Control and Prevention. Morbidity and Mortality Weekly Report
. 51(RR-10):1–29, August 9, 2002.