1. Wilson, Kathleen Marie MPH, BSN, CRNI

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CLINICAL NURSES must make sure that their adult patients have the appropriate vascular access device (VAD). Not only can the array of VAD choices be overwhelming, but patient characteristics and treatment plans must also be weighed when making the decision. Nurses need to understand VAD choices and considerations for choosing the right device for the right time.


Clinical nurses need a solid knowledge base to choose, assess, and maintain the VAD. This article reviews indications for different types of VADs and the importance of continued assessment of the patient and VAD to ensure safe and effective therapy.


Vital choice

Many critically ill patients have received multiple venipunctures and other therapies that have impaired vein integrity. Every time a needle is inserted into a vein, the vessel is injured. After the injury heals, a scar remains.1 This scarring can affect the success of future venipuncture attempts. Infusions of certain medications, such as chemotherapy, can also damage veins, making future venous access more difficult to achieve.2


These factors underscore the importance of proper VAD selection. Nurses must advocate for use of the proper VAD early in the patient encounter and throughout the course of treatment. Benefits of this proactive approach include the following:


* preventing unnecessary venipunctures


* minimizing delays in treatment


* halting further damage to veins


* saving nurses' time


* improving patient comfort and satisfaction.



Peripheral catheter options

Clinical nurses must be able to differentiate among various types of VAD. Peripheral catheters include these types:


* short peripheral


* external jugular (rarely, this site is also used for central VADs; unlike a central VAD, the peripheral catheter is short and doesn't terminate in the central circulation)


* midline.



A short peripheral VAD is typically to 13/4 in (1.6 to 4.4 cm) long. This catheter is inserted in an extremity (most acceptably, an upper extremity), and the tip terminates in a peripheral vein. This type of VAD is appropriate for short-term bloodstream access for therapies expected to last up to 1 week. It's used to administer nonirritating infusates with a pH between 5 and 9 and an osmolarity of less than 600 mOsm/L. (See Understanding key terms.)3


An external jugular peripheral VAD is placed in the external jugular vein on either side of the patient's neck, usually when other veins can't be accessed in acute care and in emergency situations. This VAD is inserted by personnel with specific training.3 Because both peripheral and, rarely, central VADs can be inserted in an external jugular vein, they can be difficult to tell apart, underscoring the need to properly identify the line on the label placed on the VAD dressing. If a label isn't present, the nurse must confirm the catheter type before using it by reviewing the patient's medical record or asking the inserting clinician.


External jugular peripheral VADs are appropriate to administer infusates with a pH between 5 and 9 and an osmolarity of less than 600 mOsm/L.4


Neck motion and the presence of facial hair, such as men's beard growth, can complicate the dressing and stabilization of external jugular VADs.5 Because poor stabilization can lead to dislodgment, these VADs are often discontinued as soon as other access can be established, especially if the planned therapy will exceed 72 hours.3


A midline peripheral VAD is used for therapies expected to last 1 to 4 weeks. It's inserted near the veins of the antecubital fossa and secured in the upper arm.3 It must be labeled as a peripheral I.V. so nurses know it's not a peripherally inserted central catheter (PICC) or central line.3 The midline catheter is advanced so that the tip resides in the upper arm and terminates before the axilla.3 The catheter tip terminates distal to the shoulder so it doesn't enter the central vasculature.


Although placed in the upper arm, a midline VAD is a type of peripheral VAD and must be distinguished from a PICC. As with external jugular VADs, visual inspection isn't sufficient for identification. The type of VAD should be identified on the dressing label; a nurse with any uncertainty about the catheter type must consult the patient's medical record. As with a short peripheral VAD, the midline catheter provides access to the bloodstream to administer nonirritating infusates with a pH between 5 and 9 and an osmolarity of less than 600 mOsm/L.4


Because it can be used for therapies lasting for several weeks, the midline catheter is useful to preserve veins in appropriate patients.3 It's also useful for patients needing short-term therapy whose short peripheral catheters are consistently failing.


Central VAD options

The tip of a central VAD rests in the central circulation, most commonly deep in the superior vena cava or at the cavo-atrial junction (superior vena cava and right atrium junction). It's an appropriate choice for administering irritating infusates that have a pH of less than 5 or greater than 9 and an osmolarity greater than 600 mOsm/L.4 The many types of central VADs include:




* tunneled and nontunneled central venous access devices (CVADs)


* implanted ports.



Hemodialysis catheters are beyond the scope of this article because they aren't used for routine vascular access.


PICCs can be used for an indefinite amount of time, but choosing them for therapy lasting 4 weeks or longer is a general guideline. Inserted peripherally by specially trained nurses, PICCs aren't as invasive or as risky as other central VADs. They're most commonly placed in the veins of the upper extremity in adults, preferably the basilic vein.3


Nontunneled, percutaneous CVADs are percutaneously inserted into the subclavian, jugular, and femoral veins (as a last resort). This type of CVAD is for use in therapies planned for less than 14 days in hospitalized patients. In adults, avoid the femoral area to minimize the risk of infection and other complications.6 If the femoral site must be used in an emergency, the catheter should be removed and a new vascular access obtained at a different site (if indicated) within 48 hours.3,6


Tunneled, cuffed CVADs are used for long-term therapy and can be in place for years.3 When the tunnel is mature, it creates a natural barrier between the vein entry site and the skin exit site, stabilizing the catheter. These VADs are typically inserted into a vein such as the internal jugular or subclavian, and the catheter is positioned from the vein entry site underneath the skin to an exit point on the chest wall.4 A cuff around the catheter anchors the catheter in the subcutaneous tissue. A tissue seal forms about 14 days after catheter insertion, stabilizing the catheter.7


An implanted port consists of a surgically implanted reservoir and a catheter tunneled under the skin to a vein. The reservoir is placed in subcutaneous tissue, typically but not always on the chest. The port is accessed with a special noncoring needle to ensure the self-sealing of the septum (where the needle enters the port) and to prevent emboli from port fragments created by needle coring. They're used for patients who need long-term I.V. therapy.4,7


Nursing considerations

Regardless of the type of VAD inserted, assess the patient regularly for signs and symptoms of infection, infiltration, and other complications, and monitor the device for any malfunction. To prevent serious problems such as catheter-related bloodstream infection (CRBI), report signs and symptoms promptly and intervene as indicated.


Remove any unnecessary line promptly. Central VADs should be discontinued as soon as they're no longer needed due to the risk of CRBIs.


Additional nursing considerations include proper flushing, aspirating for blood return to verify proper VAD placement in the vein, and working with clinicians inserting VADs to minimize the number of lumens on all VAD selections to decrease infection risk. (Detailed discussion of VAD maintenance is beyond the scope of this article.) Patients with chronic kidney disease require special consideration, especially in reference to vein-preservation techniques for patients likely needing vascular access for hemodialysis. Avoiding the use of forearm and upper arm vessels should be a top priority.


Early and regular assessment of the patient is an important step in advocating for an appropriate VAD. Remember that the patient's clinical status and therapy are dynamic. The VAD appropriate upon admission may not be the best choice several days later or for continued therapy after discharge.


Daily monitoring and reassessment are crucial because, as a patient's hospitalization progresses, the treatment plan may become more complicated or lengthy. Such changes may necessitate a switch from a peripheral VAD to a CVAD, for example. Discharge planning should be considered well in advance of the day the patient leaves the hospital.


Daily monitoring also involves an evaluation of how well the VAD is working. Are frequent and unplanned restarts occurring? Does the patient have a complicated treatment plan and a history of poor vasculature? Is the patient complaining of VAD site discomfort or tenderness with palpation? Is the blood return brisk? Is the current VAD appropriate for the prescribed therapy? Because clinical decision making surrounding VAD selection is complex, nursing assessments and documentation must be detailed and ongoing.8


Plan to advocate

The clinical nurse is a vital component of a proactive plan of care for patients with VADs. Primary components of this patient advocacy include consultation with the existing infusion team or implementation of an I.V. standards committee, which will be covered in a future article.


Understanding key terms

pH is the degree of acidity or alkalinity of a substance. The pH is inversely related to the concentration of hydrogen ion. A normal pH range is 7.35 to 7.45.9


* For infusates with a pH of 5 to 9, a peripheral VAD can be used.


* For infusates with a pH <5 or >9, a CVAD should be used to ensure that the infusate is quickly hemodiluted and to reduce its direct contact with the lining of the vessel (tunica intima), thus minimizing vessel damage.4



Here are examples of the pH levels of some common drugs:


* vancomycin hydrochloride, 3 to 5


* dopamine, 2.5 to 5.0


* ceftriaxone, 6.6 to 6.7


* phenytoin, 12.0


* metronidazole hydrochloride, 6.0 to 7.5.10



The osmotic activity of a solution may be expressed in terms of either its osmolality or osmolarity. Usually, there's little difference between these two measurements when used in clinical practice:


Osmolality refers to the osmolar concentration in 1 kg of water (mOsm/kg of H2O); usually used when referring to fluids inside the body. Normal serum osmolality ranges between 275 and 295 mOsm/kg.9


Osmolarity refers to the osmolar concentration in 1 L of solution (mOsm/L); usually used when referring to fluids outside the body.


* For solutions with an osmolarity of >600 mOsm/L, a CVAD must be used.4



Here are examples of infusates with an osmolarity >600 mOsm/L:


* 3% or 5% sodium chloride solution


* parenteral nutrition


* >10% dextrose in water.11



Tonicity is based on the infusate's effect; that is, how does it affect cells' size? (See figure below.)


* Isotonic solutions (250-375 mOsm/L) have the same concentration as body fluid so water moves very little, having no effect on cells' size. Examples include 0.9% sodium chloride solution, lactated Ringer's solution, and D5W.


* Hypotonic solutions (<250 mOsm/L) are less concentrated than body fluid so water moves into cells, causing them to swell. Examples include 0.45% sodium chloride and 2.5% dextrose in water.


* Hypertonic solutions (>375 mOsm/L) are more concentrated than body fluid so water moves out of cells, making them shrink. Examples include 5% dextrose in lactated Ringer's solution, 5% dextrose in 0.9% sodium chloride, and D10W.11



Source: Porth CM. Essentials of Pathophysiology. 3rd ed. Philadelphia, PA: Wolters Kluwer Health/Lippincott Williams and Wilkins; 2011.

Figure. Tonicity: Re... - Click to enlarge in new windowFigure. Tonicity: Red blood cells don't change size in isotonic solutions (A). They become larger in hypotonic solutions (B) and get smaller in hypertonic solutions (C).



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