Peripheral Intravenous Access

Published on 26/03/2015 by admin

Filed under Emergency Medicine

Last modified 26/03/2015

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 1 (1 votes)

This article have been viewed 11401 times

Chapter 21

Peripheral Intravenous Access

Introduction

Intravenous (IV) access is a mainstay of modern medicine. IV cannulation is a procedure performed by a wide array of health care professionals, including physicians, nurses, physician assistants, phlebotomists, and emergency medical technicians. In the emergency department (ED), uncomplicated peripheral venous access is usually secured by a nurse or technician. In the United States, more than 25 million patients have peripheral IV catheters placed each year as vascular access for the administration of medications and fluids and sampling of blood for analysis. IV access can usually be accomplished in less than 5 minutes.1–4 Despite their growing number, dedicated IV teams are very costly and not always cost-effective.5,6 Moreover, in the ED setting multiple providers may be called on to obtain IV access, thus making it an essential skill for both emergency physicians and nurses to master. Subtleties in technique are important and can be improved with practice; this is why some providers are able to place IV lines in even the most challenging situations.

Historical Perspective

Bloodletting, or bleeding, dates to the time of Hippocrates. The ancient technique consisted of tying a bandage around the arm to distend the forearm veins, opening a vein with a sharp knife, and collecting the blood into a basin. In the Middle Ages this was performed by barber-surgeons. In 1656, Sir Christopher Wren injected opium into dogs intravenously with a quill and bladder, thereby becoming the father of modern IV therapy.7 Blood transfusions also date back to the mid-1600s. The French physician Jean Denis is credited with the first successful transfusion by giving lamb’s blood to a 15-year-old boy.8,9

Originally, 16- to 18-gauge indwelling steel needles were used for IV infusions. In the 1950s the Rochester needle was introduced, which was a resinous catheter on the outside of a steel introducer needle. Because of increased comfort and mobility, plastic catheters have replaced indwelling metal needles and are now almost universal.7,10

Indications and Contraindications

Obtaining timely and adequate vascular access is a major priority during any resuscitation. In patients with normal perfusion, differences in delivery times for injections centrally versus peripherally are minimal—within seconds.11 During cardiopulmonary resuscitation (CPR), however, medications have been shown to reach the central circulation faster with central access than with peripheral venous access.12 A change in outcome, though, has not been demonstrated with the central administration of advanced cardiac life support drugs; hence, peripheral IV cannulation is the procedure of choice even during CPR because of the speed, ease, and safety with which it can be accomplished. In less critically ill patients, the role of IV therapy is more often debated and access is ultimately unnecessary in a large proportion of patients in whom it is obtained.13 In broad terms, IV access or therapy is needed in patients for whom IV medications are required or when oral therapy is inadequate (e.g., severe shock states), contraindicated (e.g., surgical emergencies), or impossible (e.g., intractable vomiting).

Saline or heparin locks are preferable when IV medications are needed and there are limited foreseeable fluid requirements. Saline locks cost less than a full IV fluid and tubing assembly and are especially helpful when vascular access is needed suddenly.14,15 Access to the catheter requires irrigation with a separate syringe and flush.

A peripheral IV central catheter (PICC) shares the attributes of both central and peripheral venous IV lines (see Chapter 24). A PICC is composed of a thin tube of biocompatible material with an attachment hub. It is inserted percutaneously, under ultrasound guidance by a dedicated PICC team, into a peripheral vein and then advanced into a large central vein, followed by radiographic confirmation of placement. PICCs are suitable for long-term vascular access for blood sampling, infusion of antibiotics and hyperosmolar solutions such as total parenteral nutrition, and infusion of certain chemotherapeutic agents. Insert a PICC line as soon as long-term access is anticipated.3

Peripheral IV lines should not be placed in extremities with massive edema, burns, sclerosis, phlebitis, or thrombosis due to risk for extravasation or suboptimal volume flow. When practical, avoid placing an IV line in extremities on the same side as radical mastectomies, though they can be used when an urgent condition exists and other peripheral access is not possible. When feasible, cannulation at infected sites, such as through an area of cellulitis, as well on extremities with shunts or fistulas, should be avoided because it may cause bacteremia or thrombosis. If possible, do not cannulate a vein over or distal to a recent fracture site on an extremity (Fig. 21-1). Veins that drain from an area affected by trauma or major vascular disruption (e.g., distal to a ruptured aorta) are also suboptimal because fluid or medications may not be delivered to the circulatory system.

Blood samples for laboratory analysis are usually drawn before IV cannulation to avoid contamination with IV fluid or medication. However, studies have shown that accurate basic electrolyte and hematologic values can be obtained with peripheral IV lines when infusions are shut off for at least 2 minutes, at least 5 mL of blood is wasted, and all tubes are filled to avoid inaccurate bicarbonate readings.16–18 By adopting this technique, one can reduce the number of peripheral needlesticks, minimize trauma or sclerosis of the vein, and improve patient satisfaction.

Ultrasound Guidance and Transillumination

Though more commonly used with central venous access, ultrasound can also assist in the placement of peripheral lines. For IV placements that have been designated “difficult” after a certain number of attempts by nursing staff, use of ultrasound guidance increases the success rate and decreases the number of attempts necessary for successful cannulation in both adult and pediatric patients.19–22 One recent prospective randomized control study, however, did not show a benefit; conflicting evidence may ultimately stem from differences in the experience of ultrasound operators.23 The caliber of the vein identified on ultrasound is predictive of its ability to be cannulated. If no vessel is identified, cannulation is not usually possible.24,25 An additional issue with ultrasound-guided peripheral IV lines is their longevity. One study has brought attention to the high premature failure rate of ultrasound-guided peripheral lines.26 This is probably related to the depth of the veins being cannulated, the length and type of catheter used, and the angle of the catheter through soft tissue.

Other devices transilluminate the veins to increase their visibility, especially in infants. Although little evidence is available to evaluate their utility, such devices, though not routinely available, can be useful, especially in departments with a large pediatric population. As emergency providers become more comfortable with these advancing technologies, ultrasound-guided or illumination-assisted insertion of peripheral lines will probably increase.

Anatomy

The success of cannulation depends on familiarity with the vascular anatomy of the extremities. In the upper extremity, the veins of the hands are drained by the metacarpal and dorsal veins, which connect to form the dorsal venous arch (Fig. 21-2). These sites are excellent for IV therapy and comfortably accommodate 22- and 20-gauge catheters. The venous supply of the wrist and forearm consists of the basilic vein, which courses along the ulnar portion of the posterior aspect of the forearm. It is often ignored because of its location but can easily be accessed if the patient’s forearm is flexed and the clinician stands at the head of the patient.27 On the radial side of the forearm, the cephalic is best known as the “intern vein.” Readily accessible, this vein can accommodate 22- to 16-gauge catheters. The median veins of the forearm course through the middle of the forearm, and the accessory cephalic veins on the radial aspect of the forearm are easily stabilized and accessible.

The antecubital veins consist of the medial cubital, basilic, and cephalic veins, and these veins are often selected for catheters or blood drawing. IV placement here is easy, but mobility of the arm is restricted once the catheter is in place. The larger veins above the antecubital space, the cephalic and basilic veins, are often more difficult to see but can be accessed without difficulty if necessary.

The relevant lower extremity venous anatomy starts with the dorsal digital veins, which become the dorsal metatarsal veins and form the dorsal venous arch. The arch ultimately splits into the great saphenous vein, which travels up the medial aspect of the ankle, and the small saphenous vein, which courses laterally up the opposite side. These are the vascular structures most easily accessible for IV therapy.

The external jugular vein is formed below the ear and behind the angle of the mandible (Fig. 21-3). It then passes downward and obliquely across the sternocleidomastoid and under the middle of the clavicle to join the subclavian vein. It is important to note the presence of valves in the external jugular, usually about 4 cm above the clavicle, because they can significantly impede IV function.28

Preparation

Safety

Universal precautions must be applied to all patients, especially in emergency care settings, in which the risk for exposure to blood is increased and the infection status of patients is largely unknown.29 One study showed that 11% of all hospital IV catheter injuries to health care workers occurred in the ED.30 Newer catheter devices have emerged that prevent inadvertent needle injuries (Fig. 21-4). The Protectiv IV Catheter Safety System has a protective sleeve that encases the sharp stylet as it is retracted from the catheter. The needle of the Insyte Autoguard Shielded IV Catheter is instantly encased inside a tamper-resistant safety barrel by pressing an activation button. The Saf-T-Intima IV catheter, Punctur-Guard Safety Winged Set, Vacutainer Safety-Lok, Shamrock safety winged needle, and Angel Wing Safety Needle systems are all types of winged safety devices with shields that advance over the needle to prevent exposure of the needle.7

Choosing the Catheter Gauge

The specific gauge of catheter to use depends on the clinical scenario (Fig. 21-5). The narrowest catheter typically used in adults is a 22 gauge, which is sufficient for the routine administration of maintenance fluids and antibiotics. A 20 or 18 gauge is necessary for the administration of blood products, and a 16-gauge needle is preferred in resuscitation settings when large amounts of fluid must be given quickly.27 A second IV line at a different location allows additional IV therapy and also acts as a backup line in critical resuscitations. An 18-gauge catheter in the antecubital fossa is the standard device for IV contrast–enhanced computed tomography (CT) studies such as pulmonary CT angiogram.

Appropriate Site

Site selection depends largely on the expected duration of IV therapy, the patient’s activity level, and the condition of the extremities. When choosing a location to initiate IV access, the best place to start is the hand and then advance cephalad as necessary. Hand veins are appropriate for 22-gauge catheters. Cephalic, accessory, or basilic veins are ideal for larger-bore IV lines. Avoid veins that are not resilient and feel hard or cordlike because they are often thrombosed.7 Deep, percutaneous antecubital venipuncture and external jugular vein cannulation are also options in patients with difficult veins or those who may need IV access quickly.7 The lower extremities veins can also be useful locations, especially in pediatric patients. In patients who have undergone radical mastectomy, avoid the arm on the same side as the surgery because circulation may be impaired, flow may be affected, and edema and other complications such as thrombosis could result.7, 22 Scalp veins are commonly used in neonates.3,31

Adjuncts for Finding a Vein

Patients often have nonvisible and nonpalpable veins. A common method of increasing venous distention is to ask patients to open and close their fist. Lowering the arm below the level of the heart can also increase venous distention. Light tapping can likewise be effective, although heavy tapping may cause the vein to spasm. If these methods are inadequate, heat packs can be applied for 10 to 20 minutes to increase venous engorgement. This is particularly useful in the pediatric population.7

Nitroglycerin ointment applied to the hands of patients with small-caliber veins has been shown to increase the diameter of the vein by two to six times and increase the rate of successful first-attempt cannulation. Once the tourniquet is applied to the wrist, a quarter inch of 2% nitroglycerin is applied to a 2.5-cm2 area, left on for 2 minutes, and then rubbed off.32 Nitroglycerin has been found to be useful and safe in the pediatric population as well.33 This technique is contraindicated in hypotensive patients.

In the late 1980s, several small studies demonstrated the potential use of a venous distention device—a cardboard mailing tube that was placed over the forearm with a sealed bulb at one end that would cause a vacuum within the tube. Of the patients predetermined to be difficult to access, 90% were cannulated when this device was used. Reported complications were few and included petechiae and discomfort.34,35

Anesthesia

Though somewhat time-consuming, local anesthesia at the site should be considered part of routine care. Local anesthesia significantly decreases pain before cannulation.36–38 Anesthetics such as lidocaine or bupivacaine may be instilled just beneath the skin at the site of planned cannulation through a tuberculin (1-mL) syringe equipped with a 27- or smaller-gauge needle. Adding bicarbonate (e.g., buffered lidocaine), warming the solution to room temperature, instilling the solution slowly, and distracting the patient during injection all contribute to reducing pain.39 In the pediatric population, 2.5 g of EMLA (eutectic mixture of local anesthetics) can be applied topically over the site.7,40 Its main disadvantage is slow onset, with as long as an hour needed for induction of anesthesia before cannulation.41 Other options include ethyl chloride topical spray,42 which temporarily numbs the skin, and oral sucrose in infants.43

IV Assembly

Review Box 21-1 itemizes the materials necessary for IV cannulation. The procedure is detailed in Figure 21-6. The first step is to prepare the IV fluids and tubing. Remove the cap from the IV tubing and the tab from the IV bag. Clamp the IV tubing shut and insert the spiked end into the IV fluid bag. Pinch the drip chamber and fill it halfway. Open the clamp slightly to flush the IV tubing. If saline locks are being used, flush them similarly before cannulation. To do this, attach the lock to a saline-filled syringe and push saline through it.