vascular access involves inherent risks to the clinician, including blood exposure and needlestick injury. Whether it is attempted on‐scene or in transit, the prehospital environment is often characterized by poor lighting, limited space, and movement in the rear of an ambulance. This offers less than ideal conditions in which to handle lancets, IV and IO needles, and other sharp supplies. A combative and/or confused patient can add to the difficulty. Transmission of HIV, hepatitis B, and hepatitis C remains a constant threat to EMS personnel, with the risks of infection following needlestick injury estimated at 0.3%, 6%–30%, and 1.8%, respectively [4]. Consistent use of universal precautions is imperative to reduce the likelihood of occupational exposures. Potential risks to the patient include bleeding, damage to adjacent structures, infection, and thrombosis, and these risks will be discussed later.
Establishing an IV is often part of EMS protocols. In many cases protocols allow for EMS clinician assessment and judgment regarding whether or not an IV is necessary. One study revealed that while over 50% of the patients who arrived at an ED via EMS had IVs in place, almost 80% of those IVs were not used in the prehospital setting. The tendency to err on the side of caution to avoid scrutiny for perceived undertreatment seemed to contribute to the discrepancy [5]. Another study similarly found that protocols seemed to drive the decision to start an IV, as opposed to an actual need for administration of medicines or fluids [6]. Medical oversight is indicated to continually evaluate the appropriateness of “precautionary” IVs in the contexts of potential risks and costs to the system and to patients.
Several studies in trauma situations have revealed a lack of significant benefit regarding prehospital vascular access. The classic EMS mantra of “two large bore IVs” for trauma patients has been muted by concern for increased on‐scene times and delayed transport to definitive medical care. Two studies have demonstrated high success rates when IVs were attempted in transit without delaying transport [7, 8]. However, guidelines provided by the Eastern Association for the Surgery of Trauma regarding prehospital IV placement or IV fluid administration for either penetrating or blunt injury patients are based on findings that no benefit is provided [9]. Multiple research studies have suggested that routine administration of IV fluids may not be helpful and, in fact, can be harmful in the prehospital setting [10, 11]. Another study endorsed “scoop and run” transport for EMS, as it found that each prehospital procedure before ED thoracotomy compounded a reduction in the odds of survival [12].
PERIPHERAL IV ACCESS
History
In 1656, Sir Christopher Wren injected opium into the veins of dogs using a quill and bladder, making him the founder of modern IV therapy. Until the 1950s, reusable steel needles were used, but the introduction of over‐the‐needle plastic IV catheters replaced indwelling metal needles, improving operator safety and allowing more patient comfort, rapid flow, and reduced infiltration [13, 14].
Flow through the catheter is based on Poiseuille’s law, dealing with pressure and resistance. The pertinent determinants of the equation include the radius of the catheter and the catheter length. Flow is directly proportional to the radius to the fourth power (r4) and inversely proportional to catheter length. As such, a large gauge, short IV catheter can profoundly improve the potential flow rate over a smaller gauge, longer catheter.
Typical locations for peripheral IV access include the antecubital fossa, veins in the forearm and dorsum of the hand and foot, external jugular vein, and scalp veins.
1. Preparation
When the decision to pursue vascular access is made, the preparation for the procedure is just as important as the skill itself. Striving for speed in the prehospital setting, assumptions regarding the patient’s health, or other neglectful behavior deviating from the practice of universal precautions can result in occupational exposure. When possible, wash hands prior to putting on gloves.
Prepare the equipment (Figure 8.1). An IV start kit is optimal (tourniquet, alcohol wipe or other cleaner, tape or a commercially available adhesive device). Select an IV needle with a catheter (Figure 8.2), saline lock, saline flush, and/or IV fluids. Check the IV catheter for integrity.
Prepare the patient for the procedure. When appropriate, discuss with the patient the reason for the procedure along with risks and benefits. Unless a true emergency exists or the patient is not able to make his or her own decisions, verbal consent should be obtained.
2. Site selection
Position the patient’s extremity to help straighten the desired vein. Apply the tourniquet proximal to the targeted area (Figure 8.3). When possible, look distally first to allow additional, more proximal attempts on the same extremity, if necessary. Once the tourniquet is applied, have the patient pump his or her fist open and closed several times to help the vasculature become engorged. Feel for a soft, spongy, nonpulsatile vessel.
Figure 8.1 IV starting equipment.
Figure 8.2 18‐ and 20‐gauge IV catheters with needles.
3. Clean the site
Use an alcohol pad, betadine, chlorhexidine, or a similar antiseptic product to clean the proposed IV site. Allow the area to dry.
4. Insertion of the IV
Hold the skin taut with one hand while inserting the needle with the dominant hand. Approach the vessel as shallow as possible (less than 30 degrees angle to the skin) with the bevel of the needle facing up or away from the patient. Once a “pop” is felt and/or a flash of blood is seen in the reservoir of the IV needle, advance the needle slightly further, and slowly slide the catheter over the needle, cannulating the vessel with the plastic catheter while not moving the needle itself (Figure 8.4).
5. Removing the needle
Hold firm pressure over the tip of the cannulated plastic catheter while the needle is withdrawn from the hub of the catheter. If applicable, push the button to retract the needle to its safe position and set it away. The needle needs to be disposed of in a sharps container as soon as the IV is secured.
Figure 8.3 Position of tourniquet proximal to target vein.
Figure 8.4 “Flash”