THIS BLOG DOES NOT PROVIDE MEDICAL ADVICE. The information is for educational purposes only. No material in this blog is intended to substitute for professional medical advice, diagnose or provide treatment. Always seek the advice of a physician or other qualified healthcare providers with any questions regarding medical conditions, treatments and / or procedures. This blog also does not supersede any medical skill or knowledge. Please refer to the manufacture's indications/instructions for use (IFU) and or the organizations internal policy and procedures (IPP) prior to performing any medical procedures. This blog is not intended to deem competency or indicate procedure appropriateness for any patient.
The peripheral IV catheter (PIVC) is the most inserted catheter for vascular access with over 300 million indwelled annually in the U.S. and 2 billion globally. The first step for successful PIVC access is to understand anatomy and physiology of the vascular system. This understanding, generally may not be taught at the academic level but, can be achieved through various vascular access organizations which usually teach didactic education followed by a hands’ on teach back session.
Understanding the anatomy and physiology of a vessel allows for appropriate sites to be selected to ensure the catheter can be used safely mitigating risk of failure which may extend the life of the PIVC. Blood vessels are composed of three walls, each wall being is as thick as a single cell. Each wall is responsible for a specific function, the Adventitia (outer wall) stabilizes the vessel through connective tissue, the media (middle wall) reacts to stimuli causing vasodilation or vasoconstriction, and the Intima (inner wall) repairs the vessel when damaged.
As patients age connective tissue breaks down at the adventitia level causing vessels to roll increasing the difficulty of first attempt access. The media layer is the thickest of the three layers reacting to pain, anxiety, cold, and warmth causing the vessel to constrict or dilate. Endothelial cells make up the intima layer repairing itself when damaged by initiating an inflammatory process known as the clotting cascade. A damaged blood vessel may lead to an infiltration and / or extravasation.
Infiltration and extravasation are sometimes used synonymously; however, the two terms have specific meanings. An infiltration is the passing of administered fluids / medications outside of the intended vessel accumulating in the surrounding tissue. Generally, this fluid / medication is well tolerated by the surrounding tissue and should be reabsorbed by the body. Administered fluid / medication which is defined as a vesicant or irritant passes outside of the vessel and is not well tolerated by the surrounding tissue is an extravasation which may cause necrosis, tissue death from the inside out.
Negative outcomes of infiltration and extravasation can be reduced through understanding the characteristics of the fluids / medication (pH and osmolarity) to be administered through PIVC as the amount of hemodilution changes incrementally distally at the posterior hand to proximately in the SVC. Osmolarity and pH are characteristics that may help determine the appropriate catheter for the administration of fluids / medications. These medication and fluid characteristics usually are available through the institution’s pharmacy.
Choosing an appropriate site to indwell a PIVC is as important as knowing anatomy and physiology of the vascular system. Avoiding areas of flexion (wrist and antecubital fossa) reduces the risk of catheter kinking, pistoning as well as loss of cannulation. Additional areas to avoid are the hand, fingers, lower extremities, and the breast area. Accessing the hand or fingers can be painful, difficult to secure and maintain securement. Patients who can perform personal hygiene, toilet, eat and wash their hands may disrupt the dressing and / or securement leading to kinking, pistoning, loss of cannulation and / or phlebitis. This may also lead to a delay of therapy based on the patient’s vascular health and limited access.
PIVC access in the foot can be difficult and generally does not hold up to the vascular access process. Additionally, the same negative outcomes of the hand would also apply to the feet which may also include sweat and bacteria that may contribute to a blood stream infection. It is also important to note most patients are wearing socks especially those patients who may be considered a fall risk.
Finally, avoiding collateral veins that are prominent on the chest and breast area. These vessels may appear healthy however, generally they cannot withstand powerful hand flushes and do not possess the hemodynamics required for fluid / medication administration. The prominence of these vessels is usually the result of an occlusion somewhere in the distal pathway.
Catheter availability for a successful insertion is related to size and length. Standards of Practice (SOP) recommend a catheter occupy less than 45% of a vessel to ensure hemodynamic blood flow around and beyond the catheter body to reduce the chance of thrombus formation. As a sidebar, thrombus formation within a vessel has the potential to travel ending up in the lungs known as a pulmonary embolus. Additionally, if the thrombus does not travel and heals into the vessel wall, the vessel is permanently narrowed known as a stenosis. Stenosed vessels would not be available for future vascular access.
Selecting the appropriate PIVC is based on the depth and diameter of the chosen vessel. The SOP suggest 50% to 60% of the catheter body dwell in the vessel body. Generally, PIVC’s can range for 1 inch to 2.25 inch and the diameters can range from a 26 gauge to 16 gauge. Gauge is the internal diameter of the catheter, which is inversely proportional to the number. The larger the number the small the internal diameter and the smaller the number the larger the internal diameter. The length of the catheter must also accommodate the angle of descent to the vessel to prevent catheter kinking during securement. The optimal angle may range from 150 to 300 depending on vessel depth.
If a vessel cannot be seen or palpated access should not be attempted. SOPs recommend 2 attempts for the first inserter and 2 attempts for the second inserter, no more than 4 attempts without the use of a visual aid (infrared, near infrared or ultrasound). Proper education and training should be obtained prior to using a visual aid.
Insertion of a PIVC catheter requires strict adherence to aseptic and sterile technique beginning with proper hand hygiene, skin antisepsis, the use of sterile PIVC and a sterile semipermeable dressing. It is important to note, if the PIVC is advanced through the skin and then removed prior to vessel cannulation, that PIVC cannot be used to reattempt access. All needles and needles over catheters are a single attempt device.
Once access is successful the PIVC must be secured through use of an engineered securement device or a semipermeable dressing. Improperly secured PIVC can lead to kinking, pistoning, loss of cannulation and / or phlebitis. Ensuring the life of a PIVC also consists of proper care and maintenance. Steps for catheter longevity requires adhering to manufactures IFU including internal policies and procedures for maintaining catheter patency dressing changes if required and proper flushing techniques.
Understanding each recommendation and / or suggestion according to the SOP and IPP for performing PIVC insertion is a holistical approach which possesses the potential to extend the life of a PIVC which may lead to improved patient outcomes. Furthermore, ultrasound guided PIVC (USGPIVC) insertion is an effective method to further evaluate the vasculature for underlying conditions which could shorten the life of the PIVC. A bilateral preinsertion ultrasound assessment allows for the visualization of deeper vasculature allowing for a larger vessel to be selected for the smallest diameter catheter to complete the patient’s infusion needs.