Intravenous (IV) therapy is a standard procedure in medical care, allowing fluids and medications to be delivered directly into a patient’s bloodstream. When continuous fluid administration is not required, but immediate access to the vein must be maintained, healthcare providers use a specialized method. This practice is known as a Keep Vein Open, or KVO, infusion. The KVO rate is a deliberate, slow trickle of fluid used to ensure the IV line remains functional and ready for use at any moment.
Defining Keep Vein Open
The KVO infusion is designed to maintain the patency of an intravenous catheter, preventing the line from clotting or becoming blocked. This is achieved by administering fluid at a minimal flow rate, significantly slower than typical hydration or medication rates. KVO flow rates are generally set between 5 and 15 milliliters per hour, though rates up to 20 milliliters per hour may be used depending on the patient and catheter type.
The small volume of fluid prevents the patient’s blood from backing up into the catheter tip and forming a clot. This low, steady flow reduces the risk of stasis and occlusion, which would otherwise require the IV site to be replaced. Standard infusion rates for fluid maintenance range from 75 to 150 milliliters per hour or higher for rapid boluses. The KVO rate ensures readiness without administering excessive fluid.
Clinical Scenarios Requiring KVO
KVO infusion ensures rapid vascular access for patients who may require urgent medical intervention. This practice is frequently used in operating rooms, allowing immediate administration of blood products or emergency medications during surgery. A patent IV line helps medical teams avoid delays that could compromise patient safety during a sudden change in condition.
KVO is also utilized for patients at high risk for rapid deterioration, such as those with potential for internal hemorrhage or anaphylactic shock. The ability to quickly infuse life-saving drugs or fluids without establishing a new IV line is crucial in these scenarios.
A KVO infusion is often ordered for patients requiring frequent, intermittent doses of IV medication, such as antibiotics or pain management drugs. The slow KVO drip keeps the line continuously functional between doses, eliminating the need to repeatedly flush the line with saline every few hours. This continuous flow prevents the internal lumen from occluding due to drug precipitation or clot formation, ensuring the next dose is delivered smoothly.
The Components of a KVO Setup
Setting up a KVO infusion requires specific equipment to ensure the slow, precise flow rate is maintained. The liquid used is typically an isotonic solution, such as Normal Saline (0.9% Sodium Chloride) or sometimes Dextrose. These solutions are compatible with most medications and have minimal impact on the body’s fluid balance.
The most important component is an electronic infusion pump, necessary to accurately control the minute volume of fluid being administered. Gravity-fed drips are too inconsistent and unreliable for such low flow rates, making the pump essential for precision. The IV tubing connects the fluid bag to the catheter and contains specialized segments that fit into the pump to regulate the flow. Access ports along the tubing allow for the injection of intermittent medications directly into the line without interrupting the KVO infusion.
Monitoring and Patient Safety
Continuous monitoring ensures the KVO infusion is effective and safe for the patient. Nurses regularly check the IV insertion site for localized complications. These include infiltration, where fluid leaks into the surrounding tissue causing swelling, and phlebitis, which is inflammation of the vein wall.
Phlebitis can present as redness, warmth, or tenderness along the vein pathway. Although the risk is low due to the minimal rate, monitoring for signs of fluid overload is important, especially in patients with heart or kidney conditions. Regular checks of the pump ensure the correct rate is maintained and that the line has not become occluded, which would cause an alarm to sound.