An intravenous (IV) line is a thin tube inserted into a vein to deliver fluids, medications, or blood directly into the bloodstream. Small air bubbles traveling with the liquid are common and typically absorbed harmlessly by the body. However, a larger volume of air entering the vein poses a serious medical risk. Understanding how to manage air in the tubing is paramount to patient safety, requiring immediate action when a significant air pocket is observed.
Understanding the Risk of Air in IV Lines
The primary danger associated with air in an IV line is a venous air embolism (VAE), where a large volume of air travels to the heart and lungs. This air can obstruct blood flow by creating an “air lock” within the right ventricle or the pulmonary artery. This blockage prevents deoxygenated blood from reaching the lungs for oxygenation, leading to circulatory collapse and acute right ventricular failure.
The volume of air causing serious harm depends on the rate of entry and the patient’s underlying health. While the body can tolerate small amounts, significant complications can arise with as little as 20 milliliters (mL) of air rapidly infused into the venous system. Fatal outcomes have been reported with volumes as low as 10 mL, though the risk increases substantially with volumes of 50 mL or more in adults.
Immediate Techniques for Removing Air Bubbles
When a noticeable air bubble is discovered in a running IV line, immediately stop the infusion and clamp the tubing closest to the patient. The most common method to clear the line is priming, which uses the IV fluid itself to push the air out. To perform this, hold the tubing vertically with the air bubble positioned below the drip chamber and above the distal end.
Slowly open the roller clamp, allowing the fluid to rush down the tubing and push the air bubble out through the end cap or an injection port. For small, stubborn bubbles, gently flick the tubing with your finger to help the tiny air pockets consolidate into a single, larger bubble. This tapping encourages the bubble to migrate upward toward the drip chamber or downward toward the exit port.
Another technique, often used for bubbles near a side port or access hub, involves the use of a sterile syringe. After thoroughly cleaning the access port, attach the syringe to the injection port closest to the air bubble, and gently withdraw the air. This aspiration method allows for the removal of air without losing a large volume of the infusion fluid. However, careful technique is required to avoid introducing contamination or adding air from the syringe. After removing the air, the entire length of the tubing must be re-inspected to confirm it is clear before resuming the infusion.
Preventing Air from Entering the Line During Setup and Use
The most effective strategy for managing air in an IV line is preventing its entry through careful setup procedures. Priming the tubing is performed before connecting the line to the patient. This involves allowing the IV fluid to completely fill the entire length of the administration set, ensuring all initial air inside the new tubing is flushed out and replaced with fluid.
When spiking a new bag of fluid, the drip chamber should be partially filled (typically one-third to one-half full) by gently squeezing it before the rest of the line is primed. This initial fluid barrier prevents air from the bag from entering the tubing as the fluid flows. Allowing the IV fluid bag to run completely empty is a significant cause of air entry into a running line.
To prevent air entry, the fluid level must be monitored closely. The roller clamp should always be closed before the bag runs dry or before changing the bag. Additionally, all connections, such as luer locks and injection ports, must be checked to ensure they are tight and fully sealed. A loose connection creates a pathway for outside air to be pulled into the system, especially when intravenous pressure is low.
Recognizing and Responding to Air Embolism Symptoms
Despite all precautions, it is important to know the signs of a full air embolism, as this is a medical emergency requiring immediate action. Symptoms often occur suddenly and can include acute shortness of breath, chest pain, and a rapid drop in blood pressure. The patient may also exhibit confusion, dizziness, or a bluish discoloration of the skin (cyanosis) due to the lack of oxygenated blood.
If a venous air embolism is suspected, the IV line must be immediately clamped to stop further air from entering the circulatory system. The patient should then be quickly placed on their left side with the head tilted down, known as the left lateral Trendelenburg position. This positioning is designed to trap the air bubble in the right side of the heart, preventing it from traveling into the pulmonary outflow tract. This maneuver helps maintain blood flow until medical help arrives. The patient should be given high-flow oxygen, and emergency medical services must be contacted immediately, as definitive care and hemodynamic support will be required.