 A drip chamber is a device used to allow gas (such as air) to rise out from a fluid so that it is not passed downstream. It is commonly employed in delivery systems of intravenous therapy and acts to prevent air embolism. The use of a drip chamber also allows an estimate of the rate at which fluid is administered. For a fluid of a given viscosity, drips from a hole of known size will be of nearly identical volume, and the number of drips in a minute can be counted to gauge the rate of flow. In this instance the rate of flow is usually controlled by a clamp on the infusion tubing; this affects the resistance to flow. However, other sources of resistance (such as whether the vein is kinked or compressed by the patient's position) cannot be so directly controlled and a change in position may change the rate of flow leading to inadvertently rapid or slow infusion. Where this might be problematic an infusion pump can be used which gives a more accurate measurement of flow rate. Drip chambers can be classified into macro-drip (about 10 to 20 gtts/ml) and micro-drip (about 60 gtts/ml) based on their drop factors. For a given drip chamber (when the fluid drips from the hole into the chamber) drop factor means number of drops per ml of the IV fluid. Flow rate can be calculated with the help of the observations from the drip chamber and its drop factor. The unit of flow rate is gtts/min, where gtts means guttae (Latin plural noun meaning “drops”).
IV fluids are infused through flexible tubing, often called an infusion set or primary set. One end of plastic tubing is connected to the bag of fluid and the other is connected to the hub of the IV catheter. There may be a smaller extension tube between the infusion set and the IV catheter hub. This may be preferable to allow for patient mobility, temporarily independent of an IV pole. Although there are many IV tubing manufacturers, there are two general sizes: micro drip and macrodrip sets. Microdrip sets produce smaller drops and thus infuse fluid slower. Every microdrip set will deliver 60 drops (gtt) per milliliter. Macrodrip sets produce larger drops and thus infuse fluid at a greater rate. Macrodrip sets deliver between 10 and 15 gtt per milliliter. The infusion set may also have inline filters, stopcocks, access ports, and shutoff clamps. It is recommended that you familiarize yourself with each accessory your facility uses and how it works prior to using it, as there are some variations between manufacturers. The primary tubing will have several components attached, including a plastic spike, a drip chamber, a roller clamp, the syringe tip and locking collar, and medication ports. Since most IV fluids are available in plastic bags that collapse as the fluid infuses, it is unnecessary to vent the tubing. Therefore most primary tubing will likely be designed without a vent. If you are setting up fluids from a glass jar, you will need a primary set that contains a vent, located above the drip chamber. The vent will allow for fluid flow out of the bottle as air flows into the bottle. The following method of setting up your IV assembly should be followed to reduce the risk of introducing foreign bodies and air into the patient: To introduce fluid into the primary line, first close the roller clamp on the primary line. To do this, move the roller to the narrow end of the device, thus pinching the tubing closed. Next, remove the plastic or rubber caps from the fluid bag and the plastic spike located at the top of the tubing. Holding the fluid bag upside down, push the plastic spike into the exposed collar on the fluid bag until the top of the drip chamber cannot be advanced further into the fluid bag. Return the bag to its proper position and squeeze the drip chamber to fill it at least half way. Open the roller clamp to flush the fluid through the tubing by moving the roller to the wider end of the tubing, releasing pressure on the tubing and allowing fluid to flow freely past the clamp. Close the clamp again as soon as fluid comes out of the distal end of the tubing. The purpose of the the drip chamber is to visualize the rate at which fluid is infusing into the patient. If the chamber becomes overfilled to the point that drip rates cannot be visualized, simply invert the bag and drip chamber, squeeze the chamber once with your fingers and return the bag to its functional position. Reevaluate the flow of the IV infusion. You may need to re-position the patient’s extremity or flush the IV line with saline to resume flow. When the roller clamp is in the open position, it will slide easily up and down the tubing. If you are using the roller clamp to set a drip rate, move it closer to the drip chamber to make it easier for yourself to reach the clamp while counting drops. If the fluid flow is to be maximized, the roller clamp will be open, and may slide down the line. To secure the clamp in place, you may need to move the roller slightly closer to the narrow end of the device, providing just enough pressure against the tube to hold the clamp in place, without any restrictions to flow. At the distal end of the tubing is a male adapter that fits into the hub of the IV catheter. A “locking collar” screws over the hub to maintain the connection, and can be found on most primary sets. Many primary sets also contain access ports to be used for administering medications. A bolus of medication may be delivered from a syringe, or a secondary line leading to a “piggyback” fluid bag may also be connected here. Since most facilities uses needleless systems, the syringes and tubing will likely screw into the tubing port with luer lock technology. Since the secondary infusion usually contains a medication, an infusion device such as a mechanical pump is recommended to ensure that it infuses over the prescribed length of time. If a pump is not available, hang the secondary infusion higher than the primary infusion. There will often be a plastic hook or extension hanger available with the secondary tubing to accomplish this. When using the piggyback setup, both the primary and secondary lines should remain open. To regulate the flow rate of the secondary infusion, use the roller clamp on the primary tubing to adjust the flow rate. In this configuration, the secondary infusion will flow preferentially into the tubing, while the primary infusion will pause. When the secondary infusion is complete, the primary infusion will resume. If the rate of delivery of the primary infusion is different than that of the secondary infusion, you must remember to adjust the rate as soon as possible after the secondary infusion is complete. If your patient will receive subsequent doses of the secondary infusion, the bag and tubing may be left hanging. The secondary tubing can be reused for 72 to 96 hours, depending on your facility’s policy. If the assembly becomes contaminated, it must be discarded immediately. The CDC guidelines recommend that tubing be changed according to the following schedule:
The Intravenous Nurses Society (INS) recommendations should also be considered:
To be sure you are following the correct procedures, you should consult your facility’s policies. Previous Next |
What is the purpose of squeezing the IV tubing drip chamber and filling it half full of fluid?
Related Posts
Copyright © 2024 ShotOnMac Inc.
