A 3-way stopcock is a small, valve-like device that typically consists of a rotating handle and three ports. These ports are labeled as ‘I,’ ‘O,’ and ‘II,’ representing the input, output, and side port, respectively. The device is commonly made of transparent or translucent materials, allowing for easy visualization of fluid flow. Here’s how it works:

1. Rotating Handle: The central component of the 3-way stopcock, the rotating handle, is responsible for directing the flow of fluids between the ports. Its design allows for precise control, enabling healthcare professionals to manage fluid administration or withdrawal accurately.

2. Ports:

   • Input Port (I): Fluid enters through this port.
   • Output Port (O): Fluid exits from this port.
   • Side Port (II): An additional opening that allows for secondary connections or the attachment of monitoring devices.

Applications in Medical Settings:

1. Intravenous (IV) Therapy: 3-way stopcocks play a pivotal role in IV therapy, providing a means to administer multiple medications or fluids through a single access point. The rotating handle allows for swift and controlled switching between different infusions, reducing the need for multiple punctures.
2. Blood Transfusions: In blood transfusions, 3-way stopcocks enable seamless switching between various blood components, ensuring a smooth and continuous flow without the need for multiple setups.
3. Arterial Blood Gas Sampling: The side port of the 3-way stopcock can be utilized to connect to a syringe, simplifying the process of drawing arterial blood samples for analysis.