A drainage system in medicine is a device used to remove unwanted fluids, air, or other materials from a wound or body cavity. This intervention prevents the accumulation of substances that could interfere with healing or cause complications like infection or tissue compression. In modern healthcare, the closed drainage system has become the standard method for managing these fluids.
This technology is an advance in patient safety and recovery because it minimizes the risk of introducing external contaminants into the body. By keeping the internal environment sealed, a closed system helps control infection, a concern historically associated with earlier drainage techniques. Understanding how this sealed mechanism operates is fundamental to appreciating its importance during recovery.
Defining Closed Drainage Systems
A closed drainage system is defined by its air-tight seal, connecting the internal surgical site or body space to an external collection device. This sealed environment is the primary difference from older, open systems, such as a Penrose drain, which allow fluid to exit onto a dressing or into an unsealed container. The closed nature of the system prevents bacteria and other environmental pathogens from traveling backward, or retrograding, into the patient.
The system’s integrity is maintained throughout the entire process, from the insertion tube to the collection reservoir. This design ensures that the collected fluid is isolated and measurable, allowing healthcare providers to accurately monitor the patient’s output and healing progress. The principle of a closed system is to maintain a continuous, one-way flow of drainage away from the wound or cavity.
This continuous flow is achieved by utilizing a mechanism that creates a pressure gradient. By establishing a lower pressure inside the system compared to the body cavity, the system actively draws out fluid and air. The goal is to remove materials and eliminate “dead space,” which is any pocket beneath the skin where fluid could accumulate and delay healing.
Essential Components and Mechanism
A typical closed drainage system is composed of three interconnected parts that maintain the necessary pressure gradient. The first component is the drain tube or catheter, a flexible, perforated tube placed directly into the area requiring drainage. This tube is made of medical-grade materials like silicone, designed to minimize tissue response and irritation.
The second part is the collection reservoir, a sterile container that receives and holds the drained fluid. This reservoir is manipulated to generate the negative pressure, or vacuum, needed for active drainage. In systems like the Jackson-Pratt (JP) or Hemovac, the reservoir is a compressible bulb or disc that is manually flattened before being sealed.
Once sealed, the elastic material of the reservoir attempts to return to its original shape, creating a vacuum inside the system. This negative pressure gently pulls fluid through the drain tube and into the collection chamber. For larger volumes or complex applications like chest drainage, the reservoir might be a specialized chamber connected to a mechanical suction unit or a water seal system to provide controlled and continuous vacuum.
Common Applications in Healthcare
Closed drainage systems are categorized by their specific application, with two recognizable types being wound drainage and thoracic drainage. Wound drainage systems, such as the Hemovac or Jackson-Pratt, are commonly used following major surgeries like mastectomy, orthopedic procedures, or extensive abdominal operations. Their purpose is to remove blood and serous fluid, preventing the formation of a seroma or hematoma—collections of fluid that can compress tissues and potentially become infected.
Thoracic drainage systems, known as chest tubes, are employed when air or fluid needs to be removed from the pleural space surrounding the lungs. Conditions like a pneumothorax (air) or hemothorax (blood) disrupt the natural negative pressure of the chest cavity, causing the lung to collapse. The chest tube, connected to a specialized collection unit, uses controlled suction or a water seal to restore the negative pressure, allowing the lung to re-expand and function normally.
Another application is managing urinary output, where indwelling urinary catheters are connected to a sealed collection bag. The use of a closed system in this context is standard practice to significantly reduce the risk of catheter-associated urinary tract infections. Regardless of the location, each closed system is engineered to control pressure and minimize the risk of infection, directly supporting the body’s healing environment.