When kidneys no longer function adequately, the body accumulates excess water, waste products, and toxins, a condition known as kidney failure. Dialysis serves as a life-sustaining treatment, artificially performing the filtering processes that healthy kidneys normally provide. It removes harmful substances and excess fluid from the blood, thereby helping to maintain the body’s internal balance.
What is SLEDD Dialysis?
SLEDD stands for Sustained Low-Efficiency Daily Dialysis. The term “sustained low-efficiency dialysis” (SLED) is also commonly used interchangeably with SLEDD.
This therapy is considered a hybrid modality, bridging the characteristics of traditional intermittent hemodialysis (IHD) and continuous renal replacement therapy (CRRT). While IHD typically involves shorter, more intense sessions, and CRRT provides continuous, slower filtration, SLEDD offers a middle-ground approach. It aims to provide a gentler yet prolonged treatment, making it a versatile option in managing kidney dysfunction, particularly in complex patient scenarios.
How SLEDD Dialysis Works
SLEDD therapy operates by circulating a patient’s blood through an external filter, called a dialyzer or “artificial kidney.” This process removes waste products and excess fluids.
The procedure typically lasts for an extended duration, ranging from 6 to 12 hours, which is longer than standard IHD but shorter than continuous CRRT. Sessions are often performed daily or every other day. This extended time frame allows for a more gradual removal of solutes and fluid, reducing rapid shifts in the body.
SLEDD utilizes conventional hemodialysis machines, but they are operated at reduced blood and dialysate flow rates. Blood flow rates generally range from 100 to 300 mL/min, and dialysate flow rates are typically between 100 and 350 mL/min. This slower, prolonged approach facilitates the removal of solutes primarily through diffusion, where waste molecules move from an area of high concentration in the blood to a lower concentration in the dialysate across a semi-permeable membrane.
When SLEDD Dialysis is Chosen
SLEDD dialysis is frequently selected for patients who require renal replacement therapy but may not tolerate the rapid fluid and solute shifts associated with standard intermittent hemodialysis. This often includes critically ill patients, especially those in intensive care units (ICUs). These patients may experience hemodynamic instability, meaning their blood pressure and circulation are difficult to maintain.
For individuals with acute kidney injury (AKI) and underlying conditions that make them vulnerable to sudden changes, SLEDD offers a gentler alternative. It helps prevent significant drops in blood pressure that can occur with faster dialysis methods. SLEDD can also be chosen as a transitional therapy for patients moving from continuous therapies to intermittent ones, or when standard IHD has been poorly tolerated.
Logistical factors also influence the choice of SLEDD. It can be a practical option in environments where continuous renal replacement therapy might be unavailable or cost-prohibitive. The ability to use standard hemodialysis equipment with modified settings makes SLEDD a flexible and accessible treatment for many facilities.
Key Aspects of SLEDD Therapy
SLEDD’s prolonged, low-efficiency nature contributes to improved hemodynamic stability for patients. The slower rates of fluid and solute removal help to prevent rapid changes in blood volume and electrolyte levels, which can be particularly beneficial for patients with cardiovascular compromise.
This modality provides effective solute clearance over its extended duration, removing waste products and toxins from the blood. While the hourly clearance rate is lower than IHD, the longer treatment time allows for a comparable overall removal of small and middle-sized molecules. SLEDD also facilitates better fluid management, enabling gradual ultrafiltration to achieve fluid balance without precipitating hypotension.
SLEDD offers flexibility in treatment scheduling. Sessions can be timed to allow for other patient activities, diagnostic procedures, or physical therapy, particularly if performed nocturnally. SLEDD is generally less costly than continuous renal replacement therapies, as it often utilizes standard hemodialysis machines and less expensive dialysate. While requiring more prolonged nursing attention compared to short IHD sessions, it can be less labor-intensive than continuous therapies that demand constant monitoring.