SLED Dialysis: A Hybrid Approach to Kidney Failure Treatment

What is SLED?

SLED is a hybrid form of dialysis that can work as an alternative to CRRT or conventional intermittent haemodialysis. SLED dialysis is typically delivered via haemodialysis technology and allows for gradual fluid removal with less haemodynamic perturbation. SLED is a standard treatment procedure for patients suffering from acute kidney injury (AKI).

SLED dialysis is feasible for critically ill patients and has been shown to provide haemodynamic control and solute removal. Moreover, SLED is beneficial for patients to treat haemodynamically unstable and critically ill pediatric patients with chronic kidney disease (CKD).
With a better understanding of SLED dialysis, let’s explore the parameters that make SLED a favourable choice for doctors.

When Do Doctors Prefer SLED for Kidney Support?

Doctors may prefer SLED when a patient with AKI exhibits haemodynamic instability. A study suggests that in SLED groups, the 30-day mortality rate is 38.4%, compared with 57.7% in the CRRT group ². SLED dialysis bridges the gap between continuous and intermittent therapies offering better fluid removal and better tolerance.

Here are some of the factors that make SLED a popular choice among doctors:

• SLED is a form of intermittent haemodialysis; however, the intensity and duration are greater than those of traditional haemodialysis. A typical SLED dialysis session is between 6 and 12 hours; however, it is shorter than a CRRT session.
• SLED uses a lower blood flow rate, typically 150-250 mL/min, which is safer for patients and reduces the chances of fluctuating blood pressure.
• Doctors prefer this technique for patients with lower blood pressure and chronic hypotension, and it is therefore a prominent SLED dialysis indication.
• Healthcare professionals prefer this procedure due to the overall process’s feasibility. Moreover, the intermittent sessions os SLED dialysis allow doctors to monitor patients easily and with minimal resource utilisation.

Let’s now understand the SLED process step by step for a comprehensive understanding.

Stepwise Working Procedure for SLED

SLED is a hybrid method and provides extended dialysis sessions that are safe and effective for patients with chronic renal diseases.
Here are the steps that showcase the working procedure for SLED:

Step 1: Preparation

A dialysis machine first connects to the patient via the vascular access site. The system uses a dialyser that filters blood for an extended period, typically 6 hours or more.

Step 2: Regulation of Blood Flow

SLED uses a slower blood flow rate, which is critical to minimise haemodynamic instability; at this stage, the rate is 150-250 mL/min.

Step 3: Removal of Dialysate and fluids:

The dialysate flow is slower at this stage, which ensures the gradual removal of excess toxins and fluids. It reduces the overall stress within patients with cardiovascular conditions.

Step 4: Administration of Anticoagulants

The next step is to use anticoagulants, depending on the patient’s condition. The use of Mild anticoagulation is a common practice during SLED dialysis to prevent clotting in the dialysis circuit.

Step 5: Monitoring and Assessments

Continuous patient assessment during dialysis is vital, especially for patients with heart conditions and unstable blood pressure. Regular assessments help adjust parameters and address patients’ changing needs.

Next, let’s understand the benefits of SLED for patients suffering from kidney disorders and long-term renal discomfort.

Clinical Benefits of SLED for Unstable Patients

Unlike CRRT vs SLED, which differ in duration and intensity, SLED ensures adequate haemodynamic stability with fewer interventions.

Here are some SLED dialysis advantages which are critical for renal-unstable patients:

• Haemodynamic Stability: The gradual, slower nature of fluid removal makes it vital for patients in critical condition. Moreover, SLED is beneficial for patients having haemodynamic instability.
• Longer Duration: The time duration for SLED dialysis is longer than that of traditional dialysis. However, the controlled flow of the process allows for the gradual removal of fluid and toxins.
• Better Tolerance: Patients who are unable to tolerate traditional haemodialysis or CRRT due to rapid shifts in electrolytes can benefit from SLED. Moreover, it reduces the overall risk of major health complications such as arrhythmias, fluid imbalances, and more.
• Less Intensive than CRRT: SLED’s requirements are lower than those of other dialysis processes and are feasible for hospitals, as it requires fewer manual interventions than CRRT.

Now, let’s understand how SLED differs from conventional dialysis through a comparative analysis.

How is SLED Different from Conventional Dialysis

SLED offers a balance between conventional haemodialysis and CRRT, unlike traditional dialysis. Additionally, SLED is slower to operate and is suited for patients with chronic kidney disorders.

Here’s a comparative difference between the two types of dialysis:

1. Duration and Frequency

• SLED: The process takes 6 to 12 hours, and the gradual approach helps achieve greater fluid and toxin removal.
• Conventional Dialysis: The process takes 3-5 hours and is generally performed three times a week, making it more intensive than SLED dialysis.

2. Blood Flow Rates

• SLED: The blood flow rates are typically between 150 and 250 mL/min. Making it a safer choice for the cardiovascular system.
• Conventional Dialysis: The process involves a high blood flow rate, usually between 300 and 500 mL/min, enabling steady filtration.

3. Haemodynamic Stability

• SLED: Blood pressures for patients remain stable during a SLED session and, therefore, are a critical element for patients having haemodynamic instability.
• Conventional Dialysis: The process involves rapid fluid removal, leading to instability and is therefore challenging for both patients and healthcare providers.

4. Anticoagulation Requirements

• SLED: The amount of anticoagulants is lower in this technique, primarily due to the slower blood flow rates, which reduces the risk of bleeding.
• Conventional Dialysis: The dialysis process may involve the use of an anticoagulant; however, for a shorter time than that of SLED and CRRT.

Also read: How to Manage Chronic Kidney Disease: A Guide from Kidney Specialists.