Poor or slow inflow or outflow in Peritoneal Dialysis – 9 Important causes

What is Poor or slow inflow or outflow in Peritoneal Dialysis?

Slow Flow Peritoneal Dialysis

• Poor or slow inflow or outflow of Peritoneal Dialysis fluid is a problem that more frequently occurs during the initial break-in period of a Peritoneal Dialysis catheter.
• This condition also can occur at any time in the course of treatment.

What causes Slow Flow Peritoneal Dialysis?

• The most common cause of Slow Flow Peritoneal Dialysis is constipation.
• It is so very important to prevent constipation after placing the Peritoneal Dialysis catheter
• Not moving your bowels enough can lead to problems with catheter function
• These problems with catheter function are slow drain time or problems with completely draining the belly.

Slow flow during peritoneal dialysis can have various causes, and it is essential to identify and address the underlying reason to ensure proper dialysis efficiency.

Poor or slow inflow or outflow in peritoneal dialysis can be caused by various factors, including:

1. Catheter Dysfunction/Catheter-related issues : The peritoneal dialysis catheter may become partially or completely blocked, kinked, or displaced, leading to reduced flow of dialysate into and out of the peritoneal cavity. The peritoneal dialysis catheter may become kinked, twisted, or blocked, leading to poor or slow flow. Catheter dysfunction can occur due to improper catheter placement, catheter migration, or catheter obstruction by fibrin, blood clots, or other debris.
2. Catheter Malposition: Improper catheter placement can result in poor flow rates during dialysis exchanges.
3. Omental Wrap: The omentum, a fold of the peritoneum, may wrap around the catheter tip, hindering the flow of dialysate.
4. Peritoneal membrane issues/Peritoneal Adhesions: The peritoneal membrane may develop scarring, thickening, or adhesions, which can impede the flow of dialysis fluid during inflow or outflow. This can occur due to peritonitis (inflammation of the peritoneal membrane), long-term exposure to dialysis solutions, or other underlying conditions affecting the peritoneum. Scar tissue or adhesions in the peritoneal cavity can cause obstruction or restriction of dialysate flow.
5. Encapsulating Peritoneal Sclerosis (EPS): EPS is a rare but severe complication of long-term peritoneal dialysis, where the peritoneal membrane thickens and fibrosis occurs, leading to reduced flow and sometimes complete obstruction. This is a rare but serious complication of long-term peritoneal dialysis. It involves the formation of excessive fibrous tissue around the peritoneal membrane, leading to thickening and narrowing of the membrane. This can cause poor or slow inflow or outflow, along with other symptoms such as abdominal pain, weight loss, and bowel obstruction.
6. Infection: Peritonitis, an infection of the peritoneal cavity, can cause inflammation and thickening of the peritoneal membrane, affecting dialysate flow. Peritonitis, which is an infection of the peritoneal membrane, can cause inflammation and swelling, leading to poor or slow flow. Peritonitis requires prompt treatment with antibiotics to resolve the infection and restore normal flow.
7. Fibrin Clots: Formation of fibrin clots within the catheter or peritoneal cavity can obstruct the flow of dialysate.
8. Inadequate Peritoneal Dialysis Solution Volume: If the prescribed dialysate volume is not sufficient, it can lead to slow flow during exchanges.
9. Dehydration: Low fluid intake or dehydration can result in reduced flow during peritoneal dialysis.
10. Constipation: Severe constipation can cause compression on the peritoneal cavity, leading to decreased flow.
11. Abdominal surgery
12. Obesity
13. Anatomical abnormalities can also contribute to poor or slow inflow or outflow in peritoneal dialysis
14. Mechanical issues: There may be issues with the dialysis system itself, such as malfunctioning or improperly calibrated equipment, inadequate pressure in the dialysis fluid bags, or issues with the connection between the catheter and the tubing.

The medical team may need to do testing, imaging examinations, or clinical evaluations to look into the underlying cause of sluggish flow during peritoneal dialysis.

Depending on the exact cause, treatment options may include changing the dialysis prescription, clearing blockages, adjusting the catheter, or treating infections. For immediate evaluation and proper therapy, patients receiving peritoneal dialysis must notify their healthcare providers of any changes in dialysis flow or symptoms.

Conversely, unidirectional poor outflow suggests either of the following:

1. Malposition of the Peritoneal Dialysis catheter in a place where the Peritoneal Dialysis fluid cannot be drained (i.e., migration of the catheter out of the true pelvis).
2. Encumbrance of catheter drainage pores by tissue or viscera. Although the force of Peritoneal Dialysis fluid inflow can more easily push bowels engorged with stool, epiploic appendices, omental wraps, or adhesions aside, the negative pressure of outflow results in collapse of these organs and tissues on the draining catheter.

Poor flow on a Peritoneal Dialysis Exchange

• The ideal drain time of the fluid during peritoneal dialysis is around 10-20 minutes
• Usually the next bag should run through in less than 5 minutes.
• If it takes longer, this usually means that there is some constipation.
• Usually you can sort this out yourself, and the fluid will drain if you move into a different position.
• Bidirectional flow problems usually indicate obstruction of the catheter lumen by clot, fibrin, or a kink or bend in the catheter.

So, what should be done to address this?

• The immediate first step is to effectively clear the bowel of excessive stool.

What if this does not work?

• If this is not effective at resolving the problem, then other causes need to be investigated.
• Discernment as to whether the flow problem is bidirectional or unidirectional (only poor outflow) helps determine the cause of the problem.
• Usually the next bag should run through in less than 5 minutes.
• If it takes longer, this usually means that there is some constipation.
• Usually you can sort this out yourself, and the fluid will drain if you move into a different position.
• Bidirectional flow problems usually indicate obstruction of the catheter lumen by clot, fibrin, or a kink or bend in the catheter.
• Plain-film roentgenographic imaging of the abdomen provides diagnostic assistance in determining the presence of constipation or malposition or kinking of the Peritoneal Dialysis catheter.
• Catheters can be repositioned by trocar or laparoscopy.
• By exclusion, outflow occlusion not related to constipation is most likely related to adhesions, omental wrapping, or epiploic appendices, and would require surgical or laparoscopic intervention and correction.
• Injection of catheters with sterile contrast by radiology can facilitate diagnosis. Inability to resolve these issues with the existing or new Peritoneal Dialysis catheter would be an indication for transfer to HD.
• The presence of fibrin or blood occluding a Peritoneal Dialysis catheter at times can be signaled by the appearance of these substances in the Peritoneal Dialysis catheter or effluent.
• Heparin should be added in a concentration of 500 to 2000 U/L to each dialysate exchange and continued for at least 24 to 48 hours after the effluent is clear.
• A catheter obstructed with blood or fibrin can be treated with push–pull infusion of dialysate or sterile saline under moderate pressure with a 50-mL syringe.
• The procedure should be discontinued if the patient has any pain or cramping.
• Alternatively there are several anecdotal reports of success utilizing different regimens of tissue plasminogen activator (tPA) infused with sterile saline or sterile water into the Peritoneal Dialysis catheter.
• No controlled studies demonstrate the safety or efficacy of this methodology, however.

Patients with comorbid conditions tend to start HD after an acute illness and have high early mortality that is wrongly attributed to their HD modality.

Patients receiving peritoneal dialysis were 1.5 times as likely to rate their dialysis care excellent overall than were patients receiving hemodialysis.

This was true for patients with different demographic and health status characteristics.

In addition, peritoneal dialysis patients more often rated their care for many specific aspects more highly than hemodialysis patients did.

These exchanges can either be performed manually (continuous ambulatory or CAPD), or using a machine (automated or APD). 

There are two ways to perform peritoneal dialysis, Continuous-Cycler Assisted Peritoneal Dialysis (CCPD) and Continuous Ambulatory Peritoneal Dialysis (CAPD), which are outlined below.  

Continuous Cycling Peritoneal Dialysis

Continuous cycling peritoneal dialysis (CCPD) is a form of peritoneal dialysis (PD) that is used to treat end-stage renal disease (ESRD). It is a home-based dialysis modality that allows for regular and automated exchange of dialysis fluid in the peritoneal cavity. Here are some key points about CCPD:

1. Procedure: CCPD involves using a machine called a cycler that automatically performs a series of dialysis exchanges while the person sleeps. The cycler controls the timing and flow of the dialysis solution, which is pumped into and out of the peritoneal cavity through a catheter.
2. Exchange process: CCPD typically consists of multiple cycles during the night, with each cycle involving a series of fills, dwells, and drains. The dialysis solution (dialysate) is infused into the peritoneal cavity, where it stays for a prescribed dwell time to facilitate the removal of waste products and excess fluids. After the dwell time, the used dialysate is drained out of the peritoneal cavity and replaced with fresh dialysate.
3. Benefits: CCPD offers several advantages, including greater flexibility and independence for individuals undergoing peritoneal dialysis. It allows for overnight dialysis, minimizing the impact on daily activities and providing more time for freedom during the day. CCPD can also offer better clearance of waste products and fluid removal compared to other forms of peritoneal dialysis.
4. Considerations: CCPD requires proper training and education to ensure that individuals can perform the exchanges safely and effectively. It also requires a suitable home environment, including space for the cycler machine and supplies, as well as regular follow-up with healthcare providers to monitor treatment efficacy and address any concerns or complications.
5. Risks and complications: As with any form of peritoneal dialysis, CCPD carries certain risks and potential complications, including infection, catheter-related issues, fluid imbalances, and hernias. Regular monitoring and adherence to proper hygiene practices are important to minimize these risks.

Continuous cycling peritoneal dialysis (CCPD) is a method of performing peritoneal dialysis exchanges using a machine called a cycler during your sleeping hours.

Generally, three to five exchanges are done each night. There is an option to drain directly to your toilet or a drain or into drain bags that you would empty when you wake up in the morning.

This program frees up your daytime hours. Each nightly session lasts at least eight to ten hours.  

Some programs leave you with a set amount of dialysate at the end of your treatment that will dwell during the day.

Continuous cyclic peritoneal dialysis (CCPD) is based on the concept of continuous equilibration dialysis proposed by Popovich et al., but incorporates the automation provided by a cycler.

CCPD uses multiple short nocturnal exchanges, while the patient is connected to the cycler and a long diurnal exchange with the patient ambulatory.

Thus, it is a virtual reversal of the CAPD schedule.

The primary objective of CCPD is to provide automated, continuous peritoneal dialysis in a convenient manner, freeing the daytime hours from all procedures. The secondary goal is to reduce the rate of peritonitis.

Continuous ambulatory peritoneal dialysis (CAPD)

Continuous Ambulatory Peritoneal Dialysis (CAPD) is a type of dialysis used to treat end-stage kidney disease (ESKD) or chronic kidney failure. Unlike hemodialysis, which is typically performed in a dialysis center, CAPD allows patients to perform dialysis at home, providing greater flexibility and independence.

Continuous ambulatory peritoneal dialysis (CAPD) is a method of performing peritoneal dialysis exchanges using gravity to drain and fill your peritoneal membrane with solutions four times each day, spaced evenly throughout the day. It usually takes about 30 minutes to complete an exchange.

The exchanges can be done in a clean environment, and you are free to be active during each dwell.

Continuous ambulatory peritoneal dialysis (CAPD) is used to treat end-stage renal failure in an increasing number of patients.

CAPD has an advantage over hemodialysis in that it allows patients greater freedom to perform daily activities; it also provides other clinical benefits.

However, the long-term effectiveness of CAPD is limited by complications, which have various causes.

Complications with an infectious cause include bacterial peritonitis, tuberculous peritonitis, and infections of the catheter exit site and tunnel.

Noninfectious complications include catheter dysfunction, dialysate leakage, hernias, and sclerosing encapsulating peritonitis.

Many imaging modalities—radiography, ultrasonography, peritoneal scintigraphy, computed tomography (CT), and magnetic resonance (MR) imaging—are useful for characterizing these complications. CT peritoneography and MR peritoneography are techniques specifically suited to this purpose.

Imaging plays a critical role in ensuring that complications are detected early and managed appropriately.

Continuous ambulatory peritoneal dialysis (CAPD) is used to treat end-stage renal failure in an increasing number of patients.

CAPD has an advantage over hemodialysis in that it allows patients greater freedom to perform daily activities; it also provides other clinical benefits.

However, the long-term effectiveness of CAPD is limited by complications, which have various causes.

Complications with an infectious cause include bacterial peritonitis, tuberculous peritonitis, and infections of the catheter exit site and tunnel.

Noninfectious complications include catheter dysfunction, dialysate leakage, hernias, and sclerosing encapsulating peritonitis.

Many imaging modalities-radiography, ultrasonography, peritoneal scintigraphy, computed tomography (CT), and magnetic resonance (MR) imaging-are useful for characterizing these complications. CT peritoneography and MR peritoneography are techniques specifically suited to this purpose.

Imaging plays a critical role in ensuring that complications are detected early and managed appropriately.

Despite the evidence in favor of Peritoneal Dialysis, there is still a growing concern about Peritoneal Dialysis technique failure, which is estimated to happen in about 40% of patients in the first year of Peritoneal Dialysis and is usually caused by recurrent or refractory peritonitis, ultrafiltration failure, and inadequate dialysis.

This therapy evolved over the past 5 decades and proved to be a viable treatment option improving the life of millions of people since its introduction to clinical practice.

It provides a similar metabolic control and patient survival in comparison to hemodialysis.

Peritoneal Dialysis is a patient centric KRT that can be performed at home and has favorable attributes of continuous filtration via actively washing the peritoneal cavity with dialysate fluid.

After the placement of a catheter into the peritoneal cavity under either general or local anaesthetic, the patient is instructed how to perform dialysis exchanges during which dialysate is instilled into the peritoneal cavity.

Starting dialysis with a Peritoneal Dialysis Catheter is preferable to an HDC in terms of patient morbidity, mortality, and cost.

It has also been shown in large observational retrospective studies that there is a survival advantage for PD over HD in the first 1 to 3 years of dialysis.

The 2013 Annual Data Report from the United States Renal Data System also shows a significantly improved adjusted probability of 5-year survival with PD compared to HD.

This early survival, for the most part, may be explained by selection bias because healthier patients may be more likely to choose PD as their modality.

Here’s how CAPD works:

1. Catheter Placement: A soft, flexible catheter is surgically inserted into the peritoneal cavity, which is the space surrounding the abdominal organs. The catheter serves as the access point for the dialysis solution.
2. Dialysis Solution: A sterile dialysis solution (dialysate) is introduced into the peritoneal cavity through the catheter. The dialysate contains a specific concentration of electrolytes and glucose.
3. Peritoneal Membrane and Exchange: The peritoneal membrane acts as a natural filter. As the dialysate fills the peritoneal cavity, waste products, excess fluids, and toxins diffuse across the membrane from the blood vessels into the dialysate. This process is called diffusion. After a prescribed dwell time (usually several hours), the used dialysate is drained out through the catheter.
4. Exchange Cycles: The process of filling, dwelling, and draining the dialysate is repeated multiple times a day, typically four to six exchanges per day. Each exchange is manually performed by the patient or a caregiver.

Continuous Ambulatory Peritoneal Dialysis (CAPD) offers several benefits as a renal replacement therapy for individuals with end-stage renal disease (ESRD). Some of the advantages include:

1. Flexibility and Independence: CAPD allows patients to perform dialysis treatments at home, giving them more control over their schedule. This method enables individuals to continue with their daily activities without being tethered to a dialysis center.
2. Fewer Dietary Restrictions: Compared to hemodialysis, CAPD may offer fewer dietary restrictions since it is a continuous process that occurs daily or several times a day. This can provide greater freedom in dietary choices.
3. Less Strict Fluid Restriction: CAPD can offer more liberal fluid intake compared to hemodialysis. As the dialysis occurs more frequently, there might be less need for strict fluid restriction between treatments.
4. Gentler on Cardiovascular System: Since CAPD is a continuous process, it can provide a more gradual and consistent removal of waste products and excess fluid, which can be gentler on the cardiovascular system compared to the rapid changes in fluid levels experienced in hemodialysis.
5. Preservation of Residual Kidney Function: Some studies suggest that CAPD may help preserve residual kidney function better than hemodialysis.
6. Lower Need for Vascular Access: Unlike hemodialysis, which requires vascular access (such as a fistula or catheter), CAPD utilizes the peritoneal membrane for dialysis, reducing the need for vascular access-related complications.
7. Decreased Requirement for Blood Thinners: CAPD does not require anticoagulants or blood thinners commonly used in hemodialysis, reducing the risk of bleeding complications.
8. Lower Cost and Utilization of Resources: CAPD, being a home-based therapy, may reduce healthcare costs associated with frequent visits to a dialysis center.

However, it’s important to note that the choice of dialysis modality depends on various factors, including the patient’s medical condition, lifestyle, preference, and the guidance of healthcare professionals. Each type of dialysis has its own advantages and considerations, and the best choice is often determined through consultation with a nephrologist or healthcare team based on individual needs and circumstances.