Peritoneal Dialysis Volume Management Challenges And Solutions

On April 21, Professor Yao Li, a member of the Standing Committee of the Nephrology Branch of the Chinese Medical Association and director of the Department of Nephrology at the First Affiliated Hospital of China Medical University, spoke on the "Challenges and Solutions of Peritoneal Dialysis Volume Management" at the 10th West Lake Forum on New Progress in Nephrology Program”, sharing her experience and views.

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The serious problem of volume overload in peritoneal dialysis patients

Professor Yao Li said that too much water in the patient's body is called volume overload or hypervolemia, which is a common clinical serious problem in patients with end-stage renal disease. At present, more than half of peritoneal dialysis patients are in a state of volume overload. Volume overload can significantly increase the risk of cardiovascular events, increase the risk of failure of peritoneal dialysis techniques, and significantly increase the risk of death of patients. In recent years, international peritoneal dialysis guidelines/conferences have also continuously emphasized the importance of volume management in peritoneal dialysis patients. It can be seen that reasonable volume control is of great significance to peritoneal dialysis patients.

Assessment of capacity overload

The assessment of volume overload in peritoneal dialysis patients mainly involves two aspects: one is patient self-assessment, patients need to measure urine output, peritoneal dialysis volume, and body weight every day, and record them every day. ~3 months to go to the hospital for regular checkups; if volume overload is found, you need to go to the hospital immediately. The second is to be evaluated by medical staff. After the patient is admitted to the hospital, the medical staff needs to judge the volume status of the peritoneal dialysis patient through physical examination, imaging examination, biomarkers, and bioelectrical impedance. Among them, commonly used indicators for bioelectrical impedance assessment include excess water (OH value) and OH normalized by extracellular water.

01 Physical Examination

The physical examination mainly includes 4 aspects, specifically:

(1) Body weight and body mass index: Among all diagnostic indicators, body weight, and body mass index are important indicators for judging volume status. By establishing a target weight and monitoring body weight changes daily, volume changes can be assessed. It should be noted that the measured body weight should be the weight without dialysate in the abdomen, and the body weight needs to be measured at the same time and place every day, using the same weighing scale, wearing the same clothes, shoes, and socks, and recording it. However, this indicator is affected by factors such as nutritional status and has certain limitations.

(2) Blood pressure: When the blood pressure of a peritoneal dialysis patient suddenly rises and drug treatment is ineffective, it may be considered whether there is a state of volume overload, and treatment measures need to be taken as soon as possible.

(3) Edema: Edema is both a symptom and a measure of body weight. It can be divided into dominant edema and recessive edema. However, edema is not specific and can only be used to assess volume overload in peritoneal dialysis patients to a certain extent.

(4) Cardiopulmonary physical examination: mainly includes auscultation to detect signs of pulmonary edema and heart failure; cardiopulmonary auscultation is widely used due to the advantages of simple operation, low cost, and repeatable monitoring; moist rales are a common sign of pulmonary edema, and are very important for diagnosis. Pulmonary edema has strong specificity, but poor sensitivity, which may lead to misdiagnosis.

In short, through the above physical examination, when a patient experiences weight gain in a short period, new-onset hypertension, sudden uncontrollable blood pressure, or symptoms such as pulmonary edema, it is necessary to consider whether the patient has a state of volume overload.

02 Imaging examination

Imaging evaluations are commonly used clinically for diagnostic methods such as chest X-ray, cardiothoracic ultrasound, vascular ultrasound, and lung ultrasound, all of which can assess whether a patient has volume overload to a certain extent.

03 Biomarker inspection

Currently, there is no accurate and specific biomarker for assessing volume overload. Studies have shown that NT-proBNP is currently positively correlated with volume overload, and is one of the biomarkers for assessing volume overload in peritoneal dialysis patients.

04 Bioelectrical Impedance

Bioelectrical impedance is a practical, convenient, and non-invasive volume status assessment tool that can identify clinically unrecognized volume overload and is considered to be one of the sensitive indicators for judging volume overload. The content of the assessment includes overall water, intracellular water, extracellular water, OH, and other indicators such as muscle water. OH >1.1 L or OH/extracellular water >7% may suggest volume overload, or extracellular water/total water >0.4 should also be considered for volume overload. However, bioelectrical impedance also has certain limitations, such as it may be inaccurate in severely overloaded patients, cannot distinguish between intravascular and extravascular volume excess, and other problems.

In short, at present, the volume load assessment methods currently in clinical use have their advantages and disadvantages. In clinical work, it is necessary to combine the respective conditions of the hospital and the clinical symptoms of the patients for comprehensive assessment and use, to achieve a clear diagnosis, precise treatment, and guarantee the patient's life and health.

Reason Analysis of Capacity Overload

After judging the volume overload, it is necessary to clarify the cause or risk factors that lead to the occurrence of volume overload. Through the intervention of common risk factors, the occurrence of excess overload can be prevented in advance. At present, the common reasons are an imbalance of intake and output, unreasonable dialysis prescription, malnutrition, poor compliance, peritoneal failure, and peritoneal dialysis complications.

(1) Imbalance of intake and output: maintaining an equal volume of body fluid is the most important goal of peritoneal dialysis treatment. Therefore, strictly limiting water and sodium intake is the key to the volume management of peritoneal dialysis patients. The formula for calculating the intake of peritoneal dialysis patients is: intake = ultrafiltration Excessive sodium intake is the main reason for the expansion of extracellular volume in chronic dialysis patients. The ideal sodium intake should be kept at the total sodium clearance level. Therefore, it is necessary to pay attention to the balance of intake and output for these patients.

(2) Poor nutritional status: most patients with peritoneal dialysis have poor nutritional status, and their energy intake is reduced. At the same time, there are amino acid small molecule protein loss and inflammatory states during the dialysis process. Malnutrition often occurs, which will lead to the immune function of the patient. Decrease, leading to inflammation, water, and sodium retention in patients. Therefore, comprehensive management is an important means for these patients.

(3) Poor treatment compliance: Strict compliance with dialysis prescriptions is the key to successful dialysis, but patients' poor compliance and non-compliance with dialysis prescriptions for dialysis are important reasons for volume overload. Therefore, medical staff should take the initiative to follow up and remind patients to treat on time.

In addition, unreasonable dialysis prescriptions, peritonitis, etc. will lead to volume overload in patients. Therefore, it is very important to develop an individualized treatment plan and prevent the development of early peritonitis.

Treatment of Volume Overload

(1) Control intake, increase output, and strengthen monitoring: control intake, strengthen body fluid management, that is, strengthen patient education, formulate a reasonable drinking water plan, and remind patients to consume less sodium salt and high-water-rich fruits and vegetables, etc., strengthen monitoring and increase output.

(2) Actively prevent and correct malnutrition: mainly including education for patients, diet adjustment, drug treatment, adequate dialysis, and improvement of the micro-inflammatory state.

(3) Strict monitoring, strengthening patient education, and improving patient compliance: including establishing a strict follow-up and monitoring system to detect compliance problems early; strengthening patient education, and improving capacity management awareness.

(4) Adjust the dialysis prescription in time according to the characteristics of the patient's peritoneum, residual renal function, and personal circumstances.

(5) Adjust the dialysis method and dialysate according to the patient's peritoneal function: including using automated peritoneal dialysis and switching to glucose dialysate.

(6) Actively prevent and treat peritonitis.

(7) Early identification of mechanical factors and active treatment: such as catheter access problems.

Summary

Finally, Professor Yao Li summarized 5 points:

(1) Volume overload is a common problem in peritoneal dialysis patients, and it hurts the prognosis of patients. 

(2) At present, there is a lack of a simple index to evaluate the volume status of peritoneal dialysis patients. According to the patient's condition and technical accessibility, the volume status of peritoneal dialysis patients can be comprehensively evaluated through physical examination, imaging, biomarkers, and bioelectrical impedance. 

(3) There are many reasons for volume overload, such as an imbalance of intake and output, poor nutritional status, poor treatment compliance, unreasonable dialysis prescription, peritoneal dialysis-related complications, and peritoneal failure, etc., which should be differentiated clinically.

(4) For patients with volume overload, it is recommended to take targeted measures according to the cause, strengthen patient education, and adjust reasonable dialysis prescriptions to improve volume overload. 

(5) The new peritoneal dialysis technology and peritoneal dialysis solution have significant therapeutic advantages in improving volume state overload.

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