What to do with peritoneal edema

The human body has a certain amount of fluid capacity, which needs to be kept balanced at all times to maintain a good physical condition. Peritoneal edema will cause a certain amount of pressure on the body, and volume overload can easily cause high blood pressure. Usually, excessive water and salt intake, reduced water and salt clearance, and the emergence of new complications are the causes of peritoneal edema. Appropriate treatment methods need to be adopted and medical treatment should be sought in a timely manner.

1. Peritoneal edema

Volume status refers to the body's fluid capacity. A good volume status depends on the balance of fluid inflow and outflow. Edema is an important sign of volume overload. During peritoneal dialysis, volume overload can easily cause hypertension, which can induce or aggravate cardiovascular complications such as left ventricular hypertrophy and congestive heart failure in peritoneal dialysis patients. Since peritoneal dialysis is performed at home, the judgment of water balance needs to be made by the patients themselves. The early symptoms of water retention are relatively hidden, and there may be no symptoms of limb edema, or only high blood pressure, which can be easily overlooked.

1. Common causes of edema

(1) Excessive water and salt intake: Peritoneal dialysis itself has a low sodium clearance capacity, especially when the patient has fluid retention. Many patients often cannot control their water and salt intake well, leading to edema due to thirst, difficulty in changing their previous living habits, or insufficient awareness of the importance of controlling fluids. Once edema occurs, it is often difficult to correct.

(2) Decreased water and salt clearance: As the duration of peritoneal dialysis treatment increases, the patient's residual renal function gradually decreases or is lost. Even if the patient's peritoneal function does not change, total water clearance will decrease due to the decrease in residual renal function. On the other hand, changes in peritoneal transport function can lead to reduced water clearance. In addition, the increased lymphatic return and lymphatic reabsorption lead to volume overload and edema in patients.

(3) The emergence of new complications: such as heart failure or worsening of existing heart disease, hypoalbuminemia, mechanical or anatomical complications, etc., which reduce the amount of peritoneal dialysis ultrafiltration.

(4) Age: Compared with the proportion of body fluid to body weight in normal adults (60% for men and 55% for women), the body fluid of the elderly is only 45% of their body weight. The reduction in body fluid in the elderly is mainly due to cell dehydration and shrinkage, a decrease in intracellular fluid, and a relative increase in extracellular fluid, which makes them prone to subtle edema. Therefore, elderly peritoneal dialysis patients are more likely to be in a state of inapparent edema, and sometimes it is inaccurate to judge their volume status based solely on clinical symptoms and signs, and physical and chemical examinations are needed.

2. How to evaluate edema

(1) Clinical assessment: Review the patient's medical history to understand whether the patient has chest tightness or shortness of breath, whether there is new or worsening cardiovascular disease, whether the patient is intolerant of the current dialysis prescription, whether the patient's water and salt intake has increased, and whether the patient's urine output has decreased. Blood pressure is an important indicator of the body's volume load status. Especially when blood pressure fails to return to normal after restricting water and salt intake and increasing peritoneal dialysis ultrafiltration, it further indicates the existence of volume load.

(2) Laboratory tests: In addition to clinical evaluation, some laboratory tests can also be performed to help determine the cause of edema, such as B-type natriuretic peptide (BNP), cardiac ultrasound, bioimpedance analysis (BIA), etc. However, the above are not the gold standard for assessing the body's volume status, so doctors need to make a comprehensive assessment based on the patient's condition.

3. How can peritoneal dialysis patients avoid edema?

(1) Record daily urine volume and ultrafiltration volume, regularly check volume load-related indicators, and limit water intake based on urine volume.

(2) Regularly evaluate peritoneal function (PET) and adjust the dialysis prescription in a timely manner according to the type of peritoneal transport to maintain an appropriate peritoneal dialysis ultrafiltration volume.

(3) For patients who have developed edema, the cause should be actively investigated and water and salt intake should be restricted. For patients with residual renal function, diuretics can be used under the guidance of a doctor, high-concentration glucose dialysis fluid can be used as appropriate, and automated peritoneal dialysis can be switched if necessary. Diabetic patients should strictly control their blood sugar.

(4) Pay attention to protecting residual renal function, avoid using nephrotoxic drugs, and avoid dehydration.

(5) Prevent and treat peritonitis and change fluids in strict accordance with operating procedures.

4. Methods to limit water and salt intake

(1) Control salt intake: Excessive salt intake can lead to water retention. The daily salt intake should be less than 3g. Avoid foods with high salt content, such as pickled products and soy sauce. Avoid using high-salt condiments such as chicken essence and MSG. You can choose low-sodium salt. Add more seasonings when cooking, such as green pepper, chili, pepper, Sichuan pepper, lemon, onion, ginger, garlic, onion, etc. to increase the flavor of food.

(2) Control water intake: Try to eat less foods with high water content and low nutritional value, such as vegetable soup and porridge. It is best to replace water and tea with foods with nutritional value such as milk and thick soup. Try to take medicine with liquid during meals. You can put the water you are allowed to drink each day in a fixed water cup and drink it in several times. Swallow it slowly in small sips instead of drinking it all at once. This is beneficial for water control and can accurately record the total daily water intake. In addition, the water temperature should be cool to avoid overheating in order to quench thirst. It is recommended to rinse your mouth with cool water and hold ice cubes (especially ice cubes made of lemonade), but do not swallow them. Brush your teeth regularly, keep toothpaste and toothbrush in the refrigerator, and eat sour foods and chew gum to keep your mouth moist.

(3) Keep good records of intake and output, especially snacks, vegetable soup, fruit, infusion volume, and water intake. Output includes dialysis ultrafiltration volume, urine volume, vomiting volume, and approximately 500-700 mL of insensible water loss per day (varies with the season). Keep the total daily intake and output roughly equal.