What is CPD (Citrate-Phosphate-Dextrose) intake in the context of intake/output?

CPD Intake in Intake/Output Monitoring

In the context of intake/output (I/O) monitoring, CPD intake refers to the volume of Citrate-Phosphate-Dextrose solution that enters a patient's system, particularly in patients undergoing Continuous Ambulatory Peritoneal Dialysis (CAPD).

Understanding CPD in Peritoneal Dialysis

• CPD (Citrate-Phosphate-Dextrose) is a solution used in peritoneal dialysis, particularly in CAPD, which serves as the dialysate fluid instilled into the peritoneal cavity 1
• For CAPD patients, the standard delivered dose involves a total Kt/Vurea of at least 2.0 per week and a total creatinine clearance of at least 60 L/wk/1.73 m² for high and high-average transporters, or 50 L/wk/1.73 m² for low and low-average transporters 1
• The typical CAPD prescription involves multiple exchanges of dialysate fluid daily, with each exchange typically being 2L in volume 1

Monitoring CPD Intake in I/O Records

• When recording CPD intake in I/O charts, healthcare providers should document the total volume of dialysate solution instilled into the peritoneal cavity during each exchange 1
• For patients on CAPD, this typically involves recording the volume of each dialysate bag (usually 2L) multiplied by the number of exchanges performed 1
• The glucose concentration in CPD solution (typically 1.5%, 2.5%, or 4.25%) should also be noted as it affects both fluid removal and caloric intake 1

Nutritional and Metabolic Implications

• CPD solutions contain dextrose (glucose), which provides additional calories to the patient - approximately 60% of the dialysate glucose load is absorbed, resulting in glucose absorption of about 100-200g per 24 hours 1
• This glucose absorption can be estimated using the formula: Glucose absorbed (g/d) = 0.89 × (g/d) × 43, where x is the total amount of dialysate glucose instilled each day 1
• The absorbed glucose from dialysate should be included when calculating a patient's total energy intake, as it can contribute significantly to daily caloric intake 1

Clinical Significance of Monitoring CPD Intake

• Accurate monitoring of CPD intake is essential for:
  • Assessing fluid balance and ultrafiltration effectiveness 1
  • Calculating the delivered dose of peritoneal dialysis 1
  • Determining the patient's total caloric intake, including glucose absorbed from dialysate 1
  • Evaluating the adequacy of dialysis treatment 1

Special Considerations

• For malnourished CAPD patients, the target dose should be adjusted upward by multiplying the standard target by the ratio of desired weight to actual weight 1
• In patients with fluid overload, careful monitoring of CPD intake and output becomes even more critical as fluid overload is associated with reduced nutrient intake 1
• For patients transitioning between different forms of dialysis, understanding the CPD component of I/O is essential for maintaining continuity of care 1

Common Pitfalls in CPD Intake Monitoring

• Failing to account for the glucose absorbed from dialysate when calculating total caloric intake 1
• Not considering the difference between instilled volume and drained volume when calculating net fluid balance 1
• Overlooking the contribution of CPD solution to the patient's electrolyte balance, particularly sodium, phosphate, and calcium levels 2