22 May 2020
The aim of this document is to:
- Provide practical considerations for the nutritional management of patients requiring acute PD for the management of AKI, particularly focusing on the associated energy gains in this patient group (including the treatment of COVID-19 patients).
This statement does not replace clinical judgement, local practices and evidence/guidelines for the nutritional management of critically ill patients.
Peritoneal dialysis (PD) involves instilling hypertonic solutions into the abdominal cavity, in order to draw fluid and other solutes across the semipermeable peritoneal membrane from the circulation. PD solutions use glucose, amino acids or icodextrin as the osmotic agent. During the period the solutions are in the peritoneal cavity (dwell time), some of these substances can be reabsorbed into the circulation.
Glucose is used as the predominant osmotic agent in most PD solutions. Studies demonstrate that glucose is absorbed during the dwell times used in PD therapy when used in the management of End Stage Kidney Disease.
In patients on continuous ambulatory peritoneal dialysis (CAPD) with normal peritoneal transport capacity, it has been estimated that up to 60-80% of the daily dialysate glucose load is absorbed; this could add up to 100-200 grams/24 hour (400-800kcal/day) (Grodstein, 1981; De Santo, 1979; Khar et al. 2019).
PD has been used in some critical care units in the UK during the current COVID-19 pandemic for the acute management of acute kidney injury (AKI). This is partly due to a shortage of continuous renal replacement therapy (CRRT) consumables and machines, but also to overcome the issue of frequent filter clotting in patients with COVID-related coagulopathy (NHS England and NHS Improvement 2020).
In the acute setting, the fluid dwell times used for PD may be shorter (1-2 hours) especially in the initial period of dialysis. This has a potential impact on the amount of nutrition absorbed from the PD solution. Shorter dwell times may translate to less glucose absorption (especially if the initial dwell time is less than 2 hours). The patient may be receiving PD on an intermittent basis rather than continuously, therefore each instillation should be considered as a separate opportunity for absorption. It is important to remember that there is no standardised PD regimen, prescriptions are individualised and can change regularly and therefore close monitoring is required.