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Author: Kajaree Giri, MD
AcademicCME (www.academiccme.com) is accrediting this educational activity for CE and CME for clinician learners. Please go to https://academiccme.com/kicr_blogposts/ to claim credit for participation.
The burden
Globally around 843.6 million patients suffer from chronic kidney disease and around 2.9 million people receive hemodialysis (HD) treatment. HD is a resource-intensive therapy which utilizes large quantities of water and electricity, generating significant biomedical waste.
Professor John Agar first introduced the concept of green nephrology and eco-dialysis to the world. He also proposed various eco-friendly ways to mitigate the problems faced by home dialysis patients being treated with intensive hemodialysis in Australia. Subsequently, various position statements were issued by Australia New Zealand Society of Nephrology, European Renal Association-European Dialysis and Transplant Association as well as Italian Society of Nephrology to navigate the concept of green dialysis.
Worldwide, approximately 89% of patients with end-stage renal disease (ESRD) undergo dialysis treatments at hemodialysis facilities. It is a treatment with significant environmental impact. The medical waste act has specifically categorized dialysis waste as those which are in contact with the blood of patients undergoing HD, which includes contaminated disposable equipment and supplies such as tubing, filters, disposable sheets, towels, gloves, aprons and laboratory coats. Dialysis waste can be further classified into contaminated and non-contaminated waste- like paper, tubings and bags which are not in contact with biological fluids.
How much waste is generated in dialysis?
A prospective study by Sahay et al, was carried out in a single dialysis unit over a period of 1 year in India. It revealed approximately 0.75 kg of waste disposables (including dialysers, bloodlines and needles) were generated in one HD session. Each person generated 1.29 kg of waste (plastic and non plastic) per HD session. Each HD session utilized 125 liters of reverse osmosis (RO) water, which is equivalent to 250 liters of raw water. In addition, 90 ml of citric acid and 130 ml of bleach was generated per session. Let's check out the visual abstract of the study:
Visual abstract by @KajareeG
Similarly, a study by Barbara Piccoli et al, showed that 1.5 to 8 kg of plastic waste was produced per dialysis session. The financial cost of waste disposal was high, ranging from 2.2 to 16 Euro per session (2.7 - 21 USD), increasing the economical burden.
What are the ways to mitigate the environmental impact of dialysis?
The “4 R” approach (reduce, reuse, recycle and repair) is an effective strategy to reduce the environmental and financial impact of dialysis waste. Reduction in the quantity of waste products is the primary target. Furthermore, comprehensive management of chronic kidney disease, with a goal of preventing the need for dialysis, should be a first line strategy. Next, implementation of incremental HD, reducing dialysate flow to reduce water waste, triage of HD waste products can be considered to reduce the burden of contaminated waste. Reuse in dialysis is mostly restricted to reusing dialysis disposables that do not come in contact with blood-contaminated products like cartridges and plastic bottles. Recycling is limited to non-contaminated plastic items, like paper and glass used in HD. Finally, repair of electronic devices and supplies including HD machines can significantly decrease the electronic waste.
Emergence of the Cradle-To-Cradle design - a biosimilar concept:
The law of conservation of mass dates from Antoine Lavoisier’s 1789 discovery which details the observation that mass is never created nor destroyed in chemical reactions. Likewise, the cradle-to-cradle concept features a regenerative design, which was proposed by M. Braungart and W. McDonough. The approach is biomimetic, which aims to create an efficient, holistic and economic framework that is essentially waste free. An example of a biomimetic system would be the organic waste of a dead tree nourishes new plants without losing their biological components. Similarly, the electrical and mechanical components that are used in dialysis units should be easily disassembled to reuse and/or recycle into new generations of equipment.
The Italian Society of Nephrology has proposed 10 affordable and feasible actions to address the environmental impact of dialysis as outlined below.
A novel technique to reduce water consumption in HD:
In the KI Reports article “A Pilot Study on the Safety and Adequacy of a Novel Eco Friendly Hemodialysis Prescription–Green Nephrology”, the authors studied a novel HD prescription with high temperature and low flow dialysate in order to reduce water consumption without compromising the adequacy and safety of dialysis.
Thirty patients with end-stage kidney disease on maintenance hemodialysis underwent 3 different HD prescriptions, for one month each:
Normal temperature with normal flow dialysate (NTNF prescription): dialysate temperature of 37℃, with a Qd of 500 ml/min
High temperature with normal flow dialysate (HTNF prescription): dialysate temperature of 38.5 ℃, with a Qd of 500 ml/min
High temperature with low flow dialysate (HTLF prescription): dialysate temperature of 38.5 ℃, with a Qd of 300 ml/min
👉Dialysis adequacy, as defined by spKt/V≥1.2, was assessed at the end of every HD session. 👉The authors have hypothesized better clearance (spKt/V and URR) with the HTNF prescription in comparison to the NTNF prescription. A total of 863 sessions of HD were performed on 30 patients over 3 months. There were no significant differences in HD adequacy between the NTNF and HTLF prescriptions (odds ratio, 1.07;95% CI, 0.75 to 1.52; P=0.45). There was no significant change in systolic blood pressure.
👉The HTLF prescription allowed to reduce the dialysate flow from 500 ml/min to 300 ml/min, resulting in a reduction in water consumption by 40%. The requirement of purified water was reduced from 120 liters to 72 liters for a single 4-hour HD session, and the daily requirement of purified water decreased from 3600 liters to 2160 liters in the HD unit (conducted HD for 3 shifts with 10 patients every shift). Hence, 1440 liters of purified water and 4320 liters of raw water were saved (rejection water:purified water 3:1). Other benefits included:
Reduction in the energy consumed by the reverse osmosis (RO) water pump
Improvement in the life of the pre treatment filters, micron filters and RO membranes
Overall reduction in the carbon foot-print
👉The authors have hypothesized that increased dialysate temperature has increased the brownian motion of the particulate matter which has increased the diffusion across the membrane and resulted in improved clearance of low-molecular-weight solutes.
👉In this study, the HTNF prescription was tolerated by most patients, barring any episodes of significant hypotension or serious adverse events. The authors of this pilot study have concluded that, a HD prescription with a high dialysate temperature of 38.5 ℃ and a low Qd of 300 ml/min is a safe and alternative practice to standard HD prescription (37 ℃, Qd 500 ml/min) and such intervention has decreased water consumption by 40% per HD session.
Here's a beautiful visual abstract summarizing the study by Krithika Mohan
The way forward:
A systematic review has proposed several simple and cost-effective eco-friendly measures to reduce the carbon footprint and environmental impact of dialysis.
Water conservation: The following measures can be taken
👉Reuse of reject water- The reject water is a highly purified tap water that has undergone rigorous treatment to effectively remove chlorine, chloramines and other substances. It can be used in various departments within the hospital settings- central sterilization department for steam generation, hospital janitor stations, hospital landscaping, garden watering, laundry facilities as well as park maintenance.
👉Redirection to the main RO unit in a closed loop circuit- this is to be monitored by the conductivity meter in the RO system.
👉The use of dry dialysis technologies like wearable artificial kidneys and sorbent dialysis may hold some promise in this field.
👉Use of pre-prepared dialysate- The total fluid consumption in the NxStage machine (NxStage Medical Inc., Lawrence, MA, USA) which is used for home hemodialysis patients in the United States is between 25-80 liters only.
👉Reduce the dialysate flow rate- Several studies have reported similar Kt/V with no significant differences between lower (400 ml/min) and standard (500 ml/min) Qd. This practice can significantly reduce water consumption - 312 liters of water per month, or 3744 liters per year.
👉Effluent water management- The effluent fluid following treatment, termed as High-density waste water (HDWW) contains elevated levels of urea, nitrites, phosphates, sulfates, ammonia. Despite this, HDWW contains low levels of organic matter and bacterial counts and can be used in agriculture purposes.
Consumable waste management:
👉Plastic reuse and recycling- Onsite segregation and reuse of non contaminated plastic like saline bottles, syringes, caps can significantly reduce waste generation.
👉Dialyser reuse- The risk benefit aspects of dialyzer reuse should be weighed and it can be accepted from a broader environmental perspective.
👉Establishment of remote dialysis units- Small dialysis units can be established at township level, which will enhance the quality of life of the patients on HD by improving adherence and can simultaneously reduce the carbon footprint, by preventing long distance travel.
Use of alternative energy sources:
👉Use of solar power- The installation of solar panels in the rooftops of hospitals and dialysis units will help to generate electricity and decrease the routine costs of conventional electricity.
Following is an infographic summarizing the measures that help to decrease the environmental impact of dialysis
Summary:
Despite the generation of a significant amount of waste in HD (each HD session in the UK produces 2.5 kg of waste, of which 38% is plastic) effective measures can be adopted to reduce its environmental impact. Only 23-28% of non-hazardous HD waste is recyclable, and the financial cost of waste disposal is also high, ranging from $2.70-$21 per session. As described earlier, reduction in the generation of waste and segregation of non-clinical waste from clinical waste are effective eco-friendly measures. Studies have shown that waste segregation by trained staff can reduce clinical waste by 30% in the UK and a study from Italy has reported that it only takes one additional minute per session to segregate hazardous and non-hazardous waste at the time of generation. In Europe, trials are underway to reprocess plastic waste to make sterile confetti through autoclaving that can be used to create new plastic items. Worldwide, various efforts are being made to create a cost effective, environmentally sustainable clinical waste management programme which will contribute towards a greener tomorrow.
To conclude, here's a beautiful VA by @jbda19 on the ways to reduce clinical waste in HD units.
AcademicCME (www.academiccme.com) is accrediting this educational activity for CE and CME for clinician learners. Please go to https://academiccme.com/kicr_blogposts/ to claim credit for participation.
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