The New Method of Isolated Haemodialysis Using Personal Isolation Tents and Hypochlorite Mist Disinfection

Background: The COVID-19 pandemic has created new challenges in managing patients receiving renal replacement therapy and the staff treating them. The Centers for Disease Control and Prevention (CDC) recommends using Personal Protective Equipment (PPE) such as N95 respirators, eye protection, gloves, and gowns to protect against virus transmission. Every time staff touches the haemodialysis machine; they should equip them. We introduced the AIR ZIPPER® patient isolation tent and the CLFine® hypochlorous acid mist to reduce the workload of our staff.

Method: The Toshin Clinic introduced two pieces of equipment on 2022/1/13, the AIR ZIPPER® patient isolation tent and the CLFine® hypochlorous acid mist. Patients with a fever or who have been in contact with COVID-19 patients were asked to enter the AIR ZIPPER® for quarantine dialysis. The haemodialysis machine was placed outside. The hypochlorous acid mist was used to disinfect the outside of the AIR ZIPPER® to make it a safe zone after the 30-minute zip was closed.

Results: A total of 96 isolation haemodialysis sessions were performed on 22 COVID-19-positive patients. There was no transmission to staff or other patients, and no patients died.

Conclusion: The introduction of the AIR ZIPPER® patient isolation tent and the CLFine® hypochlorous acid mist reduced the burden on healthcare staff and prevented the spread of SARS-CoV-2 among patients and staff. Therefore, these equipment should be introduced in every haemodialysis facility.

The global spread of COVID-19 has seriously threatened patients receiving renal replacement therapy and the staff treating them. In the United States, when nurses treat COVID-19 patients during hemodialysis, the Centers for Disease Control and Prevention (CDC) recommends the following PPE:

• N95 respirators or equivalent masks to protect against airborne transmission of the virus.
• Eye protection, such as goggles or face shields, to protect against splashes and droplets.
• Gloves to protect against contact transmission of the virus.
• Gowns or aprons to protect clothing and skin from contamination.

In addition to PPE, the CDC recommends that healthcare workers follow infection control procedures such as proper hand hygiene and environmental decontamination. The specific PPE requirements may change based on the level of exposure risk and local guidance, so healthcare workers must stay up-to-date on the latest recommendations from the CDC and other reliable sources. According to these suggestions, every time they treat a patient or operate a machine, they must wear Personal Protective Equipment (PPE). This is because even if the patient is isolated, there is no way to rapidly sanitise the space and surfaces. In some cases, UV light and ozone are used as a way of rapidly sanitising spaces and surfaces [1,2]. However, ultraviolet light has the disadvantage that it cannot sterilise surfaces that are not exposed to its rays, while ozone is highly toxic and is not recommended for sterilising spaces where people are present [3]. In order to reduce the burden on our staff, we have introduced two pieces of equipment. One is a hypochlorous acid mist for room and surface disinfection using CLFine®. The other is an AIR ZIPPER® patient isolation tent in the existing isolation room. Both products were manufactured by Nipro Corporation of Osaka, Japan. However, there was few evidence to support the use of hypochlorous acid in an ultrasonic humidifier [4]. Therefore, Nipro Corporation conducted a "28-day repeated inhalation toxicity study" on rats with a third-party organization and confirmed the results as toxicologically safe. According to the Occupational Safety and Health Act, also in the school environmental health, the concentration of chlorine in the air is 0.5 ppm or less (8 hours/day, 5 days/week or less). CL Fine® has shown an antiviral effect within these regulations [5]. The size of the AIR ZIPPER® is about a fifth of the standard 10 m3 size, down to about 2 m3. Powerful, high-efficiency particulate air filter pumps have been fitted to replace the air in the tent in less than 5 minutes at low flow rates (0.4 m³/min airflow), enabling it to operate below the negative pressure standard of 2.5 Pascal. In addition, the AIR ZIPPER® is equipped with air intake valves that open and close in a single direction towards the inside of the tent. Before the introduction of the AIR ZIPPER®, staff had to wear PPE with an N95 mask when operating the machine, not to mention puncturing and returning blood to the patient.

Patients with a fever or who have been in contact with COVID-19 patients and infected patients were asked to enter the AIRZIPPER®. The haemodialysis machine is placed outside of the AIRZIPPER®. The zipper of the AIRZIPPER® could not be closed until the puncture procedure had been completed. To reduce the spread of viruses outside the AIRZIPPER®, the high air volume (air flow rate 0.9 m3/min) allows a one-way air flow from the outside to the inside. Following the puncture, the tent zipper was sealed and the air pressure was adjusted to reach the recommended negative pressure of 2.5 Pa and above within 1 minute. Furthermore, the hypochlorous acid mist with CLFine® has the ability to disinfect viruses from the outside of the AIR ZIPPER®. Therefore, after the 30 minutes with the zipper was sealed in the isolation room, the outside of the AIR ZIPPER® was operated as a safe zone.

On 13 January 2022, two pieces of equipment arrived at the Toshin Clinic. This study was conducted from 13 January 2022 to 31 January 2023. All patients carrying COVID-19 who subsequently developed the disease were isolated and haemodialysed. Quarantine dialysis was performed in 156 times, including those who had close contact with a COVID-19 patient or who had fever. A total of 96 isolation haemodialysis sessions using AIR ZIPPER® and CL Fine® were performed on 22 COVID-19 patients (male/female: 19/3, age: 69.8 ± 14.2 years, HD duration: 5.38 ± 3.8 years) with SARS-CoV-2 infection in our clinic. Fortunately, there was no transmission to staff or other patients, and no patients died.

The current COVID-19 pandemic has brought about new challenges in the management of patients receiving renal replacement therapy, particularly in terms of infection control. In order to reduce the burden on healthcare staff, the Toshin Clinic introduced two pieces of equipment, the AIR ZIPPER® patient isolation tent and the CLFine® hypochlorous acid mist. The results of the study show that these measures were successful in reducing staff workload and preventing the spread of SARS-CoV-2 among patients and staff.

The use of the AIR ZIPPER® patient isolation tent allowed for safe haemodialysis treatment for COVID-19 positive patients, as it was equipped with high-efficiency particulate air filters and air intake valves that open and close in a single direction towards the inside of the tent. This ensured that the spread of viruses was reduced and prevented the need for staff to wear PPE with N95 masks during treatment.

The use of the CLFine® hypochlorous acid mist also contributed to the reduction of viral spread by providing surface and room disinfection. This product is toxicologically safe, according to a 28-day repeated inhalation toxicity study conducted by Nipro Corporation, and has been found to have an antiviral effect within the regulations set by the Occupational Safety and Health Act.

In conclusion, the measures taken at the Toshin Clinic serve as an effective model for other haemodialysis providers to adopt in order to deal with COVID-19 infections as well as new infections in the future. The use of the AIR ZIPPER® and CLFine® could potentially lead to improved patient and staff safety and reduced workload in the management of patients receiving renal replacement therapy. However, further studies and evaluations are necessary to validate the effectiveness and long-term safety of these measures in different settings.

These infection control measures helped to reduce staff workload and prevent infections. In conclusion, the present method should be equipped by all haemodialysis providers to deal with COVID-19 infections as well as with new infections in the future (Figure 1).

Figure 1: Isolated haemodialysis using personal isolation tents.

1. Gidari A, Sabbatini S, Bastianelli S, Pierucci S, Busti C, Bartolini D, Stabile AM, Monari C, Galli F, Rende M, Cruciani G, Francisci D. SARS-CoV-2 Survival on Surfaces and the Effect of UV-C Light. Viruses. 2021 Mar 5;13(3):408. doi: 10.3390/v13030408. PMID: 33807521; PMCID: PMC7998261.
2. Kitagawa H, Tadera K, Mori M, Kashiyama S, Nomura T, Omori K, Shigemoto N, Ohge H. The effect of pulsed-xenon ultraviolet disinfection on surfaces contaminated with vancomycin-resistant Enterococci in a Japanese hospital. J Infect Chemother. 2021 Nov;27(11):1665-1668. doi: 10.1016/j.jiac.2021.08.011. Epub 2021 Aug 19. PMID: 34419352.
3. Nicholas R, Dunton P, Tatham A, Fielding L. The effect of ozone and open air factor on surface-attached and biofilm environmental Listeria monocytogenes. J Appl Microbiol. 2013 Aug;115(2):555-64. doi: 10.1111/jam.12239. Epub 2013 Jun 3. PMID: 23621101.
4. Nguyen K, Bui D, Hashemi M, Hocking DM, Mendis P, Strugnell RA, Dharmage SC. The Potential Use of Hypochlorous Acid and a Smart Prefabricated Sanitising Chamber to Reduce Occupation-Related COVID-19 Exposure. Risk Manag Healthc Policy. 2021 Jan 22;14:247-252. doi: 10.2147/RMHP.S284897. PMID: 33519249; PMCID: PMC7837568.
5. Fuketa H. Systemic and local toxicities of inhaled administered hypochlorous acid water in rats. Jpn Pharmacol Ther. 2021;49:41-52.