#3351 TRIAL OF ISOLATED HAEMODIALYSIS WITH PATIENT-ENTRY TENT AND HYPOCHLORITE MIST
Authors: Shibata Kazuhiko , Imoto Kiyotaka , Osawa Masato 
Published: June 2023

Abstract

Background and Aims
The global spread of COVID-19 has posed a serious threat to patients receiving renal replacement therapy and to the staff who treat them. Every time they treat a patient or operate a machine, they have to wear personal protective equipment (PPE). 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 no evidence to support the use of hypochlorous acid in an ultrasonic humidifier. Therefore, Nipro Corporation conducted a “28-day repeated inhalation toxicity study” on rats with a third party organisation 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. The size of the AIR ZIPPER® is about a fifth of the standard 10m3 size, down to about 2m3. 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. Prior to the introduction of the AIR ZIPPER®, staff had to wear PPE with an N95 mask when operating the machine, puncturing and returning blood to the patient.

Method
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. The zipper of the AIRZIPPER® could not be closed until the puncture procedure had been completed. To reduce the spread of viruses outside the tent, 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 zip closed in the isolation room, the outside of the AIR ZIPPER® was operated as a safe zone.

Results
On 13 January 2022, two pieces of equipment arrived at the Toshin Clinic and all patients carrying COVID-19 who subsequently developed the disease were isolated and haemodialysed. Quarantine dialysis was performed in 156 patients, 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.

Conclusion
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.