Microbicidal efficacy of povidone-iodine in a noncontact manner applied to a continuous ambulatory peritoneal dialysis connection system

In peritoneal dialysis (PD) the dialysate is introduced into the peritoneal cavity, and the peritoneal membrane is used as the dialysis membrane. In PD, patients exchange the dialysate by themselves through the connection tube attached to the indwelling catheter that is inserted into the peritoneal cavity. Microbes may enter the peritoneal cavity during dialysate exchange, and, therefore, peritonitis is a potential complication of PD. To prevent microbial contamination, the connection tube tip is generally sealed with a protection cap containing povidone-iodine (PVP-I) during the dwelling time. This cap is designed to make direct contact with the tube tip so that microbes attached during dialysate exchange are killed by the next dialysate exchange. However, if excess PVP-I flows into the peritoneal cavity and is absorbed into the body, the complications, including thyroid dysfunction, peritoneal inflammation, and fibrous thickening, can develop. Therefore, in this study, a new manual connection system (Zero System, JMS Co., Ltd., Hiroshima, Japan) for continuous ambulatory peritoneal dialysis was investigated to confirm that the PVP-I solution within the protection cap of the new system would not flow into the fluid passing through the tube. An experiment was also performed to confirm that the microbes on the connector tip become completely nonviable after attachment of the cap for 3 hours. The cap is fitted with a sponge containing a 10% PVP-I solution, the same as for the conventional cap system. However, the system is designed to achieve disinfection without contact, unlike with the conventional system, in which disinfection is achieved by direct contact of the PVP-I-containing sponge with the open end of the attached connector. The test results demonstrated that adequate disinfection with this system can be achieved by the next exchange, while avoiding entry of PVP-I into the peritoneal cavity from the cap. The results suggest that the use of this connection system can avoid adverse reactions arising from the absorption of PVP-I and prevent the onset of peritonitis caused by microbial invasion of the peritoneal cavity.