Intervention description

In the control group, from the day of chemotherapy, the patients, when rising in the morning, before going to bed, and after defecation, will use warm water to clean the perianal area and will keep the perianal area clean and dry for 14 days. The cleaning method was to immerse the anus completely in warm water, gently wipe the anal skin with a towel, and then dry the anal skin. The water temperature will be 40–45°C, and the cleaning time will be 1–2 mi. The basic measures to prevent perianal infection are cleaning the anus and keeping it dry, which is also conventional perianal support treatment, so we chose this group as the control group.

Different concentrations of PI diluent (relative to the control treatment) will be added to the sitz bath. Patients will be randomly assigned to sitz baths with accurate PI concentrations. The duration of sitting bath treatment will be 14 days, the frequency of the sitting bath will be twice a day, the time for each sitting bath will be 10 min, the temperature of the sitting bath will be 40–45 °C, the height of the sit-down bath will be 40 cm, and the concentration of the sitting bath will be 1:100 (5% povidone iodine 20 ml + warm water 2000 ml), 1:200 (5% PI 10 ml+ warm water 2000 ml), or 1:300 (5% PI 6.7 ml+ warm water 2000 ml).

Most patients can recover from neutropenia in approximately 14 days. To facilitate the assessment and ensure the consistency of intervention, Zhou Ye, Lu Ling et al. [16, 20] conducted the perianal intervention for 14 days, which was the usual practice in previous studies, so the duration of perianal intervention was set as 14 days in this study . However, in some patients with acute myeloid leukemia, the duration of neutropenia and hospitalization is more than 14 days and up to approximately 28 days. For the special case, we will evaluate the risk factors for perianal infection after 14 days. We suggest that high-risk patients can continue to take the sitz bath, but there are no requirements on the concentration, duration and frequency of the sitz bath. At the same time, patients with hematologic malignancies are treated with systemic anti-infective therapy during myelosuppression.

If participants are unable or unwilling to complete treatment or if a physician’s assessment indicates that other medical care interventions are necessary because of serious AEs or changes in their condition, further study interventions would not be appropriate. We would consider these participants to have given up treatment. The intervention can be modified at the request of the patient or at the recommendation of the doctor.

Measures to improve patient compliance are as follows: first, health education should be carried out for patients to inform them of the benefits or necessity of perianal cleaning and sitz bath and the possible harm of not sitz bath to answer their questions and make patients fully informed, which is conducive to the guarantee of compliance; second, a perianal sitz bath inspector table should be set up so that patients or their family members can record the sitz bath situation every day in detail, including the specific time and water temperature; third, participants will be randomly checked daily for perianal sitz bathing and rewarded with incentives (e.g., masks) for high compliance.

All participants will return to usual care 14 days after the start of chemotherapy. As part of our safety protocol, we will monitor the patient for perianal skin allergies, dryness, peeling, and accidental injuries such as syncope and falls during the sitz bath. Any participants with the abovementioned abnormal situations will be contacted by the site coordinator, who will inform the doctor and researcher for timely treatment.