The study population were selected by convenience sampling method and consisted of 90 patients meeting the inclusion criteria in the First Affiliated Hospital of Yangtze University between December 2018 and December 2019, then the participants were randomly divided into experimental group, conventional treatment group, and control group, 30 cases for each. Patients in the experimental group, the conventional treatment group and the control group were treated with Ji Desheng snake pills combined with hypertonic glucose external application, moist dressing external application and surgical dressing change, respectively. During the treatment, the pressure ulcer area, wound tissue type, would effusion, pain degree, adverse actions and pressure ulcer treatment costs were observed and recorded on the 1^st, 7^th, 14^th, and 28^th days. This study was approved by the hospital ethics committee.

1) Inclusion criteria: a) age ≥ 18 years; b) first pressure ulcer treatment; c) stable control of primary disease or complications; d) compliant with the National Pressure Ulcer Advisory Panel (NPUAP) diagnostic criteria for stage III and IV pressure ulcers [3]; e) patients and their families voluntarily participated in the clinical efficacy observation study and signed informed consent.

2) Exclusion criteria: a) patients with abnormal blood glucose levels during treatment; b) patients with active wound bleeding or coagulation dysfunction; c) patients with drug allergy; d) serious heart, liver, and kidney insufficiency; e) sepsis; f) immunosuppressant or hormone therapy; g) refusal to continue the research.

In the control group, the skin around the wound was disinfected with 0.5% iodophor, and the wound was lightly moistened with a cotton ball of normal saline. If there was obvious necrotic tissue, it needed to be debrided and applied with vaseline gauze and sterile gauze. As to the experimental group, after treating the wound with the above method, 20 Ji Desheng snake pills were crushed and stirred into a paste after adding 50% glucose solution, and then evenly smeared on the wound which was then covered with sterile gauze. For the conventional treatment group, the common moist dressing was used. The choice of dressings was based on the treatment principles of stage III and IV pressure ulcers [7]. Alginate dressings were used as inner dressings to cover the pressure ulcer wounds. The size and shape of the dressings were tailored according to the size of the wound, 1 - 2 cm beyond the edge of the wound. The outer layer was adhered and fixed with a hydrocolloid dressing. If the wound was infected, silver ion dressing was then used as the inner dressing, and the outer layer was covered with gauze or cotton pad after being fixed with a hydrocolloid dressing. The dressing was changed daily in the early stage of the treatment, and the frequency of dressing changes was gradually reduced according to whether the wound had effusion, peculiar smell, and whether the dressing was clean and dry. The air bed was usually used and the patients were turned over every 2 hours. The treatment cycle was 28 days.

The observation record table of pressure ulcer therapeutic effect was set up with the 1^st, 7^th, 14^th, 21^st, and 28^th days as the observation points. The patient’s pressure ulcer area, wound tissue type, would effusion, and pain degree were recorded to calculate PUSH score, VAS pain score and wound healing rate on the 28^th day as evaluation indices of therapeutic effect. Meanwhile, the adverse actions during the treatment were recorded as safety evaluation indices and pressure ulcer treatment costs were counted as evaluation indices of cost benefit. The calculation method of pressure ulcer area (cm²) was to multiply the length of the wound (cm, take the patient’s head to toe as the vertical axis) by the width of the wound (cm, the horizontal axis was perpendicular to the vertical axis). The formula for calculating the wound healing rate on the 28^th day was: healing rate = (original wound area before treatment − wound area on the 28^th day)/original wound area before treatment × 100%.

SPSS26.0 software was utilized for statistical analysis. The measurement data was expressed as x ¯ ± s , using the single-factor ANOVA test. The count data was expressed by the number of cases and percentage (%). The comparison between groups used χ2 test, considering p < 0.05 as statistically significant.

In this study, the experimental group included 18 male patients and 12 female patients, with the average age of 73.80 ± 3.41 years; the conventional treatment group 16 males and 14 females, with the average age of 72.47 ± 7.55 years; the control group included 13 males and 17 females, with the average age of 74.73 ± 5.48 years. There were no statistically significant differences between the three groups in sex, age, BMI index, hemoglobin, albumin, mean arterial pressure, pressure ulcer location distribution, and Braden score (p > 0.05) (Table 1), indicating that the three groups of patients were comparable.

During the treatment, no adverse reactions occurred in the three groups of patients. On the 14^th, 21^th, and 28^th day, the PUSH scores of the experimental group and the conventional treatment group were significantly lower than that of the control group, and the result was statistically significant (p < 0.05), while there was no significant difference between the experimental group and the conventional treatment group (p > 0.05) (Table 2). Comparing the control group, the experimental group and the conventional treatment group, the wound healing

BMI: Body mass index, MAP: Mean arterial pressure.

^‡: compared with the control group (p < 0.05).

rates of the three groups on the 28^th day were 43.25% ± 8.53%, 70.14% ± 8.27%, and 73.99% ± 7.15%, respectively. The results showed that the experimental group and the conventional treatment group were significantly higher than the control group, with statistical significance (p < 0.05); there was no significant difference between the experimental group and the conventional treatment group (p > 0.05) (Table 3). On the 7^th, 14^th, 21^th, and 28^th day, the VAS pain scores of the experimental group and the conventional treatment group were significantly lower than that of the control group, and the result was statistically significant (p < 0.05), while there was no significant difference between the experimental group and the conventional treatment group (p > 0.05) (Table 4).

^‡: compared with the control group (p < 0.05); *: compared with the conventional treatment group (p < 0.05).

^‡: compared with the control group (p < 0.05).

The total treatment costs of the three groups were 186.47 ± 30.29 yuan, 569.73 ± 78.12 yuan, and 1043.40 ± 135.31 yuan. The conventional treatment group was the highest, followed by the experimental group, and the control group was the lowest. The result was statistically significant (p < 0.05) (Table 3).