Abstract: Objective To investigate the occurrence and influencing factors of pressure injury(PI) in gynecological lithotomy, and to provide scientific basis for reducing the risk of PI. 
Methods A total of 613 patients undergoing gynecological lithotomy were prospectively divided into occurrence group and non-occurrence group according to presence or absence of PI. The location and stage distribution of PI in gynecological lithotomy were calculated. The age, body mass index(BMI), anemia, hypoproteinemia, preoperative anxiety, duration of operation, leakage of urine, hypothermia during operation, history of PI, use of vasoactive drugs, intraoperative sweating, diabetes, hypertension, chronic liver disease, hyperlipidemia, and heart disease were compared between the two groups. Multivariate Logistic regression equation was used to analyze the influencing factors of PI in gynecological lithotomy, and the predictive value of Braden score and Waterlow scale score on PI in gynecological lithotomy was analyed. 
Results The incidence of PI in 613 patients undergoing gynecological lithotomy was 7.99%(49/613). The high to low sites were sacrococcygeal(42.86%), sciatic(18.37%), leg support contact(14.29%), scapula(10.20%), posterior part of head(8.16%) and restraint belt(6.12%); Stage Ⅲ(32.65%) was the most common stage of PI; Stage Ⅲ and Ⅳ PI in sacrococcygeal and sciatic sites were more common. There were significant differences in age, BMI, anemia, hypoproteinemia, preoperative anxiety, duration of operation, leakage of urine, hypothermia, PI history, use of vasoactive drugs, intraoperative sweating, diabetes, hypertension and chronic liver disease in occurrence group and non-occurrence group(P＜0.05). There was no significant difference in the distribution of hyperlipidemia and heart disease between the occurrence group and the non-occurrence group(P＞0.05). Multivariate Logistic regression analysis showed that age＞70 years, being lean, hypoproteinemia, duration of operation ≥2 h, hypothermia during operation, history of PI, use of vasoactive drugs, intraoperative sweating, diabetes combined with chronic liver disease were the influencing factors of PI in women undergoing lithotomy(P＜0.05). The preoperative Braden score of the occurrence group was lower than that of the non-occurrence group, while the score of Waterlow scale was higher than that of the non-occurrence group(P＜0.05). The sensitivity and specificity of Braden score in predicting PI after gynecological lithotomy were 63.27% and 86.70%, respectively. The sensitivity and specificity of Waterlow scale in predicting PI after gynecological lithotomy were 57.14% and 88.30%, respectively. The sensitivity and specificity of Braden score + Waterlow scale in predicting PI after gynecological lithotomy were 71.43% and 93.09%, respectively. The AUC of Braden score+Waterlow scale score in predicting PI after gynecological lithotomy was greater than that of single Braden score and Waterlow scale score(P＜0.05). 
Conclusion There are different degrees of PI risk in gynecologic lithotomy. Age＞70 years, being lean, hypoproteinemia, duration of operation ≥2 h, leakage of urine, hypothermia during operation, history of PI, use of vasoactive drugs, intraoperative sweating, diabetes combined with chronic liver disease are the influencing factors of PI. Braden score and Waterlow scale can effectively predict the risk of PI. It is recommended to take preventive measures against the above factors to reduce the incidence of PI during gynecological lithotomy.

Key words: gynecological surgery, pressure ulcer, analysis of influencing factors