Objective To analyze the risk factors for hypothermia during modified radical mastectomy,and construct a nomogram model for predicting the occurrence of hypothermia during modified radical mastectomy based on the risk factors.Methods A total of 383 patients received modified radical mastectomy admitted to our hospital were selected and divided into the hypothermia group(n=58)and the normal group(n=325)according to whether hypothermia occurred.The clinical data of the patients were collected,and the univariate analysis and Logistic regression analysis were used to screen out the independent risk factors for intraoperative hypothermia,and a risk nomogram model for predicting intraoperative hypothermia was constructed by R software and verified.Results There were statistically significant differences in the hypothyroidism,preoperative basal body temperature,intraoperative room temperature,operation time,anesthesia time,intraoperative blood loss,and intraoperative infusion between the two groups(P<0.05).The hypothyroidism(OR=2.156,95%CI:1.158～4.016,P=0.015),abnormal preoperative basal body temperature(OR=2.451,95%CI:1.309～4.588,P=0.005),intraoperative room temperature<23℃(OR=2.027,95%CI:1.085～3.786,P=0.027),operation time>2 hours(OR=2.316,95%CI:1.239～4.327,P=0.008),anesthesia time>3 hours(OR=2.264,95%CI:1.206～4.252,P=0.011),intraoperative infusion volume>1 500 mL(OR=2.895,95%CI:1.543～5.432,P=0.001)were the independent risk factors for the occurrence of intraoperative hypothermia.The nomogram model showed that the score of intraoperative infusion volume>1 500 mL was 100 points,hypothyroidism was 93 points,anesthesia time>3 hours was 85 points,intraoperative room temperature<23℃was 84 points,operation time>2 hours was 79 points,and abnormal preoperative basal body temperature was 75 points.The nomogram model verification results demonstrated that the C-index was 0.834;the H-L goodness-of-fit test showed χ2=11.854 and P=0.078;the calibration curve was close to the ideal curve;the area under the receiver operating characteristic curve was 0.812;and the net benefit value was high at the threshold probability from 5%to 70%.Conclusion The nomogram model constructed in this study can more accurately and reliably predict the risk of hypothermia occurring during modified radical mastectomy,which meets the clinical need for an integrated model and helps to promote the steady development of individualized medicine.