Risk Factors For Secondary Infection In ICU Patients With Severe Heat Stroke: A Single-center Retrospective Study

Objective:A retrospective analysis of severe heatstroke patients admitted to a large Class A hospital in recent ten years was performed to find out the risk factors for secondary infection,which maybe help with clinical diagnosis,treatment,and prognosis.Method:A retrospective study was conducted on patients with severe heatstroke admitted to a large Class A hospital from January 1,2011,to December 31,2021.According to whether the patients developed secondary infection 48 hours after being admitted to ICU,they were divided into a secondary infection group(24 cases)and a non-secondary infection group(105 cases).Data onto clinical indicators,infection indicators,and clinical outcomes within 24 hours after admission to the ICU were collected and compared between the two groups of patients.Independent risk factors of secondary infection in severe heat stroke were analyzed by univariate and multivariate analyses.ROC curve analysis was used to determine the threshold for positive indicators to predict secondary infection.Age,SOFA score,and number of organ injuries was included as baseline data onto multivariate analysis.Binary logistic regression analysis was used for baseline correction to analyze the effects of secondary infection on clinical outcomes including hospital death,mechanical ventilation duration,ICU length of stay,and total hospital length of stay.P<0.05 was considered statistically significant.Result:A total of 129 patients with severe heat stroke were included,all of whom were male and the average age of onset was 23 years old.Body temperature,heart rate,mechanical ventilation,use of vasopressors,total bilirubin,serum creatinine,platelet,creatine kinase,gastrointestinal dysfunction,procalcitonin and SOFA scores,mechanical ventilation duration,ICU length of stay,total hospital length of stay,and hospital death in the secondary infection group were significantly higher than those in the non-secondary infection group.The GCS score was significantly lower than that of the non-secondary infection group(all P<0.05).Secondary infection occurred on the 3rd to 10th day after ICU admission,and the peak occurred on the 3rd to 5th day after ICU admission.The most common infection sites were lung in 12 cases(50.0%),and the most common pathogens were multidrug-resistant gram-negative Acinetobacter baumannii and Klebsiella pneumonia.The number of antibiotic species used was 2 to 4.The median duration of antibiotic use was 10(7-19)days,and 13 patients(54.2%)developed septic shock.The results of multivariate analysis showed that the use of vasopressors,serum creatinine evaluated,and gastrointestinal dysfunction at admission were independent risk factors for secondary infection of severe heat stroke,and lymphocyte count increased was an independent protective factor(all P<0.05).The area under the curve of serum creatinine for predicting secondary infection of severe heat stroke at admission was 0.881(95%CI 0.804～0.959,P<0.001);The optimal cutoff value was 136μmol/L.Multivariate analysis of clinical outcomes showed that after adjusting for age,SOFA score,and number of organ injuries of patients with severe heat stroke,patients with secondary infection had longer mechanical ventilation duration and total hospital length of stay than the non-secondary infection group(P<0.05).Conclusion:Lymphocyte count increased is an independent protective factor for secondary infection in ICU patients with severe heat stroke,while the use of vasopressors,gastrointestinal dysfunction,and serum creatinine increase over 136μmol/L was are independent risk factors,which have significant predictive value for secondary infection and can be used as an indicator for clinicians to assess the risk of secondary infection in ICU patients with severe heat stroke.The mechanical ventilation duration and total hospital length of stay after secondary infection of severe heat stroke was significantly prolonged.