Influence Of Physical Restraint On Delirium Of Patients In ICU: A Nested Case-Control Study

Objective: To explore the impact of physical restraint on delirium of patients in ICU,thus providing an empirical basis for clinical reduction of delirium and improvement of restraint.Methods: A nested case-control study was conducted in a cohort of 509 ICU patients who met the inclusion criteria from June 2016 to June 2017.The cohort was followed up till the patient died or was transferred out of ICU.Data were analyzed by group design control(model 1)and individual matching selection control(model 2).Model 1 identified178 patients with newly-onset delirium in the total sample as delirium group;and 178 patients without delirium were selected as non-delirium group according to a 1: 1 ratio to obtain the independent risk factors of delirium.In model 2,178 newly-onset delirium patients of physical restraint were put into the delirium group;and a well-matched control group was established by matching each delirium patient with a non-delirium patient of the confounding factors to explore the influence of physical restraint on delirium.Statistical analysis was carried out using SPSS18.0 software.Results: Univariate analysis of the risk factors for delirium in model 1 showed that there were significant differences in age,sex,mechanical ventilation,sedation,analgesics and physical restraint between the delirium group and the non-delirium group(P <0.05).And then logistic regression analysis of these factors was performed,the final variables included age(OR = 2.992,P = 0.041),sex(OR = 1.878,P = 0.019),mechanical ventilation(OR = 4.181,P = 0.015)Sedatives(OR = 3.074,P = 0.044)and protective constraints(OR= 4.011,P = 0.028).Univariate analysis of the impact of physical restraint on delirium in model 2 found that the duration and number of restrain in the delirium group were significantly different from those in the non-delirium group(P < 0.05),while the appliance,site,time to apply and remove restraint were no significant difference between two groups(P > 0.05).The area of operating characteristic(ROC)curve for the duration of physical restraint was 0.867 and restraint of 6 days was the optimal cut-off value.From the result ofthe multivariate logistic regression analysis model,the risk of delirium in patients with physical restraint ? 6 days was 26.296 times(95%CI: 13.272~51.101)higher than in patients with physical restraint <6 days.The patients who underwent two and three times of physical restraint had a 2.378-fold(95%CI: 1.060~5.335)and 3.620-fold(95%CI:1.035~12.668)higher risk of delirium than those who had one time of physical restraint.Conclusion: The independent risk factor of delirium in ICU patients includes age,sex,mechanical ventilation,use of sedatives and physical restraint.Duration and number of physical restraint are positively related to delirium.The longer the duration of physical restraint and the higher number of restraints,the higher the risk of delirium.