Objective To analyze the risk factors for catheter-associated urinary tract infection (CAUTI) in elderly critically ill patients and construct a related risk prediction model. Methods Clinical materials of 8 905 patients with catheterization in the geriatric ICU ward of Jiangsu Provincial People's Hospital from January 2014 to June 2024 were retrospectively collected. The patients were divided into infection group (n=114) and non-infection group (n=8 791) based on the occurrence of CAUTI. Multivariate Logistic regression analysis was used to identify the risk factors for CAUTI, and a Nomogram prediction model was constructed. Internal validation was performed by the receiver operating characteristic (ROC) curve, calibration curve, and Hosmer-Lemeshow goodness-of-fit test to assess the discrimination and calibration of the prediction model. Results In this study, the incidence of CAUTI in elderly critically ill patients was 2.55‰. Multivariate Logistic regression analysis showed that age, consciousness status, renal dysfunction, duration of catheterization, and the number of catheter insertions were independent influencing factors for CAUTI in elderly critically ill patients. A Nomogram model was constructed based on the results of the regression analysis. Area under the curve (AUC) of ROC curve for internal validation by the Bootstrap method was 0.802 (95%CI, 0.796 to 0.809). The calibration curve was close to the standard curve, and the predicted values were generally consistent with the actual values, demonstrating good predictive performance of the model. Conclusion Age, renal dysfunction, consciousness status, duration of catheterization, and the number of catheter insertions are independent influencing factors for CAUTI in elderly critically ill patients. Nomogram prediction model established based on these factors is simple and feasible, with reliable predictive performance.

Objective:To figure out the timing of zeroing and the location of the zero line in the central venous pressure (CVP) monitoring and invasive arterial blood pressure (IBP) monitoring, and to provide scientific and accurate data for patients management.Methods:The liquid vessel models were used to simulate the pressure measurement process of the continuous pressure monitoring system. Based on the theory of fluid mechanics and the knowledge of blood pressure physiology and cardiovascular anatomy, the composition and influencing factors of the pressure in the fluid-filled catheter system during the zeroing and placing the transducer in the zero line of CVP and IBP, were analyzed.Results:The pressure in the liquid-filled catheter system was composed of atmospheric pressure, the pressure of pumping bag, the gravity of the water column (the vertical distance between the liquid level of Murphy's dropper and pressure transducer, ΔH), and the resistance of tube wall. This pressure value is set as a pressure of 0 mmHg (1 mmHg ≈ 0.133 kPa). In the process of pressure measurement, when the pressure transducer was placed at a horizontal position of 10 cm below the highest liquid level of the vessel, the pressure measured at different catheter tip positions was all 10 cmH 2O (1 cmH 2O ≈ 0.098 kPa); When the pressure transducer was placed at the horizontal position of the highest liquid level of the vessel, the measured pressure is 0 mmHg. Conclusion:Zeroing should repeatedly be performed only when one or more conditions (atmospheric pressure, pressure of pumping bag, gravity of ΔH water column and resistance of tube wall) are changed. In the measurement process, the pressure transducer should be placed at the zero line position at any time to eliminate the influence of hydrostatic pressure and to ensure the objective and accurate value.