Reproducibility of respiratory mechanics measurements in patients on invasive mechanical ventilation

ABSTRACT Objective: To evaluate the intra- and interexaminer reproducibility of measurements of the resistance and static and dynamic compliance of the respiratory system in patients on mechanical ventilation. Methods: This was an analytical study conducted with individuals aged ≥ 18 years who were on invasive mechanical ventilation and had no clinical diagnosis of respiratory system disease and/or chest abnormality. Three measurements of respiratory mechanics were performed with a 1-minute interval between them. The first and third measurements were performed by examiner A, the second by examiner B. The values for the resistance and static and dynamic compliance of the respiratory system were compared using the intraclass correlation coefficient. Results: A total of 198 measurements of respiratory mechanics were performed for 66 patients on mechanical ventilation. The patients had a mean age of 52.6 ± 18.6 years and a mean body mass index of 21.6 ± 2.1kg/m2; a surgical profile (61.5%) and female sex (53.8%) were predominant. Mean values were obtained for the three measurements of respiratory system resistance (A1: 15.7 ± 6.8cmH2O/L/s; B1: 15.7 ± 6.4cmH2O/L/s and A2: 15.9 ± 6.2cmH2O/L/s), respiratory system static compliance (A1: 42.1 ± 13.7mL/cmH2O; B1: 42.4 ± 14.6mL/cmH2O and A2: 42.2 ± 14.5mL/cmH2O) and respiratory system dynamic compliance (A1: 21.3 ± 7.3mL/cmH2O; B1: 21.4 ± 7.5mL/cmH2O and A2: 21.3 ± 6.2mL/cmH2O). The intraclass correlation coefficient was also calculated for respiratory system resistance (R = 0.882 and p = 0.001; R = 0.949 and p = 0.001 - interexaminer A1 versus B and B versus A2, respectively; R = 0.932 and p = 0.001 - intraexaminer); respiratory system static compliance (R = 0.951 and p = 0.001; R = 0.958 and p = 0.001 - interexaminer A1 versus B and B versus A2, respectively; R = 0.965 and p = 0.001 - intraexaminer) and respiratory system dynamic compliance (R = 0.957 and p = 0.001; R = 0.946 and p = 0.001 - interexaminer A1 versus B and B versus A2, respectively; R = 0.926 and p = 0.001 - intraexaminer). Conclusion: The measurements of resistance and static and dynamic compliance of the respiratory system show good intra- and interexaminer reproducibility for ventilated patients.

摘要
研究目的：评估机械通气（mechanical ventilation）患者呼吸系统阻力、静态顺应性与动态顺应性测量结果的检查者内及检查者间重复性。
研究方法：本研究为分析性研究，纳入年龄≥18岁、接受有创机械通气（invasive mechanical ventilation）且无呼吸系统疾病及/或胸部异常临床诊断的受试者。共开展3次呼吸力学测量，每次测量间隔1分钟。首次及第3次测量由检查者A完成，第二次测量由检查者B完成。采用组内相关系数（intraclass correlation coefficient, ICC）比较呼吸系统阻力、静态及动态顺应性的测量值。
研究结果：本研究共为66名机械通气患者完成198次呼吸力学测量。受试者平均年龄为52.6±18.6岁，平均体重指数为21.6±2.1kg/m²；其中61.5%为外科手术患者，53.8%为女性。三次测量的呼吸系统阻力均值分别为：A1：15.7±6.8cmH₂O/(L·s)、B1：15.7±6.4cmH₂O/(L·s)、A2：15.9±6.2cmH₂O/(L·s)；呼吸系统静态顺应性均值分别为：A1：42.1±13.7mL/cmH₂O、B1：42.4±14.6mL/cmH₂O、A2：42.2±14.5mL/cmH₂O；呼吸系统动态顺应性均值分别为：A1：21.3±7.3mL/cmH₂O、B1：21.4±7.5mL/cmH₂O、A2：21.3±6.2mL/cmH₂O。针对各指标计算组内相关系数结果如下：呼吸系统阻力的检查者间重复性（A1与B、B与A2）分别为R=0.882、p=0.001与R=0.949、p=0.001，检查者内重复性为R=0.932、p=0.001；呼吸系统静态顺应性的检查者间重复性分别为R=0.951、p=0.001与R=0.958、p=0.001，检查者内重复性为R=0.965、p=0.001；呼吸系统动态顺应性的检查者间重复性分别为R=0.957、p=0.001与R=0.946、p=0.001，检查者内重复性为R=0.926、p=0.001。
研究结论：针对机械通气患者，呼吸系统阻力、静态顺应性与动态顺应性的测量结果具有良好的检查者内及检查者间重复性。