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（static compliance）与动态顺应性（dynamic compliance）测量的组内及组间重现性。
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）且无呼吸系统疾病或胸部异常临床诊断的受试者。对每名受试者进行3次呼吸力学（respiratory mechanics）测量，每次测量间隔1分钟。测量者A完成第1、3次测量，测量者B完成第2次测量。采用组内相关系数（intraclass correlation coefficient）比较呼吸系统阻力、静态及动态顺应性的测量值。
研究结果：本研究共纳入66例机械通气患者，完成198次呼吸力学测量。受试者平均年龄为52.6±18.6岁，平均体质量指数为21.6±2.1kg/m²；以外科手术患者（61.5%）及女性（53.8%）居多。3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。组内相关系数计算结果显示：呼吸系统阻力的组间相关系数（测量者A1与B、B与A2分别为R=0.882、P=0.001和R=0.949、P=0.001；组内相关系数为R=0.932、P=0.001）；呼吸系统静态顺应性的组间相关系数（测量者A1与B、B与A2分别为R=0.951、P=0.001和R=0.958、P=0.001；组内相关系数为R=0.965、P=0.001）；呼吸系统动态顺应性的组间相关系数（测量者A1与B、B与A2分别为R=0.957、P=0.001和R=0.946、P=0.001；组内相关系数为R=0.926、P=0.001）。
研究结论：针对机械通气患者，呼吸系统阻力、静态及动态顺应性的测量具有良好的组内与组间重现性。