Journal of Capital Medical University ›› 2022, Vol. 43 ›› Issue (5): 728-733.doi: 10.3969/j.issn.1006-7795.2022.05.010

• Protective Assist / Support Ventilation • Previous Articles     Next Articles

Accuracy of automatic measurement of airway occlusion pressure by ventilator: bench and clinical study

Zhang Linlin, Tian Ye*, Miao Mingyue, Duan Yuqing, Tian Ying, Zhou Jianxin   

  1. Department of Intensive Care Unit, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
  • Received:2022-08-08 Online:2022-10-21 Published:2022-10-25
  • Contact: * E-mail: lbjssky@163.com
  • Supported by:
    Capital Research and Translational Application of Clinical Diagnosis and Treatment Technology(Z201100005520050).

Abstract: Objective To investigate the agreement of the airway occlusion pressure (P0.1) measured automatically by the ventilator with the standard measurement method, and the influence of different types of trigger on the automatic measurement. Methods Ventilator with automatic measurement of P0.1 using the unoccluded fitting method was selected. Bench and clinical studies were conducted in a lung simulator and mechanically ventilated patients. A total of 48 conditions were adjusted to simulate different statuses of respiratory effort and mechanics. The tested ventilator was used to deliver the pressure support ventilation to the simulator. The clinical study included 15 adult patients undergoing pressure support ventilation. In both bench and clinical studies, the pressure and flow trigger were used as random crossover. After collecting the P0.1 automatically monitored by the ventilator, the standard end-expiratory airway occlusion was performed to measure the P0.1 as the standard reference value. The Bland-Altman test was used to analyze the agreement between the ventilator monitoring value and the standard reference value, and the bias (ventilator monitoring value-standard reference value) and 95% limit of agreement were calculated. Bias in P0.1 measurement of the two triggering methods was compared. Results In the simulated lung validation, the bias (95% limit of agreement) in P0.1 measurement during pressure and flow trigger was 0.04 (-0.63-0.70) and -0.54 ( -1.44-0.36) cmH2O, respectively, which was statistically significant (P<0.001). Similar results were obtained in clinical studies, with the bias (95% limit of agreement) at pressure and flow triggering of -0.11 (-0.73-0.52) and -0.54 (-1.50-0.59) cmH2O, respectively, which was also statistically significant. Conclusion During pressure trigger, an excellent agreement was found in P0.1 measured by the ventilator the standard method. However, the ventilator measurement significantly underestimates P0.1 during flow trigger. It is recommended to switch to pressure trigger during automatic monitoring of P0.1 by ventilator.

Key words: mechanical ventilation, spontaneous breathing, respiratory effort, airway occlusion pressure, ventilator

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