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- Title
Stress Index Can Be Accurately and Reliably Assessed by Visually Inspecting Ventilator Waveforms.
- Authors
Xiu-Mei Sun; Guang-Qiang Chen; Kai Chen; Yu-Mei Wang; Xuan He; Hua-Wei Huang; Xu-Ying Luo; Chun-Mei Wang; Zhong-Hua Shi; Ming Xu; Lu Chen; Eddy Fan; Jian-Xin Zhou
- Abstract
BACKGROUND: Stress index provides a noninvasive approach to detect injurious ventilation patterns and to personalize ventilator settings. Obtaining the stress index (SI), however, requires quantitatively analyzing the shape of pressure-time curve with dedicated instruments or a specific ventilator, which may encumber its clinical implementation. We hypothesized that the SI could be qualitatively determined through a visual inspection of ventilator waveforms. METHODS: Thirtysix adult subjects undergoing volume controlled ventilation without spontaneous breathing were enrolled. For each subject, 2 trained clinicians visually inspected the pressure-time curve directly from the ventilator screen. They then qualitatively categorized the shape of pressure-time curve as linear, a downward concavity, or an upward concavity at the bedside. We simultaneously recorded airway pressure and flow signals using a dedicated instrument. A quantitative off-line analysis was performed to calculate the SI using specific research software. This quantitative analysis of the SI served as the reference method for classifying the shape of the pressure-time curve (ie, linear, a downward concavity, or an upward concavity). We compared the SI categorized by visual inspection with that by the reference. RESULTS: We obtained 200 SI assessments of pressure-time curves, among which 125 (63%) were linear, 55 (27%) were a downward concavity, and 20 (10%) were an upward concavity as determined by the reference method. The overall accuracy of visual inspection and weighted kappa statistic (95% CI) was 93% (88-96%) and 0.88 (0.82-0.94), respectively. The sensitivity and specificity to distinguish a downward concavity from a linear shape were 91% and 98%, respectively. The respective sensitivity and specificity to distinguish an upward concavity from a linear shape were 95% and 95%. CONCLUSIONS: Visual inspection of the pressure-time curve on the ventilator screen is a simple and reliable approach to assess SI at the bedside. This simplification may facilitate the implementation of SI in clinical practice to personalize mechanical ventilation.
- Subjects
LUNG injuries; APACHE (Disease classification system); ARTIFICIAL respiration; CLINICAL trials; CONFIDENCE intervals; HOSPITALS; LONGITUDINAL method; SCIENTIFIC observation; PROBABILITY theory; QUESTIONNAIRES; RESEARCH funding; STATISTICAL hypothesis testing; STATISTICS; PHYSIOLOGICAL stress; MECHANICAL ventilators; WAVE analysis; DATA analysis software; RESPIRATORY mechanics; DESCRIPTIVE statistics; INJURY risk factors
- Publication
Respiratory Care, 2018, Vol 63, Issue 9, p1094
- ISSN
0020-1324
- Publication type
Article
- DOI
10.4187/respcare.06151