RT Journal Article
SR Electronic
T1 Stress Index Can Be Accurately and Reliably Assessed by Visually Inspecting Ventilator Waveforms
JF Respiratory Care
FD American Association for Respiratory Care
SP 1094
OP 1101
DO 10.4187/respcare.06151
VO 63
IS 9
A1 Sun, Xiu-Mei
A1 Chen, Guang-Qiang
A1 Chen, Kai
A1 Wang, Yu-Mei
A1 He, Xuan
A1 Huang, Hua-Wei
A1 Luo, Xu-Ying
A1 Wang, Chun-Mei
A1 Shi, Zhong-Hua
A1 Xu, Ming
A1 Chen, Lu
A1 Fan, Eddy
A1 Zhou, Jian-Xin
YR 2018
UL http://rc.rcjournal.com/content/63/9/1094.abstract
AB 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: Thirty-six 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. (ClinicalTrials.gov registration NCT03096106.)