Stress Index Can Be Accurately and Reliably Assessed by Visually Inspecting Ventilator Waveforms

Area of Science:

• Critical Care Medicine
• Respiratory Physiology
• Mechanical Ventilation

Background:

• The stress index (SI) aids in detecting injurious ventilation patterns and personalizing ventilator settings.
• Quantitative SI analysis requires specialized equipment, limiting clinical use.
• This study explored qualitative SI assessment via visual waveform inspection.

Purpose of the Study:

• To determine if the stress index (SI) can be accurately assessed by visually inspecting ventilator pressure-time curves.
• To evaluate the reliability of qualitative SI assessment compared to quantitative methods.

Main Methods:

• Thirty-six adult patients on volume-controlled ventilation were studied.
• Clinicians qualitatively assessed pressure-time curve shapes (linear, downward concavity, upward concavity).
• Quantitative SI analysis served as the reference standard for comparison.

Main Results:

• Visual inspection achieved 93% overall accuracy in classifying pressure-time curve shapes.
• Weighted kappa statistic was 0.88, indicating strong agreement.
• High sensitivity and specificity were observed for distinguishing different curve shapes.

Conclusions:

• Visual inspection of ventilator pressure-time curves is a simple and reliable method for bedside SI assessment.
• This approach can potentially facilitate the clinical implementation of SI for personalized mechanical ventilation.