Abstract 13398: Assessment of a Continuous Monitoring Technique to Measure Adequacy of Respiration
Abstract: Objective: Respiratory status is not adequately monitored in non-intubated patients. Decisions rely on O2 saturation, respiratory rate & subjective assessment. The more important objective parameter of minute ventilation is not measured. We evaluated a non-invasive, lead-based Respiratory Variation Measurement (RVM) which provides continuous, quantitative, real time assessment of tidal volume & minute ventilation.
Methods: Respiratory signals from 5 anatomically determined lead configurations collected using an impedance-based RVM system were run through advanced algorithms (523 tests, 25 visits, 9 adult subjects). Simultaneous spirometry measurements (tidal volume & minute ventilation during normal breathing, slow breathing, erratic breathing) were obtained. RVM accuracy & precision were assessed compared to spirometry values.
Results: RVM data correlated strongly with spirometer volume measurements in all breathing maneuvers. Across all subjects, median correlation, r, for the 5 lead configurations ranged from 0.88 -0.99, with a maximum of r = 0.99 for configuration “β”. A mixed effects ANOVA analysis (subject is a random effect) discriminated (p < 0.001) for lead placement β vs 4 other lead placements. A calibration algorithm compensated for variability between patients. Calibrated RVM measurements in configuration β were most accurate (10% mean error). Data from RVM was noted to be adequate for advanced analysis of respiratory curve parameters & complexity.
Conclusions: Lead placement & a calibration algorithm enable RVM data to be used to calculate tidal volume and minute ventilation. RVM shows promise to be a new clinical parameter of respiratory adequacy, providing an early indication of respiratory compromise and assisting clinical decision making regarding the necessity of intubation and earlier intervention. Use of RVM could improve resuscitation protocols and patient outcomes while reducing overall health care costs.
- © 2011 by American Heart Association, Inc.