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This Article Full Text (PDF) All Versions of this Article: chest.07-2011v1 133/3/697    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to My Personal Article Archive Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Banner, M. J. Articles by Gentile, M. A. Search for Related Content PubMed PubMed Citation Articles by Banner, M. J. Articles by Gentile, M. A.

Ventilator advisory system employing load and tolerance strategy recommends appropriate pressure support ventilation settings: Multi-site validation study

Michael J. Banner, PhD^*; Neil R. Euliano, PhD; Neil R. MacIntyre, MD; A. Joseph Layon, MD^*; Steven Bonett, RRT^* and Michael A. Gentile, RRT

^* University of Florida, College of Medicine, Departments of Anesthesiology, Physiology, and Surgery, Gainesville, Florida Convergent Engineering, Gainesville, Florida Duke University Medical Center, Division of Pulmonary and Critical Care Medicine, Durham, North Carolina; and University of Manitoba, Department of Medicine, Winnipeg, Manitoba, Canada

MBanner{at}anest.ufl.edu

Abstract

BackgroundLoads on the respiratory muscles, reflected by non-invasively measured power of breathing (POB_N), and tolerance of these loads, reflected by spontaneous breathing frequency (f) and tidal volume (V_T), should be considered when evaluating patients with respiratory failure. Pressure support ventilation (PSV) should be applied so that muscle loads are not too high or low. We propose a computerized, ventilator advisory system employing a load (POB_N) and tolerance (f and V_T) strategy in a fuzzy logic algorithm to provide guidance for setting PSV. To validate these recommendations, we performed a multi-site study comparing the advisory system recommendations to experienced physician decisions.

MethodsAdults (n = 87) from three university sites receiving PSV had data from a combined pressure/flow sensor, positioned between the endotracheal tube and Y-piece of the ventilator breathing circuit, directed to the advisory system. Recommendations from the advisory system for increasing, maintaining, or decreasing PSV were compared at specific time points to decisions made by physician intensivists at the bedside.

ResultsThere were no significant differences in recommendations by the advisory system (n = 210) compared to those of physician intensivists to increase, maintain, or decrease PSV (p > 0.05). Physician intensivists agreed with 90.5% of all recommendations. The advisory system was very good at predicting intensivists decisions (r² = 0.90, p < 0.05) in setting PSV.

ConclusionsThe novel load and tolerance strategy of the advisory system provided automatic and valid recommendations for setting PSV to appropriately unload the respiratory muscles that were as good as the clinical judgment of physician intensivists.

Key Words: Work of breathing • Mechanical ventilation • Pressure support ventilation • Acute respiratory failure • Respiratory monitoring