The Science Journal of the American Association for Respiratory Care

2008 OPEN FORUM Abstracts

VENTILATOR ADVISORY SYSTEM RECOMMENDS APPROPRIATE PRESSURE SUPPORT VENTILATION SETTINGS: VALIDATION STUDY

S. Bonett1,3, N. R. Euliano2, C. Peters1, A. J. Layon1, E. Elamin1, A. Gabrielli1, Michael J. Banner1



Background: The purpose of the study was to validate recommendations from a computerized Advisory System employing fuzzy logic for setting pressure support ventilation (PSV) compared to recommendations of critical care RRTs. Forty-four adults (32 males, 12 females, 62 ± 15 yrs, 97 ± 30 kg) with respiratory failure from various etiologies were studied (IRB approved). RRTs used spontaneous breathing frequency ( f ) between 15 - 25 / min, tidal volume (VT) between 6 - 8 ml / kg, absence of accessory respiratory muscle use, and breathing comfort for making recommendations to decrease, maintain, or increase PSV. Their recommendations were compared to those of the Advisory System, which uses the same f and VT criteria, plus non-invasive power of breathing (work of breathing / min)1 between 5 - 10 Joules / min for recommending PSV settings. Data were analyzed using X2 and a Kappa statistic (K) (reflects the strength of agreement), alpha was set at 0.05.
PSV ranged from 5 to 18 cm H2O. No significant differences in recommendations were made by the Advisory System compared to those of RRTs for setting PSV (X2 = 0.49, p > 0.05). There was 90% agreement between the Advisory System and RRTs. K was 0.80 (K from 0.61 to 0.80 indicates substantial agreement). There were significantly many more recommendations by the Advisory System and RRTs to decrease PSV than to maintain or increase it (table).
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 experienced, critical care RRTs. The treatment philosophy of the RRTs the majority of time was to wean down PSV, the Advisory System reflected this approach.

1. Banner et al, Crit Care Med, 2006; 34: 1052