2006 OPEN FORUM Abstracts
Respiratory monitor employing a load vs. tolerance strategy recommends appropriate pressure support ventilation settings: clinical validation study
Michael A. Gentile RRT FAARC, Chun-Cheih Yang MD,
John D. Davies
RRT FAARC, Neil R. MacIntyre MD, FAARC
Duke
University
Medical
Center
,
Durham
,
NC
Background: Assessments of respiratory muscle loads,
reflected by power of breathing (work of breathing / min), and tolerance of these
loads, reflected by spontaneous breathing frequency ( f ) and tidal volume (VT),
are fundamental for patient management. Pressure support ventilation (PSV)
should be adjusted so that muscle loads are not too high or low, predisposing
to fatigue and atrophy. To address these conditions, we evaluated a respiratory
monitor employing a fuzzy logic inference system using an artificial neural
network for the non-invasive calculation of power of breathing (POBN),1 combined with f and VT to
make recommendations for setting appropriate PSV. To validate these
recommendations, we performed a clinical trial.
Methods: 30
adult patients (age 59 ± 16 yrs, wt. 92 ± 32 kg) receiving PSV were enrolled in
an IRB approved study. Data from a combined CO2/flow sensor,
positioned between the endotracheal tube and Y-piece of the ventilator
breathing circuit, were directed to a monitor (NICO2, Respironics,
Wallingford
,
CT
) and computer (Convergent Engineering,
Gainesville
,
FL
) for measurements of POBN, f and VT.
Recommendations from the monitor (to increase, maintain, or decrease PSV) for
setting PSV were examined for validity (accuracy) by a clinical team (MD and
RRT).
Results: The
range of PSV for all subjects enrolled in the study was 5 - 25 cm H2O.
There were a total of 94.5% agreements (p < 0.05); (79 agreements out of 84
recommendations) between all recommendations from the monitor when compared
with those from the clinical team.
Conclusion: Valid
recommendations for setting PSV to appropriately unload the respiratory muscles
were provided by the monitor. A respiratory monitor employing a complimentary load
(POBN) and tolerance (f and VT) strategy for assessing
patients with respiratory failure provides clinically valid recommendations for
setting PSV.
1. Banner et al, Crit Care Med 2006; 34: 1052 - 1059.