GOALI: A New Paradigm for Mechanical Ventilation

Trustees Of Boston University, Boston

Investigators

Abstract

0076818 Lutchen Objective: Two crucial deficiencies associated with pulmonary care during mechanical ventilation are:1) inadequate diagnostics on mechanical function; and 2) the propensity for ventilator induced lung injury. The first prevents efficient weaning of patients off of mechanical ventilation while the second can initiates or exacerbates a condition known as Adult Respiratory Distress Syndrome (ARDS). In this GOALI grant we will collaborate with Mallinckrodt, Inc., the world leader in mechanical ventilators, Tufts University School of Veterinary Medicine, and the Harvard Medical School to advance a new paradigm in ventilation that can solve both deficiencies. Recently, we invented an Enhanced Ventilation Waveform (EVW) and a methodology that, in principal, is "friendly" with current commercial ventilator platforms (). The EVW is a broadband waveform that combines the energies from all its frequencies in an ingenious manner. The resulting waveshape permits reliable estimates of respiratory resustance and elastance (R and E) from 0.1 - 8 Hz while simultaneously ventilating the subject with typical tidal excursions on each breath. These data can allow differentiation from among categories of structural alterations in the lung due to disease. Likewise, we have proposed a potential solution to prevent ventilator induced lung injury; namely the application of noisy or "variable ventilation" (VV). In conventional ventilation (CV) the same tidal volume and breathing period are applied on every breath. In VV the tidal volume and breath time are varied from breath-to-breath while mean ventilation is maintained (somewhat akin to natural breathing). Our group has proposed a mechanism by which VV would minimize injury. Hence, in this grant we will expand our relation with Mallinckrodt, Inc. to test the following two hypotheses: 1) If delivered clinically, the EVW would provide enhanced diagnostic information on lung mechanics, and, because it contains higher frequency components, will simultaneously provide improved ventilation distribution and blood gas levels compared to any existing CV waveforms; and 2) The EVW and VV concepts are synergistic permitting a new EVW-VV paradigm in mechanical ventilation that will a) provide continuous monitoring of the mechanical conditions in the lung; b) provide superior gas exchange compared to other modes of CV; and c) avoid or minimize the risk of ventilator induced injury. To test these hypotheses we will advance several new technologies. Our specific aims are: 1. To develop technology for delivery of an EVW and a stochastic based VV pattern with currently used commercial ventilators, and then to combine this VV pattern with the EVW on a breath-by-breath basis. One key aspect of this challenge is to develop an adaptive feedback approach for insuring delivery and monitoring of the desired EVW to the patient through a long compliant patient tubing circuit. 2. To experimentally evaluate in a sheep model of asthmatic like constriction the efficacy of the EVW waveform for monitoring lung mechanics in the time and frequency domains and for improving ventilation distribution. 3. To evaluate the diagnostic, preventative and therapeutic benefits of the combined EVW-VV approach via experimental studies in a Sheep model of ARDS.