Noninvasive motion ventilation (NIMV): a novel approach to ventilatory support

A motion platform was developed that oscillates an animal in a foot-to-head direction (z-plane). The platform varies the frequency and intensity of ac celeration, imparting periodic sinusoidal inertial forces (pG(z)) to the bo dy. The aim of the study was to characterize ventilation produced by the no ninvasive motion ventilator (NIMV) in animals with healthy and diseased lun gs. Incremental increases in pG(z) (acceleration) with the frequency held c onstant (f = 4 Hz) produced almost linear increases in minute ventilation ( VE). Frequencies of 2-4 Hz produced the greatest V(over dot)(E) and tidal v olume (VT) for any given acceleration between +/-0.2 and +/-0.8 G. Increasi ng the force due to acceleration produced proportional increases in both tr anspulmonary and transdiaphragmatic pressures. Increasing transpulmonary pr essure by increasing pG(z) produced linear increases in V-T, similar to spo ntaneous breathing. NIMV reversed deliberately induced hypoventilation and normalized the changes in arterial blood gases induced by meconium aspirati on. In conclusion, a novel motion platform is described that imparts period ic sinusoidal acceleration forces at moderate frequencies (4 Hz) to the who le body in the z-plane. These forces, when properly adjusted, are capable o f highly effective ventilation of normal and diseased lungs. Such noninvasi ve ventilation is accomplished at airway pressures equivalent to atmospheri c or continuous positive airway pressure, with acceleration forces less tha n +/-1 G(z).