Respiratory Inductance Plethysmography (RIP) for Assessment of Lung Volume Changes (ΔVL) During High Frequency Oscillatory Ventilation (HFOV)† 1183

A clinically applicable and reliable method to assess ΔVL in infants on HFOV could be of value to neonatologists when attempting to optimize gas exchange. We hypothesized that lung volume recruitment, ΔVL, could be accurately measured in both normal and saline-lavage induced RDS, using DC-coupled RIP. In five anesthetized, paralyzed and tracheostomized piglets(wt: 2-4 kg, age: 5-10 days), we compared estimates of ΔVL measured simultaneously by RIP and body plethysmography (PL) before and after saline lung lavage. HFOV (SensorMedics 3100) settings were 8 Hz and pressure amplitudes of 50 pre- and 60 cmH2O post-lavage. Mean airway pressures (Paw) were varied between 6-14 and 10-26 cmH2O pre- and post-lavage respectively. Estimates of ΔVL from RIP and PL were in close agreement pre-and post-lavage, both: 1) during active recruitment (R=0.83-0.97; slope=0.76-1.16); and 2) at steady state (see example ΔVL @ Plateau, Figure). We conclude that RIP may have clinical application for determining optimal ΔVL during HFOV, thereby avoiding lung under- and over-distension.

Figure 1