Position-dependent distribution of lung ventilation — A feasability study

The aim of this feasibility study was to determine whether the measurement setup and study protocol were able to show the effect that lung disease, body position and different levels of positive end expiratory pressure (PEEP) have on lung function. By means of a motorized rotation table and gravity sensors six pigs were rotated in steps of 30° from left to right lateral position. Regional ventilation distributions, measured by electrical impedance tomography (EIT), oxygenation and compliance measurements were performed at each position. Both, experimental and measurement setup as well as the parameters chosen to characterize lung function appear suitable for analyzing the effects of PEEP and rotation in healthy and injured lungs. The initial results show that the distribution of regional ventilation was highly gravity-dependent especially in sick lungs. Furthermore lateral rotation showed significant recruitment effects on previously collapsed lung tissue as witnessed by the increases in oxygenation at all PEEPs.