Evaluation of an electrical impedance tomography-based global inhomogeneity index for pulmonary ventilation distribution

Abstract

The GI index quantifies the gas distribution in the lung with a single number and reveals good interpatient comparability.

Effect of time and body position on ventilation in premature infants

“…In this study the GI index was used as an indicator of overall change in inhomogeneity of ventilation quantifying the total volume distribution within the lungs (23). The median value of difference in impedance between end inspiration and end expiration was calculated.…”

“…The median value of each tidal image was generated and then the sum of all differences between individual pixels calculated. This sum was then normalized to the number of pixels analyzed to make the GI universal (23). A higher GI index value is equivalent to a greater ventilation inhomogeneity.…”

“…Even though ventilation homogeneity was affected after handling, our results demonstrated that after 2 h there were minimal changes in GI in all three study groups. The changes occurring in the spontaneously breathing infants were less apparent, most likely because healthy lungs have a more homogenous distribution of air when compared with diseased lungs with low positive end-expiratory pressure (PEEP) (23,24).…”

Optimizing Perioperative Ventilation Support with Adequate Settings of Positive End-Expiratory Pressure

“…Dargaville et al have applied EIT during an incremental and decremental PEEP trial to identify the PEEP level at which the most homogeneous distribution of regional C rs and ventilation was observed in healthy, injured and surfactant-treated lungs (Dargaville et al, 2010). Zhao and colleagues applied the global inhomogeneity (GI) index (Zhao et al, 2009) to facilitate the PEEP titration in mechanically ventilated patients undergoing orthopedic surgery (Zhao et al, 2010) (Fig. 9).…”

“…Lung regions with the highest ventilation are coded in red. Bottom: global inhomogeneity (GI) index (Zhao et al, 2009) versus PEEP. The minimum value of GI index implies the PEEP level at which ventilation distribution is most homogeneous.…”