Abstract 44

Background. Dynamic pulmonary imaging (DPI) is a rapid, non-invasive, fluoroscopic method with low radiation dose to study ventilatory disorders. We used DPI for the assessment of ventilatory changes in experimental meconium aspiration.

Materials. 18 neonatal (< 3 days old) anesthetized and ventilated piglets with right lung meconium (N=7), saline (N=7) or no aspiration (controls, N=4) were studied.

Measurements. One ventilation cycle of thorax imaging before and 15, 30, 60, 90, 120, 150, 180, 210 and 240 min after aspiration was measured. Changes in the right/left lung relative level (LVL) and amplitude (AMP), reflecting X-ray transmittance and its variation through the chest, were calculated. Low values indicate poor pulmonary ventilation.

Results. Both LVL and AMP decreased similarly during the study period after meconium or saline instillation (Wald test, p<0.001). LVL was significantly (p<0.05) lower in meconium than control group at 15 min, but no differences between saline and control groups were found. AMP was significantly lower in meconium group at 15, 30, 60, 120, 210 and 240 min and in saline group at 15, 30, 60, 120 and 210 min, when compared to controls.

Conclusions. DPI is a sensitive method for evaluating ventilatory disturbances in perinatal aspiration syndromes and may prove to be a useful bedside method for the detection of ventilatory disturbances in NICUs.