Meconium aspiration syndrome (MAS) is a frequent cause of respiratory distress in neonates. Recent reports have suggested that surfactant dysfunction contributes to the pathophysiology of MAS and surfactant therapy improves oxygenation of infants with MAS. We evaluated the effect of bronchial lavage with surfactant solution in a rabbit model of meconium aspiration. All animals were given 5 mL/kg of a 20% slurry of human meconium into the endotracheal tube and mechanically ventilated. The animals were then divided into saline lavage (n = 5) or surfactant lavage (n = 5). Lavage was performed an hour after meconium instillation. After the lavage the total amount of meconium recovered was measured. Blood gas was monitored during the experiment. The amount of meconium recovered by saline lavage was 14%, and by surfactant lavage was 57%. The surfactant group had a significant improvement in gas exchange, whereas the saline group had no improvement. It was concluded that the lavage with surfactant solution effectively washed out meconium and improved gas exchange in rabbit model of MAS.

Some infants, despite being born at low gestations (< 28 weeks gestational age) do not develop RDS and are not surfactant treated. The changes in lung function during the neonatal period in such infants have not been explored, hence it is unknown whether they are similar to those of surfactant treated infants with RDS of similar gestational age. Such data would facilitate assessment of the impact of surfactant administration on the lung function abnormalities of very immature infants with RDS. We, therefore, compared the results of neonatal lung function measurements from immature infants with RDS who received surfactant to those from infants with non-RDS respiratory distress not so treated and matched to the RDS infants for gestational age and within 10% of birthweight. Compliance and functional residual capacity (FRC) were measured daily for the first five days and then at 1, 2 and 4 weeks in 16 infants, median gestational age 27 weeks (range 25-27 weeks). Although exogenous surfactant administration to the immature infants with RDS was associated with improvements in lung function, the non RDS, non surfactant treated infants had both higher compliance (p < 0.05) and lung volumes (p < 0.01) throughout the perinatal period. These results demonstrate surfactant administration does not fully correct the perinatal lung function abnormalities of very immature infants with RDS.

Patients with high serum ferritin and low transferrin saturation (TSAT) levels could be considered as presenting with dysutilization of iron for erythropoiesis. However, the long-term safety of iron administration in these patients has not been well established. An observational multicenter study was performed over 3 years. In 805 patients undergoing maintenance hemodialysis (MHD), we defined dysutilization of iron for erythropoiesis in patients with lower TSAT (<20%) and higher ferritin (�100 ng/mL) levels. A time-dependent Cox hazard model was used for the evaluation of the association between dysutilization of iron for erythropoiesis and adverse events and survival. Patients with low TSAT levels showed an increased risk of cerebrovascular and cardiovascular disease (CCVD) and death compared to patients with normal or higher TSAT levels. Patients with low ferritin and high TSAT levels had a significantly lower risk of CCVD and death compared with patients with high ferritin and low TSAT levels. Higher TSAT levels were associated with male gender, age, the absence of diabetes, low levels of high-sensitivity CRP, and low β2 microglobulin levels, but not with intravenous iron administration or ferritin levels. Although patients with low TSAT levels had a significantly higher risk of CCVD or death, high TSAT levels were not linked with iron administration. Patients, who were suspected of dysutilization of iron for erythropoiesis, had a higher risk of CCVD and death. The administration of iron should be performed cautiously for improving TSAT levels, as iron administration could sustain TSAT levels for a short term.

ObjectiveIt has been reported that hyporesponsiveness to erythropoiesis-stimulating agent (ESA) is associated with adverse events in patients on maintenance hemodialysis (MHD). However, it has not been determined whether higher iron storage is associated with an improved response, including better survival, to ESA.Design and MethodWe measured serum ferritin, hemoglobin (Hb), and transferrin saturation (TSAT) levels every three months for two years in 1,095 MHD patients. The weekly dose of ESA to Hb ratio was also calculated as an index of ESA responsiveness (ERI).ResultsA significant correlation (p<0.001, R = 0.89) between ferritin and Hb was only observed in the patients with ferritin levels <50 ng/mL. High-dose (≥50 mg/week) intravenous iron administration, female sex, low serum albumin, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use were significant predictors of a high ERI value (>280); however, serum ferritin and TSAT levels did not predict a higher ERI. In the time-dependent Cox hazard model, the risk for a composite event in the patients with a high ERI (≥280) and a high ferritin level (≥100 ng/mL) was significantly greater (hazard ratio [HR], 2.09, P = 0.033) than that for patients with a high ERI and a low ferritin (<100 ng/mL) level.ConclusionHb was dependent upon ferritin levels in patients with ferritin levels <50 ng/mL but not in patients with ferritin levels ≥50 ng/mL. Patients with hyporesponsiveness to ESA had a greater risk of composite events, but ERI was unrelated to iron storage.