Fluid balance in critically ill children with acute lung injury.

OBJECTIVES: In the Fluid and Catheter Treatment Trial (NCT00281268), adults with acute lung injury randomized to a conservative vs. liberal fluid management protocol had increased days alive and free of mechanical ventilator support (ventilator-free days). Recruiting sufficient children with acute lung injury into a pediatric trial is challenging. A Bayesian statistical approach relies on the adult trial for the a priori effect estimate, requiring fewer patients. Preparing for a Bayesian pediatric trial mirroring the Fluid and Catheter Treatment Trial, we aimed to: 1) identify an inverse association between fluid balance and ventilator-free days; and 2) determine if fluid balance over time is more similar to adults in the Fluid and Catheter Treatment Trial liberal or conservative arms. DESIGN: Multicentered retrospective cohort study. SETTING: Five pediatric intensive care units. PATIENTS: Mechanically ventilated children (age≥1 month to <18 yrs) with acute lung injury admitted in 2007-2010. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Fluid intake, output, and net fluid balance were collected on days 1-7 in 168 children with acute lung injury (median age 3 yrs, median PaO2/FIO2 138) and weight-adjusted (mL/kg). Using multivariable linear regression to adjust for age, gender, race, admission day illness severity, PaO2/FIO2, and vasopressor use, increasing cumulative fluid balance (mL/kg) on day 3 was associated with fewer ventilator-free days (p=.02). Adjusted for weight, daily fluid balance on days 1-3 and cumulative fluid balance on days 1-7 were higher in these children compared to adults in the Fluid and Catheter Treatment Trial conservative arm (p<.001, each day) and was similar to adults in the liberal arm. CONCLUSIONS: Increasing fluid balance on day 3 in children with acute lung injury at these centers is independently associated with fewer ventilator-free days. Our findings and the similarity of fluid balance patterns in our cohort to adults in the Fluid and Catheter Treatment Trial liberal arm demonstrate the need to determine whether a conservative fluid management strategy improves clinical outcomes in children with acute lung injury and support a Bayesian trial mirroring the Fluid and Catheter Treatment Trial.

Single-nucleotide polymorphisms in the ß-adrenergic receptor genes are associated with lung allograft utilization.

BACKGROUND: Pulmonary edema and associated impaired oxygenation are a major reason for rejection of donor lung allografts offered for transplantation. Clearance of pulmonary edema can be upregulated by stimulation of ß-adrenergic receptors (ßARs). Single-nucleotide polymorphisms (SNPs) in ßAR genes have functional effects in vitro and in vivo. We hypothesized that SNPs in ßAR genes would be associated with rates of utilization of donor lung allografts offered for transplantation. METHODS: Nine hundred fifty-one organ donors were genotyped for 4 amino-acid-coding SNPs in the ßAR genes. Lung allograft utilization was compared among donors stratified by genotypes. RESULTS: Utilization of donor lung allografts was 55% vs 35% (p = 0.02) among donors with GG vs AA/AG genotypes of the Ser49Gly SNP, 39% vs 32% (p = 0.04) with GG vs AA/AG genotype of Gly16Arg SNP and 37% vs 32% (p = 0.1) with CC vs GC/GG genotype of the Arg389Gly SNP. In the combined analysis, donors carrying 0 or 1 associated genotype had a utilization rate of 33%, whereas donors carrying 2 or 3 associated genotypes had utilization rates of 44% and 58%, respectively (p = 0.008). There was a stepwise decrease in chest radiograph infiltrates and an increase in partial pressure of oxygen/fraction of inspired oxygen (PaO(2)/FIO(2)) with an increasing number of these associated genotypes. CONCLUSION: Genetic variants in the ßAR genes among organ donors are associated with higher rates of lung allograft utilization. The increased utilization may be related to increased clearance of pulmonary edema and improved oxygenation in donors with favorable genotypes and suggests that ßAR agonists may have a role in donor management.

Modification of leech behavior following foraging for artificial blood.

In this study we examined whether the foraging for artificial blood affected the behavioral responsiveness of leeches to electrical stimulation of the body wall. After foraging for artificial blood, electrical stimulation of the posterior end of the leech significantly increased the percentage of stimulation trials that elicited locomotory activity--swimming and crawling--compared to the behaviors elicited when leeches did not forage or foraged for normal saline. On the other hand, shortening always dominated the behavioral profile of the leech to anterior stimulation even after foraging for artificial blood. In intact anterior end-isolated nerve cord preparations, we also found that application of artificial blood to the intact anterior end was sufficient to modify motor responsiveness to DP nerve stimulation. Full strength artificial blood had an overall negative effect on the likelihood of DP nerve stimulation initiating swimming and on the average length of elicited swim episodes compared to when pond water surrounded the anterior end. Application of a 10% solution of artificial blood to the anterior end led to an increase in the likelihood of DP nerve stimulation eliciting swimming.