A Novel Maneuver to Treat Refractory Atelectasis in Mechanically Ventilated Children.

We developed a novel airway clearance and lung recruitment maneuver for children with refractory unilateral atelectasis undergoing invasive mechanical ventilation. In this retrospective, single-center, proof of concept study, we describe the steps involved in this novel maneuver and evaluate its effectiveness in 15 patients through objective quantitation of changes in respiratory system compliance and in the degree of atelectasis assessed by a validated Modified Radiology Atelectasis Score. Compared with the premaneuver baseline, the median atelectasis score improved significantly following the maneuver (9 [7.5-10] vs. 1 [0-3.3], respectively, p < 0.01). Likewise, dynamic compliance was significantly higher following the maneuver (0.3 [0.32-0.44] vs. 0.61 [0.53-0.69] mL/kg/cm H 2 O, respectively, p < 0.01). No patients required a bronchoscopy. This simple and effective maneuver resulted in a significant improvement in the degree of atelectasis and dynamic compliance in this cohort of mechanically ventilated children with refractory unilateral atelectasis.

Scaling properties of protein family phylogenies.

BACKGROUND: One of the classical questions in evolutionary biology is how evolutionary processes are coupled at the gene and species level. With this motivation, we compare the topological properties (mainly the depth scaling, as a characterization of balance) of a large set of protein phylogenies with those of a set of species phylogenies. RESULTS: The comparative analysis between protein and species phylogenies shows that both sets of phylogenies share a remarkably similar scaling behavior, suggesting the universality of branching rules and of the evolutionary processes that drive biological diversification from gene to species level. In order to explain such generality, we propose a simple model which allows us to estimate the proportion of evolvability/robustness needed to approximate the scaling behavior observed in the phylogenies, highlighting the relevance of the robustness of a biological system (species or protein) in the scaling properties of the phylogenetic trees. CONCLUSIONS: The invariance of the scaling properties at levels spanning from genes to species suggests that rules that govern the incapability of a biological system to diversify are equally relevant both at the gene and at the species level.