Indexed oxygen delivery during pediatric cardiopulmonary bypass is a modifiable risk factor for postoperative acute kidney injury

Background: Acute kidney injury after pediatric cardiac surgery is a common complication with few established modifiable risk factors. We sought to characterize whether indexed oxygen delivery during cardiopulmonary bypass was associated with postoperative acute kidney injury in a large pediatric cohort. Methods: This was a retrospective analysis of patients under 1 year old undergoing cardiac surgery with cardiopulmonary bypass between January 1, 2013, and January 1, 2020. Receiver operating characteristic curves across values ranging from 260 to 400 mL/min/m2 were used to identify the indexed oxygen delivery most significantly associated with acute kidney injury risk. Results: We included 980 patients with acute kidney injury occurring in 212 (21.2%). After adjusting for covariates associated with acute kidney injury, an indexed oxygen delivery threshold of 340 mL/min/m2 predicted acute kidney injury in STAT 4 and 5 neonates (area under the curve = 0.66, 95% CI = 0.60 – 0.72, sensitivity = 56.1%, specificity = 69.4%). An indexed oxygen delivery threshold of 400 mL/min/m2 predicted acute kidney injury in STAT 1-3 infants (area under the curve = 0.65, 95% CI = 0.58 – 0.72, sensitivity = 52.6%, specificity = 74.6%). Conclusion: Indexed oxygen delivery during cardiopulmonary bypass is a modifiable variable independently associated with postoperative acute kidney injury in specific pediatric populations. Strategies aimed at maintaining oxygen delivery greater than 340 mL/min/m2 in complex neonates and greater than 400 mL/min/m2 in infants may reduce the occurrence of postoperative acute kidney injury in the pediatric population

An Analysis of Predator Selection to Affect Aposematic Coloration in a Poison Frog Species.

Natural selection is widely noted to drive divergence of phenotypic traits. Predation pressure can facilitate morphological divergence, for example the evolution of both cryptic and conspicuous coloration in animals. In this context Dendrobatid frogs have been used to study evolutionary forces inducing diversity in protective coloration. The polytypic strawberry poison frog (Oophaga pumilio) shows strong divergence in aposematic coloration among populations. To investigate whether predation pressure is important for color divergence among populations of O. pumilio we selected four mainland populations and two island populations from Costa Rica and Panama. Spectrometric measurements of body coloration were used to calculate color and brightness contrasts of frogs as an indicator of conspicuousness for the visual systems of several potential predators (avian, crab and snake) and a conspecific observer. Additionally, we conducted experiments using clay model frogs of different coloration to investigate whether the local coloration of frogs is better protected than non-local color morphs, and if predator communities vary among populations. Overall predation risk differed strongly among populations and interestingly was higher on the two island populations. Imprints on clay models indicated that birds are the main predators while attacks of other predators were rare. Furthermore, clay models of local coloration were equally likely to be attacked as those of non-local coloration. Overall conspicuousness (and brightness contrast) of local frogs was positively correlated with attack rates by birds across populations. Together with results from earlier studies we conclude that conspicuousness honestly indicates toxicity to avian predators. The different coloration patterns among populations of strawberry poison frogs in combination with behavior and toxicity might integrate into equally efficient anti-predator strategies depending on local predation and other ecological factors

PC_scores.DORSAL

Individual scores on the principal components derived from the dorsal spectral measurement

spectral_meassurements

Measurements of the dorsal and ventral spectral reflectance variables (ΔL, ΔS, L, S, ΣR(λ)

Data from: Mating status correlates with dorsal brightness in some but not all poison frog populations

Sexual signals are important for intraspecific communication and mate selection, but their evolution may be driven by both natural and sexual selection, and stochastic processes. Strawberry poison frogs (Oophaga pumilio) show strong color divergence among populations, but coloration also varies among individuals of the same population. The importance of coloration for female mate choice has been studied intensely, and sexual selection seems to affect color divergence in strawberry poison frogs. However, the effect of coloration on mating success under field conditions has received very little attention. Furthermore, few studies examined how phenotypic variation among individuals of the same color morph affects mate selection under natural conditions. We measured the spectral reflectance of courting and noncourting individuals and their background substrates in three geographically separated populations. In one population (Sarapiquí, Costa Rica), we found that naturally occurring courting pairs of males and females had significantly brighter dorsal coloration than individual males and females not engaged in courtship interactions. Our field observations suggest that, in the wild, females prefer brighter males while the reason for the higher courtship activity of brighter females remains unclear. Overall our results imply that brightness differences among individuals of the same color morph may actually affect reproductive success in some populations of strawberry poison frogs

A Single-Center Analysis of Methylprednisolone Use during Pediatric Cardiopulmonary Bypass

Cardiac surgery with the use of cardiopulmonary bypass (CPB) is known to induce an inflammatory response in patients. This response may be even more pronounced in pediatric patients given their small body size compared to adults. Several interventions have been instituted in an effort to attenuate this response, including the use of corticosteroids in the pump prime. However, the clinical effectiveness and potential harmful effects of steroid use have been the source of recent debate. Therefore, our institution made the decision to evaluate the use of methylprednisolone in our CPB prime. This evaluation was performed as a formal quality improvement project at The Children’s Hospital of Philadelphia. Methylprednisolone was eliminated from the CPB prime for 6 months. At the end of this time period, The Society of Thoracic Surgeons Congenital Heart Surgery Database was used to evaluate clinical outcomes of patients (n = 222). These outcomes were then compared to patients operated on during the 6 months prior to elimination of methylprednisolone (n = 303). No significant clinical benefit was identified in the group of patients who received methylprednisolone. When compared to the group who did not receive methylprednisolone, significantly more patients in the steroids group had a postoperative wound infection (p = .037) or respiratory failure requiring tracheostomy ( p = .035). No other differences in clinical outcomes were identified between the two groups. No significant differences in clinical outcomes were identified between neonates who received methylprednisolone (n = 55) and neonates who did not receive steroids (n = 58). Due to the lack of clinical benefit seen with its use, as well as its potential contribution to the incidence of wound infection, methylprednisolone continues to be excluded from the CPB prime at our institution. Methylprednisolone is still given intraoperatively at the request of the attending anesthesiologist and on bypass during orthotopic transplant procedures according to institutional protocol

Effects of frog population, clay frogs coloration and origin on the attack rate of different predator on clay frogs.

<p>Results (P-values) of generalized linear models (GLM´s), which tested whether there was an effect of population, coloration of clay frogs or clay frog origin (local versus non-local coloration) on the attack rate of different predators.</p><p>Effects of frog population, clay frogs coloration and origin on the attack rate of different predator on clay frogs.</p

Correlation between dorsal overall conspicuousness of local frogs for avian eyes and avian predation on clay frogs across frog populations.

<p>The correlation is highly significant (r = Spearman rank correlation coefficient).</p

Number of predation events in each population.

<p>Bar coloration indicates the predator category the attack was assigned to. Light grey: U- and V-shaped attack marks caused by birds; grey: holes and scratches potentially caused by birds; and black: non-bird predation. Isla Colón and Isla Solarte are island populations, while all others are located on the main land.</p

Indexed oxygen delivery during pediatric cardiopulmonary bypass is a modifiable risk factor for postoperative acute kidney injury

Background: Acute kidney injury after pediatric cardiac surgery is a common complication with few established modifiable risk factors. We sought to characterize whether indexed oxygen delivery during cardiopulmonary bypass was associated with postoperative acute kidney injury in a large pediatric cohort. Methods: This was a retrospective analysis of patients under 1 year old undergoing cardiac surgery with cardiopulmonary bypass between January 1, 2013, and January 1, 2020. Receiver operating characteristic curves across values ranging from 260 to 400 mL/min/m2 were used to identify the indexed oxygen delivery most significantly associated with acute kidney injury risk. Results: We included 980 patients with acute kidney injury occurring in 212 (21.2%). After adjusting for covariates associated with acute kidney injury, an indexed oxygen delivery threshold of 340 mL/min/m2 predicted acute kidney injury in STAT 4 and 5 neonates (area under the curve = 0.66, 95% CI = 0.60 – 0.72, sensitivity = 56.1%, specificity = 69.4%). An indexed oxygen delivery threshold of 400 mL/min/m2 predicted acute kidney injury in STAT 1-3 infants (area under the curve = 0.65, 95% CI = 0.58 – 0.72, sensitivity = 52.6%, specificity = 74.6%). Conclusion: Indexed oxygen delivery during cardiopulmonary bypass is a modifiable variable independently associated with postoperative acute kidney injury in specific pediatric populations. Strategies aimed at maintaining oxygen delivery greater than 340 mL/min/m2 in complex neonates and greater than 400 mL/min/m2 in infants may reduce the occurrence of postoperative acute kidney injury in the pediatric population