Transdermal Measurement of Glomerular Filtration Rate in Mechanically Ventilated Piglets

Transdermal measurement of glomerular filtration rate (GFR) has been used to evaluate kidney function in conscious animals. This technique is well established in rodents to study acute kidney injury and chronic kidney disease. However, GFR measurement using the transdermal system has not been validated in pigs, a species with a similar renal system to humans. Hence, we investigated the effect of sepsis on transdermal GFR in anesthetized and mechanically ventilated neonatal pigs. Polymicrobial sepsis was induced by cecal ligation and puncture (CLP). The transdermal GFR measurement system consisting of a miniaturized fluorescence sensor was attached to the pig's shaved skin to determine the clearance of fluorescein-isothiocyanate (FITC) conjugated sinistrin, an intravenously injected GFR tracer. Our results show that at 12 h post-CLP, serum creatinine increased with a decrease in GFR. This study demonstrates, for the first time, the utility of the transdermal GFR approach in determining renal function in mechanically ventilated, neonatal pigs.