The provision of continuous renal replacement therapies (CRRT) to small children has generally required the adaptation of adult machines and modified operational characteristics. CRRT prescription for younger and smaller children versus adults differs significantly due to problems concerning the extracorporeal blood volume, the need for circuit blood priming, and the adaptation of machines designed for adult-sized patients. Moreover, the provision of renal replacement therapy to infants and neonates presents a unique problem: no more than 10-15% of their blood volume should be removed by the extracorporeal circuit to prevent hypotension and anemia. In 2012, a dedicated machine, i.e. the Cardio-Renal, Pediatric Dialysis Emergency Machine (CARPEDIEM), was developed and launched the ‘fitted era’ for pediatric CRRT. In this review, we analyze how CRRT techniques have evolved for pediatric application and describe the first in vivo application of the CARPEDIEM for the safe and efficacious provision of CRRT to infants.