1 Pediatric Intensive Care Department, Gregorio Marañon University Hospital, Madrid, Spain; Maternal and Child Public Health Department, School of Medicine, Complutense University of Madrid, Spain; Health Research Institute of the Gregorio Marañón Hospital, Madrid, Spain; Research Network on Maternal and Child Health and Development (RedSAMID), Spain. Electronic address: pielvi@hotmail.com.
2 Pediatric Intensive Care Department, Gregorio Marañon University Hospital, Madrid, Spain; Health Research Institute of the Gregorio Marañón Hospital, Madrid, Spain; Research Network on Maternal and Child Health and Development (RedSAMID), Spain. Electronic address: sarahlafever@gmail.com.
3 Pediatric Intensive Care Department, Gregorio Marañon University Hospital, Madrid, Spain; Health Research Institute of the Gregorio Marañón Hospital, Madrid, Spain; Research Network on Maternal and Child Health and Development (RedSAMID), Spain. Electronic address: jimenadelcastillo@yahoo.es.