title: High levels of free haemoglobin in neonates and infants undergoing surgery on cardiopulmonary bypass.
abstract: OBJECTIVE
  Haemolysis is known to occur during surgery on cardiopulmonary bypass (CPB) and to be responsible for kidney injury. The aim of this study was to assess, in a cohort of infants, the reference levels of free haemoglobin (fHb) and their change over time postoperatively; the predicting variables of haemolysis in the intraoperative phase; and the association between fHb and renal function.
  
  
  METHODS
  A retrospective analysis in infants undergoing surgery on CPB was conducted. Children with preoperative renal dysfunction and need for extracorporeal membrane oxygenation support were excluded. fHb was sampled before and after CPB and on the first 2 postoperative days (POD).
  
  
  RESULTS
  Twenty-two patients with a median (interquartile) age of 111 (63-184) days and Aristotle score of 8 (6.4-9) were enrolled. fHb had a baseline value of 29 (24-41) mg/dl, peaked to 75 (65-109) mg/dl at CPB weaning and returned to 35 (30-55) mg/dl on POD 2 (P <0.0001). The median normalized index of haemolysis was 0.15 (0.09-0.19) g of fHb per 100 l of pumped blood. A multivariable regression model showed that, at CPB weaning, fHb levels were independently associated with left atrial venting flow (P = 0.02), and that CPB time remained the only independent variable (P = 0.034), when left atrial venting was excluded from the analysis. Acute kidney injury (AKI) occurred in 10 patients (45%). fHb levels in the 48 post-CPB hours were not significantly different between AKI and non-AKI patients: However, a significant correlation was present between creatinine on POD1 and CPBw-fHb (r = 0.48; P = 0.045); and between cystatin C on POD1 and CPBw-fHb (r = 0.58; P = 0.02).
  
  
  CONCLUSIONS
  A high rate of fHb is released during paediatric surgery with CPB in infants. fHb mainly depends on the left atrial venting flow rate and CPB duration. However, such peaks of fHb levels were not associated with renal dysfunction.
authors.affiliation: Department of Cardiology and Cardiac Surgery, Pediatric Cardiac Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy zaccaria.ricci@gmail.com z.ricci@libero.it.
authors.forename: Zaccaria
authors.initials: Z
authors.lastname: Ricci
authors.affiliation: Department of Cardiology and Cardiac Surgery, Pediatric Cardiac Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Pezzella
authors.affiliation: Department of Health Sciences, Section of Anesthesiology and Intensive Care, University of Florence, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Romagnoli
authors.affiliation: Department of Cardiology and Cardiac Surgery, Pediatric Cardiac Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Iodice
authors.affiliation: Department of Cardiology and Cardiac Surgery, Pediatric Cardiac Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Haiberger
authors.affiliation: Department of Cardiology and Cardiac Surgery, Pediatric Cardiac Surgery Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Adriano
authors.initials: A
authors.lastname: Carotti
authors.affiliation: Department of Cardiology and Cardiac Surgery, Pediatric Cardiac Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Cogo
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000209:etiology; D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006461:Hemolysis; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D008297:Male; D015999:Multivariate Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D006454:Hemoglobins; D003404:Creatinine
keywords: Acute kidney injury; Cardiopulmonary bypass; Free haemoglobin; Paediatric cardiac surgery