title: Continuous measurement of cardiac output by the Fick principle in infants and children: comparison with the thermodilution method.
abstract: OBJECTIVE
  To compare a system that continuously monitors cardiac output by the Fick principle with measurements by the thermodilution technique in pediatric patients.
  
  
  METHODS
  Prospective direct comparison of the above two techniques.
  
  
  METHODS
  Pediatric intensive care unit of a university hospital.
  
  
  METHODS
  25 infants and children, aged 1 week to 17 years (median 10 months), who had undergone open heart surgery were studied. Only patients without an endotracheal tube leak and without a residual shunt were included.
  
  
  METHODS
  The system based on the Fick principle uses measurements of oxygen consumption taken by a metabolic monitor and of arterial and mixed venous oxygen saturation taken by pulse- and fiberoptic oximetry to calculate cardiac output every 20s.
  
  
  METHODS
  In every patient one pair of measurements was taken. Continuous Fick and thermodilution cardiac output measurements were performed simultaneously, with the examiners remaining ignorant of the results of the other method.
  
  
  RESULTS
  Cardiac output measurements ranged from 0.21 to 4.55 l/min. A good correlation coefficient was found: r2 = 0.98; P < 0.001; SEE = 0.41 l/min. The bias is absolute values and in percent of average cardiac output was - 0.05 l/min or - 4.4% with a precision of 0.32 l/min or 21.3% at 2 SD, respectively. The difference was most marked in a neonate with low cardiac output.
  
  
  CONCLUSIONS
  Continuous measurement of cardiac output by the Fick principle offers a convenient method for the hemodynamic monitoring of unstable infants and children.
authors.affiliation: Children's Hospital, Johannes Gutenberg University, Mainz, Germany.
authors.forename: C F
authors.initials: CF
authors.lastname: Wippermann
authors.forename: R G
authors.initials: RG
authors.lastname: Huth
authors.forename: F X
authors.initials: FX
authors.lastname: Schmidt
authors.forename: J
authors.initials: J
authors.lastname: Thul
authors.forename: M
authors.initials: M
authors.lastname: Betancor
authors.forename: D
authors.initials: D
authors.lastname: Schranz
mesh_terms: D000293:Adolescent; D000367:Age Factors; D015982:Bias; D002302:Cardiac Output; D006348:Cardiac Surgical Procedures; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008991:Monitoring, Physiologic / Q000379:methods; D010092:Oximetry / Q000379:methods*; D010101:Oxygen Consumption; D011182:Postoperative Care; D011446:Prospective Studies; D015203:Reproducibility of Results; D016037:Single-Blind Method; D013815:Thermodilution / Q000379:methods*