title: Low inferior vena caval catheters for hemodynamic and pulmonary function monitoring in pediatric critical care patients.
abstract: OBJECTIVE
  To assess the value of low inferior vena caval (LIVC) catheters for estimating central venous pressure in pediatric intensive care patients and to assess influences of intra-abdominal pressures and mean airway pressure on these measurements.
  
  
  METHODS
  Prospective cohort of consecutive patients.
  
  
  METHODS
  Pediatric intensive care unit.
  
  
  METHODS
  Thirty patients ranging in age (18, 0-1 yrs; four, 1-3 yrs; four, 3-10 yrs; four, > or =10 yrs).
  
  
  METHODS
  Interventions included catheterizations via internal jugular, subclavian, and common femoral veins, as well as direct right atrial catheterization during surgery; arterial catheter placement; airway pressure monitoring during mechanical ventilation; indirect intra-abdominal pressure monitoring via bladder catheter pressure readings; and arterial and central venous blood gas analysis. LIVC vein catheters were placed below the origin of the renal veins.
  
  
  RESULTS
  LIVC pressure was highly correlated with central venous pressure (n=30, r2=.965, p=.0001). LIVC pressure did not correlate with intra-abdominal pressure (n=18, r2=.000). Mean airway pressure did not correlate with central venous pressure (n=11, r2=.106). The pH of LIVC blood was similar to that of central venous blood (n=18, r2=.941, p=.0001). PCO2 values of inferior vena cava and central venous blood correlated (r2=.945, p=.0001). However, agreement between inferior vena cava and central venous PO2 and oxyhemoglobin saturation was poor (PO2, r2=.066; oxyhemoglobin saturation, r2=.000).
  
  
  CONCLUSIONS
  LIVC catheters whose tips lie below the origin of the renal veins predict central venous pressure in pediatric intensive care unit patients. Intra-abdominal pressure and mean airway pressure do not affect this relationship, within the wide range of values for these variables included in this study. Blood samples drawn from femoral venous catheters can be used to monitor acid-base balance and partial pressure of carbon dioxide.
authors.affiliation: Pediatric Critical Care, Marshfield Clinic and St. Joseph's Hospital, Marshfield, WI 54449, USA. fernandez.edward@marshfieldclinic.org
authors.forename: Edward G
authors.initials: EG
authors.lastname: Fernandez
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Green
authors.forename: Michael
authors.initials: M
authors.lastname: Sweeney
mesh_terms: D001784:Blood Gas Analysis; D001794:Blood Pressure; D002405:Catheterization, Central Venous / Q000379:methods*; D002408:Catheters, Indwelling; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric; D016018:Least-Squares Analysis; D008991:Monitoring, Physiologic / Q000379:methods*; D011446:Prospective Studies; D012121:Respiration, Artificial; D014682:Vena Cava, Inferior