INFERIOR VENA-CAVAL PRESSURE RELIABLY PREDICTS RIGHT ATRIAL PRESSURE IN PEDIATRIC CARDIAC SURGICAL PATIENTS

Objective: To compare ''central venous pressure'' in pediatric patient s in a clinical setting as measured from catheters in the infrahepatic inferior vena cava and the right atrium. Design: Prospective, unblind ed study. Setting: Cardiothoracic intensive care unit of a tertiary ca re university hospital. Patients: Thirty-three pediatric cardiac surgi cal patients, 2 days to 92 months of age (mean 24 +/- 4 months). Inter ventions: Ah patients had intraoperative placement of an 8-cm, double- lumen, femoral venous catheter and a transthoracic right atrial cathet er. Patients were studied for 0 to 2 days after surgery. Measurements and Main Results: Measurements were obtained during mechanical and spo ntaneous ventilation. Although not statistically identical, measuremen ts of ''central'' venous pressure in the inferior vena cava and right atrium correlated well (r(2) = .87 for mechanical ventilation; r(2) = .83 for spontaneous ventilation). Of 31 data pairs in mechanically ven tilated patients, the absolute difference in pressures was as large as 3 mm Hg in three patients and <3 mm Hg in all the rest. In 15 spontan eously breathing patients, there were only three data measurements whe re the difference in pressure was 2 mm Hg and none of the differences was greater. In spontaneously breathing patients, the phasic changes d ue to respiratory variations in venous pressure were in phase in both the intrathoracic and intra-abdominal catheter positions. Conclusions: We conclude that while ''central'' venous pressures measured in the i nferior vena cava and in the right atrium are not statistically identi cal, any differences are well within clinically important limits, Plac ement of central venous pressure catheters in the inferior vena cava b y the femoral venous approach is a reliable alternative to cannulating the superior vena cava in pediatric patients without clinically impor tant intra-abdominal pathology and with anatomic continuity of the inf erior vena cava with the right atrium. Relatively short femoral vein c atheters allow adequate measurement of central venous pressure without concern for exact catheter tip position and without the risk of right atrial perforation, intracardiac arrhythmias, and inadvertent punctur e of carotid and intrathoracic structures. Unlike previously reported results in neonates, we found that the phasic changes of venous pressu re with the respiratory cycle were similar in both intrathoracic and i ntra-abdominal recordings, making this an inappropriate clinical indic ator of venous catheter tip position.