Influence of infusion flow rates on central venous pressure measurements through multi-lumen central venous catheters in intensive care.

Objective: To study the influence on central venous pressure (CVP), measured at the distal port, of crystalloid infusions administered through the proximal port(s) of a central venous multi-lumen catheter.

Patients: Thirty-one intensive care patients.

Interventions: CVP was measured at the distal port of a multi-lumen catheter inserted in the subclavian or internal jugular vein. Using the proximal port(s), saline (0.9%) was infused at rates varying from 2 ml/h to 14,340 ml/h.

Results: CVP measured before the infusion and during infusion (after 30 s to 1 min) were not significantly different. Positive pressure ventilation with PEEP (5.6 +/- 2.5 cmH(2)O) and/or norepinephrine infusion (0.25 +/- 0.21 microg kg(-1) min(-1)) did not produce any significant change in CVP during infusion.

Conclusion: The administration of crystalloids at different flow rates through the proximal port(s) of a multi-lumen catheter placed in the superior vena cava does not affect CVP measurement at the distal port, even in mechanically ventilated patients or patients receiving vasopressors.