Measurement of central venous pressure from a peripheral intravenous catheter in the prone position during spinal surgery.

INTRODUCTION

A central venous pressure (CVP) measurement is used to assess intravascular status. Although this is usually accomplished by the placement of a central venous catheter (CVC), there are circumstances when placement may be technically difficult or impossible. The current study evaluates the feasibility of measuring CVP from a peripheral intravenous (IV) cannula in the prone position.

METHODS

CVP was simultaneously measured from a central venous catheter (CVC-P) and from a peripheral IV cannula (PVP). The continuity of the peripheral IV cannula with the central venous system was demonstrated by a change in the PVP during a sustained inspiratory effort.

RESULTS

The study cohort included 18 patients. All patients had 2 peripheral IV cannulae, and 10 PVP measurements were taken from each site. In 4 of the 36 cannulae (11%), there was no increase in the PVP in response to a sustained inspiratory effort. For these 4 cannulae, the PVP to CVC-P difference was 13 +/- 4 mm Hg. In the 32 cannulae in which the PVP increased in response to a sustained inspiratory effort, the PVP to CVC-P difference was 2 +/- 1 mm Hg (P < 0.0001), and the difference between the PVP and the CVC-P was <or=5 mm Hg in all of the sample sets. The accuracy of the technique did not vary based on the location of the peripheral cannula, its size, or the actual CVP reading.

CONCLUSION

Provided that the PVP increases to a sustained inspiratory breath, there is a clinically useful correlation between the PVP and the actual CVP in the prone position.