Intravenous literature: Ait-Oufella, H., Boelle, P.Y., Galbois, A., Baudel, J., Margetis, D., Alves, M., Offenstadt, G., Maury, E. and Guidet, B. (2012) Comparison of superior vena cava and femoroiliac vein pressure according to intra-abdominal pressure. Annals of Intensive Care. 2:21. Click here for the provisional full text.
Background -Â Previous studies have shown a good agreement between central venous pressure (CVP) measurements from catheters placed in superior vena cava and catheters placed in the abdominal cava/common iliac vein. However, the influence of intra-abdominal pressure on such measurements remains unknown.
Methods -Â We conducted a prospective observational study in a tertiary teaching hospital. We enrolled patients who had indwelling catheters in both superior vena cava (double lumen catheter) and femoro-iliac veins (dialysis catheter) and into the bladder. Pressures were measured from all the sites, CVP, femoro-iliac venous pressure (FIVP) and intra-abdominal pressure. Statistical analysis: Data are expressed as mean +/- standard deviation or median (interquartile range) according to distribution. The intra-class correlation coefficient (ICC) was used to assess concordance between CVP and FIVP.
Results -Â 30 patients were enrolled (age 62 +/- 14 years, SAPS II 62 (52-76)). 50 complete sets of measurements were performed. All the studied patients were mechanically ventilated (PEP 3 cmH20 (2-5)). We observed that the concordance between CVP and FIVP decreased when intra-abdominal pressure increased. We identified 14 mmHg as the best intra-abdominal pressure cutoff and we found that CVP and FIVP were significantly more in agreement below this threshold than above (94% versus 50%, P<0.005).
Conclusion -Â We reported for the first time that intra-abdominal pressure affected agreement between CVP measurements from catheter placed in superior vena cava and catheters placed in the femoro-iliac vein. Agreement was excellent when intra-abdominal pressure was below 14 mmHg.