Does femoral venous pressure measurement correlate well with intrabladder pressure measurement? A multicenter observational trial

Purpose: To investigate if femoral venous pressure (FVP) measurement can be used as a surrogate measure for intra-abdominal pressure (IAP) via the bladder. Methods: This was a prospective, multicenter observational study. IAP and FVP were simultaneously measured in 149 patients. The effect of BMI on IAP was investigated. Results: The incidences of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) were 58 and 7% respectively. The mean APACHE II score was 22 +/- 10, SAPS 2 score 42 +/- 20, and SOFA score 9 +/- 4. The mean IAP was 11.2 +/- 4.5 mmHg versus 12.7 +/- 4.7 mmHg for FVP. The bias and precision for all measurements were -1.5 and 3.6 mmHg respectively with the lower and upper limits of agreement being -8.6 and 5.7. When IAP was above 20 mmHg, the bias between IAP and FVP was 0.7 with a precision of 2.0 mmHg (lower and upper limits of agreement -3 and 4.6 respectively). Excluding those with ACS, according to the receiver operating curve analysis FVP = 11.5 mmHg predicted IAH with a sensitivity and specificity of 84.8 and 67.0% (AUC of 0.83 (95% CI 0.81-0.86) with P < 0.001). FVP = 14.5 mmHg predicted IAP above 20 mmHg with a sensitivity of 91.3% and specificity of 68.1% (AUC 0.85 (95% CI 0.79-0.91), P < 0.001). Finally, at study entry, the mean IAP in patients with a BMI less then 30 kg/m(2) was 10.6 +/- 4.0 mmHg versus 13.8 +/- 3.8 mmHg in patients with a BMI >= 30 kg/m(2) (P < 0.001). Conclusions: FVP cannot be used as a surrogate measure of IAP unless IAP is above 20 mmHg.