Can femoral venous pressure be used as an estimate for standard vesical intra-abdominal pressure measurement?

Abstract

Intra-abdominal hypertension (IAH) is highly prevalent in critically ill patients admitted to the intensive care unit and is associated with an increased morbidity and mortality. The present study investigated whether femoral venous pressure (FVP) can be used as a surrogate parameter for intra-abdominal pressure (IAP) measured via the bladder in IAH grade II (IAP <20 mmHg) or grade III (IAP ≥20 mmHg). This was a single-centre prospective study carried out in a tertiary adult intensive care unit. IAP was measured via the bladder with a urinary catheter with simultaneous recording of the FVP via a femoral central line. If the IAP was <20 mmHg external weight to a maximum of 10 kg was applied to the abdomen with subsequent measurements of IAP and FVP. Eleven patients were enrolled into the study. IAH (IAP >12 mmHg) was identified in five patients (42%) and abdominal compartment syndrome (ACS, IAP >20 mmHg with new onset organ failure) in two (18%) with all-cause study mortality of 18%. The mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 21 ± 5, Simplified Acute Physiology (SAPS 2) score 49 ± 8, and Sequential Organ Failure Assessment (SOFA) score 9 ± 3. At baseline the bias between IAP and FVP was 3.2 with a precision of 3.63 mmHg (limits of agreement [LA] -4.1, 10.4). At 5 kg and 10 kg, the bias was 2.5 with a precision of 3.92 mmHg (LA -5.4, 10.3) and 2.26 mmHg (LA -2.1, 7.0) respectively. A receiver operating characteristic analysis for FVP to predict IAH showed an area under the curve of 0.87 (95% confidence interval 0.74-0.94, P=0.0001). FVP cannot be recommended as a surrogate measure for IAP even at IAP values above 20 mmHg. However, an elevated FVP was a good predictor of IAH.