Comparison between Femoral and Superior Approach Central Venous Pressure Measurements in Critically Ill - Mechanically Ventilated Patients

Central venous catheterization is one of the most commonly used invasive procedures in critically ill patients. Superior approach (internal jugular and subclavian veins) is the most frequently anatomical site used for central venous catheter (CVC) insertion. However, access through it may lead to several substantial serious and life threatening complications such as pneumothorax, haemothorax, air embolism, arterial puncture, bleeding, dysrhythmias and thoracic duct injury. In contrast, femoral route is safe, standard and popular procedure as it avoids many of the potential peri-insertion and mechanical complications of the superior approach. In addition, the femoral route is also considered by many to be the easiest site for central venous access and can be quickly learned by inexperienced operators.^(1–4) But the question that has been raised about the reliability and accuracy of central venous pressure reading obtained from the femoral vein and to what extent it equally reliable with CVP readings obtained from the superior approach ? To answer this question, the current study was conducted to compare the measures of central venous pressure (CVP) at two different sites (superior versus femoral).

Prospective comparative cross - over design was used to conduct this study. Thirty consecutive adult mechanically ventilated patients were recruited in this study. CVP was measured from both sites hourly for 6 consecutive hours. Positive end-expiratory pressure, mean airway pressure, and intra-abdominal pressure were recorded & measured simultaneously.

For 180-paired measurements obtained from superior approach veins and femoral vein were statistically analyzed using intra-class correlation coefficients (ICC). A statistically significant high correlation (ICC 0.868, p-value < 0.001) has been showed between the both sites. The difference was normally distributed around the mean with a standard deviation of 1.11 mm Hg. i.e., on an average, the femoral CVP measurements were higher than superior approach CVP of 1.64 mm Hg.