The relationship between inferior vena cava diameter measured by bedside ultrasonography and central venous pressure value

Objective: We aimed to present inferior vena cava (IVC) diameter as a guiding method for detection of relationship between IVC diameter measured noninvasively with the help of ultrasonography (USG) and central venous pressure (CVP) and evaluation of patient’s intravascular volume status.

Methods: Patients over the age of 18, to whom a central venous catheter was inserted to their subclavian vein or internal jugular vein were included in our study. IVC diameter measurements were recorded in millimeters following measurement by the same clinician with the help of USG both at the end-inspiratory and end-expiratory phase. CVP measurements were viewed on the monitor by means of piezoelectric transducer and recorded in mmHg. SPSS 18.0 package program was used for statistical analysis of data.

Results: Forty five patients were included in the study. The patients had the diagnosis of malignancy (35.6%), sepsis (13.3%), pneumonia, asthma, chronic obstructive pulmonary disease (11.1%). 11 patients (24.4%) required mechanical ventilation while 34 (75.6%) patients had spontaneous respiration. In patients with spontaneous respiration, a significant relationship was found between IVC diameters measured by ultrasonography at the end of expiratory and inspiratory phases and measured CVP values at the same phases (for expiratory p = 0.002, for inspiratory p= 0.001). There was no statistically significant association between IVC diameters measured by ultrasonography at the end of expiration and inspiration and measured CVP values at the same phases in mechanically ventilated patients.

Conclusions: IVC diameter measured by bedside ultrasonography can be used for determination of the intravascular volume status of the patients with spontaneous respiration.