Is internal jugular vein extensibility associated with indices of fluid responsiveness in ventilated patients?

Abstract

Ultrasound of the inferior vena cava provides rapid and non-invasive assessment of fluid responsiveness. We hypothesized that the extensibility of the internal jugular vein (IJV) as well reflects intravascular volume state. We assessed IJV dimensions together with pulse pressure variation (PPV) as dynamic index for fluid responsiveness in mechanically ventilated patients. Of 50 patients after cardiac surgery were assessed. Ultrasound of IJV dimensions as well as collection of hemodynamic data were performed in 30° and horizontal (0°) position, and the ventilator- and position-induced IJV extensibilities (E-IJV) were calculated. Mean ventilator-induced E-IJV in 30° position was 56%, and mean PPV in 30° position was 13.7%. Changing the patient's position from 30° to 0° significantly reduced ventilator-induced E-IJV as well as PPV. Pearson's correlation test revealed significant association between ventilator-induced E-IJV and fluid responsiveness deduced from PPV in 0° position (r = 0.43, P < 0.005). An E-IJV threshold >5% identified patients with significantly elevated PPV values. Ultrasound of the IJV and PPV as a dynamic index for fluid responsiveness can be associated under certain defined conditions. Whether or not ultrasound of the IJV can be useful to predict patient intravascular volume state should be further studied using invasive cardiac output monitoring.