Inferior Vena Cava Diameter and Central Venous Pressure Correlation During Cardiac Surgery

Objective: The purpose of this study was to determine whether a relationship exists between the inferior vena cava diameter (IVCD) or the superior vena cava diameter (SVCD) measured at the point of entry into the right atrium using transesophageal echocardiography (TEE) and the central venous pressure (CVP) under different experimental conditions.

Design: Prospective study.

Setting: University hospital, single institution.

Participants: Seventy patients undergoing elective cardiac surgery.

Interventions: CVP, IVCD, and SVCD were measured in a 2-dimensional, long-axis midesophageal bicaval view at end-diastole with electrocardiographic synchronization. Data were recorded during suspended ventilation, before and after leg elevation, and at different levels of positive end-expiratory pressure (0, 5, and 10 cmH₂O).

Measurements and Main Results: The relationship between IVCD and CVP had 2 portions: A first (CVP ≤11 mmHg) in which the IVCD showed a strong correlation with the CVP (R = 0.801, p < 0.001; CVP = 2.009 + [0.312 * IVCD]) and a second (CVP >11 mmHg) in which the correlation was poor (R = 0.272, p = 0.065). No correlation between SVCD and CVP was observed.

Conclusion: A strong correlation between TEE-derived IVCD measured at the point of entry into the right atrium and CVP was observed in cardiac surgical patients when CVP was ≤11 mmHg.

Key Words: inferior vena cava, central venous pressure, superior vena cava, transesophageal echocardiography, positive end-expiratory pressure