Effect Of Different Transducer Positions On Central Venous Pressure In Different Positions

Objective: To observe the effect of different transducer positions on central venous pressure (CVP) in the different position.Method: Forty ASAI～II adult patients with spinal operation on general anesthesia were received the right internal jugular vein puncture, after induction and endotracheal intubation. In the supine positon, the midaxillary line at the fourth intercostal was marked with A, and the four fifths of the anteroposterior(AP) at fourth intercostal was marked with B, then record CVP when the transducer located both at A and B. Turning the patients to the prone position, and remeasuring CVP at A and B. Then, marking the transducer positions where CVP was equal with that of supine position. The transducer position was based on the back of chest wall, the distance from transducer position to the back of chest wall was measured vertically. Data were expressed as mean±SD(range).Results: 1) In supine position, A there was a different in CVP between A and B(P<0.05). 2) In prone position, CVP changed both at A or B compare with supine position(P<0.05). 3)In prone position, the transducer position changed four fifths of the AP at fourth intercostal when CVP is same as A,the transducer position changed two fifths of the AP at fourth intercostal when CVP is same as B.Conclusions: 1)In supine position, a CVP transducer should be positioned at the four fifths of the AP at fourth intercostal.2) in prone position, the CVP transducer should be approximately set at the two fifths of the AP at fourth intercostal. 3)The range of CVP is from lcmH₂O to 6cmH₂O.