Uppermost blood levels of the right and left atria in the supine position: implication for measuring central venous pressure and pulmonary artery wedge pressure.
BACKGROUND
To eliminate the influence of hydrostatic pressure, proper transducer positions for central venous pressure and pulmonary artery wedge pressure are at the uppermost blood levels of right atrium (RA) and left atrium (LA). This study was performed to investigate accurate reference levels of central venous pressure and pulmonary artery wedge pressure in the supine position.


METHODS
Chest computed tomography images of 96 patients without history of cardiothoracic surgery, heart disease, or cardiothoracic anatomical abnormality were retrospectively reviewed. The anteroposterior (AP) diameter of the thorax and the vertical distances from the skin on the back to the most anterior portion of RA (RA height) and LA (LA height) were measured. Their ratios were abbreviated, respectively, as RA height/AP diameter and LA height/AP diameter. Data are expressed as mean +/- SD (range).


RESULTS
There was a significant difference [4.6 +/- 1.0 (1.6-6.4) cm; P < 0.001] between RA and LA heights. AP diameter was positively correlated with RA and LA heights (R = 0.839 and 0.700, respectively; P < 0.001). There was also a significant difference between RA height/AP diameter [0.83 +/- 0.03 (0.71-0.91)] and LA height/AP diameter [0.62 +/- 0.04 (0.52-0.72)] (P < 0.001).


CONCLUSIONS
In the supine position, a central venous pressure transducer should be positioned approximately 4.6 cm higher than a pulmonary artery wedge pressure transducer. The external reference level for central venous pressure seems to be at approximately four fifths of the AP diameter of the thorax from the back, and that for pulmonary artery wedge pressure seems to be at approximately three fifths of the AP diameter.
Seo
Jeong-Hwa
JH
Department of Anesthesiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
Jung
Chul-Woo
CW
Bahk
Jae-Hyon
JH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002496:Central Venous Pressure; D005260:Female; D006325:Heart Atria / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011669:Pulmonary Wedge Pressure; D013902:Radiography, Thoracic / Q000379:methods; D012015:Reference Standards; D012189:Retrospective Studies; D016683:Supine Position; D014057:Tomography, X-Ray Computed / Q000379:methods