The feasibility of measuring renal blood flow using transesophageal echocardiography in patients undergoing cardiac surgery.
BACKGROUND
There is no reliable method to monitor renal blood flow intraoperatively. In this study, we evaluated the feasibility and reproducibility of left renal blood flow measurements using transesophageal echocardiography during cardiac surgery.


METHODS
In this prospective noninterventional study, left renal blood flow was measured with transesophageal echocardiography during three time points (pre-, intra-, and postcardiopulmonary bypass) in 60 patients undergoing cardiac surgery. Sonograms from 6 subjects were interpreted by 2 blinded independent assessors at the time of acquisition and 6 mo later. Interobserver and intraobserver reproducibility were quantified by calculating variability and intraclass correlation coefficients.


RESULTS
Patients with Doppler angles of >30 degrees (20 of 60 subjects) were eliminated from renal blood flow measurements. Left renal blood flow was successfully measured and analyzed in 36 of 60 (60%) subjects. Both interobserver and intraobserver variability were <10%. Interobserver and intraobserver reproducibility in left renal blood flow measurements were good to excellent (intraclass correlation coefficients 0.604-0.999). Left renal arterial luminal diameter for the pre, intra, and postcardiopulmonary bypass phases, ranged from 3.8 to 4.1 mm, renal arterial velocity from 25 to 35 cm/s, and left renal blood flow from 192 to 299 mL/min.


CONCLUSIONS
In patients undergoing cardiac surgery, it was feasible in 60% of the subjects to measure left renal blood flow using intraoperative transesophageal echocardiography. The interobserver and intraobserver reproducibility of renal blood flow measurements was good to excellent.
Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China.
Ping-Liang
PL
Yang
David T
DT
Wong
Shuang-Bo
SB
Dai
Hai-Bo
HB
Song
Ling
L
Ye
Jin
J
Liu
Bin
B
Liu
D000328:Adult; D000368:Aged; D006348:Cardiac Surgical Procedures / Q000009:adverse effects; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D018618:Echocardiography, Doppler, Color; D017548:Echocardiography, Transesophageal; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D015588:Observer Variation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012079:Renal Circulation; D015203:Reproducibility of Results; D055815:Young Adult