Does caval aorta index correlate with central venous pressure in intravascular volume assessment in patients undergoing endoscopic transuretheral resection of prostate?

BACKGROUND AND OBJECTIVE: Ultrasonography has been suggested as a useful noninvasive tool for intravascular volume assessment in critically ill-patients. Fluid absorption is an inevitable complication of transurethral resection of the prostate (TURP). However, there are few data comparing the caval aortic index with central venous pressure (CVP) measurement for intravascular volume assessment in patients undergoing TURP. MATERIALS AND METHODS: This is a prospective observer blinded study carried out on 50 patients who underwent elective TURP. The primary outcome measure of our study was the correlation of the caval aorta (Ao) index with CVP, and the secondary outcome measures were the sensitivity and specificity of the caval Ao index. RESULTS: There was a positive correlation of inferior vena cava/Ao (IVC/Ao) index to CVP (R = 0.9 and significant P = 0.001*). The sensitivity and specificity of the IVC/Ao index were measured to predict the CVP. A CVP ≤7 cm H(2)O correlated with IVC/Ao index 0.8 ± 0.3 mean ± standard deviation (SD) (sensitivity 0.93, specificity 0.66), a CVP of 8-12 cm H(2)O correlated with IVC/Ao index 1.5 ± 0.2 mean ± SD (sensitivity 0.96, specificity 0.42), and a CVP >12 cm H(2)O correlated with IVC/Ao index 1.8 ± 0.07 mean ± SD (sensitivity 0.93, specificity 0.58). CONCLUSION: Sonographic caval Ao index is useful for the evaluation of preoperative and intraoperative volume status, especially in major surgeries with marked fluid shift or blood loss and had the advantage of being noninvasive, safe, quick, and easy technique with no complications.