Decision to Intervene with Various Lasix Doses in Adult Renography

Objectives Diuretic renography (DR) is a crucial non-invasive study to identify patients with hydronephrosis who would benefit from surgical rather than medical intervention. Although there is a consensus for optimal Lasix dose in pediatric DR, Lasix dose in adults remains controversial. This study retrospectively evaluated three Lasix doses and correlated imaging findings with the final decision to intervene.

Methods Sixty one patients (35 female, 26 male), age range 20-87 years, mean age 54 years with hydronephrosis underwent 67 DR studies at two different hospitals in a major health system. All patients received an average dose of 15 mCi Tc-99m DTPA intravenously. Twenty five patients received 20mg and another 25 received 40 mg of Lasix intravenously at 30 minutes post DTPA injection. Eleven patients underwent 17 studies and received 0.3 mg/Kg of Lasix at 10 minutes after DTPA injection. All patients had follow up examinations by a urologist or a nephrologist who decided on intervention versus observation.

Results Review of patients’ renal scan reports revealed that quantitative analysis was not always used in the diagnoses of obstruction. The diagnosis of obstruction was sometimes based on visual evaluation of images and renogram curves. The comparison of different protocols revealed agreement between the scan and urologist decision to intervene in 20/25 (80%) of patients with 20 mg of Lasix, 17/25 (68%) with 40 mg of Lasix and 12/17 (70%) of patients with 0.3 mg/Kg of Lasix.

Conclusions There was no major difference in three different Lasix dose administrations and medical/surgical intervention in our patient population. However, a larger sample size and strict quantitative studies are required to better analyze the different Lasix doses with patient outcomes. We recommend a unified protocol to obtain a higher sensitivity in management of patients with hydronephrosis.