Nonhemorrhagic decrements in hematocrit values after percutaneous renal biopsy.

Seventy patients without bleeding after a percutaneous renal biopsy (PCB) were studied to define the incidence of decrements in hematocrit values, hypotension, and bradycardia. Hematocrit values decreased greater than or equal to 0.5% in 60% of the patients, greater than or equal to 1% in 44%, and greater than or equal to 2% in 34% of patients. After PCB, an increase of greater than or equal to 1% occurred in 55% of the patients with hematocrit nadirs of greater than or equal to 1%. Hematocrit values increased 3.0% +/- 0.6% in 8/19 patients with a previous decrease of greater than or equal to 2% but continued to decrease in 13% of the patients. A weight gain or positive fluid balance occurred in 29%, hypotension in 7%, and relative bradycardia in 4% of the patients. These studies show that a decrease in hematocrit values and hypotension may occur in patients after PCB without bleeding. This may result from hemodilution and increased parasympathetic discharge and as part of a natural spectrum of decreasing hematocrit levels coincident with PCB.