ON SEVERAL OCCASIONS during the past 5 years we have recorded the gradual appearance of hypotension in previously normotensive or mildly hypertensive patients undergoing percutaneous renal biopsy. Most of these hypotensive episodes have been mild and have not interfered with the biopsy routine which we usually follow.1 Those episodes of hypotension which we encountered early in our experience with percutaneous renal biopsy we attributed, in passing, to procaine hydrochloride sensitivity, to side-effects of the meperidine-secobarbital premedication, or to some influence of the patient's psyche on his vascular tone. As our biopsy experience has grown, however, we have found a more specific etiology for at least some of these episodes.
We have a combined percutaneous renal biopsy experience of over 800 cases. In this series we have encountered 15 individuals in whom systolic blood pressures have declined during biopsy to levels below 90 mm Hg (as low as 40 mm