[Asymptomatic blood pressure and pulse rate changes during intravenous urography. Ionic contrast media vs. nonionic...

In 8,232 examinations of intravenous urography (4,832 examinations with ionic contrast media and 3,400 examinations with nonionic contrast media), systemic blood pressure and pulse rate were continuously monitored by an automatic blood pressure and pulse rate monitoring device before and after injection of contrast media. The intravenous injection of ionic contrast media caused mild to moderate hypotensive reactions (20%-39% decrease of systemic blood pressure) in 7 examinations (0.14%) and severe hypotensive reactions (greater than 40% decrease of systemic blood pressure) in 12 examinations (0.25%). There were no clinical symptoms other than hypotensive reactions in 8 of the 19 examinations (42.1%). On the other hand, the intravenous injection of nonionic contrast media did not cause severe hypotensive reactions but mild hypotensive reactions (20%-29% decrease of systemic blood pressure) in 3 examinations (0.09%). These 3 examinations did not have clinical symptoms other than hypotensive reactions. Of the 19 examinations using ionic contrast media, the hypotensive reactions with significant change of pulse rate (greater than 20%) was associated with increase of pulse rate in 17 examinations and decrease of pulse rate in 2 examinations. On the other hand, the hypotensive reactions had an association with a significant increase (greater than 20%) of the pulse rate in only one of the 3 examinations using nonionic contrast media. The pulse rate was unchanged after injection of contrast media in the remaining 2 examinations although there was mild hypotension. In conclusion, nonionic contrast media caused fewer and less severe changes in blood pressure and pulse rate without obvious clinical symptoms compared with ionic contrast media.