Pulmonary edema following ritodrine-saline infusion in premature labor

Twenty-three patients with premature uterine contractions occurring between the 27th and 35th weeks of pregnancy were treated in a prospective and randomized study with intravenous ritodrine in a 0.1 wt/vol% solution of isotonic saline (N = 12) or isotonic glucose (N = 11). The aim of the study was to record the effects of these agents on the water-salt metabolism. In both the saline and the glucose groups there was a statistically significant fall in hemoglobin, hematocrit, and serum albumin (P less than .001). This fall correlated significantly with the dose of ritodrine (P less than .001). Serum renin and aldosterone levels revealed a statistically significant increase (P less than .0005). Seven of 12 patients in the saline group, but none in the glucose group, developed pulmonary congestion requiring treatment. The combination of ritodrine and saline should be used very cautiously, and the authors recommend accurate monitoring of the fluid balance during ritodrine treatment.