Kathy L. Aleš

We studied 40 women in the third trimester of pregnancy to determine whether alterations in serum calcium levels or in urinary calcium excretion would distinguish patients with preeclampsia from normal pregnant women or women with other forms of gestational hypertension. Our population included 10 normal pregnant women, 5 pregnant women with transient hypertension, 6 with chronic hypertension, 7 with chronic hypertension and superimposed preeclampsia, and 12 with preeclampsia. The serum levels of ionized calcium, phosphate, and 1,25-dihydroxyvitamin D were not different among the various groups. In contrast, the mean (+/- SD) 24-hour urinary calcium excretion in the patients with preeclampsia or hypertension with superimposed preeclampsia was significantly lower (42 +/- 29 and 78 +/- 49 mg) than that in normal pregnant women (313 +/- 140 mg per 24 hours), women with transient hypertension (248 +/- 139 mg per 24 hours), or women with chronic hypertension (223 +/- 41 mg per 24 hours) (P less than 0.0001). The hypocalciuria in the women with preeclampsia was associated with a decreased fractional excretion of calcium. Although the mean creatinine clearance was reduced in the women with preeclampsia, the range of values overlapped with those in the other groups. In contrast, we observed little or no overlap with respect to calcium excretion. We conclude that preeclampsia is associated with hypocalciuria due to increased tubular reabsorption of calcium. Measurement of calcium excretion may be useful in distinguishing preeclampsia from other forms of gestational hypertension.

While monitoring blood pressure is a routine part of intraoperative management, several methods have been proposed to characterize intraoperative hemodynamic patterns as predictors of postoperative complications. In this prospective study of a high-risk population of hypertensive and diabetic patients undergoing elective noncardiac surgery, one objective was to compare different approaches to the assessment of intraoperative hemodynamic patterns to identify those patterns most likely to be associated with postoperative complications. Twenty-one per cent of the 254 patients sustained cardiac or renal complications after operation. Patients with more than 1 hour of greater than or equal to 20-mmHg decreases in mean arterial pressure (MAP) or patients with less than 1 hour of greater than or equal to 20-mmHg decreases and more than 15 minutes of greater than or equal to 20-mmHg increases were at highest risk for postoperative complications. Together these two patterns had a 46% sensitivity rate and a 70% specificity rate in predicting postoperative complications. Using 20% change in intraoperative MAP produced results nearly identical to 20-mmHg changes. When the duration of 20-mmHg changes was accounted for, changes of a greater magnitude (e.g., 40 mmHg) were not significant independent predictors of complications. The use of the mean difference from preoperative MAP was misleading because patients who experienced both high and low MAPs tended to have nearly normal mean MAPs, but high complication rates. The absolute magnitude of intraoperative MAPs, regardless of the preoperative levels, also was evaluated. The overall mean intraoperative MAP was not a significant predictor of complications. Specific intraoperative MAPs (e.g., less than 70 mmHg and more than 120 mmHg) also were evaluated. While neither was a significant predictor, there was a trend for increased complications among patients whose MAPs decreased to less than 70 mmHg. Intraoperative blood pressure should be analyzed in relation to the patient's preoperative blood pressure. Prolonged changes of more than 20 mmHg or 20% in relation to preoperative levels were significantly related to complications.