Experience using centralized spirometry in the phase 2 randomized, placebo-controlled, double-blind trial of denufosol in patients with mild to moderate cystic fibrosis.

BACKGROUND: Centralized spirometry may significantly improve quality of spirometry and reduce variability of this outcome measure in clinical trials in cystic fibrosis (CF). METHODS: Spirometry was performed during the phase 2 randomized, placebo-controlled, double-blind clinical trial of denufosol in patients with mild to moderate CF using American Thoracic Society guidelines. Uniform spirometers were used with electronic data transmission of all the data to a reading center. Spirometry was evaluated for quality by a central reader based on start of test, cough during the test, and evidence of a plateau. RESULTS: A total of 1418 spirometry values were assessed in 89 subjects during the trial. In only 5 instances did the central reading center need to give feedback to sites regarding the quality of spirometry. The study site data matched the central reading center's data for all but 78 (6%) spirometry values in 33 patients. Many of these differences were small with only 35 (3%) values differing by more than 50 mL in 26 patients. CONCLUSION: Spirometry in this clinical trial was of high quality with low rate of significant centralized over-read.

Prevention of preeclampsia: a randomized trial of atenolol in hyperdynamic patients before onset of hypertension.

OBJECTIVE: To determine if assessment of maternal hemodynamics could predict women at risk for the development of preeclampsia, if treatment directed at hemodynamic abnormalities before the onset of hypertension could prevent preeclampsia, and if mothers could be treated in a way that protects fetal growth. METHODS: A double-blinded, randomized controlled trial was conducted. Subjects were considered to be at risk for preeclampsia if their cardiac output was greater than 7.4 L/min before 24 weeks' gestation. Nulliparous and diabetic subjects at risk were treated with 100 mg of atenolol or placebo. Cardiac output was measured by Doppler technique. Inulin and para-aminohippurate clearances were performed. RESULTS: Treatment with atenolol reduced the incidence of preeclampsia from 5 of 28 (18%) to 1 of 28 (3.8%), (P = .04). Nulliparous women determined to be at risk for preeclampsia were similar to diabetic women at risk. Each was significantly heavier and had inulin and para-aminohippurate clearances greater than the control group. Treatment with atenolol was associated with infants weighing 440 g less than infants in the nulliparous placebo group, (P = .02). No effect on birth weight was seen in the diabetic patients. Mothers of the smallest infants who were treated with atenolol could be identified by unexpectedly large reductions in cardiac output. CONCLUSION: Measurement of cardiac output in the second trimester identified women at risk for preeclampsia. Treatment with atenolol decreased the incidence of preeclampsia. Nulliparous and diabetic women at risk for preeclampsia were similar with regard to maternal hemodynamics, maternal weight, and renal function. Treatment with atenolol was associated with reduced infant birth weight.

Maternal hemodynamics and aortic diameter in normal and hypertensive pregnancies.

The aortic diameters of 89 normotensive pregnant women were compared with those of nine rigorously defined preeclamptic women and 59 women who required antihypertensive therapy. Over the course of normal pregnancy, the diameter increased significantly; it was larger in preeclamptic than in normotensive women throughout pregnancy. The aortic diameter in women with high-resistance hypertension was smaller than that in normotensive women and in those with high-output, low-resistance hypertension, but it was larger in women with low-resistance hypertension than in normotensive women. The aortic diameter increased after treatment of high-resistance hypertension with hydralazine, but decreased after treatment of high-output, low-resistance hypertension.

Maternal hemodynamics in pregnancies complicated by hyperthyroidism.

The hemodynamics of six pregnant women with hyperthyroidism were studied before and after therapy. Cardiac output was measured by Doppler technique, and blood pressure by automated cuff. When compared with values in euthyroid pregnant women, blood pressure (83.6 mmHg, P less than .001), heart rate (89.2 beats per minute, P less than .001), cardiac output (11.2 L/minute, P less than .001), and stroke volume (123 mL, P less than .001) were significantly elevated. Total peripheral resistance was significantly reduced (609 dyne.second.cm-5, P less than .001). Despite normalization of thyroid indices after therapy, cardiac output remained markedly elevated (9.7 L/minute, P less than .001) and vascular resistance remained reduced (708 dyne.second.cm-5, P = .01). Although the hemodynamics of pregnant thyrotoxic women normalize with therapy, they remain significantly hyperdynamic.

Maternal hemodynamics in normal and preeclamptic pregnancies: a longitudinal study.

Preeclampsia is a disease unique to pregnancy that contributes substantially to maternal and fetal morbidity and mortality. The condition has been thought to be one of hypoperfusion in which increased vascular resistance characterizes the associated hypertension. This study was designed to test an alternative hypothesis, that preeclampsia is characterized by high cardiac output. In a blinded longitudinal study of nulliparas with uncomplicated pregnancies, cardiac output was measured serially by Doppler technique. Cardiac output was elevated throughout pregnancy in patients who became preeclamptic (P = .006). Six weeks postpartum, the hypertension of the preeclamptic subjects had resolved but cardiac output remained elevated (P = .001) and peripheral resistance remained lower than in the normotensive subjects (P = .001). This study demonstrates that preeclampsia is not a disease of systemic hypoperfusion and challenges most current models of the disease based on that assumption.

A comparison of intramarginal and extramarginal excision of hypertrophic burn scars.

Hypertrophic scarring is common in burn patients. The treatment of such scarring is difficult, and recurrence of the hypertrophic changes after scar revision is not uncommon. It has been suggested that intramarginal excision diminishes the chances of recurrent hypertrophic scarring, but we could not find any papers in the literature actually comparing intramarginal and extramarginal excisions. We therefore reviewed our experience with intramarginal and extramarginal excision of hypertrophic scars. Between October 30, 1979, and March 26, 1986, we excised 50 hypertrophic scars in 23 burn patients. Thirty-one (62 percent) of the excisions were intramarginal and 19 (38 percent) were extramarginal. We compared the results and observed that the intramarginal excisions yielded better results than the extramarginal excisions.

Proof of safety vs proof of hazard.

This paper refines and extends the work of Bross (1985, Biometrics 41, 785-793). One method to determine whether an environment is safe or hazardous is to frame the problem in the context of hypothesis testing. Any "proof" of safety or hazard will depend on the size of both the Type I and Type II errors associated with the test. Many past environmental monitoring programs, however, have ignored the power of the design, regardless of whether the objective was proof of safety or hazard.

Partial excision of residual burn lesions.

Most burn victims have unattractive residual lesions, which may include hypertrophic donor sites, unsightly skin grafts, hypertrophic scars, and mature scars with altered pigmentation or texture. Some of these lesions can be treated by total excision in one or more stages or they can be reconstructed utilizing grafts, flaps, Z-plasties, or tissue expansion. But frequently these procedures are either not indicated or not elected by the patient. In such a situation, the only surgical option is partial excision, with the goal of making the lesion less conspicuous and more easily concealed by clothing. Whether or not such partial excisions are worthwhile is the obvious question. We could not find an answer in the literature and therefore decided to review our own experience. Between 6/30/81 and 3/12/86, 92 such procedures were performed and followed in 25 patients. Partial excision of hypertrophic donor sites, unsightly skin grafts, and hypertrophic scars did yield improved appearance in most patients. However, partial excision of mature scars, ie, areas of altered pigmentation or texture, did not have the same success. We continue to treat the first three types of lesions in this fashion but no longer include the latter.