Building a comprehensive clinical information system from components. The approach at Intermountain Health Care.

OBJECTIVES: To discuss the advantages and disadvantages of an interfaced approach to clinical information systems architecture. METHODS: After many years of internally building almost all components of a hospital clinical information system (HELP) at Intermountain Health Care, we changed our architectural approach as we chose to encompass ambulatory as well as acute care. We now seek to interface applications from a variety of sources (including some that we build ourselves) to a clinical data repository that contains a longitudinal electronic patient record. RESULTS: We have a total of 820 instances of interfaces to 51 different applications. We process nearly 2 million transactions per day via our interface engine and feel that the reliability of the approach is acceptable. Interface costs constitute about four percent of our total information systems budget. The clinical database currently contains records for 1.45 m patients and the response time for a query is 0.19 sec. DISCUSSION: Based upon our experience with both integrated (monolithic) and interfaced approaches, we conclude that for those with the expertise and resources to do so, the interfaced approach offers an attractive alternative to systems provided by a single vendor. We expect the advantages of this approach to increase as the costs of interfaces are reduced in the future as standards for vocabulary and messaging become increasingly mature and functional.

Does epidural analgesia cause dystocia?

STUDY OBJECTIVE: To analyze the effects of epidural analgesia for labor when dystocia occurs. DESIGN: Retrospective cohort study. SETTING: Academic health center. PATIENTS: 641 low risk, nulliparous women in spontaneous labor. INTERVENTIONS: 406 (63%) women received epidurals analgesia and 253 (37%) did not. Sixty women (9.4%) required an abdominal delivery for dystocia. MEASUREMENTS AND MAIN RESULTS: Women receiving epidural analgesia were more likely to be white, receive care from an attending physician, need labor augmentation, and deliver a heavier infant. Multivariate analysis identified five variables predictive of dystocia and abdominal delivery: pitocin augmentation odds ratio (O.R.) = 3.9 (2.0 to 7.6), duration of labor more than 20 hours O.R. = 2.4 (1.3 to 4.4), high epidural dose O.R. = 2.2 (1.2 to 4.1), birthweight over 4,000 grams O.R. = 2.0 (1.0 to 4.2), and early placement of epidural O.R. = 1. 9 (1.0 to 3.5). Repeating the regression after excluding the 20 women who developed abnormal labor prior to epidural placement (18 of 20 women had protracted dilatation) demonstrated that pitocin augmentation O.R. = 4.0 (1.8 to 4.), high epidural dose O.R. = 3.0 (1.9 to 6.2), duration of labor greater than 20 hours O.R. = 2.7 (1.3 to 5.7), and birthweight over 4,000 grams O.R. = 2.1 (0. 9 to 4.8) were associated with dystocia. CONCLUSION: Epidural analgesia appears to be a marker of abnormal labor rather than a cause of dystocia. High concentration anesthetics and epinephrine should be avoided, as they may influence labor. Randomized, controlled trials of this technique will be difficult to do; our work should reassure patients and their clinicians that epidural analgesia does not adversely affect labor.

Penicillin desensitization in the treatment of syphilis during pregnancy.

The objective of this study was to compare patients' hospital course, complications, and charges for oral and intravenous (i.v.) desensitization regimens for the treatment of syphilis in the penicillin-allergic gravida. We performed a retrospective search of medical records at two tertiary-level teaching hospitals and reviewed the hospital course of penicillin-allergic gravidas who underwent penicillin desensitization. Between August 1988 and December 1995, 16 procedures for penicillin desensitization were carried out: 11 oral procedures, and 6 i.v. procedures. There were no significant differences between the patients in the oral and i.v. desensitization groups with respect to demographic characteristics, duration of time in a monitored bed, or length of hospital stay. The oral regimen was less expensive than the i.v. regimen ($144.06 vs. $319.48). In our experience, oral and i.v. regimens provide effective desensitization for the treatment of syphilis in penicillin-allergic gravidas. However, the oral route offers ease of administration and substantial cost savings, making it the preferred method.

Relationship between pregnancy-induced hypertension and placenta previa: a population-based study.

OBJECTIVE: Our purpose was to investigate, in a large population-based cohort, the hypothesis that the risk of pregnancy-induced hypertension is lower among pregnancies complicated by placenta previa compared with pregnancies occurring in women with fundally implanted placentas. STUDY DESIGN: Data for this retrospective cohort study were derived from the computerized Atlee perinatal database of the Reproductive Care Program, Nova Scotia, Canada. Women who were delivered in the province between 1980 and 1993 were included in the study. Patients with pregnancy-induced hypertension were clinically diagnosed by the presence of elevated blood pressure, proteinuria, or edema. The risk of pregnancy-induced hypertension was compared between women diagnosed with placenta previa and those with a normally implanted placenta, after adjustment for potential confounders through multivariable logistic regression models based on the method of generalized estimating equations. RESULTS: During the 14 years (1980 to 1993), 121,082 singleton pregnancies were registered in the program, 416 (0.4%) of which had a confirmed diagnosis of placenta previa. Women with chronic hypertension had a relative risk of 1.2 (95% confidence interval 0.4 to 3.7) for placenta previa compared with normotensive women. However, the risk of pregnancy-induced hypertension was reduced by half among those with placenta previa (relative risk 0.5, 95% confidence interval 0.3 to 0.7). Adjustments for potential confounders, including maternal age, parity, prepregnancy body weight, prior cesarean delivery, prior spontaneous or induced abortions, and cigarette smoking, had no influence on this association. Analyses on the basis of stratification of women by parity (nulliparous vs multiparous), cigarette smoking (smoker vs nonsmoker), and gestational duration (< 28, 28 to 32, 33 to 36, and > 37 completed weeks) consistently showed reduced risks for pregnancy-induced hypertension among women with placenta previa, indicating that the association was not a result of shortened duration of gestation among women with placenta previa. CONCLUSIONS: The results from this study clearly show a decreased frequency of pregnancy-induced hypertension among those pregnancies with placenta previa. We speculate that the pathophysiologic mechanisms for this finding may be due to altered placental perfusion seen among women diagnosed with placenta previa.

Influence of hypertensive disorders and cigarette smoking on placental abruption and uterine bleeding during pregnancy.

OBJECTIVE: To assess the influence of hypertensive disorders in pregnancy on the subsequent risk of placental abruption and uterine bleeding of unknown aetiology, and to examine the combined effects of hypertensive disorders and cigarette smoking during pregnancy on the risk of uteroplacental bleeding disorders. DESIGN: Retrospective cohort study. SETTING: Data for this study were derived from the Nova Scotia Atlee Perinatal database, Canada, comprising of women who were delivered in the province between 1980 and 1993. POPULATION: 120,666 pregnancies resulting in singleton births, of which 13,360 pregnancies were complicated by pre-eclampsia and/or chronic hypertension. MAIN OUTCOME MEASURES: Risks and relative risks of placental abruption and uterine bleeding of unknown aetiology in pregnancies complicated by chronic hypertension, mild and severe pre-eclampsia, and chronic hypertension with superimposed pre-eclampsia, each compared with normotensive patients. Adjusted relative risks were obtained through the fit of multivariable logistic regression models based on the method of generalised estimating equations. RESULTS: Chronically hypertensive women had no increased risk of abruption (RR 1.4; 95% CI 0.5-3.6), while women whose pregnancies were complicated by severe pre-eclampsia (RR 3.8; 95% CI 2.1-6.9), and chronic hypertension with superimposed pre-eclampsia (RR 2.8; 95% CI 1.2-6.3) showed strong associations with placental abruption. However, none of the hypertensive disorders were associated with uterine bleeding of unknown aetiology. The association between placental abruption and hypertensive disorders varied by parity. Parous women with chronic hypertension and superimposed pre-eclampsia were at greater risk of placental abruption (aRR 3.8; 95% CI 1.9-7.8) than nulliparous women with chronic hypertension and superimposed pre-eclampsia (aRR 1.6; 95% CI 0.5-4.9). The joint effects of smoking and hypertension had a greater effect on the risk of placental abruption than would have been expected based on their individual effects. CONCLUSIONS: The pattern of association between placental abruption and hypertension varied in relation to the specific type of hypertensive disorder. However, uterine bleeding of unknown aetiology was not associated with hypertension. Findings from this study suggest that placental abruption and uterine bleeding of unknown origin are aetiologically distinct obstetric complications with respect to hypertensive disorders during pregnancy.

Preeclampsia and preterm birth subtypes in Nova Scotia, 1986 to 1992.

The goal of this study was to evaluate the influence of preeclampsia on preterm delivery, examining whether the association varied among preterm birth subtypes defined by gestational age and precipitating events. A population-based, longitudinal study of the association between mild and severe preeclampsia and preterm birth subtypes was conducted among 59,851 women (resulting in a total of 78,086 pregnancies) delivering singleton live births in the province of Nova Scotia, Canada between 1986 and 1992, utilizing the Nova Scotia Atlee perinatal database. Very preterm (< 33 weeks' gestation) and moderately preterm (33-36 weeks' gestation) births were further classified as occurring due to (1) membrane rupture, (2) medical intervention, and (3) spontaneous onset of labor (before membrane rupture). Mild and severe preeclampsia occurred in 8.7 and 1.7% of pregnancies, respectively, after exclusions of multiple births. After adjustment for confounders by multivariable logistic regression based on the generalized estimating equations, severe preeclampsia was strongly associated with the risk of very preterm birth (RR = 80.8, 95% CI: 54.2-120.6), and moderately preterm birth (RR = 41.8, 95% CI: 34.0-51.4) due to medical intervention. A less dramatically elevated risk of very preterm (RR = 2.1, 95% CI: 1.1-4.0) and moderately preterm (RR = 2.2, 95% CI: 1.7-2.9) birth due to medical intervention was apparent among pregnancies complicated by mild preeclampsia. Very preterm births due to membrane rupture were too rare to examine, but moderately preterm births due to membrane rupture were not associated with preeclampsia. Preeclampsia was associated with an increase in the risk of moderately preterm births due to spontaneous labor (RR = 1.9, 95% CI: 1.3-2.8), but not very preterm births (RR = 1.0, 95% CI: 0.7-1.2). Substantial variability was observed in the association between preeclampsia and preterm birth in relation to the subtypes defined by gestational age and pathway, with strong associations between hypertension and medically induced preterm births. The results indicate a need to separate preterm births into subcategories to properly evaluate the association between preeclampsia and preterm births and interventions to reduce the adverse effects of preeclampsia.

Effect of maternal age and parity on the risk of uteroplacental bleeding disorders in pregnancy.

OBJECTIVE: To examine the risk of placental abruption, placenta previa, and uterine bleeding of unknown etiology in relation to advanced maternal age and parity in a large, population-based study. METHODS: Data for this study were derived from the Nova Scotia Atlee perinatal provincial data base, Canada, an ongoing project on human reproduction. Women who delivered between 1980 and 1993 (n = 123,941) in the province of Nova Scotia were included in the study, with the exception of pregnancies resulting in multiple births (n = 2859) and those missing data on maternal age or parity (n = 14). Multivariable logistic regression models based on the method of generalized estimating equations were used to generate odds ratios after adjustment for multiple confounders. RESULTS: The frequency of abruption was increased slightly among younger women (relative risk [RR] 1.3, 95% confidence interval [CI] 1.0-1.7), compared with women ages 25-29 years, but there was no increase with advancing maternal age. In contrast, the risk of placenta previa increased dramatically with advancing maternal age, with women older than 40 years having a nearly ninefold greater risk than women under the age of 20, after adjustment for potential confounders, including parity. Uterine bleeding of unknown etiology was not associated with advanced maternal age, except for a slight increase among women over 40 (RR 1.3, 95% CI 1.0-1.6). The risk of placenta previa and placental abruption was increased with higher parity among younger women only, but uterine bleeding of unknown etiology was more weakly associated with higher parity. In addition, an analysis of the joint effects of age and parity on placental abruption indicated a strong parity effect for women under 30 years, whereas the risk of placenta previa increased with increasing parity up to age 35 years. Uterine bleeding of unknown etiology also indicated a parity effect that was restricted to women under 25 years. CONCLUSION: Multiparity is associated with the risk of placenta previa and, to a lesser extent, placental abruption, but not with other uterine bleeding. Increasing maternal age is associated independently with the risk of placenta previa, but not with either of the other two conditions. Finally, the increased risks of uteroplacental bleeding disorders with advanced parity among the younger women (ie, 20-25 years, parity 3+) may reflect effects of close pregnancy spacing, or confounding by unmeasured factors that characterize women who have many pregnancies at a relatively young age. Overall, the findings suggest that the three uteroplacental bleeding disorders do not share a common etiology in relation to maternal age and parity, and that placenta previa is linked to aging of the uterus and the effects of repeated pregnancies.

Race, age, and cesarean delivery in a military population.

OBJECTIVE: To evaluate the relationship between race, age, and the risk of cesarean delivery. METHODS: This was a cohort study of 3603 nulliparous enlisted United States Navy women who were on active duty and had a singleton delivery between October 1987 and September 1989. Type of delivery and complications of pregnancy, labor, or delivery were identified through hospital discharge diagnoses codes. Demographic risk factors were obtained from military personnel files. RESULTS: Women over age 30 had a significantly increased risk of cesarean delivery (odds ratio [OR] 1.4, 95% confidence interval [CI] 1.1-1.9) compared with women under age 30. Multiple logistic regression modeling adjusted for education, marital status, military rank, type of hospital, and complications of pregnancy, labor and delivery showed African-American women over age 30 to have a significantly increased risk for cesarean delivery (OR 2.2, 95% CI 1.1-4.2) compared with white women over age 30. Among women under 30, African-Americans were not at a greater risk of cesarean delivery (OR 1.1; 95% CI 0.89-1.3). Other demographic factors were not related to the risk of cesarean delivery, but complications of pregnancy, labor, and delivery were strong predictors. CONCLUSION: We observed an increased risk in this unique population over age 30. Active duty military women serve as a useful population to examine demographic differences because of equitable access to medical care.

Twin delivery and neonatal and infant mortality: a population-based study.

OBJECTIVE: To examine the effect of mode of delivery on twin survival, especially among very premature twin births, in a population-based historical cohort study. METHODS: A total of 4428 pairs of live-born twins, birth weight 500 g or greater, were included based on data from vital records of the entire state of North Carolina for the period 1988-1991. The main outcome measures were Apgar score at 5 minutes (less than 7 versus 7 or greater), neonatal death, and infant death. RESULTS: After controlling for birth weight, twin order, fetal presentation, ethnicity, maternal age, marital status, and adequacy of prenatal care, we found that cesarean delivery was associated with reduced risks (by 50-60%) of low 5-minute Apgar score and neonatal and infant deaths among infants born weighing 500-749 g (P < .05). The cesarean delivery benefited the second twins more than the first twins. Among infants weighing more than 1000 g, the mode of delivery was not associated with either low Apgar score or neonatal and infant mortality. CONCLUSION: Our study suggests that cesarean delivery for twins with estimated fetal weights less than 1000 g together with a more liberal use of vaginal delivery for twins with estimated fetal weights more than 1000 g would have a net effect of increasing perinatal survival while lowering the overall cesarean delivery rate.

Comparison of a trial of labor with an elective second cesarean section.

BACKGROUND: In an attempt to reduce the rate of cesarean section, obstetricians now offer a trial of labor to pregnant women who have had a previous cesarean section. Although a trial of labor is usually successful and is relatively safe, few studies have directly addressed the maternal and perinatal morbidity and mortality associated with this method of delivery. METHODS: We performed a population-based, longitudinal study of 6138 women in Nova Scotia who had previously undergone cesarean section and had delivered a singleton live infant in the period from 1986 through 1992. RESULTS: A total of 3249 women elected a trial of labor, and 2889 women chose to undergo a second cesarean section. There were no maternal deaths. The overall rate of maternal morbidity was 8.1 percent; 1.3 percent had major complications (a need for hysterectomy, uterine rupture, or operative injury) and 6.9 percent had minor complications (puerperal fever, a need for blood transfusion, or abdominal-wound infection). Although the overall rate of maternal complications did not differ significantly between women who chose a trial of labor and the women who elected cesarean section (odds ratio for the trial-of-labor group, 0.9; 95 percent confidence interval, 0.8 to 1.1), major complications were nearly twice as likely among women undergoing a trial of labor (odds ratio, 1.8; 95 percent confidence interval, 1.1 to 3.0). Apgar scores, admission to the neonatal intensive care unit, and perinatal mortality were similar among the infants whose mothers had a trial of labor and those whose mothers underwent elective cesarean section. CONCLUSION: Among pregnant women who have had a cesarean section, major maternal complications are almost twice as likely among those whose deliveries are managed with a trial of labor as among those who undergo an elective second cesarean section.

Hypertensive disorders of pregnancy and stillbirth in North Carolina, 1988 to 1991.

BACKGROUND: The objectives of this study were (i) to assess the effect of hypertensive disorders of pregnancy on the risk of stillbirth, and (ii) to characterize the relationship between hypertension and stillbirth separately by gravidity, race, 'explained' versus 'unexplained' causes of stillbirth, and antepartum versus intrapartum stillbirths. METHODS: The study was based on a retrospective cohort of approximately 400,000 pregnancies identified through the birth and fetal death certificates in North Carolina, USA, between 1988 and 1991. Multivariable polytomous logistic regression was used to generate odds ratios comparing stillbirth risk in hypertensive compared to non-hypertensive mothers, adjusted for potential confounders. RESULTS: The risk of chronic hypertension was 7.6 per 1000 pregnancies, while pregnancy-induced hypertension (PIH) and eclampsia were reported in 36.6 and 6.0 per 1000 pregnancies, respectively. Pregnancies among chronic hypertensives were more likely to result in losses after 28 weeks gestation (RR = 3.29, 95% CI: 2.43-4.43), while the risk ratio was 2.16 (95% CI: 1.45-3.22) for losses prior to 28 weeks' gestation. Pregnancies to patients with PIH were at 1.42 (95% CI: 1.15-1.79) times greater risk of terminating in late stillbirth, while the risk ratio for eclampsia was 2.23 (95% CI: 1.51-3.30). The risk ratio for 'explained' antepartum stillbirth was higher than intrapartum stillbirth for all of the hypertensive diseases. CONCLUSIONS: Hypertensive disorders were found to have a strong adverse impact on stillbirth suggesting that early diagnosis of hypertension during pregnancy and adequate medical intervention may help reduce the risk of stillbirth.

Myocardial infarction and coronary artery dissection in pregnancy.

Myocardial infarction associated with pregnancy is a relatively rare event, usually related to maternal risk factors for ischemic heart disease such as hypertension and diabetes mellitus. Coronary artery dissection represents an even more uncommon event and generally occurs in peripartum women without predisposing risk factors. A 31-year-old patient's postpartum course was complicated by the development of probable acute fatty liver of pregnancy followed by myocardial infarction and coronary artery dissection. The acute fatty liver of pregnancy and the cardiac event in our patient may both be vasospastic events related to vascular hypersensitivity.

Preconception care: a means of prevention.

Preconceptional health promotion should provide a prevention framework for interactions with all women of childbearing potential. Preconceptional counselling is properly directed by specialists in the field of obstetrics and gynaecology, but a multispecialty effort may be needed to achieve adequate information for decision-making. Preconceptional health care offers an important opportunity for physicians involved in women's health to expand a primary care and a primary prevention focus. The obstetrician or gynaecologist is not only involved in acute diagnosis and treatment plans but also in disease prevention, risk and behaviour modification and counselling, which are integral parts of primary prevention and co-ordinated women's health care.

Birth-weight-for-gestational-age patterns by race, sex, and parity in the United States population.

OBJECTIVES: To describe birth-weight-for-gestational-age patterns by race, sex, and parity in the United States population, and to discuss the measurements of gestational age by different methods, the pitfalls of each method, and the potential effects of the errors on birth-weight-for-gestational-age curves. METHODS: We used the computerized certificates of live births from the entire population in 1989, consisting of more than four million infants born to residents of the United States. Gestational age was based on the date of the last menstrual period (LMP) modified by the clinical estimate in those situations in which normal distribution of birth weight does not apply. Birth weights for the tenth, 25th, 50th, 75th, and 90th percentiles were calculated by each gestational age and by race, sex, and parity. RESULTS: Eight sets of smoothed birth-weight-for-gestational-age curves were created for black-white, male-female, and primipara-multipara comparisons in sequence. Compared with previous major curves, our curves were closer to those in which the gestational age was derived from the LMP. There were marked differences observed between our curves and those in which the gestational age was based on ultrasound estimation. CONCLUSION: In the measurement of gestational age, the LMP may produce misclassification of gestational age, thereby elevating birth weight percentiles in preterm births and lowering birth weight percentiles in postterm births. However, ultrasound estimation is likely to create a differential misclassification of gestational age, which exerts the opposite effect of lowering birth weight percentiles early in gestation and increasing the percentiles late in gestation.

Cesarean delivery: a reconsideration of terminology.

The terminology we employ influences our perceptions. Thus, we believe in reviewing terminology regularly. The term "cesarean section" should be abandoned. A medical procedure is rarely named after a historic figure, and almost never after an ancient Roman law. Cesarean section has recently been amended to cesarean birth; however, the term is still inadequate. The word "hysterotomy" more appropriately describes the procedure we regularly perform. The adjectives used to describe cesarean birth should also be reevaluated. If we are to keep the term "classical" for the original fundal vertical uterine incision, then the other designations of hysterotomy should retain the same architectural context. Contemporary hysterotomy should be used in reference to a low transverse cesarean. Neoclassical hysterotomy might be used to describe the low vertical procedure. Transitional hysterotomy may be an appropriate term for the "hockey stick" or "J" incision. Cesarean delivery best describes a postmortem cesarean. Vaginal birth after cesarean (VBAC) is inappropriate because a vaginal birth after a cesarean section would not occur if cesarean section refers to a perimortem procedure. Vaginal birth after hysterotomy should be substituted for VBAC. Such revision of our terminology will keep obstetrics at the forefront of medical science and bring us most efficiently into the 21st century.