Identification of factors associated with delayed treatment of obstetric hypertensive emergencies

Abstract

Background: Obstetric hypertensive emergency is defined as having systolic blood pressure ≥160 mm Hg or diastolic blood pressure ≥110 mm Hg, confirmed 15 minutes apart. The American College of Obstetricians and Gynecologists recommends that acute-onset, severe hypertension be treated with first line-therapy (intravenous labetalol, intravenous hydralazine or oral nifedipine) within 60 minutes to reduce risk of maternal morbidity and death.

Objective: Our objective was to identify barriers that lead to delayed treatment of obstetric hypertensive emergency.

Study design: A retrospective cohort study was performed that compared women who were treated appropriately within 60 minutes vs those with delay in first-line therapy. We identified 604 patients with discharge diagnoses of chronic hypertension, gestational hypertension, or preeclampsia using International Classification of Diseases-10 codes and obstetric antihypertensive usage in a pharmacy database at 1 academic institution from January 2017 through June 2018. Of these, 267 women (44.2%) experienced obstetric hypertensive emergency in the intrapartum period or within 2 days of delivery; the results from 213 women were used for analysis. We evaluated maternal characteristics, presenting symptoms and circumstances, timing of hypertensive emergency, gestational age at presentation, and administered medications. Chi square, Fisher's exact, Wilcoxon rank-sum, and sample t-tests were used to compare the 2 groups. Univariable logistic regression was applied to determine predictors of delayed treatment. Multivariable regression model was also performed; C-statistic and Hosmer and Lemeshow goodness-of-fit test were used to assess the model fit. A result was considered statistically significant at P<.05.

Results: Of the 213 women, 110 (51.6%) had delayed treatment vs 103 (48.4%) who were treated within 60 minutes. Patients who had delayed treatment were 3.2 times more likely to have an initial blood pressure in the nonsevere range vs those who had timely treatment (odds ratio, 3.24; 95% confidence interval, 1.85-5.68). Timeliness of treatment was associated with presence or absence of preeclampsia symptoms; patients without preeclampsia symptoms were 2.7 times more likely to have delayed treatment (odds ratio, 2.68; 95% confidence interval, 1.50-4.80). Patients with hypertensive emergencies that occurred overnight between 10 pm and 6 am were 2.7 times more likely to have delayed treatment vs those emergencies that occurred between 6 am and 10 pm (odds ratio, 2.72; 95% confidence interval, 1.27-5.83). Delayed treatment also had an association with race, with white patients being 1.8 times more likely to have delayed treatment (odds ratio, 1.79; 95% confidence interval, 1.04-3.08). Patients who were treated at <60 minutes had a lower gestational age at presentation vs those with delayed treatment (34.6±5 vs 36.6±4 weeks, respectively; P<.001). For every 1-week increase in gestational age at presentation, there was a 9% increase in the likelihood of delayed treatment (odds ratio, 1.11; 95% confidence interval, 1.04-1.19). Another factor that was associated with delay of treatment was having a complaint of labor symptoms, which made patients 2.2 times as likely to experience treatment delay (odds ratio, 2.17; 95% confidence interval, 1.07-4.41).

Conclusion: Initial blood pressure in the nonsevere range, absence of preeclampsia symptoms, presentation overnight, white race, having complaint of labor symptoms, and increasing gestational age at presentation are barriers that lead to a delay in the treatment of obstetric hypertensive emergency. Quality improvement initiatives that target these barriers should be instituted to improve timely treatment.

Keywords: barrier; blood pressure; hypertension; hypertensive emergency; preeclampsia.