A Prospective Study of Clinical Characteristics and Interventions Required in Critically Ill Obstetric Patients

A new modified obstetric early warning score for prognostication of severe maternal morbidity

BACKGROUND

Maternal mortality is still a major challenge for health systems, while severe maternal complications are the primary causes of maternal death. Our study aimed to determine whether severe maternal morbidity is effectively predicted by a newly proposed Modified Obstetric Early Warning Score (MOEWS) in the setting of an obstetric intensive care unit (ICU).

METHODS

A retrospective study of pregnant women admitted in the ICU from August 2019 to August 2020 was conducted. MOEWS was calculated 24 h before and 24 h after admission in the ICU, and the highest score was taken as the final value. For women directly admitted from the emergency department, the worst value before admission was collected. The aggregate performance of MOEWS in predicting critical illness in pregnant women was evaluated and finally compared with that of the Acute Physiology and Chronic Health Evaluation II (APACHE II) score.

RESULTS

A total of 352 pregnant women were enrolled; 290 women (82.4%) with severe maternal morbidity were identified and two of them died (0.6%). The MOEWSs of women with serious obstetric complications were significantly higher than those of women without serious obstetric complications [8(6, 10) vs. 4(2, 4.25), z = -10.347, P < 0.001]. MOEWSs of 24 h after ICU admission had higher sensitivity, specificity and AUROC than MOEWSs of 24 h before ICU admission. When combining the two MOEWSs, sensitivity of MOEWS was 99.3% (95% CI: 98-100), specificity 75.8% (95% CI: 63-86), positive predictive value (PPV) 95.1% (95% CI: 92-97) and negative predictive value (NPV) 95.9% (95% CI: 86-100). The areas under the receiver operator characteristic (ROC) curves of MOEWS were 0.92 (95% CI: 0.88-0.96) and 0.70 (95% CI: 0.63-0.76) of the APACHE II score.

CONCLUSION

The newly proposed MOEWS has an excellent ability to identify critically ill women early and is more effective than APACHE II. It will be a valuable tool for discriminating severe maternal morbidity and ultimately improve maternal health.

Prognosticating Fetomaternal ICU Outcomes

Although no scoring system is as yet fully validated for predicting maternal outcomes in critically ill obstetric patients, prognostication may be done objectively using severity predicting models. General critical care scoring systems which have been studied in obstetric patients are outcome prediction models (Acute Physiology and Chronic Health Evaluation [APACHE] I-IV, Simplified Acute Physiology Score [SAPS] I-III, Mortality Probability Model [MPM] I-IV) and organ dysfunction scores (Multiple Organ Dysfunction Score [MODS], Logistic Organ Dysfunction Score [LODS], Sequential Organ Failure Assessment [SOFA]). General critical care scoring systems may overpredict mortality rates in obstetric patients secondary to an altered physiology of organ systems during pregnancy. Obstetric prediction models were developed keeping in mind the physiological characteristics of obstetric population. They are Modified Early Obstetric Warning System (MEOWS), Obstetric Early Warning Score (OEWS), Maternal Early Warning Trigger (MEWT), and disease-specific obstetric scoring systems. The APACHE II model and MPM II are most often used scoring systems for predicting maternal mortality. The SOFA model is the best predictive model for sepsis in obstetrics. APACHE II and SAPS are more useful for nonobstetric population. Recent studies have also underscored the applicability of the OEWS in intensive care unit (ICU) settings with results comparable to the more elaborate APACHE II and SOFA scores. The Early Warning System helps in identifying acutely deteriorating pregnant and postpartum women in non-ICU settings who may require critical care. Fetal outcomes are largely dependent upon maternal outcomes. Prognostic systems applied to mothers may help in estimation of perinatal mortality and morbidity.