Acuity Assessment in Obstetrical Triage

Objective: A five-category Obstetrical Triage Acuity Scale (OTAS) was developed with a comprehensive set of obstetrical determinants. The purposes of this study were: (1) to compare the inter-rater reliability (IRR) in tertiary and community hospital settings and measure the intra-rater reliability (ITR) of OTAS; (2) to establish the validity of OTAS; and (3) to present the first revision of OTAS from the National Obstetrical Triage Working Group.

Methods: To assess IRR, obstetrical triage nurses were randomly selected from London Health Sciences Centre (LHSC) (n = 8), Stratford General Hospital (n = 11), and Chatham General Hospital (n= 7) to assign acuity levels to clinical scenarios based on actual patient visits. At LHSC, a group of nurses were retested at nine months to measure ITR. To assess validity, OTAS acuity level was correlated with measures of resource utilization.

Results: OTAS has significant and comparable IRR in a tertiary care hospital and in two community hospitals. Repeat assessment in a cohort of nurses demonstrated significant ITR. Acuity level correlated significantly with performance of routine and second order laboratory investigations, point of care ultrasound, nursing work load, and health care provider attendance. A National Obstetrical Triage Working Group was formed and guided the first revision. Four acuity modifiers were added based on hemodynamics, respiratory distress, cervical dilatation, and fetal well-being.

Conclusion: OTAS is the first obstetrical triage scale with established reliability and validity. OTAS enables standardized assessments of acuity within and across institutions. Further, it facilitates assessment of patient care and flow based on acuity.