Analyzing the heterogeneity of labor and delivery units: A quantitative analysis of space and design

Abstract

This study assessed labor and delivery (L&D) unit space and design, and also considered correlations between physical space measurements and clinical outcomes. Design and human factors research has increased standardization in high-hazard industries, but is not fully utilized in medicine. Emergency department and intensive care unit space has been studied, but optimal L&D unit design is undefined. In this prospective, observational study, a multidisciplinary team assessed physical characteristics of ten L&D units. Design measurements were analyzed with California Maternal Quality Care Collaborative (CMQCC) data from 34,161 deliveries at these hospitals. The hospitals ranged in delivery volumes (<1000->5000 annual deliveries) and cesarean section rates (19.6%-39.7%). Within and among units there was significant heterogeneity in labor room (LR) and operating room (OR) size, count, and number of configurations. There was significant homogeneity of room equipment. Delivery volumes correlated with unit size, room counts, and cesarean delivery rates. Relative risk of cesarean section was modestly increased when certain variables were above average (delivery volume, unit size, LR count, OR count, OR configuration count, LR to OR distance, unit utilization) or below average (LR size, OR size, LR configuration count). Existing variation suggests a gold standard design has yet to be adopted for L&D. A design-centered approach identified opportunities for standardization: 1) L&D unit size and 2) room counts based on current or projected delivery volume, and 3) LR and OR size and equipment. When combined with further human factors research, these guidelines could help design the L&D unit of the future.

Fig 1. Labor unit, labor room, and operating room size for each hospital.

1A. Labor unit size comparison overlay. Each solid line box represents scaled size (ft²) of a labor unit, including all labor rooms, operating rooms, storage areas, hallways, provider workspaces, and patient and family areas. Provider call rooms and locker rooms were not included. The dashed line box represents the mean square footage of all units. Mean labor room and operating room shown to scale in grey for reference. Nine labor units included because, for hospital E, no blueprints available to measure total unit square footage. *Hospitals listed in ascending order by unit square footage (independent of randomized hospital identification) to protect identity. 1B. Labor room size comparison overlay. Each solid line box represents the mean labor room size (ft²) within a labor unit. The dashed line represents the mean labor room size across units. **No blueprints available to obtain standard deviation. 1C. Operating room size comparison overlay. Each solid line box represents the mean operating room size (ft²) within a labor unit. The dashed line represents the mean operating room size across units.

Fig 2. Distribution of count and number of configurations of labor rooms and operating rooms.

Box and whisker plots represent median, first and third quartiles, and range for labor room and operating room counts and configurations across ten L&D units. Criteria for a different room configuration included different shape, equipment layout, entry location, or mirror image configuration.

Fig 3. Distribution of labor room to operating room distances by labor unit.

Box and whisker plots represent median, first and third quartiles, and range for the distances (ft) from each labor room to each operating room. n = Labor room count multiplied by operating room count. This number represents the number of possible distances required to transport a patient from a labor room to an operating room on L&D (i.e.: for an intrapartum Cesarean section or exam under anesthesia for postpartum hemorrhage).

Fig 4. Unit, labor room and operating room delivery capacity.

4A. Ratio of labor unit square footage to annual delivery volume, or the number of square feet per annual delivery by hospital. *Hospital E excluded (unable to measure unit square footage). 4B. Ratio of annual vaginal deliveries to labor room count, or the mean number of vaginal deliveries in each labor room per year by hospital. 4C. Ratio of annual cesarean deliveries to operating room count, or the mean number of Cesarean deliveries in each operating room per year by hospital.

Fig 5. Scale renderings of labor room (5A) and operating room (5B).

Room size, common equipment and approximate number of providers shown to scale. Flat black squares represent hospitals with lowest and highest mean room square footage. Upright walls represent mean square footage of all hospitals.