Strengths and Limitations
A strength of our study was the use of equally sized decile groups for
the analysis within our initial cohort analysis as opposed to comparing
groups by various QBL cutoffs. This allowed us to find an initial
inflection range of clinical significance in a less statistically
arbitrary manner. Furthermore, as a hospital that was an early
participant in the implementation of obstetric hemorrhage bundles, we
are able to assess QBL results versus clinically important morbidities
in a system with a standardized hemorrhage response. Finally, a strength
of our study was the use of data measured using quantitative blood loss
methods; most prior existing data informing clinical practices used
blood loss quantified by visual estimation, which has been shown to
significantly underestimate large volume blood loss by as much as
33-50% when compared to direct or quantitative
measurement.9-12 Visually estimated blood loss is thus
a poorly defined, inaccurate, and unreliable means of measuring
morbidity associated with obstetrical bleeding.
Our study also has limitations. We did not create any adjusted models
that would account for possible confounding factors that may impact
either total blood loss or baseline risk for morbid outcomes. Future
studies should consider stratifying results by factors such as delivery
mode and underlying co-morbidities. We were also limited by only two
years of data analyzed from a single institution with a population that
may not have outcomes that are generalizable to all birthing people.
However, as other institutions start to incorporate the use of
postpartum hemorrhage bundle protocols that include the utilization of
QBL, there is a great opportunity to replicate this data in the future
with larger multi-site cohorts.