There was a greater proportion of female patients in the dataset than males (47.1% males, χ2=95, df=1, p<0.0001). This pattern was consistent across each of the four hospitals (χ2=4.1, df=3, p=.25). The median age of patients at the first presentation (in cases where multiple presentations occurred within the analysis period) was 51 years (IQR: 31-72).
ED length of stay (ED LOS)The median LOS was 5 hours and 35 minutes (IQR: 3 hours and 39 minutes to 7 hours and 51 minutes). Overall, 74.53% of the presentations had a stay longer than 4-hours (95% CI 74.05% to 75.02%). The duration of the 95th percentile ED LOS was 878 minutes (14 hours and 38 minutes). Among the four hospitals, the median ED LOS was consistently the shortest at Hospital A and, with the exception of 2008, consistently the longest at Hospital F (Table 16).
|Year||Hospital||Number of ED presentations meeting criteria||Median LOS (minutes)||Median TAT (minutes)||Median number of tests|
Table 16. Median LOS, TAT, and number of tests by hospital and year.
Pathology testing characteristics
Maximum test TAT before dischargeThe median maximum test TAT before discharge from ED was 58 minutes (IQR: 40-88 minutes). The duration of the 95th percentile maximum test TAT was 3 hours and 40 minutes. There was a moderate positive correlation between maximum TAT and LOS (ρ=0.42; 95% CI: 0.39-0.41). The median TAT at Hospital A was the shortest and at Hospital F it was the longest among four hospitals (see Table 16). This was the same pattern observed for LOS.
Number of testsHalf the presentations involved a minimum of four pathology tests (IQR: 3-6 tests). The number of tests varied more between the calendar years for Hospitals D and E than Hospitals A and F (Table 16). There was a weak positive correlation between the number of tests in a test order episode and ED LOS (ρ=0.14; 95% CI: 0.12-0.15).
Number of pathology departments involvedOf the presentations meeting the inclusion criteria, 77.52% included tests from two pathology departments, most often clinical chemistry and haematology. The results in Table 17 suggest that, as more pathology departments were involved in fulfilling the test order, both the maximum test TAT and the ED LOS were longer.
|Number of labs||Number of test order episodes||Median TAT (minutes)||Median LOS (minutes)|
Table 17. The number of test order episodes which involved one through six different pathology departments, and the associated median TAT and LOS.
Test order typeEMR was implemented through 2008 and 2009, and became available at Hospital A in 2010, while at Hospitals D, E, and F it was also available for the 2009 period. Each test order episode could be created exclusively using the paper system, exclusively using the EMR system, or using a combination of the two systems. After the implementation of EMR was complete at all hospital EDs, (i.e., 2010), around 74% (in 2010) to 76% (in 2011) of test order episodes were created using EMR; around 2% (in both 2010 and 2011) used only the paper system; and 22% (in 2011) to 24% (in 2010) used a combination of both EMR and paper systems (Figure 3).
Figure 3. Percentage of test order episodes of each order type across the study period.
Across all hospital EDs the median TAT and ED LOS were longest for presentations where the test order episode was created using both the paper and EMR systems compared to presentations where the test order episode was created using the paper or EMR system exclusively (Table 18).
|Hospital||Order Type||Number of ED presentations meeting criteria||Median TAT (minutes)||Median LOS (minutes)|
Table 18. Median LOS and TAT by hospital and order type.
ED presentation characteristics
Triage categoryMore than 85% of presentations were triaged as potentially life threatening or potentially serious (categories 3 and 4, respectively). Figure 4 shows that the distribution of patient volume between triage categories was not uniform across the four hospitals (χ2=815, df=12, p<0.0001).
Figure 4. Percentage of ED presentations by triage category in each hospital.
The median test TAT and ED LOS were shorter for presentations with the triage category of immediately life threatening (category 1) than for presentations in the other four triage categories (Table 19).
|Triage||Number of ED presentations meeting criteria||Median TAT (IQR) (minutes)||Median LOS (QIR) (minutes)|
|Immediately life threatening (1)||309||54 (36,77)||271 (175,418)|
|Imminently life threatening (2)||3541||60 (43,89)||293 (209,410)|
|Potentially life threatening (3)||14682||58 (40,89)||335 (240,471)|
|Potentially serious (4)||11928||56 (39,86)||353 (250,490)|
|Less urgent (5)||754||53 (36,82)||317 ((220,452)|
Table 19. Median LOS and TAT by triage category.
Mode of separationOf the presentations meeting the inclusion criteria, 41.70% had their treatment completed within the ED and were discharged to home, and 56.17% of patients were eventually admitted or transferred to another ward or hospital (Table 20). The median TATs of the different modes of separation varied from 49 to 65 minutes and the median LOS ranged from 246 to 395 minutes (Table 20). Both median TAT and median LOS were longer for patients who were admitted and discharged as an inpatient within ED than for patients with another mode of separation.
|ED mode of separation||Number of ED presentations meeting criteria||Median TAT (minutes)||Median LOS (minutes)|
|Admitted/transferred to another ward/hospital||17534||62||395|
|Admitteed: Died in ED||40||65||302|
|Left at own risk||625||49||246|
Table 20. Median LOS and TAT by ED mode of separation.