Use of the SONET Score to Evaluate High Volume Emergency Department Overcrowding: A Prospective Derivation and Validation Study

Table 5

Association between ED crowding and LWBS patients using the different scoring systems in the derivation study. The number of LWBS patients increased in proportion to the severity of ED crowding as determined by both NEDOCS and SONET scores when comparing all three categories (). However, the number of LWBS patients was higher in both overcrowded and severely overcrowded statuses determined by the SONET but not the NEDOCS. This study showed a positive association between increasing numbers of LWBS patients as a function of ED crowding levels.

ED crowding status estimation	Number of LWBS patients every two hours ()
	NEDOCS score	SONET score
Not overcrowded	0.5 (1.0)	0.7 (1.4)
Overcrowded	1.7 (1.8), (0.106)	3.1 (2.8), (<0.001)
Severely overcrowded	4.1 (3.7), (<0.001)	5.3 (4.4), (<0.001)

LWBS: left without being seen; : the number of patients. value of the comparison between two groups of patients under the different ED crowding conditions (not overcrowded versus overcrowded). value of the comparison between two groups of patients under the different ED crowding conditions (overcrowded versus severely overcrowded).