Table 2.

Main causes of overcrowding.

Factors	Causes
Input due to the volume of patients arriving and waiting to be seen	Presentations with more urgent and complex care needs • Emergencies
	Increase in presentations by the elderly
	High volume of low-acuity presentations (LAPs)
	Access to primary care • The poor and uninsured who lack primary care
	Limited access to diagnostic services in community • The malfunctioning of health care services in the community
	Inappropriate use of emergency services • Unnecessary visits • “Frequent flyer” patients • Nonurgent visits • The majority of ED incomings resulted from self-referral process
	The number of escorts accompanying a patient
Throughput due to the time to process and/or treat patients	ED nursing staff shortages Low staffing and resource levels
	Presence of junior medical staff in ED
	Delays in receiving test results and delayed disposition decisions
	Number of tests (blood test and urinalysis) required to be performed per patient
	Too long a consultation time
	Patient degree of gravity
	Bed availability (both in the ED and in the hospital)
Output due to the volume of patients leaving the ED	Boarding
	Exit block
	Lack of available hospital beds
	Inefficient planning of discharging patients
Others	An increase in closures of a significant number of EDs
	Time of the year • Influenza season • Seasonal illness
	Weekend, holiday periods
	COVID-19