The effect of COVID-19 on emergency medical service call volumes and patient acuity: a cross-sectional study in Niagara, Ontario

The global outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), is a major public health problem. The first case of COVID-19 in Canada was documented on January 25th, 2020 in Ontario [1]. Since then, Ontario has seen a large COVID-19 outbreak and at the time of writing is continuing to experience a rise in the number of positive cases [1]. As the impact of the COVID-19 pandemic on health care systems has become a concern in Ontario, paramedic services have begun to plan for anticipated impacts. Planning of this nature involves the ongoing monitoring of call volumes and types to anticipate future resource needs. There has been mixed information concerning the demand for emergency medical services (EMS). Perceptions abound that EMS will experience potential surges, during which containment is challenging yet crucial to the success of the health system response [2, 3]. These are countered by anecdotes that EMS calls have decreased, as people are avoiding involvement with the health system for fear of infection [4].

Volumes of EMS calls are important to understand since they impact the response times, and are part of quality of EMS care [5]. Fluctuations in call volumes can result in more or less EMS resources available to attend to emergencies and could affect patient outcomes [6]. Therefore, in order to adequately plan and assist other EMS in Ontario and across Canada with similar planning, problems, and questions, it is important to understand the precise effect of the pandemic on EMS. Niagara EMS (NEMS) provides emergency medical services for an area in Southern Ontario with a population of about half a million people [7]. The average age of the population is 44 years old, with 64% of the population falling into the category of being 15 to 64 years of age; 48% are male; 89% are of European descent; 4% are Indigenous peoples; between 1 and 11% describe themselves as having non-European heritage (e.g. Asian); median post-tax family income is $72,105 and single-parent family income is $46,684 [7].

NEMS is a large service that, in June of 2016, had approximately 3.9% of Ontario’s EMS call volumes [8]. Niagara region operates both an ambulance communications service with a dispatch centre, and a land ambulance service providing primary and advanced care paramedic services. There are approximately 343 full and part time paramedics in employment with the service, and 33 ambulances staffed at peak. These characteristics allow for reasonable comparisons to be made with other EMS service in Ontario. Though EMS in Ontario appears to have been affected by the COVID-19 pandemic, the specific impact of COVID-19 on Ontario EMS has not yet been critically and robustly examined. The following is an assessment of the change in call types and acuity before and during the first wave of COVID-19.

A total of 114,507 EMS calls were made to NEMS for the period of January 1 to May 26 between 2016 and 2020, inclusive (Table 1). Of the total calls from 2016 to 2020, determinants representing a larger absolute proportion of all calls include sick person (16.8%), falls (15.4%), breathing problems (11.2%), and chest pain (8.9%). Overall, the incidence rate of EMS calls per person-year decreased in 2020 compared to 2016–2019.

In our study we found that overall, the incidence rate of EMS calls from Jan-May 2020 significantly decreased compared to EMS calls made during the same timeframe in 2016–2019. This is in keeping with anecdotal reports in Canada describing a decrease in EMS calls beginning in April 2020 [4, 15]. In the U.S, a survey found that people were abstaining from calling 9-1-1, regardless of the severity of the health event, due to fear of COVID-19 [16]. A serious consequence of this behaviour of avoiding the ED is that high acuity patients are waiting to seek necessary care until they are too unwell to be treated adequately [17].

We found that call volumes for several determinants increased, such as 9-1-1 calls for cardiac arrest, stroke, and heart attacks. Evidence exists in the literature to support the finding of increased cardiac arrests. Data from Northern Italy shows that during the pandemic, out-of-hospital cardiac arrests has increased by 58.0% [18]. A New York study has found that the incidence of out-of-hospital cardiac arrests needing resuscitation has tripled in 2020 compared to the same time frames in 2019 [19]. Other US data shows that 911 calls for cardiac arrest rose in March by 45.0%, likely because people have been waiting too long before seeking care [17]. Indeed, fear of contracting COVID-19 may have contributed to EMS avoidance, even for patients experiencing life-threatening health events, resulting in the apparent increase in cardiac events and stroke. There is some evidence to suggest that our findings of increased cardiac arrests could also be related to SARS-CoV-2 itself. A systematic review found a correlation between COVID-19 and cardiovascular complications, despite COVID-19 being a respiratory disease [20]. However, we were not able to examine if any of the patients presenting with cardiac arrest or heart attack were diagnosed with COVID-19.

In addition to negatively impacting physical health, the COVID-19 pandemic has also been a threat to mental health [21, 22]. Overdose/poisoning demonstrated the largest increase in call volumes than any other call determinant. One group at an elevated risk for experiencing the negative mental health impacts of the COVID-19 pandemic are those who used substances or are in recovery [23]. In order to control the spread of COVID-19, multiple safe injection sites have remained closed during the pandemic. It is possible that these closures could have contributed to the alarming increase in overdoses/poisonings seen in the current study. Some safe injection sites in Ontario have reopened after noticing an increase in overdoses and noting the role that these sites play in harm reduction [24]. The interruption of regular primary health care and the switch to use of virtual care versus in-person care may also have impacted overdose numbers. Patients using prescription opioids may be monitored by urine testing less frequently and primary care may have been forced to be less vigilant while prescribing narcotics in these altered circumstances. Additionally, physical distancing measures may have led to an increase in social isolation and stress, increasing the risk of overdose for those who use substances due to lack of support and emotional strain. In support of this theory, lack of social support has been shown to predict non-fatal drug overdose in females, and mental health problems, such as depression, have been shown to predict overdose in both males and females [25]. It is worth noting that 9-1-1 calls for mental health appear to have decreased during the pandemic, although not significantly. Previously, 9-1-1 may have been called prior to an overdose, and those cases would have been identified as mental health issues. However, if patients are avoiding calling 9–1-1, there may be a subsequent increase in incidences of overdose.

Several call determinants decreased from January 2020 to May 2020. Unexpectedly, EMS calls regarding breathing problems and sick people decreased. An explanation for this could be the introduction of a new MPDS card on April 30, 2020; the ‘pandemic protocol card’. Calls that would have previously been categorized as “sick person” or “breathing problems”, the determinants associated with COVID-19, became categorized as ‘pandemic protocol’. The pandemic protocol card was meant to provide an opportunity for an altered response to call types identified as potential COVID-19 cases during periods that threaten to overwhelm EMS resources. The protocol encompasses a variety of presentations, including shortness of breath and chest pain. For this reason, categorizing a patient in only one protocol would result in misclassification. Therefore, call volumes for breathing problems and sick person may not have decreased as much as we reported.

Of all determinants that experienced a decrease in call volumes, motor vehicle collisions (MVC) decreased the most. People may have been commuting and travelling less frequently and had been encouraged to stay at home, therefore were less likely to become involved in car accidents. A study in Michigan, USA, examining the effect of shelter-in-place orders on orthopaedic trauma, also found that motor vehicle collisions decreased by 17% in March 2020 relative to March 2019 [26]. Although Ontario did not issue a shelter-in-place order, citizens were instructed to stay-at-home which may offer an explanation for the decrease in the number of MVC.

The number of patients presenting as high acuity (CTAS Level 1) and lower acuity (CTAS level 4) increased during the pandemic. A possible explanation for this is that lower acuity patients are not seeking care in time, so that when EMS is called they present as high acuity [16]. However, the increase in overdoses could also be contributing to higher patient acuity upon scene arrival. EMS calls for emergent (CTAS Level 2) and urgent (CTAS Level 3) situations have decreased from January 2019 to May 2020. This finding may also be explained by a fear of contracting COVID-19 in emergency rooms, and therefore avoiding EMS.

We have confirmed that overall, EMS calls in the Niagara region have significantly decreased during the first 5 months of the COVID-19 pandemic, whilst some types increased. Specifically, EMS calls for overdose increased the most out of any other call determinant, while calls for motor vehicle collisions decreased more than any other determinant. Calls related to high patient acuity levels significantly increased, while EMS calls for urgent and emergent patients significantly decreased. Our findings suggest that the COVID-19 pandemic could have contributed to a decrease in EMS calls overall, and increased certain types of calls, including an increase in the number of high acuity patients. The results of this study may be generalizable to other geographical areas with similar population sizes and characteristics but may not be generalizable to areas that don’t provide universal healthcare. These findings may be of interest to other EMS as they plan for future pandemics or second waves of COVID-19, including the ability to predict call type in an effort to adjust a targeted response. This information can also provide an opportunity for dialogue between EMS agencies and health care partners on the consequences of delays in seeking treatment.