Out-of-hospital cardiac arrest during the COVID-19 pandemic in the Province of Padua, Northeast Italy.

To the Editor,

Authors from Lombardy, Italy, and Paris, France have recently reported an increase in the incidence of out-of-hospital cardiac arrest (OHCA), suggesting a direct or indirect effect of COVID-19. As hypothesized, fewer patients received bystander-initiated cardiopulmonary resuscitation (CPR), and emergency medical services (EMS) arrival time and mortality were higher in both studies. In contrast, OHCA incidence and bystander-CPR in King County, USA remained similar to that of previous years. Accordingly, we decided to investigate whether these worrying observations were present in OHCAs occurring in the Province of Padua. Of note, Padua is the most populated and densely inhabited province of Veneto Region, northeast of Italy (2142 km2, 936,274 inhabitants) and, together with Lombardy, was the first area to have an outbreak of COVID-19 outside China. Between 21st February and 30th April 2020, a total of 17,960 COVID-19 cases were reported in the Veneto region.

Using retrospective data from the EMS database, we compared OHCAs occurred between 1st March and 30th April 2020 and the same period in 2019 (Table 1 ). During the active COVID-19 period, the EMS dispatch centre responsible for the study area had a 18% increase in daily calls (525 ± 97 vs 446 ± 44; P < 0.001) and a 7% increase in daily ambulances missions (240 ± 27 vs 225 ± 18; P < 0.001). During this period, EMS responded to a total of 200 OHCAs, consistent with the 206 OHCAs in the same period in 2019 and with characteristics of patients that did not differ substantially. We observed a numerical reduction in bystander-witnessed cases (13/52 [25%] vs. 17/59 [29%]; P = 0.65) and bystander-CPR rate (10/55 [18%] vs. 15/60 [25%]; P = 0.38). The median time between the call and EMS arrival was 1.2 min longer in 2020 than in 2019. When we break down the total arrival time in its main components (call to dispatch, dispatch to departure, and departure to arrival), we found that the culprit interval was the time between the call and EMS departure. In particular, a delay was seen during call taking and dispatch (2.4 [1.7–3.1] vs 2.0 [1.6–2.8]; P = 0.002) and between dispatch and departure (3.9 [2.5–6.0] vs 3.5 [2.4–4.6]; P = 0.003). The increase in the call taking and dispatch process can be explained by the need to ask questions about COVID-19 status (tested positive or COVID-like symptoms), and the increased dispatchers' workload (+17% of calls received). Instead, the delay in ambulances departure is mainly explained by the time needed to wear personal protective equipment. Also, ambulance sanitization and the moderate increase (+7%) in ambulance missions might account for departures delays. Interestingly, the time between EMS departure and arrival (i.e., road travel time) was significantly reduced (7.3 min [5.4–11] vs. 8.3 min [5.7–12]; P = 0.04), likely related to the 80% reduction in road traffic in the area due to lockdown (8th March–18th May 2020). Of note, resuscitation manoeuvres were less attempted by EMS (45/114 [39%] vs. 48/90 [53%]; P = 0.048) in the COVID-19 period, fear of infection might have contributed to this variation. Rates of ROSC, transport with ongoing CPR, and out-of-hospital death remained similar in the two periods.

Table 1

Characteristics of OHCAs and EMS system between 1st March and 30th April 2020 and the same period in 2019.

	2020 (March 1–April 30)	2019 (March 1–April 30)	P value
Total number of calls received, n	32,047	27,193	/
Calls received per day, mean (SD)	525 (97)	446 (44)	<0.001
Emergency missions, n	14,629	13,714	/
Emergency missions per day, mean (SD)	240 (27)	225 (18)	<0.001
Total OHCA cases, n	200	206	/
Age, mean (SD)	79 (17)	77 (14)	0.23
Male sex, n (%)	89/175 (51%)	98/179 (55%)	0.46
Aetiology, n (%)
Medical, n (%)	175/197 (89%)	179/204 (88%)	0.73
Trauma, n (%)	15/197 (7.6%)	17/204 (8.3%)	0.79
Drowning, n (%)	1/197 (0.5%)	0/204 (0%)	0.31
Overdose, n (%)	0/197 (0%)	1/204 (0.5%)	0.32
Electrocution, n (%)	0/197 (0%)	0/204 (0%)	/
Asphyxia, n (%)	6/197 (3.0%)	7/204 (3.4%)	0.83
Bystander witnessed, n (%)	13/52 (25%)	17/59 (29%)	0.65
Bystander CPR, n (%)	10/55 (18%)	15/60 (25%)	0.38
Minutes between call and EMS arrival, median (IQR)	16 (12–22)	15 (11–19)	0.01
Minutes between call and departure, median (IQR)	6.1 (4.8–8.7)	6.0 (4.6–7.2)	0.04
Minutes between call and dispatch, median (IQR)	2.4 (1.7–3.1)	2.0 (1.6–2.8)	0.002
Minutes between dispatch and departure, median (IQR)	3.9 (2.5–6.0)	3.5 (2.4–4.6)	0.003
Minutes between EMS departure and arrival, median (IQR)	7.3 (5.4–11)	8.3 (5.7–12)	0.04
Resuscitation attempted by EMS, n (%)	45/114 (39%)	48/90 (53%)	0.048
Outcomes among EMS treated OHCAs
ROSC, n (%)	2/45 (4.4%)	4/48 (8.3%)	0.45
Transported with ongoing CPR, n (%)	4/45 (8.9%)	2/48 (4.2%)	0.35
Out-of-hospital mortality, n (%)	39/45 (87%)	42/48 (87%)	0.90
Outcomes among all OHCAs
ROSC, n (%)	2/200 (1.0%)	4/206 (1.9%)	0.43
Transported with ongoing CPR, n (%)	4/200 (2.0%)	2/206 (1.0%)	0.39
Out-of-hospital mortality, n (%)	194/200 (97%)	200/206 (97%)	0.96

Categorical variables are reported as number and percentage, and the continuous variables are presented as mean and standard deviation (SD) or as median and interquartile range (IQR). Continuous variables were compared with Student’s t-test or the Mann–Whitney test, and categorical variables using the χ² test. Statistical analysis was performed with Stata software (version 13, StataCorp, College Station, TX, USA). Percentages may not total 100 because of rounding. CPR: cardiopulmonary resuscitation, EMS: emergency medical service, OHCA: out-of-hospital cardiac arrest, ROSC: return of spontaneous circulation.

Compared with findings from Lombardy and Paris, we did not observe an increase in OHCA incidence and mortality, in line with what reported in Seattle and King County, USA. Instead, a delay in EMS arrival and a numerical reduction in bystander-CPR rate was observed. Further research is needed to clarify the direct and indirect effects of COVID-19 on OHCA, with particular attention to regional variations.

Conflicts of interest

All authors do not have conflict of interest to declare.