To the Editor: Despite the risk of rapid respiratory failure 1 and cardiac complications 2 due to Covid-19, it is unclear whether there is an association between Covid-19 and out-of-hospital cardiac arrest. The Lombardy region of Italy was among the first areas to have an outbreak of Covid-19 outside China, 3 and the first case there was diagnosed on February 20, 2020, in Lodi Province. 4 Using the Lombardia Cardiac Arrest Registry (Lombardia CARe), we compared out-of-hospital cardiac arrests that occurred in the provinces of Lodi, Cremona, Pavia, and Mantua during the first 40 days of the Covid-19 outbreak (February 21 through March 31, 2020) with those that occurred during the same period in 2019 (February 21 through April 1, to account for the leap year). We reviewed daily reports of new Covid-19 cases recorded by the National Department of Civil Protection 5 and cases of out-of-hospital cardiac arrest in the electronic database of the emergency medical system to identify either symptoms suggestive of Covid-19 (fever lasting ≥3 days before out-of-hospital cardiac arrest, with cough, dyspnea, or both) or positive results of testing to detect SARS-CoV-2 in pharyngeal swabs obtained before the out-of-hospital cardiac arrest or after death. (Details are provided in the Supplementary Appendix, available with the full text of this article at NEJM.org.)During the study period in 2020, a total of 9806 cases of Covid-19 were reported in the study territory. During this period, 362 cases of out-ofhospital cardiac arrest were identified, as compared with 229 cases identified during the same period in 2019 (a 58% increase). Increases of various magnitudes in the numbers of cases of out-ofhospital cardiac arrest were seen in all four provinces (Table S1 in the Supplementary Appendix). The sex and age of the patients were similar in the 2020 and 2019 periods, but in 2020, the incidence

Aims An increase in out-of-hospital cardiac arrest (OHCA) incidence has been reported in the very early phase of the COVID-19 epidemic, but a clear demonstration of a correlation between the increased incidence of OHCA and COVID-19 is missing so far. We aimed to verify whether there is an association between the OHCA difference compared with 2019 and the COVID-19 epidemic curve. Methods and results We included all the consecutive OHCAs which occurred in the Provinces of Lodi, Cremona, Pavia, and Mantova in the 2 months following the first documented case of COVID-19 in the Lombardia Region and compared them with those which occurred in the same time frame in 2019. The cumulative incidence of COVID-19 from 21 February to 20 April 2020 in the study territory was 956 COVID-19/100 000 inhabitants and the cumulative incidence of OHCA was 21 cases/100 000 inhabitants, with a 52% increase as compared with 2019 (490 OHCAs in 2020 vs. 321 in 2019). A strong and statistically significant correlation was found between the difference in cumulative incidence of OHCA between 2020 and 2019 per 100 000 inhabitants and the COVID-19 cumulative incidence per 100 000 inhabitants both for the overall territory (ρ 0.87, P < 0.001) and for each province separately (Lodi: ρ 0.98, P < 0.001; Cremona: ρ 0.98, P < 0.001; Pavia: ρ 0.87, P < 0.001; Mantova: ρ 0.81, P < 0.001). Conclusion The increase in OHCAs in 2020 is significantly correlated to the COVID-19 pandemic and is coupled with a reduction in short-term outcome. Government and local health authorities should seriously consider our results when planning healthcare strategies to face the epidemic, especially considering the expected recurrent outbreaks.

Introduction An increase in the incidence of OHCA during the COVID-19 pandemic has been recently demonstrated. However, there are no data about how the COVID-19 epidemic influenced the treatment of OHCA victims. Methods We performed an analysis of the Lombardia Cardiac Arrest Registry comparing all the OHCAs occurred in the Provinces of Lodi, Cremona, Pavia and Mantua (northern Italy) in the first 100 days of the epidemic with those occurred in the same period in 2019. Results The OHCAs occurred were 694 in 2020 and 520 in 2019. Bystander cardiopulmonary resuscitation (CPR) rate was lower in 2020 (20% vs 31%, p<0.001), whilst the rate of bystander automated external defibrillator (AED) use was similar (2% vs 4%, p = 0.11). Resuscitation was attempted by EMS in 64.5% of patients in 2020 and in 72% in 2019, whereof 45% in 2020 and 64% in 2019 received ALS. At univariable analysis, the presence of suspected/confirmed COVID-19 was not a predictor of resuscitation attempt. Age, unwitnessed status, non-shockable presenting rhythm, absence of bystander CPR and EMS arrival time were independent predictors of ALS attempt. No difference regarding resuscitation duration, epinephrine and amiodarone administration, and mechanical compression device use were highlighted. The return of spontaneous circulation (ROSC) rate at hospital admission was lower in the general population in 2020 [11% vs 20%, p = 0.001], but was similar in patients with ALS initiated [19% vs 26%, p = 0.15]. Suspected/confirmed COVID-19 was not a predictor of ROSC at hospital admission. Conclusion Compared to 2019, during the 2020 COVID-19 outbreak we observed a lower attitude of laypeople to start CPR, while resuscitation attempts by BLS and ALS staff were not influenced by suspected/confirmed infection, even at univariable analysis.

Since December 2019, the world has been facing the life-threatening disease, named Coronavirus disease-19 (COVID-19), recognized as a pandemic by the World Health Organization. The response of the Emergency Medicine network, integrating "out-of-hospital" and "hospital" activation, is crucial whenever the health system has to face a medical emergency, being caused by natural or human-derived disasters as well as by a rapidly spreading epidemic outbreak. We here report the Pavia Emergency Medicine network response to the COVID-19 outbreak. The "out-of-hospital" response was analysed in terms of calls, rescues and missions, whereas the "hospital" response was detailed as number of admitted patients and subsequent hospitalisation or discharge. The data in the first 5 weeks of the Covid-19 outbreak (February 21-March 26, 2020) were compared with a reference time window referring to the previous 5 weeks (January 17-February 20, 2020) and with the corresponding historical average data from the previous 5 years (February 21-March 26). Since February 21, 2020, a sudden and sustained increase in the calls to the AREU 112 system was noted (+ 440%). After 5 weeks, the number of calls and missions was still higher as compared to both the reference pre-Covid-19 period (+ 48% and + 10%, respectively) and the historical control (+ 53% and + 22%, respectively). Owing to the overflow from the neighbouring hospitals, which rapidly became overwhelmed and had to temporarily close patient access, the population served by the Pavia system more than doubled (from 547.251 to 1.135.977 inhabitants, + 108%). To minimize the possibility of intra-hospital spreading of the infection, a separate "Emergency Department-Infective Disease" was created, which evaluated 1241 patients with suspected infection (38% of total ED admissions). Out of these 1241 patients, 58.0% (n = 720) were admitted in general wards (n = 629) or intensive care unit (n = 91). To allow this massive number of admissions, the hospital reshaped many general ward Units, which became Covid-19 Units (up to 270 beds) and increased the intensive care unit beds from 32 to 60. In the setting of a long-standing continuing emergency like the present Covid-19 outbreak, the integration, interaction and team work of the "out-of-hospital" and "in-hospital" systems have a pivotal role. The present study reports how the rapid and coordinated reorganization of both might help in facing such a disaster. AREU-112 and the Emergency Department should be ready to finely tune their usual cooperation to respond to a sudden and overwhelming increase in the healthcare needs brought about by a pandemia like the current one. This lesson should shape and reinforce the future.

Objective: The Lombardy region was among the areas most affected by COVID-19 infection worldwide; the Lombardy Emergency Medical System (EMS) responded immediately to this emergency. We analyzed several critical aspects to understand what occurred in that region. Methods: This retrospective study compares the events managed by the dispatch center and the characteristics of the patients transported to the hospital-age, sex, SpO 2 , deaths-managed by the EMS in Brescia and Bergamo provinces between March-April 2020 and March-April 2019. Ambulances' waiting time at the hospitals before discharging patients and the patients' severity at emergency department admission were also analyzed. Results: EMS managed 37,340 events in March-April 2020, þ51.5% versus 2019. "Breathing" or "Infective" events reported to the dispatch center increased more than tenfold (OR 25.1, p < 0.0001) in March 2020 and twofold in April 2020 compared to 2019 (OR 3, p < 0.0001). Deaths increased þ246% (OR 1.7, p < 0.0001), and patients not transported to hospital þ481% (OR 2.9, p < 0.0001) in March 2020 compared