The impact of COVID-19 pandemic on out-of-hospital cardiac arrest: An individual patient data meta-analysis.

AIM: Prior studies have reported increased out-of-hospital cardiac arrests (OHCA) incidence and lower survival during the COVID-19 pandemic. We evaluated how the COVID-19 pandemic affected OHCA incidence, bystander CPR rate and patients' outcomes, accounting for regional COVID-19 incidence and OHCA characteristics. METHODS: Individual patient data meta-analysis of studies which provided a comparison of OHCA incidence during the first pandemic wave (COVID-period) with a reference period of the previous year(s) (pre-COVID period). We computed COVID-19 incidence per 100,000 inhabitants in each of 97 regions per each week and divided it into its quartiles. RESULTS: We considered a total of 49,882 patients in 10 studies. OHCA incidence increased significantly compared to previous years in regions where weekly COVID-19 incidence was in the fourth quartile (>136/100,000/week), and patients in these regions had a lower odds of bystander CPR (OR 0.49, 95%CI 0.29-0.81, p = 0.005). Overall, the COVID-period was associated with an increase in medical etiology (89.2% vs 87.5%, p < 0.001) and OHCAs at home (74.7% vs 67.4%, p < 0.001), and a decrease in shockable initial rhythm (16.5% vs 20.3%, p < 0.001). The COVID-period was independently associated with pre-hospital death (OR 1.73, 95%CI 1.55-1.93, p < 0.001) and negatively associated with survival to hospital admission (OR 0.68, 95%CI 0.64-0.72, p < 0.001) and survival to discharge (OR 0.50, 95%CI 0.46-0.54, p < 0.001). CONCLUSIONS: During the first COVID-19 pandemic wave, there was higher OHCA incidence and lower bystander CPR rate in regions with a high-burden of COVID-19. COVID-19 was also associated with a change in patient characteristics and lower survival independently of COVID-19 incidence in the region where OHCA occurred.

Presentation and Outcomes of Adults With Overdose-Related Out-of-Hospital Cardiac Arrest.

Importance: Drug overdose (OD) is a public health challenge and an important cause of out-of-hospital cardiac arrest (OHCA). Existing studies evaluating OD-related OHCA (OD-OHCA) either aggregate all drugs or focus on opioids. The epidemiology, presentation, and outcomes of drug-specific OHCA are largely unknown. Objective: To evaluate the temporal pattern, clinical presentation, care, and outcomes of adult patients with OHCA overall and according to the drug-specific profile. Design, Setting, and Participants: This cohort study of adults with OHCA in King County Washington was conducted between January 1, 2015, and December 31, 2021. Etiology of OHCA was determined using emergency medical service, hospital, and medical examiner records. Etiology was classified as non-OD OHCA or OD-OHCA, with drug-specific profiles categorized as (1) opioid without stimulant, (2) stimulant without opioid, (3) opioid and stimulant, or (4) all other nonstimulant, nonopioid drugs. Statistical analysis was performed on July 1, 2023. Exposure: Out-of-hospital cardiac arrest. Main Outcomes and Measures: The primary outcome was survival to hospital discharge. The secondary outcome was survival with favorable functional status defined by Cerebral Performance Category 1 or 2 based on review of the hospital record. Results: In this cohort study, there were 6790 adult patients with emergency medical services-treated OHCA from a US metropolitan system. During the 7-year study period, there were 702 patients with OD-OHCA (median age, 41 years [IQR, 29-53 years]; 64% male [n = 450] and 36% female [n = 252]) and 6088 patients with non-OD OHCA (median age, 66 years [IQR, 56-77 years]; 65% male [n = 3944] and 35% female [n = 2144]). The incidence of OD-OHCA increased from 5.2 (95% CI, 3.8-6.6) per 100 000 person-years in 2015 to 13.0 (95% CI, 10.9-15.1) per 100 000 person-years in 2021 (P < .001 for trend), whereas there was no significant temporal change in the incidence of non-OD OHCA (P = .30). OD-OHCA were more likely to be unwitnessed (66% [460 of 702] vs 41% [2515 of 6088]) and less likely to be shockable (8% [56 of 702] vs 25% [1529 of 6088]) compared with non-OD OHCA. Unadjusted survival was not different (20% [138 of 702] for OD vs 18% [1095 of 6088] for non-OD). When stratified by drug profile, combined opioid-stimulant OHCA demonstrated the greatest relative increase in incidence. Presentation and outcomes differed by drug profile. Patients with stimulant-only OHCA were more likely to have a shockable rhythm (24% [31 of 129]) compared with patients with opioid-only OHCA (4% [11 of 295]) or patients with combined stimulant-opioid OHCA 5% [10 of 205]), and they were more likely to have a witnessed arrest (50% [64 of 129]) compared with patients with OHCA due to other drugs (19% [14 of 73]) or patients with combined stimulant-opioid OHCA (23% [48 of 205]). Patients with a combined opioid-stimulant OHCA had the lowest survival to hospital discharge (10% [21 of 205]) compared with patients with stimulant-only OHCA (22% [29 of 129]) or patients with OHCA due to other drugs (26% [19 of 73]), a difference that persisted after multivariable adjustment. Conclusions and Relevance: In a population-based cohort study, the incidence of OD-OHCA increased significantly from 2015 to 2021, with the greatest increase observed among patients with a combined stimulant-opioid OHCA. Presentation and outcome differed according to the drug-specific profile. The combination of increasing incidence and lower survival among among patients with a opioid-stimulant OHCA supports prevention and treatment initiatives that consider the drug-specific profile.

Acute SARS-CoV-2 Infection and Incidence and Outcomes of Out-of-Hospital Cardiac Arrest.

Importance: Little is known about how COVID-19 affects the incidence or outcomes of out-of-hospital cardiac arrest (OHCA), and it is possible that more generalized factors beyond SARS-CoV-2 infection are primarily responsible for changes in OHCA incidence and outcome. Objective: To assess whether COVID-19 is associated with OHCA incidence and outcomes. Design, Setting, and Participants: This retrospective cohort study was conducted in Seattle and King County, Washington. Participants included persons aged 18 years or older with nontraumatic OHCA attended by emergency medical services (EMS) between January 1, 2018, and December 31, 2021. Data analysis was performed from November 2022 to March 2023. Exposures: Prepandemic (2018-2019) and pandemic (2020-2021) periods and SARS-CoV-2 infection. Main Outcomes and Measures: The primary outcomes were OHCA incidence and patient outcomes (ie, survival to hospital discharge). Mediation analysis was used to determine the percentage change in OHCA incidence and outcomes between prepandemic and pandemic periods that was attributable to acute SARS-CoV-2 infection vs conventional Utstein elements related to OHCA circumstances (ie, witness status and OHCA location) and resuscitation care (ie, bystander cardiopulmonary resuscitation, early defibrillation, and EMS response intervals). Results: There were a total of 13 081 patients with OHCA (7102 dead upon EMS arrival and 5979 EMS treated). Among EMS-treated patients, the median (IQR) age was 64.0 (51.0-75.0) years, 3864 (64.6%) were male, and 1027 (17.2%) survived to hospital discharge. The total number of patients with OHCA increased by 19.0% (from 5963 in the prepandemic period to 7118 in the pandemic period), corresponding to an incidence increase from 168.8 to 195.3 events per 100 000 person-years. Of EMS-treated patients with OHCA during the pandemic period, 194 (6.2%) were acutely infected with SARS-CoV-2 compared with 7 of 191 EMS-attended but untreated patients with OHCA (3.7%). In time-series correlation analysis, there was a positive correlation between community SARS-CoV-2 incidence and overall OHCA incidence (r = 0.27; P = .01), as well as OHCA incidence with acute SARS-CoV-2 infection (r = 0.43; P < .001). The survival rate during the pandemic period was lower than that in the prepandemic period (483 patients [15.4%] vs 544 patients [19.2%]). During the pandemic, those with OHCA and acute SARS-CoV-2 infection had lower likelihood of survival compared with those without acute infection (12 patients [6.2%] vs 471 patients [16.0%]). SARS-CoV-2 infection itself accounted for 18.5% of the pandemic survival decline, whereas Utstein elements mediated 68.2% of the survival decline. Conclusions and Relevance: In this cohort study of COVID-19 and OHCA, a substantial proportion of the higher OHCA incidence and lower survival during the pandemic was not directly due to SARS-CoV-2 infection but indirect factors that challenged OHCA prevention and treatment.

Association between bystander physical limitations, delays in chest compression during telecommunicator-assisted cardiopulmonary resuscitation, and outcome after out-of-hospital cardiac arrest.

BACKGROUND: Promptly initiated bystander cardiopulmonary resuscitation (CPR) improves survival from out-of-hospital cardiac arrest (OHCA). Many OHCA patients require repositioning to a firm surface. We examined the association between repositioning, chest compression (CC) delay, and patient outcomes. METHODS: We used a quality improvement registry from review of 9-1-1 dispatch audio recordings of OHCA among adults eligible for telecommunicator-assisted CPR (T-CPR) between 2013 and 2021. OHCA was categorized into 3 groups: CC not delayed, CC delayed due to bystander physical limitations to reposition the patient, or CC delayed for other (non-physical) reasons. The primary outcome was the repositioning interval, defined as the interval between the start of positioning instructions and CC onset. We used logistic regression to assess the odds ratio of survival according to CPR group, adjusting for potential confounders. RESULTS: Of the 3,482 OHCA patients eligible for T-CPR, CPR was not delayed in 1,223 (35%), delayed due to repositioning in 1,413 (41%), and delayed for other reasons in 846 (24%). The repositioning interval was longest for the physical limitation delay group (137 secs, IQR-148) compared to the other delay group (81 secs, IQR-70) and the no delay group (51 secs, IQR-32) (p < 0.001). Unadjusted survival was lowest in the physical limitation delay group (11%) versus the no delay (17%) and other delay (19%) groups and persisted after adjustment (p = 0.009). CONCLUSION: Bystander physical limitations are a common barrier to repositioning patients to begin CPR and are associated with lower likelihood of receiving CPR, longer times to begin CC, and lower survival.

Incidence, Mechanism, and Outcomes of On-Plane Versus Off-Plane Cardiac Arrest in Air Travelers.

Background Air travel affords an opportunity to evaluate resuscitation performance and outcome in a setting where automated external defibrillators (AEDs) are readily available. Methods and Results The study cohort included people aged ≥18 years with out of hospital cardiac arrest (OHCA) traveling through Seattle-Tacoma International Airport between January 1, 2004 and December 31, 2019 treated by emergency medical services (EMS). The primary outcomes were pre-EMS therapies (cardiopulmonary resuscitation, application of AED), return of spontaneous circulation, and survival to hospital discharge. Over the 16-year study period, there were 143 OHCA occurring before EMS arrival, 34 (24%) on-plane and 109 (76%) off-plane. Cardiac etiology (81%) was the most common mechanism of arrest. The majority of arrests were bystander-witnessed and presented with a shockable rhythm; these characteristics were more common in off-plane OHCA compared with on-plane (witnessed: 89% versus 74% and shockable: 72% versus 50%). Pre-EMS therapies including cardiopulmonary resuscitation and AED application were common regardless of arrest location. Compared with on-plane OHCA, off-plane OHCA was associated with greater rates of return of spontaneous circulation (68% versus 44%) and 3-fold higher rate of survival to hospital discharge (44% versus 15%). All survivors of on-plane OHCA had AED application with defibrillation before EMS arrival. Conclusions When applied to air travel volumes, we estimate 350 air travel-associated OHCA occur in the United States and 2000 OHCA worldwide each year, nearly a quarter of which happen on-plane. These events are survivable when early arrest interventions including rapid arrest recognition, AED application, and CPR are deployed.

Risk for Acquiring Coronavirus Disease Illness among Emergency Medical Service Personnel Exposed to Aerosol-Generating Procedures.

We investigated the risk of coronavirus disease (COVID-19)- patients transmitting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to emergency medical service (EMS) providers, stratified by aerosol-generating procedures (AGP), in King County, Washington, USA, during February 16-July 31, 2020. We conducted a retrospective cohort investigation using a statewide COVID-19 registry and identified 1,115 encounters, 182 with ≥1 AGP. Overall, COVID-19 incidence among EMS personnel was 0.57 infections/10,000 person-days. Incidence per 10,000 person-days did not differ whether or not infection was attributed to a COVID-19 patient encounter (0.28 vs. 0.59; p>0.05). The 1 case attributed to a COVID-19 patient encounter occurred within an at-risk period and involved an AGP. We observed a very low risk for COVID-19 infection attributable to patient encounters among EMS first responders, supporting clinical strategies that maintain established practices for treating patients in emergency conditions.

Association between functional status at hospital discharge and long-term survival after out-of-hospital-cardiac-arrest.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) causes brain injury. Functional status of survivors at hospital discharge is a core resuscitation measure, frequently using the Cerebral Performance Category (CPC) or modified Rankin Scale (mRS). Which scale better predicts long-term survival following OHCA is not known. METHODS: We evaluated long-term survival after hospital discharge in a retrospective cohort of persons resuscitated from OHCA in King County, WA from 2007 to 2015. Patients were independently assessed at discharge using both scales, leveraging the regional quality improvement registry, which records the 5-level CPC, and concurrent research studies involving the Resuscitation Outcomes Consortium, which used the 7-level mRS, taken from information in the hospital record. The risk of mortality associated with CPC and mRS categories was estimated using Kaplan-Meier survival analysis and Cox proportional hazards regression. RESULTS: Among 878 eligible patients discharged alive, there were 358 deaths during 9118.5 person-years of follow-up. Overall 1, 5 and 10-year survival was 84.4%, 68.5%, and 53.7% and varied according to CPC and mRS (p < 0.01 per Kaplan-Meier). Compared to CPC-1, hazard ratio (HR) increased incrementally for CPC-2 = 1.33 (1.03-1.73), CPC-3 = 1.90 (1.37-2.65), and CPC-4 = 8.25 (5.63-12.10). Compared to mRS = 0, HR for mRS-1 = 1.02 (0.66-1.58), mRS-2 = 1.52 (1.00-2.32), mRS-3 = 1.41 (0.92-2.14), mRS-4 = 2.00 (1.37-2.97), and mRS-5 = 4.90 (3.23-7.44). CONCLUSION: In OHCA survivors, CPC and mRS scales both predicted long-term survival. However mRS 0-1 and 2-3 groups did not have distinct prognoses, suggesting that a consolidated mRS score may simplify capture of relevant prognostic information for survival predictions.

Emergency Medical Services and Do Not Attempt Resuscitation directives among patients with out-of-hospital cardiac arrest.

BACKGROUND: Emergency Medical Services (EMS) are often involved in end-of-life circumstances, yet little is known about how EMS interfaces with advance directives to forego unwanted resuscitation (Do Not Attempt Resuscitation (DNAR)). We evaluated the frequency of these directives involved in out-of-hospital cardiac arrest (OHCA) and how they impact care. METHODS: We conducted a cohort investigation of adult, EMS-attended OHCA from January 1 to December 31, 2018 in King County, WA. DNAR status was ascertained from dispatch, EMS, and hospital records. Resuscitation was classified according to DNAR status: not initiated, initiated but ceased due to the DNAR, or full efforts. RESULTS: Of 3152 EMS-attended OHCA, 314 (9.9%) had a DNAR directive. DNAR was present more often among those for whom EMS did not attempt resuscitation compared to when EMS provided some resuscitation (13.2% [212/1611] vs 6.6% [101/1541], (p < 0.05). Of those receiving resuscitation with a DNAR directive (n = 101), the DNAR was presented on average 6 min following EMS arrival. A total of 82% (n = 83) had EMS efforts ceased as a consequence of the DNAR while 18% (n = 18) received full efforts. Full-efforts compared to ceased-efforts were more likely to have a witnessed arrest (67% vs 36%), present with shockable rhythm (22% vs 6%), achieve spontaneous circulation by time of DNAR presentation (50% vs 4%), and have family contradict the DNAR (33% vs 0%) (p < 0.05 for each comparison). CONCLUSIONS: Approximately 10% of EMS-attended OHCA involved DNAR. EMS typically fulfilled this end-of-life preference, though wishes were challenged by delayed directive presentation or contradictory family wishes.

Occupational exposures and programmatic response to COVID-19 pandemic: an emergency medical services experience.

Rigorous assessment of occupational COVID-19 risk and personal protective equipment (PPE) use is not well-described. We evaluated 9-1-1 emergency medical services (EMS) encounters for patients with COVID-19 to assess occupational exposure, programmatic strategies to reduce exposure and PPE use. We conducted a retrospective cohort investigation of laboratory-confirmed patients with COVID-19 in King County, Washington, USA, who received 9-1-1 EMS responses from 14 February 2020 to 26 March 2020. We reviewed dispatch, EMS and public health surveillance records to evaluate the temporal relationship between exposure and programmatic changes to EMS operations designed to identify high-risk patients, protect the workforce and conserve PPE. There were 274 EMS encounters for 220 unique COVID-19 patients involving 700 unique EMS providers with 988 EMS person-encounters. Use of 'full' PPE including mask (surgical or N95), eye protection, gown and gloves (MEGG) was 67%. There were 151 person-exposures among 129 individuals, who required 981 quarantine days. Of the 700 EMS providers, 3 (0.4%) tested positive within 14 days of encounter, though these positive tests were not attributed to occupational exposure from inadequate PPE. Programmatic changes were associated with a temporal reduction in exposures. When stratified at the study encounters midpoint, 94% (142/151) of exposures occurred during the first 137 EMS encounters compared with 6% (9/151) during the second 137 EMS encounters (p<0.01). By the investigation's final week, EMS deployed MEGG PPE in 34% (3579/10 468) of all EMS person-encounters. Less than 0.5% of EMS providers experienced COVID-19 illness within 14 days of occupational encounter. Programmatic strategies were associated with a reduction in exposures, while achieving a measured use of PPE.

Clinical Characteristics of Patients With Coronavirus Disease 2019 (COVID-19) Receiving Emergency Medical Services in King County, Washington.

Importance: The ability to identify patients with coronavirus disease 2019 (COVID-19) in the prehospital emergency setting could inform strategies for infection control and use of personal protective equipment. However, little is known about the presentation of patients with COVID-19 requiring emergency care, particularly those who used 911 emergency medical services (EMS). Objective: To describe patient characteristics and prehospital presentation of patients with COVID-19 cared for by EMS. Design, Setting, and Participants: This retrospective cohort study included 124 patients who required 911 EMS care for COVID-19 in King County, Washington, a large metropolitan region covering 2300 square miles with 2.2 million residents in urban, suburban, and rural areas, between February 1, 2020, and March 18, 2020. Exposures: COVID-19 was diagnosed by reverse transcription-polymerase chain reaction detection of severe acute respiratory syndrome coronavirus 2 from nasopharyngeal swabs. Test results were available a median (interquartile range) of 5 (3-9) days after the EMS encounter. Main Outcomes and Measures: Prevalence of clinical characteristics, symptoms, examination signs, and EMS impression and care. Results: Of the 775 confirmed COVID-19 cases in King County, EMS responded to 124 (16.0%), with a total of 147 unique 911 encounters. The mean (SD) age was 75.7 (13.2) years, 66 patients (53.2%) were women, 47 patients (37.9%) had 3 or more chronic health conditions, and 57 patients (46.0%) resided in a long-term care facility. Based on EMS evaluation, 43 of 147 encounters (29.3%) had no symptoms of fever, cough, or shortness of breath. Based on individual examination findings, fever, tachypnea, or hypoxia were only present in a limited portion of cases, as follows: 43 of 84 encounters (51.2%), 42 of 131 (32.1%), and 60 of 112 (53.6%), respectively. Advanced care was typically not required, although in 24 encounters (16.3%), patients received care associated with aerosol-generating procedures. As of June 1, 2020, mortality among the study cohort was 52.4% (65 patients). Conclusions and Relevance: The findings of this cohort study suggest that screening based on conventional COVID-19 symptoms or corresponding examination findings of febrile respiratory illness may not possess the necessary sensitivity for early diagnostic suspicion, at least in the prehospital emergency setting. The findings have potential implications for early identification of COVID-19 and effective strategies to mitigate infectious risk during emergency care.

Seizure-like presentation in OHCA creates barriers to dispatch recognition of cardiac arrest.

PURPOSE: Early recognition of out-of-hospital cardiac arrest (OHCA) by 9-1-1 dispatchers is a critical first step along the resuscitation pathway. Barriers to recognition may lead to adverse outcomes among patients. This study aims to determine the impact of seizure-like activity among OHCA patients during 9-1-1 calls. METHODS: We evaluated a retrospective cohort study of all adult, non-traumatic OHCAs that occurred prior to emergency medical services (EMS) arrival on scene in a major metropolitan area from 2014-2018. Dispatch recordings were reviewed to determine if seizure-like activity was reported by the caller using key descriptor phrases such as "seizing," "shaking," or "convulsing." We compared patient demographics, arrest factors, and hospital outcomes using a regional OHCA quality improvement database. RESULTS: Among 3502 OHCAs meeting our inclusion criteria, 149 (4.3%) contained seizure-like activity. When compared to patients without seizure-like activity (3353; 95.7%), patients presenting with seizure-like activity were younger (54 vs. 66 years old; p < 0.05), had a witnessed arrest (88% vs 45%; p < 0.05), presented with an initial shockable rhythm (52% vs. 24%; p < 0.05), and survived to hospital discharge (44% vs. 16%; p < 0.05). The seizure-like activity group also had a longer median time to dispatcher identification of the cardiac arrest [130 s (72,193) vs 62 s (43,102); p < 0.05]. CONCLUSIONS: Reported seizure-like activity among patients in cardiac arrest poses a barrier to recognition of cardiac arrests by dispatchers leading to delays in resuscitation instructions.

Assessment of Selected Overdose Poisoning Indicators in Health Care Administrative Data in 4 States, 2012.

OBJECTIVES: In 2012, a consensus document was developed on drug overdose poisoning definitions. We took the opportunity to apply these new definitions to health care administrative data in 4 states. Our objective was to calculate and compare drug (particularly opioid) poisoning rates in these 4 states for 4 selected Injury Surveillance Workgroup 7 (ISW7) drug poisoning indicators, using 2 ISW7 surveillance definitions, Option A and Option B. We also identified factors related to the health care administrative data used by each state that might contribute to poisoning rate variations. METHODS: We used state-level hospital and emergency department (ED) discharge data to calculate age-adjusted rates for 4 drug poisoning indicators (acute drug poisonings, acute opioid poisonings, acute opioid analgesic poisonings, and acute or chronic opioid poisonings) using just the principal diagnosis or first-listed external cause-of-injury fields (Option A) or using all diagnosis or external cause-of-injury fields (Option B). We also calculated the high-to-low poisoning rate ratios to measure rate variations. RESULTS: The average poisoning rates per 100 000 population for the 4 ISW7 poisoning indicators ranged from 11.2 to 216.4 (ED) and from 14.2 to 212.8 (hospital). For each indicator, ED rates were usually higher than were hospital rates. High-to-low rate ratios between states were lowest for the acute drug poisoning indicator (range, 1.5-1.6). Factors potentially contributing to rate variations included administrative data structure, accessibility, and submission regulations. CONCLUSIONS: The ISW7 Option B surveillance definition is needed to fully capture the state burden of opioid poisonings. Efforts to control for factors related to administrative data, standardize data sources on a national level, and improve data source accessibility for state health departments would improve the accuracy of drug poisoning surveillance.

Factors associated with civilian drivers involved in crashes with emergency vehicles.

Motor vehicle crashes involving civilian and emergency vehicles (EVs) have been a known problem that contributes to fatal and nonfatal injuries; however, characteristics associated with civilian drivers have not been examined adequately. This study used data from The National Highway Traffic Safety Administration's Fatality Analysis Reporting System and the National Automotive Sampling System General Estimates System to identify driver, roadway, environmental, and crash factors, and consequences for civilian drivers involved in fatal and nonfatal crashes with in-use and in-transport EVs. In general, drivers involved in emergency-civilian crashes (ECCs) were more often driving: straight through intersections (vs. same direction) of four-points or more (vs. not at intersection); where traffic signals were present (vs. no traffic control device); and at night (vs. midday). For nonfatal ECCs, drivers were more often driving: distracted (vs. not distracted); with vision obstructed by external objects (vs. no obstruction); on dark but lighted roads (vs. daylight); and in opposite directions (vs. same directions) of the EVs. Consequences included increased risk of injury (vs. no injury) and receiving traffic violations (vs. no violation). Fatal ECCs were associated with driving on urban roads (vs. rural), although these types of crashes were less likely to occur on dark roads (vs. daylight). The findings of this study suggest drivers may have difficulties in visually detecting EVs in different environments.

Aging and the impact of distraction on an intersection crossing assist system.

It is known that distraction reduces the benefits of collision avoidance systems by slowing a driver's response. The current study examined the impact of a drivers' use of an in-vehicle intersection crossing assist system under demanding cognitive load conditions. Forty eight drivers crossed a busy rural intersection in a simulated environment while completing four blocks of trials, in half of which they used the assist system and engaged in a working memory task. Participants were dichotomized into older and younger age groups. The results showed a tendency towards conservative driving in a single-task condition when only using the assist system. A similar shift in driving style was observed when drivers crossed the intersection while engaged in a secondary task. Using the in-vehicle intersection crossing assist system under cognitively demanding conditions did not result in adverse consequences-the impact of distraction was different compared to a typical collision avoidance system. Older drivers showed some evidence of more conservative intersection crossing, however they also appeared to rely more on the in-vehicle assist system when presented with an extraneous additional task.