Operational experience of the Dutch helicopter emergency medical services (HEMS) during the initial phase of the COVID-19 pandemic: jeopardy on the prehospital care system?

Treatment of severely injured patients requires rapid medical intervention. In the Netherlands, the Helicopter Emergency Medical Services (HEMS) and HEMS-ambulance are dispatched to treat severely injured patients [1, 2]. Up to 7600 deployments occur annually among four HEMS regions. The purpose of HEMS deployment is to rapidly transport the specialized team to the scene and consequently to add opportunity for advanced prehospital procedures, such as advanced airway management, chest tube placement, medication administration and surgical interventions [3]. As such, HEMS forms an integral part of the prehospital emergency medical care chain.

The SARS-CoV-2 virus has disrupted global and local medical supply chains [4‐6]. Although many non-emergency medical and surgical conditions can be treated after the rapid escalation of COVID-19 infections has stabilized, emergency conditions and trauma cases still require immediate assessment and timely resolution. To combat the spread of the virus and prevent an uncontrolled outbreak with limited resources, national lockdown protocols have taken effect in the Netherlands since March 13th 2020 [7]. As a result, the incidence of trauma-related injuries are thought to decrease during the national lockdown. It is hypothesized that this decrease may be attributable to the decrease in the trauma population at risk. However, evidence exists on the negative effects of social isolation on physical- and mental health during the COVID-19 pandemic, which could result in a shift towards more dispatches for domestic violence, excessive drug abuse and suicides [8].

Currently, the indications and principles for the management of the acutely injured have remained similar as in non-pandemic circumstances. However, it remains to be elucidated whether the incidence and type of medical emergency responses during a nationwide lockdown have altered compared to a non-lockdown period. Therefore, the present study aims to describe the HEMS (including HEMS-ambulance) operations during the COVID-19 pandemic and compare these to the same time period one year prior. In addition, the authors describe their initial experience with HEMS safety and precaution protocols during the pandemic period and the rate of COVID-19 infections among HEMS personnel.

This is the first study to describe the experiences of a physician staffed HEMS during the COVID-19 pandemic and to compare these data to non-pandemic circumstances. No differences in operational- and medical characteristics were found for HEMS and HEMS-ambulance dispatches between the initial phase of the COVID-19 pandemic in the Netherlands and the same time frame 1 year prior.

Overall, a decrease in incidence of mission dispatches (i.e., non-canceled dispatches) was observed during the COVID-19 pandemic compared to the historical cohort. This decrease in dispatches and increase in cancelled missions was primarily observed in the first month of the COVID-19 pandemic in the Netherlands. Ambulance vehicle dispatches were less frequent than 1 year prior, whereas helicopter dispatches gained in operability during the COVID-19 pandemic. The foremost reason for deployment by HEMS-ambulance vehicle was distance and time, rather than meteorological conditions compared to the prior year.

In terms of the cause of injury, this study found a significant decrease in the number of falls during the COVID-19 study period. This could be due to a lower number of work-related and intoxication-related accidents. However, we were not able to obtain detailed injury cause data due to the retrospective design of the study and the nature of data collection. No increase in violence related injuries (i.e., gunshot wounds (GSW) and stabbings) was observed. In the United States reports from increased violence related—and penetrating injuries (primarily from GSW) have emerged, posing a challenge for the, arguably, already strained health system [13]. In the Netherlands, however, a relatively small proportion of the total number of trauma patients has penetrating injuries in both non-pandemic [14] and pandemic circumstances.

Previous experience from the influenza pandemic and SARS epidemic has shown how mental health can be adversely affected and how it can potentially lead to an increase in suicide ideation and behavior in the population at risk [15]. In this study, the rate of self-inflicted injuries did not significantly differ from the historical control group. However, as the present study is limited to 3 months and solely includes HEMS dispatch data the long-term effects of prolonged social isolation and -distancing on the incidence of self-inflicted injuries remain to be elucidated [16]. Therefore, future efforts should focus on closely monitoring underlying mental health related injuries during the current pandemic.

As prehospital care providers operate along the frontline, they are considered the foundation of maturated trauma systems. Due to the time sensitive nature of the emergency dispatches and inability to screen patients for COVID-19 before treatment, HEMS potentially have a relatively high exposure rate to COVID-19. Safety procedures and protective measures are, therefore, crucial for HEMS and emergency medical staff. The safety protocol used in the present study can be considered similar to those used by other European HEMS services, as described by Hilbert-Carius et al. [17]. These guidelines can be used to ensure safe and sustained operability of emergency medical services. The potential loss of prehospital care providers as a result of becoming infected can be considered a serious threat to the prehospital care chain. In the Netherlands, HEMS physicians consist of a team of trauma surgeons or anesthesiologists. At our institution, three HEMS physicians were unable to take call for a mean 25 (range 8–53) days due to positive testing for COVID-19. This was primarily due to the prolonged absence of one physician, who did not return to the HEMS service in the study period. Moreover, one HEMS physician had obligations to take additional in-hospital tasks related to COVID-19, causing a gap in operational capacity within the team [18]. Trauma surgeons, therefore, took significantly more calls during the COVID-19 pandemic compared to 1 year prior to remain operable. Even though at the start of the COVID-19 outbreak in the Netherlands a rigorous personal protective protocol was implemented, care provider infections were imminent and posed a substantial stress on the operability of the HEMS.

As rapid transport is pivotal to decrease prehospital mortality the question arises whether prehospital care systems are being overwhelmed by COVID-19 patients and are unable to maintain the same level of responsiveness for severely ill or injured patients. No difference was observed between the time that the call was made to dispatch the HEMS and the arrival on the scene. Compatible with this finding, the rate of prehospital fatalities remained similar as in non-pandemic circumstances.

In terms of operability, the HEMS performed roughly a similar number of prehospital interventions during the COVID-19 pandemic compared to 1 year prior. Specifically, similar rates of advanced airway management were observed. A study by Tran et al. evaluated the risk of transmission of SARS-CoV-1 to health care providers performing endotracheal intubation and found a 6.6 higher risk of infection [19]. As the tracheal viral load is considered to be high in COVID-19 patients, prehospital endotracheal intubation can also be considered a high-risk intervention for the exposure to SARS-CoV-2, showing the need for personal protective equipment in prehospital care personnel [20].

In the beginning of April 2020 the American College of Surgeons (ACS) stated concerns with regards to trauma centers, fearing operability could potentially be compromised due to the surging number of COVID-19 cases in the US [21]. In the state of New York, novel CPR protocols have emerged to achieve early prehospital triage that meets the trauma center capacity. Cardiopulmonary resuscitation in these patients is currently withheld when the return of spontaneous circulation (ROSC) is not achieved [22]. In this study, we did not observe differences in initial resuscitation efforts performed on the scene by HEMS, nor differences in termination of resuscitation when ROSC could not be achieved.

The findings of the present study have to be interpreted within the scope of its design. The retrospective observational design reduces the strength of the conclusions from the statistical analysis. Furthermore, this study is limited to the operations of the HEMS Lifeliner 1, in one of the four Dutch HEMS operational areas. Therefore, the national distribution during the COVID-19 pandemic is not included in this study. As the scope of this study was primarily to describe prehospital characteristics associated with the operability of HEMS during the COVID-19 pandemic, the present study did not include in-hospital outcomes of the studied patient sample. Currently, a multicenter study at our institution is ongoing to capture in-hospital outcomes of both trauma- and non-trauma related presentations at the emergency room and to monitor the incidence of underlying mental-health related injuries during the COVID-19 pandemic.

The reported incidence of HEMS deployments decreased and the number of cancelled missions increased in the initial phase of the COVID-19 pandemic in the Netherlands compared to the same period 1 year prior. No major differences in operational- and injury characteristics were found for HEMS and HEMS-ambulance dispatches in both study periods. Safety protocols are crucial to limit the risk of COVID-19 cases among HEMS personnel, as the continued operability of HEMS during pandemic circumstances is pivotal to the prehospital emergency care chain. Future efforts that monitor in-hospital outcomes of both trauma- and non-trauma related injuries during pandemic circumstances are needed.