Helicopter emergency medical service for time critical interfacility transfers of patients with cardiovascular emergencies

Peri-operative Mortality and Morbidity of Complex Abdominal Aortic Aneurysm Repair in Switzerland: A Swissvasc Report

OBJECTIVE

Complex abdominal aortic aneurysms (cAAA) pose a clinical challenge. The aim of this study was to assess the 30 day mortality and morbidity rates for open aneurysm repair (OAR) and fenestrated or branched endovascular aortic repair (F/B-EVAR), and the effect of hospital volume in patients with asymptomatic cAAA in Switzerland.

METHODS

Retrospective, cohort study using data from Switzerland's national registry for vascular surgery, Swissvasc, including patients treated from 1 January 2019 to 31 December 2022. All patients with asymptomatic, true, non-infected cAAA were identified. The primary outcome was 30 day mortality and morbidity rates reported using the Clavien-Dindo classification. Outcomes were compared between OAR and F/B-EVAR after propensity score weighting.

RESULTS

Of the 461 patients identified, 333 underwent OAR and 128 underwent F/B-EVAR for cAAA. At 30 days, the overall mortality rate was 3.3% after OAR and 3.1% after F/B-EVAR (p = .76). Propensity score weighted analysis indicated similar morbidity rates for both approaches: F/B-EVAR (OR 0.69, 95% CI 0.45 - 1.05, p = .055); intestinal ischaemia (1.8% after OAR, 3.1% after F/B-EVAR, p = .47) and renal failure requiring dialysis (1.5% after OAR, 5.5% after F/B-EVAR, p = .024) were associated with highest morbidity and mortality rates. Treatment specific complications with high morbidity were abdominal compartment syndrome and lower limb compartment syndrome following F/B-EVAR. Overall treatment volume was low for most of the hospitals treating cAAA in Switzerland; outliers with increased mortality rates were identified among low volume hospitals.

CONCLUSION

Comparable 30 day mortality and morbidity rates were found between OAR and F/B-EVAR for cAAA in Switzerland; lack of centralisation was also highlighted. Organ specific complications driving death were renal failure, intestinal ischaemia, and limb ischaemia, specifically after F/B-EVAR. Treatment in specialised high volume centres, alongside efforts to reduce peri-procedural kidney injury and mesenteric ischaemia, offers potential to lower morbidity and mortality rates in elective cAAA treatment.

Severity-Driven Trends in Mortality in a Large Regionalized Critical Care Transport Service

OBJECTIVE

The epidemiology accompanying helicopter emergency medical services (HEMS) transport has evolved as agencies have matured and become integrated into regionalized health systems, as evidenced primarily by nationwide systems in Europe. System-level congruence between Europe and the United States, where HEMS is geographically fragmentary, is unclear. In this study, we provide a temporal, epidemiologic characterization of the largest standardized private, nonprofit HEMS system in the United States, STAT MedEvac.

METHODS

We obtained comprehensive timing, procedure, and vital signs data from STAT MedEvac prehospital electronic patient care records for all adult patients transported to UPMC Health System hospitals in the period of January 2012 through October 2021. We linked these data with hospital electronic health records available through June 2018 to establish length of stay and vital status at discharge.

RESULTS

We studied 90,960 transports and matched 62.8% (n = 57,128) to the electronic health record. The average patient age was 58.6 years ( 19 years), and most were male (57.9%). The majority of cases were interfacility transports (77.6%), and the most common general medical category was nontrauma (72.7%). Sixty-one percent of all patients received a prehospital intervention. Overall, hospital mortality was 15%, and the average hospital length of stay (LOS) was 8.8 days ( 10.0 days). Observed trends over time included increases in nontrauma transports, level of severity, and in-hospital mortality. In multivariable models, case severity and medical category correlated with the outcomes of mortality and LOS.

CONCLUSION

In the largest standardized nonprofit HEMS system in the United States, patient mortality and hospital LOS increased over time, whereas the proportion of trauma patients and scene runs decreased.

Hospital incidence, mortality, and gender disparities in patients treated for type A aortic dissections in Switzerland - a secondary data analysis of Swiss DRG statistics

AIMS OF THE STUDY

The incidence of type A aortic dissection (TAAD) has increased in several countries in recent decades, but epidemiological data for Switzerland are lacking. Furthermore, there are conflicting data regarding a gender-disparity with higher type A aortic dissection mortality in women. This study analysed sex-specific hospital incidence and in-hospital mortality rates of TAAD in Switzerland.

METHODS

This study is a secondary data analysis of case-related hospital discharge data from the Swiss Federal Statistical Office for 2009-2018. Cases that were hospitalised and surgically treated for type A aortic dissection were included in this analysis. Standardised incidence rates were calculated using the European standard population in 2013. All-cause in-hospital mortality rates were calculated as raw values and standardised for age, sex, and the van Walraven comorbidity score.

RESULTS

A total of 2117 participants were included in this study, of whom 67.1% were male. The age-standardised cumulative hospital incidence for type A aortic dissection treatment was 3.5 per 100,000 (95% CI: 3.3-3.7) for men and 1.7 (1.6-1.8) per 100,000 for women (p <0.001). The incidence rates increased in both sexes during the observed decade. The adjusted mortality rates for treatment of TAAD decreased from 27.6% (26.7-28.5%) in 2009 to 18.5% (17.9-19.1%) in 2018 in women, and they decreased from 19.0% (18.4-19.6%) to 12.3% (11.9-12.7%) in the same period in men. Multivariable logistic regression analysis revealed that female sex was significantly associated with higher mortality, with an odds ratio of 1.39 (1.07-1.79) (p = 0.012).

CONCLUSIONS

Hospital incidence rates for the treatment of type A aortic dissection increased in both sexes over the observed decade. The mortality rate was significantly higher in women than it was in men, but it decreased in both sexes. TAAD remains a cardiovascular emergency with a high mortality rate even after emergency surgery.

Helicopter Ambulance Transport to the Emergency Department: Demographic and Clinical Factors Impacting Outcomes in a Turkish Medical Center

BACKGROUND Helicopter ambulances (HAs) are a significant component of pre-hospital emergency medical services. This study presents a report on the demographic and clinical factors associated with transport to the emergency department (ED) by HA of 161 patients to a single center in Turkey. MATERIAL AND METHODS Demographic data, diagnoses in arriving center's ED, transferred distance, and outcomes of 161 patients transferred by HAs between March 01, 2019 and May 31, 2021 were retrospectively evaluated. Mortality rates of the cases were compared both with age and according to the distance traveled within the diagnostic groups. RESULTS There were 134 patients (83.2%) with internal diseases, and cardiovascular diseases were the leading cause (68 patients, 41.6%); 27 patients (16.7%) were transferred due to trauma. The mean distance traveled with HAs was 167.1 km (range, 47.0-1316.0) and the median transfer time was 50 min. The most common form of hospitalization after ED arrival was intensive care hospitalization (n=78, 48.4%). Mortality increased as the transfer distance increased in elderly patients, as well as those with a cardiac or trauma-related diagnosis (P=0.015, P=0.044, P=0.028, respectively). CONCLUSIONS Most patients transferred by HA had severe disease. ED physicians dealing with patient transfer by HAs should be prepared for severe cases, both in the HA and in the ED. HAs may be preferred when making the transfer decision for elderly patients, trauma patients, and those with cardiac disease.

Pre-hospital endotracheal intubation in severe traumatic brain injury: ventilation targets and mortality-a retrospective analysis of 308 patients

BACKGROUND

Traumatic brain injury (TBI) remains one of the main causes of mortality and long-term disability worldwide. Maintaining physiology of brain tissue to the greatest extent possible through optimal management of blood pressure, airway, ventilation, and oxygenation, improves patient outcome. We studied the quality of prehospital care in severe TBI patients by analyzing adherence to recommended target ranges for ventilation and blood pressure, prehospital time expenditure, and their effect on mortality, as well as quality of prehospital ventilation assessed by arterial partial pressure of CO2 (PaCO2) at hospital admission.

METHODS

This is a retrospective cohort study of all TBI patients requiring tracheal intubation on scene who were transported to one of two major level 1 trauma centers in Switzerland between January 2014 and December 2019 by Swiss Air Rescue (Rega). We assessed systolic blood pressure (SBP), end-tidal partial pressure of CO2 (PetCO2), and PaCO2 at hospital admission as well as prehospital and on-scene time. Quality markers of prehospital care (PetCO2, SBP, prehospital times) and prehospital ventilation (PaCO2) are presented as descriptive analysis. Effect on mortality was calculated by multivariable regression analysis and a logistic general additive model.

RESULTS

Of 557 patients after exclusions, 308 were analyzed. Adherence to blood pressure recommendations was 89%. According to PetCO2, 45% were normoventilated, and 29% had a SBP ≥ 90 mm Hg and were normoventilated. Due to the poor correlation between PaCO2 and PetCO2, only 33% were normocapnic at hospital admission. Normocapnia at hospital admission was strongly associated with reduced probability of mortality. Prehospital and on-scene times had no impact on mortality.

CONCLUSIONS

PaCO2 at hospital admission is strongly associated with mortality risk, but normocapnia is achieved only in a minority of patients. Therefore, the time required for placement of an arterial cannula and prehospital blood gas analysis may be warranted in severe TBI patients requiring on-scene tracheal intubation.

Hospital Incidence, Treatment, and Outcome of 885 Patients with Thoracoabdominal Aortic Aneurysms Treated in Switzerland over 10 Years-A Secondary Analysis of Swiss DRG Data

Despite the development of fenestrated and branched endovascular aortic repair (f/bEVAR), the surgical management of thoraco-abdominal aortic aneurysms (TAAAs) remains a major challenge. The aim of this study was to analyse the hospital incidence and hospital mortality of patients treated for TAAAs in Switzerland. Secondary data analysis was performed using nationwide administrative discharge data from 2009-2018. Standardised incidence rates and adjusted mortality rates were calculated. A total of 885 cases were identified (83.2% nonruptured (nrTAAA), 16.8% ruptured (rTAAA)), where 69.3% were male. The hospital incidence rate for nrTAAA was 0.4 per 100,000 women and 0.9 per 100,000 men in 2009, which had doubled for both sexes by 2018. For rTAAA, there was no trend over the years. The most common procedure was f/bEVAR (44.2%), followed by OAR (39.5%), and 9.8% received a hybrid procedure. There was a significant increase in endovascular procedures over time. The all-cause mortality was 7.1% with nrTAAA and 55% with rTAAA. The mortality was lower for rTAAA when f/bEVAR or hybrid procedures were used. A ruptured aneurysm and higher comorbidity were associated with higher hospital mortality. This study demonstrates that the treatment approach has changed significantly over the observed period. The use of f/bEVAR nearly tripled in nrTAAA and doubled in rTAAA during this decade.

The forgotten cohort-lessons learned from prehospital trauma death: a retrospective cohort study

BACKGROUND

Trauma related deaths remain a relevant public health problem, in particular in the younger male population. A significant number of these deaths occur prehospitally without transfer to a hospital. These patients, sometimes termed "the forgotten cohort", are usually not included in clinical registries, resulting in a lack of information about prehospitally trauma deaths. The aim of the present study was to compare patients who died prehospital with those who sustained life-threatening injuries in order to analyze and potentially improve prehospital strategies.

METHODS

This cohort study included all primary operations carried out by Switzerland's largest helicopter emergency medical service (HEMS) between January 1, 2011, and December 31, 2021. We included all adult trauma patients with life-threatening or fatal conditions. The outcome of this study is the vital status of the patient at the end of mission, i.e. fatal or life-threatening. Injury, rescue characteristics, and interventions of the forgotten trauma cohort, defined as patients with a fatal injury (NACA score of VII), were compared with life-threatening injuries (NACA score V and VI).

RESULTS

Of 110,331 HEMS missions, 5534 primary operations were finally analyzed, including 5191 (93.8%) life-threatening and 343 (6.2%) fatal injuries. More than two-thirds of patients (n = 3772, 68.2%) had a traumatic brain injury without a significant difference between the two groups (p > 0.05). Thoracic trauma (44.6% vs. 28.7%, p < 0.001) and abdominal trauma (22.2% vs. 16.1%, p = 0.004) were more frequent in fatal missions whereas pelvic trauma was similar between the two groups (13.4% vs. 12.9%, p = 0.788). Pneumothorax decompression rate (17.2% vs. 3.7%, p < 0.001) was higher in the forgotten cohort group and measures for bleeding control (15.2% vs. 42.7%, p < 0.001) and pelvic belt application (2.9% vs. 13.1% p < 0.001) were more common in the life-threating injury group.

CONCLUSION

Chest decompression rates and measures for early hemorrhage control are areas for potential improvement in prehospital care.

Factors influencing on-scene time in a physician-staffed helicopter emergency medical service (HEMS): a retrospective observational study

BACKGROUND

For helicopter emergency service systems (HEMS), the prehospital time consists of response time, on-scene time and transport time. Little is known about the factors that influence on-scene time or about differences between adult and paediatric missions in a physician-staffed HEMS.

METHODS

We analysed the HEMS electronic database of Swiss Air-Rescue from 01-01-2011 to 31-12-2021 (N = 110,331). We included primary missions and excluded missions with National Advisory Committee for Aeronautics score (NACA) score 0 or 7, resulting in 68,333 missions for analysis. The primary endpoint 'on-scene time' was defined as first physical contact with the patient until take-off to the hospital. A multivariable linear regression model was computed to examine the association of diagnosis, type and number of interventions and monitoring, and patient's characteristics with the primary endpoint.

RESULTS

The prehospital time and on-scene time of the missions studied were, respectively, 50.6 [IQR: 41.0-62.0] minutes and 21.0 [IQR: 15.0-28.6] minutes. Helicopter hoist operations, resuscitation, airway management, critical interventions, remote location, night-time, and paediatric patients were associated with longer on-scene times.

CONCLUSIONS

Compared to adult patients, the adjusted on-scene time for paediatric patients was longer. Besides the strong impact of a helicopter hoist operation on on-scene time, the dominant factors contributing to on-scene time are the type and number of interventions and monitoring: improving individual interventions or performing them in parallel may offer great potential for reducing on-scene time. However, multiple clinical interventions and monitoring interact and are not single interventions. Compared to the impact of interventions, non-modifiable factors, such as NACA score, type of diagnosis and age, make only a minor contribution to overall on-scene time.

Inter-Hospital Transfer of Patients With Ruptured Abdominal Aortic Aneurysm in Switzerland

OBJECTIVE

To analyse the association between inter-hospital transfer and hospital mortality in patients with ruptured abdominal aortic aneurysms (rAAA) in Switzerland.

METHODS

Secondary data analysis of case related hospital discharge data from the Swiss Federal Statistical Office for the years 2009 - 2018. All cases with rAAA as primary or secondary diagnosis were included. Cases with rAAA as a secondary diagnosis without surgical treatment and cases that had been transferred to another hospital without surgical treatment at the referring hospital were excluded. Logistic regression models for hospital mortality were constructed with age, sex, type of admission, van Walraven comorbidity score, type of treatment, insurance class, hospital level, and year of treatment as independent variables.

RESULTS

A total of 1 798 cases with rAAA were treated either surgically (62.5%) or palliatively (37.5%) in Switzerland from 1 January 2009 to 31 December 2018. Of these cases, 72.9% were treated directly (surgically or palliatively) at the hospital of first presentation, whereas 27.1% of all cases with rAAA were transferred between hospitals. The overall crude hospital mortality was 50.3%; being 23.1% in the surgically treated cohort and 95.7% in the palliatively treated cohort. Inter-hospital transfer was associated with better survival compared with patients who were admitted directly (OR 0.52; 95% CI 0.36 - 0.75; p < .001). Treatment in major hospitals was associated with significantly higher mortality rate compared with university hospitals (OR 1.98; 1.41 - 2.79; p < .001). There was no evidence of an association between open repair and hospital mortality (OR 1.06; 0.77 - 1.48; p = .72) compared with endovascular repair.

CONCLUSION

In a healthcare system such as Switzerland's with a highly specialised rescue chain, transfer of haemodynamically stable patients with rAAA is probably safe. In this setting, centralised medical care might outweigh the potential disadvantages of a short delay due to patient transfer. Further studies are needed to address potential confounding factors such as haemodynamic and anatomical features.

Prehospital Stroke Care Part 1: Emergency Medical Services and the Stroke Systems of Care

Acute stroke care begins before hospital arrival, and several prehospital factors are critical in influencing overall patient care and poststroke outcomes. This topical review provides an overview of the state of the science on prehospital components of stroke systems of care and how emergency medical services systems may interact in the system to support acute stroke care. Topics include layperson recognition of stroke, prehospital transport strategies, networked stroke care, systems for data integration and real-time feedback, and inequities that exist within and among systems.

Helicopter inter-hospital transfer for patients undergoing extracorporeal membrane oxygenation: a retrospective 12-year analysis of a service system

Background

Patients undergoing extracorporeal membrane oxygenation (ECMO) are critically ill and show high mortality. Inter-hospital transfer of these patients has to be safe, with high survival rates during transport without potentially serious and life-threatening adverse events. The Swiss Air-Rescue provides 24-h/7-days per week inter-hospital helicopter transfers that include on-site ECMO cannulation if needed. This retrospective observational study describes adverse events of patients on ECMO transported by helicopter, and their associated survival.

Methods

All patients on ECMO with inter-hospital transfer by helicopter from start of service in February 2009 until May 2021 were included. Patients not transported by helicopter or with missing medical records were excluded. Patient demographics (age, sex) and medical history (type of and reason for ECMO), mission details (flight distance, times, primary or secondary transport), adverse events during the inter-hospital transfer, and survival of transferred patients were recorded. The primary endpoint was patient survival during transfer. Secondary endpoints were adverse events during transfer and 28-day survival.

Results

We screened 214 ECMO-related missions and included 191 in this analysis. Median age was 54.6 [IQR 46.1–62.0] years, 70.7% were male, and most patients had veno-arterial ECMO (56.5%). The main reasons for ECMO were pulmonary (46.1%) or cardiac (44.0%) failure. Most were daytime (69.8%) and primary missions (n = 100), median total mission time was 182.0 [143.0–254.0] min, and median transfer distance was 52.7 [33.2–71.1] km. All patients survived the transfer. Forty-four adverse events were recorded during 37 missions (19.4%), where 31 (70.5%) were medical and none resulted in patient harm. Adverse events occurred more frequently during night-time missions (59.9%, p = 0.047). Data for 28-day survival were available for 157 patients, of which 86 (54.8%) were alive.

Conclusion

All patients under ECMO survived the helicopter transport. Adverse events were observed for about 20% of the flight missions, with a tendency during the night-time flights, none harmed the patients. Inter-hospital transfer for patients undergoing ECMO provided by 24-h/7-d per week helicopter emergency medical service teams can be considered as feasible and safe. The majority of the patients (54.8%) were still alive after 28 days.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-022-01018-0.

Airway management in a Helicopter Emergency Medical Service (HEMS): a retrospective observational study of 365 out-of-hospital intubations

Background

Airway management is a key skill in any helicopter emergency medical service (HEMS). Intubation is successful less often than in the hospital, and alternative forms of airway management are more often needed.

Methods

Retrospective observational cohort study in an anaesthesiologist-staffed HEMS in Switzerland. Patient charts were analysed for all calls to the scene (n = 9,035) taking place between June 2016 and May 2017 (12 months). The primary outcome parameter was intubation success rate. Secondary parameters included the number of alternative techniques that eventually secured the airway, and comparison of patients with and without difficulties in airway management.

Results

A total of 365 patients receiving invasive ventilatory support were identified. Difficulties in airway management occurred in 26 patients (7.1%). Severe traumatic brain injury was the most common indication for out-of-hospital Intubation (n = 130, 36%). Airway management was performed by 129 different Rega physicians and 47 different Rega paramedics. Paramedics were involved in out-of-hospital airway manoeuvres significantly more often than physicians: median 7 (IQR 4 to 9) versus 2 (IQR 1 to 4), p < 0.001.

Conclusion

Despite high overall success rates for endotracheal intubation in the physician-staffed service, individual physicians get only limited real-life experience with advanced airway management in the field. This highlights the importance of solid basic competence in a discipline such as anaesthesiology.