Optimizing remote and rural prehospital resources using air transport of thrombectomy candidates.

BACKGROUND: In Finland, the yearly number of mechanical thrombectomies for acute stroke is increasing and more patients are transported over 100 km to the comprehensive stroke centre (CSC) for definitive care. This leaves the rural townships without immediate emergency medical services (EMS) for hours. In this study we compare the EMS' estimated return times to own station after the handover of a thrombectomy candidate between two transport methods: (1) using ground transportation with an ambulance to the CSC or (2) using a hydrid strategy starting the transportation with an ambulance and continuing by air with a helicopter emergency medical services unit (HEMS). METHODS: We reviewed retrospectively all thrombectomy candidates' transportations from the hospital district of South Ostrobothnia to definitive care at the nearest CSC, Tampere University Hospital from June 2020 to October 2022. The dispatch protocol stated that a thrombectomy candidate's transport begins immediately with an ambulance and if the local HEMS unit is available the patient is handed over to them at a rendezvous. If not, the patient is transported to the CSC by ground. Transport times and locations of the patient handovers were reviewed from the CSC's EMS database and the driving time back to ambulance station was estimated using Google maps. The HEMS unit's pilot's log was reviewed to assess their mission engagement time. RESULTS: The median distance from the CSC to the ambulances' stations was 188 km (IQR 149-204 km) and from the rendezvous with the HEMS unit 70 km (IQR 51-91 km, p < 0.001). The estimated median driving time back to station after the patient handover at the CSC was 145 min (IQR 117-153 min) compared to the patient handover to the HEMS unit 53 min (IQR 38-68 min, p < 0.001). The HEMS unit was occupied in thrombectomy candidate's transport mission for a median of 136 min (IQR 127-148 min). CONCLUSION: A hybrid strategy to transport thrombectomy candidates with an ambulance and a helicopter reallocates the EMS resources markedly faster back to their own district.

Low titer group O whole blood and risk of RhD alloimmunization: Rationale for use in Finland.

BACKGROUND: Prehospital low-titer group O whole blood (LTOWB) used for patients with life-threatening hemorrhage is often RhD positive. The most important complication following RhD alloimmunization is hemolytic disease of the fetus and newborn (HDFN). Preceding clinical use of RhD positive LTOWB, we estimated the risk of HDFN due to LTOWB prehospital transfusion in the Finnish population. STUDY DESIGN AND METHODS: We collected data on prehospital transfusions in Tampere and Helsinki University Hospital areas. Using the mean of reported alloimmunization rates in trauma studies (24%) and a higher reported rate representing trauma patients of 13-50 years old (42.7%), we estimated the risk of HDFN and extrapolated it to the whole of Finland. RESULTS: We estimated that in Finland, with the current prehospital transfusion rate we would see 1-3 cases of severe HDFN due to prehospital LTOWB transfusions every 10 years, and fetal death due to HDFN caused by LTOWB transfusion less than once in 100 years. DISCUSSION: The estimated risk of serious HDFN due to prehospital LTOWB transfusion in the Finnish population is similar to previous estimates. As Finland routinely screens expectant mothers for red blood cell antibodies and as the contemporary treatment of HDFN is very effective, we support the prehospital use of RhD positive LTOWB in all patient groups.

A hybrid strategy using an ambulance and a helicopter to convey thrombectomy candidates to definite care: a prospective observational study.

BACKGROUND: Mechanical thrombectomy is the treatment of choice for large vessel occlusion strokes done only in comprehensive stroke centres (CSC). We investigated whether the transportation time of thrombectomy candidates from another hospital district could be reduced by using an ambulance and a helicopter and how this affected their recovery. METHODS: We prospectively gathered the time points of thrombectomy candidates referred to the Tampere University Hospital from the hospital district of Southern Ostrobothnia. Primary and secondary transports were included. In Hybrid transport, the helicopter emergency medical services (HEMS) unit flew from an airport near the CSC to meet the patient during transport and continued the transport to definitive care. Ground transport was chosen only when the weather prevented flying, or the HEMS crew was occupied in another emergency. We contacted the patients treated with mechanical thrombectomy 90 days after the intervention and rated their recovery with the modified Rankin Scale (mRS). Favourable recovery was considered mRS 0-2. RESULTS: During the study, 72 patients were referred to the CSC, 71% of which were first diagnosed at the PSC. Hybrid transport (n = 34) decreased the median time from the start of transport from the PSC to the computed tomography (CT) at the CSC when compared to Ground (n = 17) transport (84 min, IQR 82-86 min vs. 109 min, IQR 104-116 min, p < 0.001). The transport times straight from the scene to CT at the CSC were equal: median 93 min (IQR 80-102 min) in the Hybrid group (n = 11) and 97 min (IQR 91-108 min) in the Ground group (n = 10, p = 0.28). The percentages of favourable recovery were 74% and 50% in the Hybrid and Ground transport groups (p = 0.38) from the PSC. Compared to Ground transportation from the scene, Hybrid transportation had less effect on the positive recovery percentages of 60% and 50% (p = 1.00), respectively. CONCLUSION: Adding a HEMS unit to transporting a thrombectomy candidate from a PSC to CSC decreases the transport time compared to ambulance use only. This study showed minimal difference in the recovery after thrombectomy between Hybrid and Ground transports.

Impact of the first response unit on prehospital on-scene time among paramedic-suspected stroke patients: a retrospective before-after cohort study in Finland.

BACKGROUND: Revascularization of an occluded artery by either thrombolysis or mechanical thrombectomy is a time-critical intervention in ischaemic stroke. Each link in the stroke chain of survival should minimize the delay to definitive treatment in every possible way. In this study, we investigated the effect of routine dispatch of a first response unit (FRU) on prehospital on-scene time (OST) on stroke missions. METHODS: Medical dispatch of FRU together with an emergency medical service (EMS) ambulance was a routine strategy in the Tampere University Hospital area before 3 October 2018, after which the FRU has only been dispatched to medical emergencies on the decision of an EMS field commander. This study presents a retrospective before-after analysis of 2,228 paramedic-suspected strokes transported by EMSs to Tampere University Hospital. We collected data from EMS medical records from April 2016 to March 2021, and used statistical tests and binary logistic regression to detect the associations between the variables and the shorter and longer half of OSTs. RESULTS: The median OST of stroke missions was 19 min, IQR [14-25] min. The OST decreased when the routine use of the FRU was discontinued (19 [14-26] min vs. 18 [13-24] min, p < 0.001). The median OST with the FRU being the first at the scene (n = 256, 11%) was shorter than in cases where the FRU arrived after the ambulance (16 [12-22] min vs. 19 [15-25] min, p < 0.001). The OST with a stroke dispatch code was shorter than with non-stroke dispatches (18 [13-23] min vs. 22 [15-30] min, p < 0.001). The OST for thrombectomy candidates was shorter than that for thrombolysis candidates (18 [13-23] min vs. 19 [14-25], p = 0.01). The shorter half of OSTs were associated with the FRU arriving first at the scene, stroke dispatch code, thrombectomy transportation and urban location. CONCLUSION: The routine dispatch of the FRU to stroke missions did not decrease the OST unless the FRU was first to arrive at the scene. In addition, a correct stroke identification in the dispatch centre and thrombectomy candidate status decreased the OST.

Less is more - The Finnish Prehospital Stroke Scale prospective validation.

OBJECTIVES: The current bifurcation of the acute stroke care pathway requires prehospital separation of strokes caused by large vessel occlusion. The first four binary items of the Finnish Prehospital Stroke Scale (FPSS) identify stroke in general, while the fifth binary item alone identifies stroke due to large vessel occlusion. The straightforward design is both easy for paramedics and statistically beneficial. We implemented FPSS based Western Finland Stroke Triage Plan, including medical districts of a comprehensive stroke center and four primary stroke centers. PATIENTS AND METHODS: The prospective study population was consecutive recanalization candidates transported to the comprehensive stroke center within the first six months of implementing the stroke triage plan. Cohort 1 consisted of n=302 thrombolysis- or endovascular treatment candidates transported from the comprehensive stroke center hospital district. Cohort 2 comprised ten endovascular treatment candidates transferred directly to the comprehensive stroke center from the medical districts of four primary stroke centers. RESULTS: In Cohort 1, FPSS sensitivity for large vessel occlusion was 0.66, specificity 0.94, positive predictive value 0.70, and negative predictive value 0.93. Of the ten Cohort 2 patients, nine had large vessel occlusion, and one had an intracerebral hemorrhage. CONCLUSIONS: FPSS is straightforward enough to be implemented in primary care services to identify candidates for endovascular treatment and thrombolysis. When used by paramedics, it predicted two-thirds of large vessel occlusions with the highest specificity and positive predictive value reported to date.

Cortical symptoms described in emergency calls for patients with suspected large vessel occlusion: a descriptive analysis of 157 emergency calls.

BACKGROUND: Emergency medical dispatchers typically use the dispatch code for suspected stroke when the caller brings up one or more symptoms from the face-arm-speech triad. Paramedics and emergency department physicians are trained to suspect large vessel occlusion stroke when the stroke patient presents with hemiparesis and cortical symptoms: neglect, aphasia, and conjugate eye deviation (CED). We hypothesized that these symptoms could be evident in the emergency call. In this study, we aimed to describe common symptoms mentioned in the emergency calls for paramedic-suspected thrombectomy candidates. Secondly, we wanted to explore how the question about CED arises in the Finnish suspected stroke dispatch protocol. Our third aim was to find out if the symptoms brought up in suspected stroke and non-stroke dispatches differed from each other. METHODS: This was a retrospective study with a descriptive analysis of emergency calls for patients with paramedic-suspected large vessel occlusion stroke. We listened to the emergency calls for 157 patients transported to Tampere University Hospital, a Finnish comprehensive stroke centre. Two researchers listened for symptoms brought up in these calls and filled out a pre-planned case report form. RESULTS: Speech disturbance was the most common symptom brought up in 125 (80%) calls. This was typically described as an inability to speak any words (n = 65, 52% of calls with speech disturbance). Other common symptoms were falling down (n = 63, 40%) and facial asymmetry (n = 41, 26%). Suspicion of stroke was mentioned by 44 (28%) callers. When the caller mentioned unconsciousness the emergency dispatcher tended to use a non-stroke dispatch code. The dispatchers adhered poorly to the protocol and asked about CED in only 57% of suspected stroke dispatches. We found CED in 12 emergency calls and ten of these patients were diagnosed with large vessel occlusion. CONCLUSION: In cases where paramedics suspected large vessel occlusion stroke, typical stroke symptoms were described during the emergency call. Speech disturbance was typically described as inability to say anything. It is possible to further develop suspected stroke dispatch protocols to recognize thrombectomy candidates from ischemic cortical signs such as global aphasia and CED.

Emergency medical dispatchers' ability to identify large vessel occlusion stroke during emergency calls.

BACKGROUND: In acute ischemic stroke, conjugated eye deviation (CED) is an evident sign of cortical ischemia and large vessel occlusion (LVO). We aimed to determine if an emergency dispatcher can recognise LVO stroke during an emergency call by asking the caller a binary question regarding whether the patient's head or gaze is away from the side of the hemiparesis or not. Further, we investigated if the paramedics can confirm this sign at the scene. In the group of positive CED answers to the emergency dispatcher, we investigated what diagnoses these patients received at the emergency department (ED). Among all patients brought to ED and subsequently treated with mechanical thrombectomy (MT) we tracked the proportion of patients with a positive CED answer during the emergency call. METHODS: We collected data on all stroke dispatches in the city of Tampere, Finland, from 13 February 2019 to 31 October 2020. We then reviewed all patient records from cases where the dispatcher had marked 'yes' to the question regarding patient CED in the computer-aided emergency response system. We also viewed all emergency department admissions to see how many patients in total were treated with MT during the period studied. RESULTS: Out of 1913 dispatches, we found 81 cases (4%) in which the caller had verified CED during the emergency call. Twenty-four of these patients were diagnosed with acute ischemic stroke. Paramedics confirmed CED in only 9 (11%) of these 81 patients. Two patients with positive CED answers during the emergency call and 19 other patients brought to the emergency department were treated with MT. CONCLUSION: A small minority of stroke dispatches include a positive answer to the CED question but paramedics rarely confirm the emergency medical dispatcher's suspicion of CED as a sign of LVO. Few patients in need of MT can be found this way. Stroke dispatch protocol with a CED question needs intensive implementation.

Prehospital administration of blood products: experiences from a Finnish physician-staffed helicopter emergency medical service.

BACKGROUND: Massive infusions of crystalloids into bleeding hypotensive patients can worsen the outcome. Military experience suggests avoiding crystalloids using early damage control resuscitation with blood components in out of hospital setting. Civilian emergency medical services have since followed this idea. We describe our red blood cell protocol in helicopter emergency medical services (HEMS) and initial experience with prehospital blood products from the first 3 years after implementation. METHODS: We performed an observational study of patients attended by the HEMS unit between 2015 and 2018 to whom packed red blood cells, freeze-dried plasma, or both were transfused. The Student's two-sided T-test was used to compare vitals in prehospital phase with those at the hospital's emergency department. A p-value < 0.05 was considered significant. RESULTS: Altogether, 62 patients received prehospital transfusions. Of those, 48 (77%) were trauma patients and most (n = 39, 81%) suffered blunt trauma. The transfusion began at a median of 33 (IQR 21-47) minutes before hospital arrival. Median systolic blood pressure showed an increase from 90 mmHg (IQR 75-111 mmHg) to 107 mmHg (IQR 80-124 mmHg; P < 0.026) during the prehospital phase. Four units of red blood cells were handled incorrectly when unused red blood cells were returned and required disposal during a three-year period. There were no reported adverse effects from prehospital transfusions. CONCLUSION: We treated two patients per month with prehospital blood products. A prehospital physician-staffed HEMS unit carrying blood products is a feasible and safe method to start transfusion roughly 30 min before arrival to the hospital. TRIAL REGISTRATION: The study was retrospectively registered by the Tampere University Hospital's Medical Director (R19603) 5.11.2019.

Time-resolved fluorescence imaging of islet cell autoantibodies.

Time-resolved fluorescence of lanthanide chelates has been widely used in bioanalytical assays. Long fluorescence time, large Stokes shift, and minute fading out of the fluorescence over years are major advantages of the lanthanides over the conventional fluorescent dyes. We have now applied time-resolved fluorescence imaging (TRFI) also for measurement of type 1 diabetes mellitus (T1DM)-related islet cell autoantibodies (ICA). Retaining the accuracy of conventional ICA, TRFI has over 10 times better signal-to-noise ratio than the conventional fluorochromes. The technology allows objective determination of fluorescence intensity with the camera and computer software, and serial dilutions for obtaining the antibody titer in autoantibody-positive samples are unnecessary. We now describe the TRFI as a method and its application for measurement of ICA.

Real-time PCR for rapid diagnosis of entero- and rhinovirus infections using LightCycler.

BACKGROUND: PCR techniques have proved to be more sensitive than traditional cell culture in the diagnosis of enterovirus and rhinovirus infections and are widely used in clinical virus laboratories. However, PCR assays are relatively time-consuming and labor intensive, particularly if separate hybridization steps are used to confirm the specificity of positive findings. OBJECTIVES: The aim of the present study was to develop fast and sensitive real-time PCR assay, which would allow simultaneous detection of entero- and rhinoviruses and their quantification in clinical and experimental samples. STUDY DESIGN: Two real-time RT-PCR protocols were developed using LightCycler (LC) technology; SYBRGreen and hybridization probe assays. The sensitivity of these assays to detect entero- and rhinoviruses was compared with that of a traditional reference RT-PCR-hybridization assay and cell culture. All PCR protocols used the same primers amplifying the 5'-non coding region (NCR) of entero- and rhinoviruses. The LC probe assay and the reference RT-PCR used almost identical detection probes, which bind to enterovirus specific amplicons. RESULTS AND CONCLUSIONS: Both real-time PCR assays were equally sensitive as the reference RT-PCR-assay and all were more sensitive than cell culture. Both real-time assays quantified reliably the amount of the virus and took much shorter time than the reference RT-PCR. As the real-time SYBRGreen assay detects both entero- and rhinoviruses it can be used for primary screening of samples, which can be positive for either of these viruses. The real-time probe-assay can confirm the presence of enterovirus in SYBRGreen positive samples or it can be used for selective screening of enteroviruses e.g. from CSF samples.